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81
THE REDUCTIVE COUPLI NG OF AROMATIC POLYNUCLEAR N ITRO COMPOUNDS by ME ILING B.S. A THESIS IN CHEMISTRY Submitted to t he Graduate Faculty of Texas Technological College in Partial Fulfillment of the Requirements for the ·Degree of MASTER OF SCIENCE Approved the " IS .. --..... I Aecepted Dean of the Gt-aduate School

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Page 1: Cha1~~~--tiJ ~ommittee

THE REDUCTIVE COUPLING OF AROMATIC

POLYNUCLEAR NITRO COMPOUNDS

by

MEILING TSAI~ B.S.

A THESIS

IN

CHEMISTRY

Submitted to t he Graduate Faculty of Texas Technological College

in Partial Fulfillment of the Requirements for

the ·Degree of

MASTER OF SCIENCE

Approved

Cha1~~~- -tiJ the ~ommittee

" IS .. --..... I

Aecepted

Dean of the Gt-aduate School

Page 2: Cha1~~~--tiJ ~ommittee

T3

no '*3 coy. ^ ACKNOWLEDGMENT

I am deeply Indebted to Dr. H. J« Shine for his sug­

gestion of the problem investigated herein^ and for his

valuable advice and criticism which he has extended on all

phases of the work. My thanks go also to other members of

the Chemistry Department for the aid^ advice and encourage­

ment which they have been kind enough to give.

ii

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TABLE OF CONTENTS Page

LIST OF TABLES vli

LIST OF FIGURES viii

CHAPTER

I. INTRODUCTION 1

II. REVIEW OF THE LITERATURE 3

Reductive Coupling of 1-Nltronaphthalene. . 3

Reductive Coupling of Nitro Compounds with Metal Hydride Complexes 7

Reduction with Lithi\am Aluminum

Hydride 7

Reduction with Sodium Borohydrlde . . 9

PotassiiATO Borohydrlde 10

Reduction with Lithium Borohydrlde . . 11

Reduction with Sodium Trimethoxyborohydride 11

Reduction with Sodium Triethoxyaluminvimhydride . . . • , 12

Reductive Coupling of Nitro Compounds

Miscellaneous Methods . . . . * • . • 13

Reduction with Diborane 13

Coupling of Organometallies by

Nitrous Oxide l4

Hydrogenolysis of Nitro Group 15

III. EXPERIMENTAL l8

Reduction with Lithium Aluminum Hydride. . 18

Preparation and Analysis of Lithium

Aluminum Hydride Solution . . . . 18

Reduction with Lithium Alumin\am Hydride 20

ill

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iv

Direct addition method 20

Extraction method 20

Inverse addition method 20

Reduction of Nitrobenzene 21

NB-LAH-I 21

NB-LAH-II 22

NB-LAII-III 22

Reduction of 1-Nltr©naphthalene 23

NN-LAH-I 23

NN-LAH-II 24

NN-LAH-III 25

NN-LAH-IV 26

NN-LAH-V 26

NN-LAH-VI 27

NN-LAH-VII (Inverse addition) 29

Reduction of 5-Bromo-l-nitronaphthalene. . 33

Reduction of l,l*-Azonaphthalene 34

AN-LAH-I 34

AN-LAH-II 34

Reduction with Sodium Borohydrlde 35

Materials 35

Standardization of Sodium Borohydrlde

Solution 35

Reduction of l-Nltr©naphthalene 36

NN-NBH-I 36

NN-NBH-II 38 NN-NBH-III 39

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V

Reduction of p-Dlnitrobenzene 4l

Attempted Hydrogenolysis of

1-Naphthylamlne 42

Reduction with Potassium Borohydrlde . . . 43

Determination of Purity of Potassium

Borohydrlde 43

Reduction of Nitrobenzene 43

Reduction of l-Nltr©naphthalene . . . . 44

NN-KBH-I 44

NN-KBH-II 45

NN-KBH-III 46

NN-KBH-IV 47

Reduction of p-Dlnitrobenzene 48

DNB-KBH-I 48

DNB-KBH-II 50

Reductl©n with Lithium Borohydrlde . . . . 52

NN-LBH-I 52

NN-LBH-II 53

NN-LBH-III 54

Reduction with Diborane 56

NN-DB-I 56

NN-DB-II 57

Preparation of Naphthyl Lithl\im and Its Reaction with Nitrous Oxide 57

NL-NO-I 57

NL-NO-II 58

Infra-Red Absorptl©n Spectrum ©f the C©mp©und (A), DNB-KBH-I 59

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vi

Discussion of Results 62

IV. CONCLUSIONS 67

REFERENCES CITED 53

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LIST OF TABLES

TABLE Page

I. The Reduction of 1-Nltronaphthalene with Lithium Aluminum Hydride 32

II. The Reducti©n of l-Nltronaphthalene with S©di\im B©r©hydride 4l

III. The Reducti©n ©f l-Nltronaphthalene with P©tassium Bor©hydride 48

IV. Infra-Red Spectrum ©f the C©mp©und (A), DNB-KBH-I 60

vli

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LIST OF FIGURES

FIGURE Page

1. Infra-Red Spectrum ©f the C©mp©\ind ( A ) , DNB-KBH-I 61

v i i i

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CHAPTER I

INTRODUCTION

It is generally considered as a comm©n pr©perty ©f

ar©matic nitr© c©mpounds that they are tr£Lnsf©rmed Int© az©xy-,

azo-, or hydrazo c©mp©unds by the actl©n of mild reducing

agents in an alkaline medium, such as sodium methoxide in

methanol, zinc and alcoh©lic potash, arsenous ©xide in aque-

©us s©dium hydroxide or zinc dust and alcoh©lic ammonia (l).

Although azoxy- and az©benzene have been prepared in high

yield by the actl©n ©f these reagents, ©nly a few meth©ds can

be applied t© the preparati©n of azoxy- or azonaphthalenes

directly fr©m nitr©naphthalenes (2),

During the past decade a c©nsiderable am©unt of re­

search has been directed toward the reduction of organic com­

pounds with metal hydride complexes. Among such reductions,

Br©wn and Nystr©m (3) have reported the reductive coupling

of nitrobenzene with lithium aluminum hydride to form azo-

benzene. In the research work to be described. Investigation

of the actions of metal hydride complexes and other related

reducing agents on l-nltr©naphthalene was undertaken with the

hope of causing coupling to l,l'-azonaphthalene.

The results rep©rted in this thesis sh©w the vast dif­

ference in the behavi©r ©f 1-nitronaphthalene from that of

nitrobenzene; further the results indicate that hydr©gen©ly-

tic cleavage ©f nitro group of 1-nltronaphthalene takes place

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during the course ©f reductl©n. The results will als© sh©w

that nucle©philic replacement ©f nitr© gr©up takes place in

the benzene series in certain circumstances. The experimen­

tal work described in this thesis shows how the products ©f

the reduction were isolated and identified.

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CHAPTER II

REVIEW OF THE LITERATURE

Reductive Coupling ©f 1-Nitr©naphthalene

D©er (4) and Kl©buk©wski (5) had claimed t© ©btaln

az©naphthalene by the destructive dlstillati©n ©f nltr©-

naphthalene over zinc dust or lime. Their azonaphthalene,

the lem©n-yell©w substance ©f the c©mp©siti©n 02(flil^^2' ^^^^'

ing p©lnt 280°, was, h©wever, identified as l,2:5,6-dlben-

z©phenazlne by Witt (6), Therefore Wacker (7) was the first

one t© obtain azonaphthalene or the related azoxy- and hydra-

zonaphthalene, directly fr©m reductive coupling of nltr©-

naphthalene. Fr©m the mixture ©f l-nltr©naphthalene with

aram©nium chl©ride and zinc dust in aque©us alc©h©l system,

Wacker ©btained mainly l-naphthylhydr©xylamine and small

am©unt ©f l,l'-az©xynaphthalene. He explained the f©rmatl©n

©f l,l'-az©xynaphthalene as the dlspr©p©rtl©natl©n ©f 1-

naphthylhydr©xylamine f©rmed fr©m the acti©n ©f reducing

agent ©n l-nitr©naphthalene.

NHOH

Page 12: Cha1~~~--tiJ ~ommittee

T© pr©ve this c©urse he succeeded in ©btainlng l,l*-azoxy-

naphthalene in 28-305 yield by merely heating 1-naphthyl-

hydr©xylamine is©lated fr©m the reducti©n pr©ducts. H©wever

he did n©t menti©n the ls©lation ©f 1-naphthylamlne which,

as indicated, is also f©rmed in the disproportionati©n.

The c©urse of reductive coupling of nitro compounds

is now generally believed as the reaction between nitros©

and hydroxylamin© c©mp©unds which are the first and sec©nd

reducti©n products to be formed.

2H NO NHOH

^ ^ 2H r r ^

" ^ ^ ^ " ^ ^

-H 0

O-r^ 2H

(y-^ 2H

Q K N H - N . ^

By the electrolytic reduction with potential and current

density properly adjusted, the product ©f each stage can be

Page 13: Cha1~~~--tiJ ~ommittee

identified (l).

Whereas ©nly little az©xynaphthalene was ©btained fr©m

the neutral reductl©n, absolutely no azoxynaphthalene was ©b-

tainable from an alkaline medium, which, on the ©ther hand,

had been sh©wn t© be essential for the preparation of az©xy-

or azobenzene (l). Yet s©me substituted 1-naphthalenes

yielded az©xynaphthalene derivatives fr©m b©th neutral and

alkaline medium; ©ccasi©nally in almost quantitative yield.

Wacker thus obtained 5,5'-dinitroaz©xynaphthalene with zinc

dust and ammonium chloride in alcoh©l, and phenylhydrazine

and s©dium hydr©xide in alc©h©l; l,8-dinitr©naphthalene gave

the same result, l,l»az©xynaphthalene-5,5*-disulf©nlc acid

was ©btained in 65^ yield fr©m s©dium l-nitr©naphthalene-5-

sulfonate with gluc©se ©r phenylhydrazine ajid sodium hydrox­

ide in alcohol (8).

In contrast with nitrobenzene, which gave 23.65 of

ethylaniline and 29,7^ of azobenzene when treated with ethyl

magnesium iodide, 1-nitronaphthalene gave 32^ of ethyl

1-naphthylamine and 7.1^ of 1,1»-azonaphthalene with the

same reducing agent (9).

An extensive investigation ©f the reductive c©upling

©f 1-nitronaphthalene was undertaken by Cumming and Steel

(lO). Sodium-amalgam, and sodium hydroxide and zinc in al­

coholic s©luti©n failed t© give any satisfact©ry result. By

varying the am©unt of sodium hydroxide and the type ©f s©l-

vent, it was c©ncluded that the presence of sodium hydroxide

Page 14: Cha1~~~--tiJ ~ommittee

appeared to hinder the reduction t© az©xynaphthalene and

tended t© pr©duce tar and naphthylamine. With zinc and am-

m©nium chloride in aqueous-ale©hoi solution, the reductive

coupling to©k place at 70°. Bel©w 70° naphthylhydr©xylamine

was f©rmed, while at higher temperature, that is, ab©ve 75°>

naphthylamine was the main pr©duct. Az©xy-, az©-, and hydra-

z©naphthalene were obtained consecutively by varying the

am©unt ©f zinc added. H©wever, the validity ©f this neutral

reducti©n method is questionable, because a melting point of

274° was given for l,l»-hydrazonaphthalene (true melting

p©int 153 ) and n© percentage yield was given f©r the products

obtained.

Although an alkaline mediiam was demonstrated to be un­

satisfactory for the chemical reductive coupling of 1-nitro­

naphthalene, in the case of the electrolytic reductl©n ©f

nitr©naphthalene the yield ©f hydraz©naphthalene increased

with increasing pH ©f the catholyte. C©ncentrated solutions

of the mixtures of sodium and potassium xylene sulfonate auid

also of xylenesulfonic acid were fo\md to be excellent sol­

vents for nitro compounds. The yield of hydrazonaphthalene

was, however, undetermined (11).

The chemical method of the reductive coupling of nitro-

naphthalene has been shown, with few excepti©ns, as unsatis-

fact©ry. Therefore the Sandmeyer reaction has served ex­

clusively as the source of azonaphthalenes. A modified

method gives 1,1'-azonaphthalene in 80^ yield and 2,2'-

Page 15: Cha1~~~--tiJ ~ommittee

azonaphthalene in 90$ yield by increasing the rate of addi­

tion of the diazoni"um s©luti©n t© the c©upllng medium c©n-

sisting of copper sulfate and hydr©xylamine in aque©us am-

moTXia (12).

Reductive Coupling ©f Nitr© Compounds

with Metal Hydride C©mplexes

Reducti©n with Lithium Aluminum Hydride

Lithium aluminum hydride is a micr©crystalllne s©lid

which is stable in dry air at r©©m temperature. It has been

p©stulated t© exist as a complex salt Li+ /!SlHi 7 The aluml-

n\m hydride ion, ^KlY^T/", in ether solution has a tetrahedral

structure.

Lithivim aluminum hydride may be heated without appre­

ciable dec©mp©siti©n t© temperatures bel©w 100° in vacu©.

At 150°, dec©mp©slti©n results in the ev©lutl©n ©f hydr©gen

and f©rmati©n ©f lithium hydride and aluminum. The vig©r©us

reaction of lithium aluminiAra hydride with water liberates

hydrogen. Lithium aliJminum hydride is soluble in c©mp©unds

©f the ether class. The ethereal s©luti©ns are miscible with

s©me hydr©carbons, permitting reacti©n t© be carried ©ut in

which the reactants are ether inscluble but hydr©carb©n

s©luble.

The reducti©n ©f ar©matic nitr© c©mp©unds with lithium

aluminum hydride usually yields az© derivatives acc©rding to

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8

the overall equation (I3)

NO,

+ 2LiAIH, ^ \ /-f^^N-^ ^-H2LiAI02+4H,

With nitrobenzene in anhydrous ether and addition of lithium

aluminum hydride soluti©n in the same s©lvent at -78 and

subsequent reacti©n at r©©m temperature, Br©wn and Nystr©m

(3) have ©btained az©benzene in 855 yield.

Although Kvajisnlcka indicated that the nitr© gr©up in

m-nitr©benzaldehyde was unattacked by lithium aluminum hy­

dride (l3)i the ©pp©site has been ©bserved by Gayl©rd ajid

Snyder (l4). The latter ©btained m,m*-az©benzyl alc©h©l fr©m

m-nitr©benzaldehyde. The yield, h©wever, was 28.55 > very much

l©wer than the 85$ yield ©f azobenzene from nitrobenzene.

CHO

Li All^

k^NO^

HgOH

N = ^

CH-OH

Although lithium aluminum hydride reduction ©f nitr©-

benzene involves the participation of two molecules, f©rma-

tion of the az© gr©up fr©m 2,2'-dinitrodiphenyl is intra-

m©lecular (1, 15).

NO^ 0^ N==N

/

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n Ried and Muller (l6) reported that the reduction of

4,4»-dinitroaz©benzene with lithium aluminum hydride in a

tetrahydr©furan-ether mixture yielded 555 ©f 4,4'-diamin©-

az©benzene with n© evidence ©f p©lyaz© c©mp©unds. Wlbert and

Jahn have sh©wn that the lithium aluminum hydride reducti©n

©f p-nitr©toluene yields 65^ ©f p-az©t©luene and 10$ ©f p-

toluidine (17). These are the ©nly tw© cases ©f the f©rma-

ti©n of amines in the lithium aluminum hydride reduction of

aromatic nitro c©mp©unds in the benzene series. There has

been n© report on the aromatic nitro comp©unds ©f series

other than benzene.

Reduction with Sodium B©rohydride

Sodlvim b©r©hydride is a white crystalline, salt-like

s©lid ©f remarkable stability. The s©lid b©r©hydride is

stable in dry air t© 300°. N© apparent change ©ccurs in

vacuo at temperatures approaching 400°. The decomp©siti©n

bec©mes rapid ab©ve 550 giving principally hydr©gen and a

trace ©f diborane. The solid bor©hydride Ignites t© a free

flame in air and burns quietly (I8). S©dium b©rohydride

dissolves in cold water without extensive ev©lutl©n ©f hy-

dr©gen, and no appreciable reaction with water at r©©m tem­

perature occurs above pH 11.5. The bor©hydride is n©t ap­

preciably soluble in ethers. It is very soluble in liquid

ammonia and in the lower aliphatic amines. The best sol­

vents recommended are diglyme (diethylene glycol dimethyl

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10

ether) and triglyme (triethylene glycol dimethyl ether) (19).

Chalkin aind Brown (20) reported in their investigation

of reductions with sodium bor©hydride that the nitr© gr©up

was resistant t© attack. This was c©nfirmed by several ©ther

w©rkers. However, Weil and Panson rep©rted that nitrobenzene,

when refluxed with sodium b©r©hydride in the presence ©f

s©dium hydr©xide at temperature between 90° and 100 in diglyme,

yielded 585 ©f az©xybenzene (21).

P©tassi\am B©r©hydride

P©tassium b©r©hydride is a white crystalline material

which is n©n-hygr©sc©pic and stable in mclst and dry air.

Decompositi©n without melting occurs at about 500° in vacuo

without evoluti©n ©f hydrogen. Ignition to a free flame in

air results in quiet burning (22).

Water s©luti©ns of the bor©hydride are stabilized up

to the reflux temperature by the addition of base. The ma­

terial is soluble in water, alcohol and liquid ammonia and

generally insoluble in ethers and hydrocarbcns.

It was reported that the aromatic nitro group is re­

sistant to attack by potassium borohydrlde (13, 23). As is

sodium b©r©hydride, potassiiim b©r©hydride is used mainly for

the reduction of carbonyl groups (24).

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11

Reduction with Lithium Borohydrlde

Lithium b©r©hydride is a white crystalline salt-like

s©lid. It is quite hygr©sc©pic and may ©ccasicnally ignite

©n ccntact with water. The comp©und melts at 284° with de-

comp©siti©n. Pr©l©nged heating in vacu© ab©ve 200 als© re­

sults in dec©mp©siti©n. The b©r©hydride is s©luble with

reaction in the lower alc©h©ls. The preferred s©lvent f©r

©rganic reducti©n is tetrahydrofuran; it is als© s©luble in

l©wer ethers and amines.

When nitr©benzene is refl\ixed with excess lithiiim

b©r©hydride in an ether-tetrahydr©furan mixture, 30^ ©f the

nitr©benzene is rec©vered al©ng with 22^ ©f aniline and 30^

©f an Intractable dark red ©11 (25). The reducti©n ©f p-

nitr©benzyl chl©rlde and 5-chl©r©methyl-l-nitr©naphthalene

with lithium hydride and a little lithium b©r©hydride in

tetrahydr©furan yields 7^ o^ p-nitr©t©luene and Sj^ ©f 5-

methyl-l-nltr©naphthalene respectively. In b©th cases 8-20^

of the azo compound is also formed (26).

Reducticn with Sodium Trimeth©xyb©r©hydride

Sodium trimethoxyb©r©hydride is readily prepared by

the reacticn ©f sodiuim hydride with trimethyl borate in the

presence of tetrahydrofuran as solvent (27).

NA"*" H " + B ( 0 C H J 3 ^ NA'^CB(0CH3)3Hr

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12

It is insoluble in simple ethers, such as diethyl and di-n-

butyl, but is moderately soluble in dioxane and highly sol­

uble in tetrahydrofuran. Brown and Meed (27) reported that

in diethyl ether, nitr©benzene was n©t attacked by s©diiim

trimethoxyb©rohydride, whereas in the boiling di-n-butyl

ether two moles of sodium trimethoxyb©r©hydride were c©nsumed

per mole of nitrobenzene. The nature of the reduction pro­

duct was not investigated.

Reducti©n with S©dium Trieth©xyaluminumhydride

When m©n©meric aluminum ethylate is heated with s©dium

hydride in tetrahydr©furan at 70—75°* a complex, sodium

trieth©xyaluminumhydride, Na^l (OCgH-)^!^^, is rapidly f©rmed.

It is collected as gray powder but can be obtained as col©r-

less micr©crystalline p©wder. Its ethereal s©luti©n sh©ws

n© ion-conductivity even after the addition ©f pyridine,

which sh©ws the negligible diss©ciatlon ©f m©lecule. Never­

theless the replacement ©f the s©dium i©n with certain cation

groups is possible.

(C6H5)3SNCI + NA CAI(0C2H5)3H) > NA"" Cr+ i;(C6H5)3SN)'"(AK0C2H5)3Hr

Its anion which shows krypton c©nfigurati©n can be c©nceived

as a hydride i©n stabilized thr©ugh the c©mplex-f©rmati©n

with alviminum alcoholate. It is thus made capable of attack­

ing a polar multiple bond.

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13

It is decomposed quickly by water and ©ther hydroxyl-

group containing comp©unds. The c©mplex and its s©luti©ns

are air-sensitive. F©r its applicati©n in reducti©n, the

original tetrahydrofuran s©luti©n fr©m the preparation is

utilized. Azobenzene is ©btained In 68^ yield fr©m the re-

duct i©n of nitrobenzene at 65° (28).

Reductive Coupling ©f Nitr© C©mp©unds

Miscellaneous Meth©ds

During the past several years various new methods ©f

reductive coupling ©f nitr© c©mp©unds, m©stly ©f the benzene

series, have been devel©ped. Am©ng them, the f©ll©wing are

©f the interest in c©nsidering their applicability to the

naphthalene series.

Reduction with Dib©rane

Brown and Subba Rao (29) have used diborane as a re­

ducing agent for organic functional groups. It is different

from metal hydrides in that it is an acidic type of reducing

agent; it is believed to fimction throiigh an attack on am

electron rich center in the functional group. Dib©rane is

prepared by adding a s©luti©n of sodium borohydrlde in diglyme

to a solution of b©r©n trifluorlde etherate in the same s©lvent,

3NABH^+4BF3(C2H5)20 ^ZBgHg + SNABF^ + "^^^2^5)2^

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14

and the gas ev©lved is swept by a current ©f nitr©gen gas

int© a diglyme ©r tetrahydr©furan s©lutl©n ©f the c©mp©und

t© be reduced.

Az©benzene is listed as a rapidly reduced c©mp©und,

c©nsumlng 1,9 m©les ©f dib©rane per m©le in ©ne h©ur, while

nitr©benzene is apparently reduced ©nly slightly.

Coupling ©f Organometallies by Nitr©us Oxide

Nitrous oxide reacts with primary, secondary amd ter­

tiary alkyl lithium compounds and with most aryl lithium com-

p©unds. Pr©m the reacticn ©f phenyl lithium with nitr©us

oxide, lithium benzenediazotate, azobenzene, triphenylhydrazine

and phenol are obtained besides benzene and diphenyl. Berin-

ger, e_t aJ. (30), accounted the f©rraati©n ©f az©benzene and

triphenylhydrazine as the further reacticn ©f the first-f©rmed

lithiim benzenediaz©tate with m©re phenyl lithium. Pr©m phenyl

lithium and nitr©us ©xide, they ©btained a 4.8^ yield ©f phen©l,

7.25 ©f az©benzene and 21^ ©f triphenylhydrazine with small

quamtities ©f benzene, and diphenyl. With 1-naphthyl lithium

they obtained 3^ of l-naphth©l, 8.8j ©f naphthalene aind lOJ

of 1,1•-az©naphthalene with m©derate am©unts ©f a yell©w s©lid

which decomposed above 28O . The lithium-comp©unds were easily

prepau»ed from the corresponding brom©-c©mp©unds and metallic

lithium in absolute ether.

Meier obtained somewhat different results from the re­

action of phenyl lithium with nitrous oxide; he obtained 7.85

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15

of phenol, 305 of azobenzene, a moderate amount ©f diphenyl

and small am©unts ©f triphenylhydrazine, benzidine and hydra-

zobenzene. He explained the c©urse ©f f©rmation ©f the varl©us

c©mp©unds as f©ll©ws (3I).

N<N0U

"t-NgO ^(y

1 Li gO -1-

N=N

" ^ ^ ^ ^

NH-NH

" ^ ^ ^

N-N-Li Li

O r^^^^r-fT^

+ • ^ ^ i ^ ' ^ ^ ^ " ^ ^ ^ ^ ^

Hydr©gen©lysis ©f Nitro Gr©up

As early as in 1877, Klobuk©wski (5) indicated that

naphthalene was c©llected am©ng the ©ther c©mp©unds, such as

ammonia and a yellow oil, fr©m the destructive distlllati©n

©f nitr©naphthalene with lime. The residue ©f the distilla-

ti©n which melted at 275 was claimed as az©naphthalene by

him. The f©rmati©n ©f naphthalene was n©t rec©rded by his

precurs©r. Doer (4), in his destructive distillation of nitro

naphthalene with zinc dust. This fact has apparently been

Page 24: Cha1~~~--tiJ ~ommittee

16

left unconfirmed hithert©.

It is a well established fact that ©ne ©f the nitr©

gr©ups in o- ©r p-dinitr©benzene is easily replaceable with

electr©negative gr©ups. Evsms and Pry claimed t© have ob­

tained o- and p-az©t©luene respectively from o- and p-dinitr©

benzene by the actl©n ©f magnesium-amalgam in ethaLn©l ©r

raethan©l (32). While the replaceability ©f nitr© gr©up by

an electr©negative methyl gr©up is, perhaps, feasible, the

entry ©f methyl gr©up fr©m b©th methaji©l and ethan©l is

questi©nable.

Antener (33) ©btained p,p*-dimeth©xyaz©benzene and

p-nitr©suiis©le fr©m the reacti©n ©f p-dinitr©benzene with

s©dium and methan©l. He viewed the replacement ©f ©ne nitr©

gr©up as taking place initially, f©ll©wed by subsequent re­

duction of the other nitro group to the az© c©mp©und.

/r-\ N3X)CH3 / - \ / ^ \ ^ _ / ~ \ OCH3

Alth©ugh well-defined cases ©f the hydr©gen©lysis ©f

ar©matic nitr© gr©ups by complex metal hydrides have not been

reported in the literature, some examples exist in the alipha

tic series. Backer (34) obtained a small amount of

CH (SO^CH^)p from the action of lithium aluminum hydride ©n

0pNCH(S02CH^)p. Adams and M©Je (35) ©btained a 60^ yield ©f

bis-(l,4-naphthalenedibenzenesulf©namid©-2)-methauie by the

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17

acti©n ©f lithium aluminum hydride on bis-(l,4-naphthalenedi-

benzenesulf©namld©-2)-nitr©methan©l. In the reducti©n ©f

l,2-dlnitr©-l,2-dlphenylethane with lithium aluminum hydride,

D©m©w and Fust (36) ©btained l-amin©-l,2-diphenylethane; ©ne

of the nitro groups was hydrogenolized while the other was

reduced to amino gr©up.

Page 26: Cha1~~~--tiJ ~ommittee

CHAPTER III

EXPERIMENTAL

Reducti©n with Lithium Aliminum Hydride

Preparati©n and Analysis ©f Lithivtm Aluminum Hydride S©luti©n

The lithium aluminum hydride used was a pr©duct ©f

Metal Hydrides, Inc©rp©rated (l8). It was a gray-white gran­

ular p©wder ©f 95J purity. The ethereal s©lutl©n was pre­

pared in a S©xhlet Extra©ti©n Apparatus; the lithium aluminum

hydride p©wder which was crushed carefully in a mcrtar was

extracted with b©iling anhydr©us ether f©r six t© seven h©urs.

The clear s©lutl©n thus f©rmed was st©red in a br©wn b©ttle

pr©tected by a calcium chl©ride drying tube and was kept in

a c©©l dark place.

Pelkin's meth©d (37) was used f©r the determinati©n

©f the c©ncentrati©n ©f lithium aluminum hydride s©luti©n.

The foll©wing s©luti©ns were prepared.

S©luble starch indicat©r s©luti©n.- A slurry ©f ©ne

gram s©luble starch was added t© 100 ml b©iling water. After

c©©ling, three grams ©f p©tassium iodide was added. The so-

luti©n was st©red in a br©wn b©ttle and the surface ©f s©lu-

tion was c©vered with a thin layer ©f t©luene in ©rder t©

keep fr©m bacteri©l©gical acti©n.

S©dium thiosulfate soluti©n,- Appr©ximately 25 g ©f

s©dium thi©sulfate pentahydrate and 0.2 g ©f anhydr©us s©dium

18

Page 27: Cha1~~~--tiJ ~ommittee

19

carb©nate were diss©lved in ©ne liter ©f water. This s©lu-

ti©n was standardized with weighed i©dine each time bef©re

use.

The standardizati©n ©f the s©dium thi©sulfate s©lutl©n

was carried ©ut as f©ll©ws: Ab©ut 0.5 g ©f i©dine was weighed

exactly to 0.1 mg and dissolved in 100 ml water c©ntaining

5 g of potassium iodide and 5 ml of Z% hydrochl©ric acid.

This was titrated with the s©dium thi©sulfate s©luti©n. When

the c©l©r of iodine almost disappeared, 2 ml of starch indi-

catcr s©luti©n was added and the s©luti©n was titrated exactly

to the point where the solutl©n turned t© c©l©rless. Dupli­

cate titrati©ns were carried ©ut in every case.

Solution of iodine in benzene.- Approximately 52.3 6

of iodine was dissolved in one liter of anhydrous benzene.

The exact c©ncentrati©n ©f the iodine s©luti©n was n©t essen­

tial, since an excess ©f s©luti©n was t© be used and back-

titrated with standardized s©dium thl©sulfate s©luti©n.

Titrati©n ©f lithium aluminum hydride s©luti©n.-

Exactly 2 ml ©f the ethereal s©luti©n ©f lithium aluminum

hydride was added as rapidly as p©ssible with shaking t© 20

ml ©f the iodine solution in amhydrous benzene. After add­

ing a few ml of water and few drops of glacial acetic acid,

the mixed s©luti©n was titrated with the standardized s©di\im

thiosulfate s©lution with vig©r©us shaking. Tw© samples and

a blank were titrated f©r each batch ©f the lithium aluminum

hydride s©luti©n.

Page 28: Cha1~~~--tiJ ~ommittee

20

In the presence ©f excess i©dine, each m©le ©f lithium

aluminum hydride reacts with tw© m©les ©f l©dine t© f©rm

lithium i©dide and aluminum iodide with evoluti©n ©f hydr©-

gen.

LiAIH4 -I- 2 1 ^ ^ ^Hgt Lil -h AII3

Reducti©n with Lithium Aluminum Hydride (38)

Direct additi©n meth©d. The s©luti©n ©f lithium alum-

in\im hydride was placed in a three-neck flack equipped with

a mechanical stirrer driven by a spark-free m©t©r, a reflux

condenser, and a dropping funnel. Calcium chloride tubes

were attached t© the ©pen end ©f c©ndenser and funnel. The

ethereal s©luti©n ©f the comp©und t© be reduced was added t©

the stirred lithium alviminum hydride s©luti©n. After reacti©n

was c©mplete, ice water, alcne, ©r its mixture with ethyl ace­

tate, was added t© dec©mp©se the ccmplexes. The resulting

mixture was treated as described later.

Extra©ti©n meth©d. l,l*-Az©naphthalene, being ©nly

slightly s©luble in diethyl ether, was placed in the thimble

of a Soxhlet apparatus and the s©lution ©f lithium aluminum

hydride was kept b©iling in the flask bel©w. After all ©f

the azonaphthalene was extracted, the mixture was treated

as described later.

Inverse addition meth©d. The apparatus was similar

to the direct addition method. The solution of lithium

Page 29: Cha1~~~--tiJ ~ommittee

21

aluminum hydride was added to the soluti©n ©f the c©mp©und

t© be reduced. The subsequent treatment was the same as pre­

vious ones.

Reduction ©f Nitr©benzene

For the purpose ©f reducti©n "Chemical Pure" grade

nitr©benzene was dried ©ver anhydr©us calcium chl©ride ©ver-

night and distilled under reduced pressure; b.p. 101.5^/25

mm Eg.

NB-LAH-I. Lithium alTAminum hydride p©wder, 4.5 g

(0.12 m©le), was refluxed with 150 ml ©f abs©lute diethyl

ether f©r ©ne h©ur. After the s©lutl©n was c©©led t© r©©m

temperature, 10 g (0.08 m©le) ©f nitr©benzene in I30 ml ether

was added thr©ugh the dr©pping fiinnel s© as t© keep the s©lu-

tion refluxing gently. During the ccurse ©f additi©ri, a change

©f c©lor t© yellow, deep yellow, orauige amd finally red br©wn

was ©bserved. After the t©tal additi©n, the mixture was stir­

red f©r ©ne m©re h©ur. Then 25 ml ©f ethyl acetate and 2 ml

of water were added for dec©mp©siti©n, and the c©ntents were

p©ured into 100 ml of ice-water. Seventy-five milliliters

of 105 sulfuric acid was added and the mixture was filtered.

The ether layer was separated from the filtrate and was eva­

porated t© dryness ©n a steam bath. The slurry and water

portion were extracted with porti©ns ©f benzene until the

benzene was n© l©nger c©l©red. The residue fr©m the ether

layer was combined with the benzene extract. The benzene

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22

soluti©n was ccncentrated and treated with charc©al. After

c©©ling, red-©rauige leaflets ©f az©benzene crystallized ©ut.

They were filtered and washed with c©ld benzene. Yield:

3 g (40.55^), m.p. 67-68°.

NB-LAH-II. The same am©unts ©f reactants were used

as ab©ve. At the end ©f reaction, 100 ml of ice water was

added foll©wed by acidificati©n with dilute sulfuric acid.

After the acid was added, the ether layer was separated, and

the aque©us layer was extracted with f©ur p©rti©ns ©f 25 ml

ether. The ether was evap©rated ©ff, and s©lid mass was

taken int© ethan©l and treated with charccal. The ©range-

red leaflets, az©benzene, weighed 4.2 g (56.7$ yield), m.p.

65-67^.

NB-LAH-III. Lithium aluminum hydride, 5.2 g (0.l4

m©le), was refluxed with 200 ml of diethyl ether for two

hours. The flask was immersed in a dry ice-acetone mixture

of -80°, and 11.0 g (0.09 mole) of nitrobenzene in I30 ml of

diethyl ether was added. The mixture was all©wed t© warm t©

ro©m temperature (over a period of 21 hours). Then, 70 ml

of ice-cold water was added to decomp©se the complexes and

the contents were poured into 100 ml ©f ice water. Subse­

quent treatment as in NB-LAH-II yielded 4.4 g (58.4^) ©f the

final pr©duct, deep bright red leaflets, m.p. 66-68°.

Page 31: Cha1~~~--tiJ ~ommittee

23

Reduction of 1-Nitr©naphthalene

For the reduction of 1-nitr©naphthalene, the stan­

dardized s©luti©n ©f lithiiim aluminum hydride was used. The

nltronaphthalene which was slightly br©wnish-yell©w, was ©b-

tained fr©m Dlstillati©n Pr©ducts industries (39). It was

dissclved in ethan©l and treated with charccal. The light

yell©w needles thus ©btained fr©m ethan©l melted at 6o°.

This was used in the f©ll©wing reducti©ns.

NN-LAH-I. The first batch ©f the lithiiom aluminum

hydride s©luti©n was prepared fr©m 7 g of lithium aluminiim

hydride extracted with 300 ml ©f abs©lute diethyl ether f©r

17 h©urs. Standardlzati©n ©f the lithium aluminum hydride

sh©wed it t© be O.I336 M.

1-Nitr©naphthalene, 3.5 g (0.02 m©le), in I50 ml ©f

diethyl ether was added dr©pwise t© 200 ml (0.026 ai©le) ©f

lithium aluminum hydride s©luti©n. After the additi©n, the

mixture was stirred f©r tw© h©urs. During the addlti©n and

the subsequent stirring, the c©lor ©f mixture changed fr©m

yellow to orange brown. At the end of stirring, 70 ml ©f

ice-cold water was added t© dec©mp©se the c©mplexes. When

the water was being added, the mixture turned purplish and

the ether layer finally became light red. The c©ntents ©f

the flask were poured int© 200 ml ©f ice water amd 100 ml ©f

20^ sulfuric acid was added. The ether layer was separated

amd evapcrated to dryness. The water layer was clear, yet

Page 32: Cha1~~~--tiJ ~ommittee

24

when it was extracted with benzene, a brown solid appeared

between the two layers. This solid was separated fr©m the

liquid phases by use ©f a centrifuge.

The residue fr©m the ether p©rtl©n was c©mbined with

the benzene extracts. A dark ©11, smelling of 1-naphthyl­

amine, remained after evaporating ©ff the benzene. It s©lid-

if led upon washing with 10$ hydrochl©ric acid. After being

washed with water and dried, it weighed 1.8 g. Repeated

treatment with charccal in benzene and finally crystalllza-

ti©n from glacial acetic acid, gave a slightly brownish red

product 0.1 g, m.p. 188-190° (sublimed). The yield of the

final pr©duct ©f l,l»-az©naphthalene was 3.5^.

NN-LAH-II. P©ur grams ©f lithium aluminum hydride

was extracted with 300 ml ©f ether f©r five hours. The con-

centrati©n ©f the lithium alumin\im hydride 3©luti©n was

0.445 M.

1-Nitr©naphthalene, 6 g (0,035 m©le), in 90 ml ether

was added t© 100 ml (0.044 m©le) ©f the lithium aluminum hy­

dride soluti©n kept at -76 . After 18 h©urs, the tempera­

ture ©f mixture reached 4 and 70 ml of ice-cold water was

added. The contents were poured int© 100 ml ©f ice water

ajid the ether layer was separated and evap©rated. The water

solution and slurry were extracted with porti©ns ©f benzene.

The residue ©f ether layer was added t© the c©mbined benzene

extracts. The red s©lutl©n gave a dark ©11 when the benzene

was evap©rated ©ff ©n a steam bath. Subsequent treatment as

Page 33: Cha1~~~--tiJ ~ommittee

25

in NN-LAH-I yielded n© satisfactcry result, th©ugh traces of

both 1-naphthylamine and l,l»-az©naphthalene were believed

t© be present.

NN-LAH-III. 1-Nitr©naphthalene, 5 g (0.029 mole), in

70 ml diethyl ether was added dropwise t© 100 ml (0.044 m©le)

©f the lithium aluminum hydride soluti©n which was c©oled t©

-80 . After the additi©n, the mixture was stirred f©r ©ne

h©ur at -65° to -70°. Seventy milliliters of ethyl acetate

was then added. During the course of stirring and addition

of the ethyl acetate no c©l©r change was ©bserved. After

the additi©n ©f the ethyl acetate, hcwever, the c©l©r changed

int© red and the vig©r©us ev©lutl©n of gas was observed as

the mixture was warmed up to ro©m temperature. Apparently

n© reduction of 1-nitronaphthalene or decomp©siti©n ©f lithium

aluminum hydride took place at the temperature lower than -65°

As the temperature was raised, the dec©mp©siti©n ©f lithium

aluminum hydride ©ccurred suddenly acc©mpanied by s©me reduc­

tion of 1-nitronaphthalene. The slurry was separated from

the solution and extracted with porti©ns ©f benzene. The

©riginal ether solutl©n was evap©rated and the residue was

combined with the benzene extract. The soluti©n was washed

with lOJ hydrochloric acid and water. After treatment with

charcoal 3.0 g (60^) of unreacted 1-nitronaphthalene was re­

covered from ethanol; a small amount of a red oil was als©

©btained.

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26

NN-LAH-IV. 1-Nitr©naphthalene, 3.8 g (0.022 m©le),

in 70 ml ether was added t© 50 ml (0.027 m©le) ©f the lithium

aluminum hydride s©lutl©n c©©led t© -76°. The mixture was

allowed to warm up to -30° in 3.5 hours and 50 ml of ethyl

acetate was added t© dec©mp©se the complexes. The mixture

showed no change in c©l©r during the c©urse ©f warming and

decomposition. However, when treated with acid, as in NN-

LAH-III, and extracted with benzene, the benzene deepened in

c©l©r amd finally became dark br©wn. By evap©rati©n and sub­

limation most of the original 1-nitr©naphthalene was reccvered

with s©me intractable dark tar.

NN-LAH-V. 1-Nitr©naphthalene, 17.3 g (O.l m©le), in

150 ml ether was added dr©pwise int© 400 ml (0.2 m©le) ©f

lithium aluminum hydride soluti©n. The addlti©n was c©n-

tr©lled in such a mamner that tw© t© three dr©ps was added

each time and n© further s©luti©n was added until the ev©lu-

ti©n ©f gas had ceased. Five h©urs was taken f©r total addi­

tion. During the course of addition a series ©f c©l©r change,

br©wnish ©ramge, reddish br©wn and dark br©wn, was ©bserved.

After the t©tal additi©n, the mixture was stirred f©r another

hour and 100 ml of ice-cold water was added for the decomp©-

siti©n. The cclor ©f the s©luti©n became lighter up©n the

additi©n ©f the water. The c©ntents were poured into I50 ml

of ice-water, and the ether layer was separated and evapora­

ted. The residue ©f evap©rati©n was added t© the benzene

extract of water soluti©n and slurry.

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27

The benzene s©luti©n was extracted with six 100 ml

p©rtl©ns of saturated oxalic acid s©luti©n and then washed

three times with 100 ml p©rti©ns ©f water. After evaporating

©ff the benzene, 2.94 g ©f a pitch-like substance remained.

By subllmati©n in vacu© (3 mm Hg) ab©ve 165°, 0.77 g (5.3^

yield) ©f bright red l,l'-az©naphthalene was c©llected.

After two crystallizations from glacial acetic acid, it melted

at 189-190°.

The oxalic acid extracts and water washings were com­

bined and concentrated on a steam bath to about 200 ml. Steam

distillation, after making alkaline with sodium hydroxide so-

luti©n, f©ll©wed. The distillate was extracted with ether

and the ether solution was dried over amhydrous calcium chlo­

ride for two days. After the calci\im chloride was filtered

off, dry hydr©gen chl©ride gas was bubbled thr©ugh amd the

resulting salt was filtered and washed with anhydr©us ether.

The free amine was liberated by neutralizati©n; it weighed

2.19 g (15.3y yield). Recrystallizati©n fr©m aque©us ethan©l

yielded 1.35 g* slightly purplish pr©duct, m.p, 48°.

NN-LAH-VI. Eight grams ©f lithium aliiminum hydride

was extracted with 250 ml ©f abs©lute ether f©r seven h©urs.

Standardizati©n sh©wed the c©ncentrati©n ©f lithium aluminum

s©luti©n t© be 0.8l4 M.

NN-LAH-V was repeated with 230 ml (0.2 m©le) ©f lithium

aluminum hydride s©luti©n and 17.3 g (0.1 m©le) ©f 1-nitro­

naphthalene. After decomp©sing the reacti©n mixture with

Page 36: Cha1~~~--tiJ ~ommittee

28

ice-cold water, it was made acidic with 10^ hydr©chl©ric

acid. The ether was evapcrated ©ff fr©m the mixture at r©©m

temperature and the mixture was then steam distilled. A

red ©11 with naphthalene-like ©d©r was c©llected, and was

extracted with ether. The aquecus p©rtl©n was discarded.

After evap©ratlng off the ether, a red oil was ob­

tained which was subjected to sublimation under atmcspheric _ ©

pressure at 80-90 . N© sizeable am©unt ©f s©lid was obtained,

although there was a smell of naphthalene on the condenser.

The red oil, remaining from attempted sublimation, weighed

2.0 g. When treated with concentrated hydrochlcric acid it

s©lidified. The s©lid after treatment with charccal and

crystallizaticn fr©m water weighed 1.0 g. One half gram ©f

this was diss©lved in 20 ml water and a few chips of ice were

added. Acetic anhydride, 5 nil, was added under vigor©us stir­

ring f©ll©wed Immediately by 5 g anhydr©us s©dium acetate in

25 ml ©f water. (4o) After c©©ling, the white solid was

filtered and recrystallized from ethanol after treatment with

charcoal. The acetyl-1-naphthylamine thus formed melted at

158-159°.

The residue from steam distillatl©n was made alkaline

and steam distilled again. The distillate was extracted with

ether after saturating with s©dium chl©ride. The same treat­

ment as in NN-LAH-V yielded 2.5 g of 1-naphthylamine hydr©-

chloride. Pree amine was liberated by neutralization of the

aqueous solution of naphthylamine hydrochloride with lOJ of

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29

sodium hydroxide s©luti©n. The mixture was immersed in an

ice bath f©r five minutes and filtered by sucti©n. The s©lid

was washed with three p©rti©ns ©f 5 ml water; m.p. 48.5-50°.

The t©tal yield ©f 1-naphthylamine was 2.8 g (19.6^^).

The residue fr©m the sec©nd steam distillati©n was

all©wed t© stand and the supernatant liquid was siph©ned ©ff.

The s©lid was centrifuged and washed with lOJ hydr©chl©ric

acid several times and finally with water. The residue was

very dark in c©l©r. It weighed 11.16 g. Sublimati©n in ©

vacu© up t© 190 yielded n© az©naphthalene but a charred

residue.

NN-LAH-VII (Inverse addition). Lithium aluminum hy­

dride soluti©n was prepared by the extra©ti©n ©f 3 g ©f the

s©lid with 150 ml anhydr©us ether. The soluti©n was f©und

t© be 0.525 M.

1-Nltr©naphthalene, 10.38 g (O.06 m©le), was diss©lved

in 150 ml ©f anhydr©us ether in a 1000 ml three-neck flask

which was immersed in a running-water bath at 20 , One hun­

dred milliliters (O.O525 m©le) ©f the lithium aluminum hy­

dride s©luti©n was added dr©pwise in 45 minutes. A series

of col©r changes was ©bserved. After the additi©n ©f 5 ml

of lithium aluminum hydride s©luti©n, the ©riginal light

yellow solution became turbid; this turbidity seemed to deepen

with further additi©n. When about two-thirds of the s©luti©n

was added, the c©l©r ©f the mixture was br©wnish yellow. At

the end of the t©tal addition, the col©r was br©wnlsh ©range.

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30

One hundred milliliters of ice-water was added dropwise

after ten nsinutes of stirring. As the water was added, the

color of the mixture changed to orange and finally to deep

red. The mixture was acidified with dilute hydrochloric

acid and the ether was distilled off at room temperature

under reduced pressure.

The mixture was extracted with two 100 ml portions of

benzene. Some dark solid appeared between the two layers.

The benzene solution with dark solid in it was extracted

with two 100 ml portions of 10^ hydrochloric acid and then

was washed with three 50 ml portions of water.

All the acid extracts* ond washings were combined with

the aqueous part of the original reaction mixture, and were

made alkaline with sodium hydroxide solution and steam dis­

tilled. About 1.3 liters of distillate was collected. The

distillate was made acidic with hydrochloric acid and extracted

with 100 ml, 70 ml and 70 ml of ether.

The ether solution was dried with amhydrous sodium sul­

fate overnight. The ether was evaporated after filtering off

the sodiiim sulfate. The residue weighed 1.06 g, from which

0.0381 g (0.55 yield) of naphthalene was collected by subli­

mation at atmospheric pressure from 80° to 90 . After treat­

ment with charcoal and recrystallizatlon from ethanol it

melted at 79-2-81.2 (Literature 80.22°).

Hie residue remaining after sublimation was dissolved

in water, treated with charcoal amd evaporated to dryness.

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31

giving 0.22 g of s©lid. This, with acetic anhydride gave

an acetyl derivative, m.p. 156-158° (literature f©r 1-naph-

thylaunlne derivative, 159°).

The aque©us part ©f the steam distillate was made

alkaline with s©dlum hydr©xide and extracted with 270 ml

ether in three porti©ns. The aque©us s©luti©n was discarded

and the ether extracts were dried with anhydr©us s©dium sul­

fate ©vernight. Pr©m the same treatment as in NN-LAH-V, O.98

g ©f 1-naphthylamine hydr©chl©rlde was ©btained. The acetyl

derivative melted at I56-I58 . The tctal 1-naphthylamine

hydr©chl©ride was 1.2 g (11.2^ yield).

The benzene s©luti©n with suspended dark solid was

filtered by sucti©n. The s©lid was washed with six 20 ml

p©rti©ns ©f b©iling benzene and then with tw© 50 ml porti©ns

©f b©iling water. The benzene washings were c©mbined with

the benzene s©luti©n. The dark br©wn s©lid charred and burnt

sl©wly in a flairae, leaving a residue.

The benzene s©luti©n was evap©rated amd the resulting

dark ©11 weighed 4.3 g. By sublimati©n ab©ve I80 in vacu©

0.165 g (1.95^ yield) ©f 1,1'-azonaphthalene was obtained as

red needles. After recrystallizatlon from glacial acetic

acid it melted at l85-l88°.

The results of reduction ©f l-nitr©naphthalene with

lithiiom al\aminum hydride are summarized in Table I.

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32

TABLE I

THE REDUCTION OP 1-NITRONAPHTHALENE WITH LITHIUM ALUMINUM HYDRIDE

1-nitr©-naphtha-

Expt.lene N©. (m©le)

Lithium aluminum hydride

% m©le)

Temper­ature

Pr©ducts and yields

0.02

0.035

0.024

0.022

0.1

0.1

0.06

0.026 25

0.04

0.044

0.027

0.2

0.2

-76 t© 4

-70 t© -65

-65 t© -30

25

25

0.0525 20

1-Naphthylamine, n©t separated. l,l*-Az©naphthalene, 3.5^. Dark br©wn s©lid, main pr©duct.

1-Naphthylamine, trace. 1,1*-Az©naphthalene, trace, Dark brcwn s©lid, main pr©duc t.

1-Nitr©naphthalene, 60^ rec©very. Red ©11.

Tar 1-Nitr©naphthalene, rec©vered.

l,l*-Az©naphthalene, 5.3^. 1 -Naphthylamine, 15.35 . Dark br©wn s©lid.

1-Naphthylamine, 19.6%. Naphthalene, trace. Dark br©wn s©lid.

Naphthalene, 0.5^. 1 -Naphthylamine, 11. 2 . 1,1* -Az©naphthalene, 1.955 . Dark br©wn s©lid.

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33

Reducti©n of 5-Bromo-l-nitronaphthalene

Lithium aluminum hydride, 5.2 g (0.I3 mole), was re­

fluxed with 100 ml of anhydrous ether for ©ne h©ur, and then

immersed in am ice bath. Ten grams (0.04 m©le) ©f 5-br©m©-

l-nitr©naphthalene in 250 ml ©f amhydr©us ether was added in

thirty minutes. The mixture was stirred f©r tw© m©re h©urs

at ro©m temperature. Sufficient water was then added to de­

compose complexes. The ether layer was separated and evapor­

ated to dryness. The water layer was extracted with benzene

and the residue from ether soluti©n was added t© the benzene

extract.

The benzene extract was washed with lOJ hydr©chl©ric

acid followed by water. The washings and the solid which

appeared in washing were combined.

The benzene soluti©n free from amine was evaporated

to dryness. A dark col©red solid, weighing 6.85 g, was ob­

tained from which 2 g (22.8j ) at first tho\ight t© be 5,5*-

dibr©m©-l,l*-azonaphthalene, m.p. 222.5-223.5 , was obtained

after treatment with charcoal and recrystallizati©n fr©m

benzene. Bogoslovskii amd Kazok©va (4l) gave 210 as the

melting p©int of 5,5*-dibr©m©-l,l*-az©naphthalene; h©wever,

according to Mr. R. L. Snell (42) the melting point of the

azo is 274-275° while the melting point of the azoxy is 210 . ©

Analysis (43) of the comp©und, m.p. 222.5-223.5 showed that

this compound is neither the expected azo- nor azoxy compound

Page 42: Cha1~~~--tiJ ~ommittee

34

It is possible that the comp©und ©btained is a m©lecular c©m-

plex of the azo- and az©xy.

Pound: c, 53.57; H, 2.69; N, 6.17; Br, 35.83^. Calcd. for azo: c, 54^57; H, 2.75; N, 6.37; Br, 36.31^. Calcd. for azoxy: C, 52.66; H, 2.65; N, 6.l4; Br, 35.04^.

Reduction of l,l'-Az©naphthalene

AN-LAH-I. 1,1'-Azonaphthalene, 1.15 g (0.004 mole),

was stirred in 350 ml of anhydrous ether. Not all of the

comp©und dlss©lved. This mixture was added t© 20 ml (O.Ol

m©le) of lithium aliimin\im hydride solution, c©©led t© -78°

in a dry ice-acet©ne bath. The temperature was then allowed

to rise to -10° in 28 hours. No color chamge was observed.

At the end of 28 hours, 50 ml of ethyl acetate was added.

The ethyl acetate was evaporated off and the mixture was

acidified with lOJ hydrochl©ric acid. The red s©lid was fil­

tered and washed with acid and water. The ©riginal 1,1'-

az©naphthalene was all rec©vered, m.p. 189-190*^.

AN-LAH-II, l,l'-Az©naphthalene, 1,11 g, was placed in

the thimble ©f a S©xhlet extraction apparatus. Fifty milli­

liter (0.027 mole) of lithium aluminum hydride solution was

kept boiling in the flask underneath for nine h©urs. N© ap­

preciable change ©f c©l©r was ©bserved during refluxing.

After the refluxing, the mixture was treated as ab©ve. The

total original azonaphthalene was recovered, m.p. 189-190°.

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35

Reduction with S©dium B©r©hydride

Materials

Sodium b©r©hydride used in the f©ll©wing reducti©ns

was ©btained fr©m Metal Hydrides, Inc©rp©rated (l8). It was

a white p©wder ©f 98^ purity. Diglyme (diethylene glyc©l

dimethyl ether) was the pr©duct ©f The Mathes©n C©mpany, In-

corporated (44). It was placed over s©lid s©dium b©r©hydride

©vernight and distilled.

Standardizati©n ©f S©dium B©r©hydride S©lutl©n

A s©luti©n was made ©f 10.35 g of s©dium b©rohydride

in 200 ml ©f diglyme; the s©lutl©n was filtered.

The f©ll©wing s©luti©ns were prepared.

S©dium thi©sulfate s©luti©n, 0.1 N, Twenty-five grams

©f s©dium thi©sulfate pentaJiydrate and 0,2 g ©f anhydr©us

s©dium carbonate were dissolved in ©ne liter ©f water.

Sulfuric acid, 4 N. Fifty milliliters ©f ccncentrated

sulfuric acid (36 N) was diluted t© 450 ml.

P©tassium i©date s©luti©n, 0.25 N. P©tassium i©date,

52.1754 g, was diss©lved in water and made up t© 250 ml in a

volumetric flask.

Duplicate analyses ©f the s©dlum thi©sulfate s©luti©n

gave 0.09952 N and 0.1014 N; average 0.1004 N.

For the standardization of sodium b©r©hydride s©luti©n

(45), 100 ml ©f the borohydrlde s©luti©n was taken and added

Page 44: Cha1~~~--tiJ ~ommittee

36

t© 50 ml ©f 0.25 N p©tassium i©date s©luti©n. The excess

i©date was back titrated with standardized scdium thl©sulfate

s©luti©n. Duplicate samples were taken; 34.96 ml amd 35-01

ml ©f the thi©sulfate s©luti©n were ccnsumed respectively,

which averaged 34.98 ml. The scdium b©rohydride, therefore,

contained 42.53 mg/ml.

Reduction ©f 1-Nitr©naphthalene

NN-NBH-I. Three grams (0.075 m©le) ©f s©dium b©r©-

hydride was placed with 30 ml ©f diglyme in a 250 ml flask

equipped with a reflux c©ndenser and a therm©meter. Ten

grams (O.058 m©le) ©f 1-nitronaphthalene was added while the

sodium bor©hydride was n©t c©mpletely diss©lved. Heat was

ev©lved and a vig©r©us reacti©n ©ccurred. The temperature

reached 210° and the mixture became dark c©l©red. After

this vig©r©us reactl©n, the temperature dr©pped and the mix­

ture was heated at 90-100° f©r 22.5 h©urs. Sufficient water

was added to dec©mp©se the excess s©dium b©r©hydride, f©ll©wed

by acidification with hydrochloric acid. The mixture was then

steam distilled in order to remove diglyme.

In the distillate s©me white s©lid was c©llected which

smelled ©f naphthalene. Ab©ut 300 ml ©f the distillate was

collected. After being in a refrigerator overnight, the dis­

tillate was filtered by sucti©n. A small am©unt ©f pinkish

s©lid was ccllected. It was dec©l©rlzed in an etham©l s©lu-

ti©n and recrystallized fr©m aqueous-ethan©l. Platelike

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37

crystals with a strong naphthalene odor were obtained; m.p,

78-80°,

The residue from the steam distillati©n was made al­

kaline with sodium hydroxide s©lution and steam distilled

again. The distillate smelled ©f naphthylamine and diglyme.

A large am©unt ©f ether was used t© extract the distillate

and the water layer was discarded. Dry hydrcgen chlcride

gas was passed thr©ugh the ether s©luti©n, after drying ©ver

anhydr©us s©dlum sulfate, and the resulting 1-naphthylamine

hydr©chl©ride was filtered. The hydr©chl©ride smelled of

diglyme. After neutralization with sodium hydroxide soluti©n,

a precipitate of amine was obtained which was not further

worked-up.

The oily substance in the hot residue of steam dis­

tillation solidified upon c©©llng. It weighed 4.08 g. When

sublimed in vacu© up t© 170°, a small am©unt ©f naphthylamine

was collected. The solid was dissolved in hot benzene and

dissolved material was filtered off. After evaporating off

the benzene, 2 g of dark red substance was left behind. By 0

the sublimati©n of this dark red substamee up to 190 in

vacuo, about 0.2 g of yellow substamce was collected. It

o © melted between I30 and 175 . Crystallizati©n from ethyl

acetate gave a fine, yellow, neutral c©mp©und, m.p. 213-214°;

analysis (43) gave

H 6.68; C 82.48; N 9.75^

Page 46: Cha1~~~--tiJ ~ommittee

38

NN-NBH-II. Eighty milliliters (0.06 m©le) ©f the

s©dium b©r©hydride s©luti©n was placed in a 500 ml three-

neck flask Immersed in an ice bath. Ten grams (O.058 m©le)

of 1-nitronaphthalene in 35 ml diglyme was added under mechan­

ical stirring and the mixture was warmed slowly to r©©m tem­

perature. After 18.5 h©urs ©f stirring I50 ml ©f water was

added f©ll©wed by lOJ hydr©chl©ric acid t© make acidic. The

mixture turned dark red and then tarry br©wn. It was steaun

distilled.

Ab©ut 1.5 1. ©f the distillate was c©llected. Plate-

like crystals appeared as the distillate was c©©led. The

distillate was filtered by sucticn. Crude naphthalene weighed

0.5^ g (7.3^ yield). After dec©l©rizatl©n amd recrystalliza-r. o

tion from ethanol it weighed 0.23 &> m.p. 81 .

The distillate which was collected fr©m the steam dis-

tillati©n of the alkaline s©luti©n was c©mbined with the ab©ve

1-naphthylamine, made acidic with hydr©chl©ric acid and the

water was distilled ©ff under reduced pressure. The residue

was diss©lved in h©t water and treated with charc©al, amd

crystallized. It weighed 3.05 g (29^ yield). Free amine

liberated with s©dium hydr©xide melted at 48 .

The residue fr©m steaun distillatl©n was acidified and

extracted with benzene. A dark s©luti©n was ©btained which

gave 2.97 g of tarry substamce after evap©rati©n. It was

dissolved in benzene, chlor©f©rm amd acetic acid c©nsecutive-

ly amd treated with charc©al, but n© c©l©r impr©vement was

Page 47: Cha1~~~--tiJ ~ommittee

39

©bserved. Fr©m sublimati©n under reduced pressure up t©

190° ©nly a little dark-red ©11 was ©btained,

NN-NBH-III. 1-Nitr©naphthalene, 10 g (O.O58 m©le),

in 50 ml ©f diglyme was added int© 55 ml (0,063 m©le) ©f the

diglyme s©lutl©n ©f s©dium b©r©hydrlde c©©led t© 0°, Even

th©ugh the reacti©n flask was immersed in an ice bath, a

n©tlceable ev©luti©n ©f gas was ©bserved amd the c©l©r ©f

mixture changed gradually fr©m the ©riginal light yell©w t©

br©wnish yellew. After 25 hours ©f stirring the ev©luti©n

©f gas appeared to have ceased. The mixture was stirred f©r

three m©re h©urs at r©©m temperature and then 35 ml ©f water

was added dr©pwlse. At the end ©f reacti©n, the c©l©r ©f

the mixture was a transparent, deep red. After the additi©n

of water, it became a brownish red. The whole content of

the flask was vacuum distilled at 2 mm Hg t© rem©ve diglyme,

N© naphthalene was smelled in the distillate. The residue

was then diluted with water amd the gummy dark red substance

fl©ating ©n the surface of liquid was skimmed off. After suc­

cessive washings with water the gummy material solidified.

The washings were returned t© the aque©us s©luti©n fr©m which

the solid had been removed. The selid weighed 7 g.

The liquid, which was turbid yell©w, did n©t smell ©f

naphthalene, but up©n acidifying it devel©ped the smell ©f

naphthalene and s©me s©lid precipitated. The precipitate was

filtered ©ff and s©dium hydroxide s©luti©n was added t© the

filtrate. It becaime red brown amd still smelled of naphthalene.

Page 48: Cha1~~~--tiJ ~ommittee

40

The liquid was acidified again and vacuum distilled. Naph­

thalene was collected from the distillate, 0.043 g (0.58j

yield), m.p. 79-80°.

The brown solid fr©m the ©riginal mixture was not af­

fected by dilute acid. It burned with a bright s©©ty flame;

©n prolonged heating it burned completely leaving no residue.

It was slightly s©luble in ethan©l, diethyl ether and s©luble

in benzene, ethyl acetate and cencentrated sulfuric acid.

Digesti©n of some of the s©lid with 4 N sulfuric acid, f©l-

l©wed by steam distillati©n gave s©me yell©w needles ©f

1-nitr©naphthalene, m.p. 58-60 . Vacuum sublimati©n ©f s©me

©f the s©lid gave only a small amount of red oil. !nie solid

dec©mp©sed ab©ve I50 . It was ©bvi©usly ©rganic in nature,

but n© inf©rmati©n was ©btained c©ncerning the type ©f c©m-

p©und.

The results ©f s©dium b©r©hydride reducti©n ©f 1-nitr©-

naphthalene are summarized in Table II.

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41

TABLE II

THE REDUCTION OF 1-NITRONAPHTHALENE WITH SODIUM BOROHYDRIDE

Expt N©.

l-Nltr©-naphtha­lene (m©le)

S©dium b©r©-hydride (m©le)

Temper­ature

0.058

0.058

0.058

0.075

0.063

0.063

210, 90-100

25

0 t© 25

Pr©ducts and yields

Naphthalene, undetermined. 1-Naphthylamine, undetermined. Yellcw needle. Br©wn s©lid.

Naphthalene, 7.3^. 1-Naphthylamine, 29$ . Br©wn s©lid.

Naphthalene, 0.58^. 1-Naphthylamine, not is©lated, Br©wn s©lid, 7 g.

Reduction of p-Dinitr©benzene

p-Dlnitrobenzene, 0.5 g* in 10 ml of chl©r©f©rm was

added to one gram of sodiiom b©r©hydride and a few pellets ©f

s©dium hydroxide in 30 ml ethanol. After being kept at ro©m

temperature f©r 26 h©urs, the ©range-red mixture was acidi­

fied with 10^ hydr©chlorlc acid. After the ©rganic s©lvents

were evap©rated ©ff, the mixture was made alkaline amd ex­

tracted with ether. After evaporating ©ff the ether, a

yellowish brown solid remained which had a cinnamon odor.

After the treatment with charcoal and recrystallizatlon from

alcohol-ethyl acetate mixture, deep yellow needles with a

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42

melting point of 189-192° were obtained. The melting p©int

©f 4,4'-diamin©az©xybenzene is 190° (46),

Attempted Hydr©gen©lysis ©f 1-Naphthylamine

The 1-naphthylamine used in this reacti©n was purified

fr©m dark "Technical Grade" 1-naphthylamine, The dark 1-

naphthylamine was dissclved in ether and precipitated as the

hydr©chl©ride with dry hydr©gen chlcride gas. The precipi­

tate was filtered and washed with ether until the washing was

no longer c©l©red. The s©lid was dried and diss©lved in b©il-

ing water. The s©luti©n was treated with charc©al three times

t© ©btaln a col©rless s©luti©n. Free amine was liberated by

neutralization with dilute sodium hydr©xide s©luti©n. The

white needles were filtered and washed with dilute aque©us ©

ethamol, m,p. 50-51 .

Purified 1-naphthylamine, 3.1^ g (p.022 mole), in 25

ml ©f diglyme was added t© 1,2 g (O.03 m©le) ©f s©dium b©r©-

hydride in 25 ml ©f diglyme at r©©m temperature. After stir­

ring at ro©m temperature f©r 23 h©urs, the mixture was heated

at 70^ f©r 5 hours. Water was added t© dec©mp©se c©mplexes

and the mixture was acidified with saturated ©xallc acid s©-

luti©n. Vig©r©us ev©luti©n ©f gas was ©bserved as water and

acid were added. The mixture was steam distilled. Naphtha­

lene was not smelled in the transparent distillate.

The residue from steam distillation was made alkaline

and extracted with ether. The subsequent treatment of the

Page 51: Cha1~~~--tiJ ~ommittee

43

purple solution gave 2.73 g (69.7^ recovery) of 1-naphthyla­

mine hydrochloride. The free amine liberated melted at 48-

50°.

Reduction with P©tassium B©r©hydride

Potassium bor©hydride used in the f©ll©wlng reducti©ns

was ©btained from Metal Hydrides, Inc©rp©rated (l8). It was

a white crystalline p©wder ©f 95^ purity.

Determinati©n ©f Purity of P©tassium B©r©hydride

The same method (45) as used in the determination of

the c©ncentrati©n ©f s©dlum b©r©hydride s©luti©n was used.

Potassium b©r©hydride, 0,0230 g, was diss©lved in 25 ml ©f

0.5 N s©dium hydr©xide. T© this s©luti©n 50 ml ©f 0.25 N

potassium iodate s©luti©n was added. The am©unt ©f 0.1004

N of sodium thiosulfate soluti©n used in the titrati©n was

92.19 ml. The purity ©f p©tassium b©r©hydride p©wder was

100 (50 X 0.25 - 92.19 X 0.1004) X 6.744 0.0230

- 95.0^

Reducti©n of Nitrobenzene

Potassium borohydrlde, 10.0 g (0.I8 mole), was sus­

pended in 150 ml of methan©l c©ntaining a few pellets of

potassium hydroxide. To this suspension, 11,07 g (O.09 mole)

of nitrobenzene in 50 ml of ethamol was added and the mixture

Page 52: Cha1~~~--tiJ ~ommittee

44

was heated under reflux for 46 hours. After the mixture was

co©led, dilute hydr©chl©ric acid was added dr©pwise until n©

m©re evoluti©n ©f gas was ©bserved. At the end of reaction,

the color of mixture was ©range. The mixture was extracted

with ether. The ether was separated and evap©rated ©ff and

the residue was chilled in an ice bath. An ©range wax-like

substance was formed which failed to crystallize. The sub­

stamce was steam distilled. Unreduced nitr©benzene was dis­

tilled ©ff first, f©ll©wed by az©xybenzene, which s©lidifled

up©n standing. The s©lid was filtered and dried in a vacuum

desiccat©r; 5,98 g (67^ yield) was ©btained. Dec©l©rizing

in ethfim©l amd recrystallizing fr©m petr©leum ether gave

light ©range needles of melting point 34-36°; 5,17 g (58.0^

yield).

The above reduction was repeated with the addition of

s©di\im hydroxide instead of potassium hydroxide to stabilize

potassium b©r©hydride. The yield ©f az©xybenzene was 11%,

Reductl©n ©f 1-Nitr©naphthalene

NN-KBH-I. 1-Nitr©naphthalene, 10 g (0,058 mole), and

4 g (0,07 mole) of potassium bor©hydride were stirred int©

250 ml of methanol which was purified previously to free from

acetone. The soluti©n was heated under reflux f©r 2 h©urs,

Alth©ugh the solution became darker as the result of heating,

it still smelled of 1-nitronaphthalene. Dilute hydrochl©ric

acid was added after cooling at the end of refluxing. The

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45

mixture was filtered and the solid residue was washed with

water. No precipitate was observed as the filtrate was

neutralized with sodium hydroxide soluti©n, which indicated

that n© 1-naphthylamine was f©rmed.

The s©lid remaining fr©m filtratl©n was sublimed t©

give 7.86 g (78.6^) ©f crude l-nitr©naphthalene. The residue

of sublimation was tar-like substance. The crude nltronaph­

thalene was dissolved in ethamol and treated with chare©al

and recrystallized; it weighed 7.05 g, m,p, 56-59 .

NN-KBH-II. P©tassium b©r©hydride, 3,5 g (0,06l5 m©le),

with ©ne graim ©f s©diiim hydroxide was suspended in 100 ml of

a mixed solvent which was comp©sed ©f 30 ml ©f water, 30 ml

of methanol and 50 ml of ethanol. T© this was added 6,15 g

(0,0355 mole) of 1-nitronaphthalene in 100 ml ©f etham©l amd

the mixture was stirred at r©©m temperature f©r 4o h©urs.

Then 25 ml of lOJ hydr©chl©ric acid was added t© the reacti©n

mixture, which was br©wnish red in c©lor. The mixture was

filtered and the filtrate was c©ncentrated under reduced pres­

sure at r©©m temperature. The dark br©wn substamce which ap­

peared upon concentration was filtered amd washed with water;

it smelled of naphthalene.

The filtrate and washings were combined and neutralized

with s©dlum hydroxide s©luti©n amd the white precipitate was

extracted with ether. By the usual treatment 0,48 g {1,1%

yield) ©f 1-naphthylamine hydr©chl©ride was ©btained. The

acetyl derivative melted at 157.5-159 .

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46

All solids were combined amd dissolved int© h©t ethyl

acetate. A brown solid, 1.10 g, was obtained after treating

with a large amount ©f charccal. Sublimati©n ©f this yielded

0.50 g (8,15 rec©very) ©f 1-nitr©naphthalene, Dec©l©rizati©n

and recrystallizati©n yielded yellew needles of melting point

56.5-58°.

NN-KBH-III. The reduction was carried ©ut as in

NN-KBH-II with 3,5 g (0,02 m©le) ©f l-nitr©naphthalene ex­

cept s©dium hydr©xide was n©t added. The reactien mixture

was kept stirring f©r 48 h©urs at 15-20°, It was then poured

into 200 ml of ice-cold dilute hydrochl©rlc acid. After the

ev©luti©n ©f hydr©gen had ceased, the mixture was filtered

and the precipitate (A) was washed with water.

The filtrate and washings were c©mbined and steam

distilled after making alkaline. White needles, 0,11 g,

which were first assumed t© be 1-naphthylamine were ccllected

from the distillate. After recrystallizing from ethanol, the

l©ng pinkish needles melted at 96-97 . A mixture with 1-

naphth©l showed a great melting point depressi©n; the mixture

melted from 59° to 98 , The melting p©int ©f 1-naphthol is

94° (47). Not enough c©mp©und was ©btained f©r further iden­

tification.

The precipitate (A) was dark brown, weighed 4.47 g.

It decomp©sed ab©ve 250 . It yielded n© az©naphthalene by

sublimati©n and did n©t change c©l©r up©n treatment with

charc©al. A dark tar with an ©d©r of 1-naphthylamine remained

Page 55: Cha1~~~--tiJ ~ommittee

47

after the evaporati©n ©f its benzene extract, 1-Nitr©naph-

thalene, weighing 0.12 g, was ©btained fr©m steam distilla-

ti©n, m.p. 56.5-58°,

NN-KBH-IV. P©tassium b©r©hydride, 3,5 g (0,062 m©le),

was diss©lved with ©ne gram ©f detergent in 50 ml ©f water.

To this s©luti©n 6.25 g of 1-nitronaphthalene in 50 ml ether

was added. The detergent was added to emulsify two immiscible

phases. The soluti©n was b©iled f©r 44 hours. The total ©ri­

ginal comp©und was recevered unchanged.

The results ©f the reducti©n ©f l-nitr©naphthalene

with potassium borohydrlde are summarized in Table III.

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48

TABLE III

THE REDUCTION OF 1-NITRONAPHTHALENE WITH POTASSIUM BOROHYDRIDE

Potassium bor©-

Expt, hydride No. (mole)

3

4b

l-Nltro­naphtha­lene

(mole)

Temper­ature

Products amd y ie lds

0.07

0.062

0.062

0.062

0.058

0.036

0.02

0.036

l-Nltronaphthalene, 65 18.6% recovery.

Tar

1-Naphthylamine, 7.7^ 80 1-Nitr©naphthalene,

8.1^ reccvery.

White needle, 15-20 m.p. 96-97 , 0.11 g.

Dark br©wn s©lid.

100 1-Nitr©naphthalene, 100^ recevery.

a.-One graun ©f s©dium hydr©xide was added. b.-One gram ©f detergent was added.

Reducti©n ©f p-Dinitr©benzene

DNB-KBH-I. p-Dinitr©benzene, 5 g (0.03 m©le), was

extracted in a S©xhlet extra©tl©n apparatus with 200 ml ©f

b©iling ethan©l c©ntaining 15 g (O.26 m©le) ©f potassium

bor©hydride with few pellets ©f potassium hydroxide. The

col©r ©f s©luti©n turned int© green, dark green, red amd

finally brownish red. After 48 hours the mixture was c©©led

in an ice bath and acidified with dilute sulfuric acid. The

brownish precipitate was filtered amd washed thor©ughly with

water to remove inorganic substances, leaving a dark red

Page 57: Cha1~~~--tiJ ~ommittee

49

powder.

The dark red am©rph©us p©wder weighed 3,21 g. It was

degested with benzene and filtered. The dark red p©wder

(A), weighing 1.40 g, remaining was ins©luble in acid, base,

ethan©l, or diethyl ether. It was slightly soluble in ben­

zene and nitr©benzene, and soluble in concentrated sulfuric

acid with deep blue coloration. It ignited Instantly when

brought to a flame and the black residue burned ©ff even­

tually. Qualitative analysis shewed the presence ©f nitro­

gen without halogen. It was stable up to 360 but charred

at higher temperature. It was reduceable with tin and hydro­

chloric acid to form a colorless compound. On the assumption

that an amine was formed by the reduction, an acetyl deriva­

tive was prepared directly from the reduction mixture and its

melting point was compared with N,N'-diacetyl-p-dlaminoben-

zene. The acetyl derivative of reduction product melted at

306.5-307° while that of authentic N,N»-diacetyl-p-dlamino-

benzene was also 306.5-307 . Analysis (43) of the red solid.

Found: C, 65.64; H, 4.19; N, 22.69^. Calcd. for ^2^'^19^1^2' ^' ^5.89; H, 4.38; N, 22.42^.

Calcd. for Cgi^H^^N^O^: C, 66.19; H, 3.94; N, 22.52^.

The benzene washings of the red powder was evaporated

to dryness. The residual red solid weighed I.81 g. By sub­

limation at 80-90 in vacuo, O.15 g ©f yellewish needles

were ©btained. The residue ©f sublimati©n appeared t© be

TKXAS TECMNOUHilCAL CULLBGK LWBAJCfc

LUBBOCK. TEXAS

Page 58: Cha1~~~--tiJ ~ommittee

50

the saime red powder as above. The yellow needles were de-

colorized and recrystallized from ethamol. White needles

having a melting point of 58-61.5° was obtained. They were

neutral, s©luble in h©t ethanel and ccntained nitr©gen. Ele­

mental analysis (43) sh©wed the substance t© be p-nitrophene-

t©le; 3.2^ yield.

Pound: C, 57.62; H, 5-46; N, 8.62%, Calcd, for CgH^NO^: C, 57.48; H, 5.46; N, 8,38 ,

The acidic filtrate from the original mixture was

evaporated on a steam bath to remove ethanol, A brownish

yell©w solid was filtered and washed with water, weighing

0.25 g. By sublimation, yellow needles having a melting

p©int ©f 112-114,5° was ©btained, N©t en©ugh c©mp©und was

©btained f©r further Identificaticn.

The ab©ve reacti©n was repeated with©ut the additi©n

©f p©tassium bor©hydride, i,e,, 5 g of p-dinitr©benzene was

extracted in a Soxhlet extraction apparatus with 200 ml of

boiling ethanol containing few pellets of p©tassium hydr©xide

for 48 hours, p-Nltrophenetole, 2,3 g, was ©btained by the

same treatment as ab©ve, m.p. 58-60 (46.3^ yield).

DNB-KBH-II. Fifteen grams ©f potassium b©r©hydrlde

was suspended in 100 ml of N,N*-dimethylanillne under mechan­

ical stirring. To this suspension, a solution of 5 g of

p-dinitrobenzene in the same s©lvent was added. The color

©f p-dinitr©benzene s©lution was dark red; the c©l©ratlon

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51

resulted as s©©n as the s©lute was disselved in the selvent.

The mixture was stirred at 90-100 f©r 43 h©urs. After c©©l-

ing to ro©m temperature, 150 ml ©f ^% hydr©chloric acid was

added dr©pwise.

The mixture was made alkaline and steam distilled t©

rem©ve dimethylaniline and unreacted p-dinitr©benzene. The

s©lld residue of steam distillation was filtered off amd

washed with water thor©ughly t© rem©ve any contaminating

inorganic material. The solid was dark in col©r, weighing

1.69 g. It was washed pertionwise with 70 ml ©f b©lllng ben­

zene. The residue ©f benzene washing was brewn c©l©red p©w-

der, weighing 0,12 g, which burned sl©wly with©ut residue.

It did n©t have melting peint but charred ab©ve 220°.

Tw© different f©rms of solid crystallized out from the

benzene washing after it had been cooled: (A) an orange

powder, weighing O.2327 g amd (B) red needles, weighing

0,732 g. Repeated crystallization of the tw© separated s©lids

revealed that b©th had tw© different s©lld f©rms, red needles

and copper leaflets, depending on the conditi©ns ©f crystal-

llzati©n. B©th s©lids had a melting point of 215-217°. Their

mixture showed no melting point depression. Analysis (43)

showed them to be 4,4'-dinitroazobenzene (38.8^ yield).

Found: C, 53-35; H, 3.17; N, 20.35^. Calcd. for C^2%^4^2- ^' 53.07; H, 2,96; N, 20.58$ .

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52

Reduction with Lithium B©r©hydride

The lithium bor©hydride, which was a micr©crystalline

p©wder, was a pr©duct ©f Metal Hydrides, Inccrporated (l8).

NN-LBH-I. Lithium b©r©hydride, I.06 g (0.046 m©le),

was refluxed with 50 ml ©f anhydr©us ether f©r 30 minutes.

1-Nltr©naphthalene, 8.46 g (0.049 m©le), in 100 ml ether was

added and the mixture was heated t© gentle reflux f©r 40 h©urs.

At the end of refluxing, the mixture was a cloudy, deep yellow.

The mixture was c©©led amd 100 ml of ice-water was added; it

changed int© a clear ©range s©luti©n up©n the additien ©f the

water, A gummy ©range material separated ©ut up©n acidiflca-

tl©n with hydr©chl©ric acid. The mixture was thus separated

int© three parts: (A) acid aque©us s©luti©n, (B) ether

extract of the above gummy precipitate, (C) benzene s©luti©n

which c©ntained substances inscluble in ether.

The acidic s©luti©n (A) was c©ncentrated on a steam

bath and then steaim distilled after making alkaline. The

usual treatment gave 0.42 g (0.48 ^ yield) ©f 1-naphthylaunine

hydrochloride. The free amine ©btained subsequently melted

at 47-49°.

The ether s©luti©n (B) was evaperated t© dryness. The

residue appeared as a red ©11 smelling ©f naphthalene. H©w-

ever further treatment with charcoal and repeated recrystal­

lizatlon yielded only 1-nitronaphthalene O.06 g, m.p. 56-58°.

The tar obtained after evaporation of the benzene so-

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53

lution (C) gave a trace ©f 1-nitronaphthalene contaminated

with red oil. After the removal of 1-nitronaphthalene, the

red oil smelled of naphthalene. However n© naphthalene c©uld

be crystallized ©ut fr©m the red ©11.

NN-LBH-II. The tetrahydrefuran used in this and the

f©ll©wing experiments was ©btained fr©m Dlstillati©n Pr©ducts

Industries (39). It was placed ©ver selid s©dium hydr©xide,

redistilled and stored over s©dium metal.

l-Nltronaphthalene, 8,25 g (0,045 mole), in 30 ml

tetrahydrofuran was added to the s©lutl©n ©f 1,43 g (0.066

mole) of lithium bor©hydride in 40ml ©f tetrahydrofuran.

The mixture was stirred at r©©m temperature f©r ©ne h©ur and

50 ml ©f water was added t© the ©range-red mixture. A few

milliliters of this orange-red mixture was taken and acidi­

fied; the mixture changed into dark gray at ©nee. Therefere

n© acid was added t© the mixture. The flask centents were

evap©rated under reduced pressure at r©©m temperature. A red

oily layer separated from aqueous layer after the tetrahydro­

furan was evaporated. It was extracted with benzene until

benzene was no longer col©red. The benzene extract was dried

over anhydrous sodium sulfate,

•Rie residual aqueous portion was c©©led in am ice bath

and acidified with hydr©chl©ric acid, A light yellcw am©r-

phous solid (A) precipitated out. This was filtered and wash­

ed with ice-cold water. After being kept inside a vacuum

desiccator overnight, the solid chamged into dark tar smelling

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54

of 1-nitronapIithalene. The tar was diss©lved in benzene and

passed thr©ugh an alumina c©lumn ©f 1 cm diameter and 25 cm

length. The first p©rtion ©f benzene elutien was red c©l©red

which was followed by a dark soluti©n. The red s©luti©n,

after evaporation gave a red solid which smelled of naphtha­

lene. However, by the subsequent recrystallizatlon fr©m

aqueous-alcohol, ©nly 0,32 g ©f l-nltr©naphthalene was re­

covered, m,p, 55-58°,

The benzene soluti©n, after rem©val ©f s©dium sulfate,

was passed thr©ugh am alumina c©lumn, 2 cm in diameter and

30 cm in length. The benzene eluted, red s©luti©n gave ©nly

a red solid which smelled ©f 1-naphthylamlne after evap©ra-

tion. It was washed with acid and the acid solutl©n was c©m-

bined with the original acidic s©luti©n (B) remaining after

the filtratl©n ©f (A). The brewnish residue, after acid

washings, gave only tar by sublimation.

The acidic soluti©n (B) was made alkaline and steam

distilled. Prom the distillate, 1.10 g (12.9^ yield) ©f

1-naphthylamine hydr©chl©ride was ©btained. The free amine

obtained by neutralization melted at 47-49 .

The ethamolic washing ©f the column after elution gave

only a tar-like substance after evap©ratl©n. 1-Nitr©naphtha­

lene, 0.07 g, was c©llected fr©m sublimati©n ©f the tar.

The total recovery of 1-nitronaphthalene was O.39 g (^,1%),

NN-LBH-III. 1-Nltronaphthalene, 17.3 g (O.l mole),

in 35 ml of tetrahydrofuran was added to 35 ml of a tetra-

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55

hydrofuran s©lutl©n of 1,77 g (0.08I mole) of lithium boro­

hydrlde immersed in an ice bath. After 3,5 hours ©f stir­

ring at r©©m temperature, the red mixture was ceoled to -50°,

amd 150 g of dry ice powder was added under stirring. The

mixture was kept at ro©m temperature ©vernight. Water was

added and the tetrahydrefuran was evaperated ©ff at r©©m

temperature under reduced pressure. After the mixture was

free fr©m the tetrahydr©furan, it was extracted with ether.

The ether extract (A) was washed with 10^ hydr©chl©ric acid

(B).

Four grams of white crystalline pr©duct separated fr©m

the aque©us portion after chilling. This was proved to be

inorganic lithium salt by flame test and qualitative analysis.

The filtrate, after removal ©f the salt, was acidified with

c©ncentrated hydr©chl©ric acid. A light yellcw s©lid was

precipitated ©ut. This was similar to (A) in NN-LBH-II, and

decomposed into dark tar in a vacuum desiccator. This tar,

weighing 0,5 g, dissolved in sodium hydroxide giving a faint

smell of ammonia. No precipitate appeared on acidification

after treatment with charcoal. The filtrate from the light

yellow solid was extracted with ether (C) and the aqueous

portion was discarded,

A dark tar, weighing O.O8 g, having a phenolic smell

remained after evap©rati©n ©f the ether extract (C), N©

solid obtained after the treatment with charcoal in ethanol.

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56

The acid washing (B) was made alkaline and steaim dis­

tilled. Further treatment of distillate gave 2,03 6 (11.3^

yield) of 1-naphthylamine hydr©chl©ride, The free amine

liberated by s©dium hydroxide melted at 46-48°,

The dark tar which was ©btained fr©m the evap©ration

of the ether extract (A) gave 4,24 g (2h.6% recovery) ©f 1-

nitronaphthalene, m,p. 56,5-58°.

Reduction with Diborane

NN-DB-I. Sodium bor©hydride, 2,22 g (O.O56 m©le),

in 100 ml of diglyme was added dropwise t© 11,1 g (0,078

m©le) of boron trifluorlde etherate in an hour. The diborane

thus fonned was swept with a current of dry nitrogen into

5 g (0,029 mole) of 1-nitronaphthalene in I50 ml of tetra­

hydrofuran in another flask. As no color change was observed,

m©re diborane^ liberated fr©m 6.66 g (0,17 m©le) ©f s©dlum

bor©hydride and 30 g (0,24 m©le) of bor©n triflu©ride ether­

ate was bubbled int© the solution of 1-nitronaphthalene,

Acetone was used to trap the diborane issuing from the re­

action flask. When all of the sodium b©r©hydride had been

added and gas evoluti©n had ceased, ethan©l was added t© the

tetraUtiydrofviran s©luti©n, Vig©rous ev©lution ©f gas was ob­

served. The solution was evaporated on a steam bath until a

precipitate appeared. The mixture was then cooled and fil­

tered. The solid was washed with dilute hydrochl©ric acid.

The dark purplish solid weighed 5.84 g. By sublimation.

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57

4.64 g (935 ) of 1-nltronaphthalene was recovered, m.p. 58-/- o

6o .

NN-DB-II. NN-DB-I was repeated with the addition of

one graim ©f zinc dust t© the s©luti©n ©f l-nitr©naphthalene

The same treatment gave 4.97 g (99.4 ^ reccvery) of 1-nitro­naphthalene, m.p. 58.5-60 ,

Preparation ©f Naphthyl Lithium and lis Reaction with Nitr©us Oxide

NL-NO-I. Thirty-five milliliters ©f anhydrous ether

was placed in a 250 ml three-neck flask equipped with a me­

chanical stirrer, a reflux condenser, amd a dropping funnel

and gas inlet amd outlet tubes. The flask was flushed with

dry nitrogen. Lithium shavings, 1,50 g (p, 2l6 mole), was

added at once and the mixture was stirred, l-Brom©naphtha-

lene, 20.7 g (O.l m©le), in 35 ml ©f anhydr©us ether was

added dropwise in 2,5 hours. The col©r ©f mixture changed

into dark purple. At the end of reacti©n 50 ml ©f anhydr©us

ether was added and the flask was Immersed in ice-s©dium

chloride mixture.

Nitrous oxide gas was bubbled slowly through the solu­

tion for one hour. The c©l©r of the mixture became darker.

Twenty milliliters of methanol followed by 80 ml of water

was added. The ether was evaporated at r©©m temperature.

The mixture smelled strongly of naphthalene. The alkaline

solutl©n was decanted amd the residual dark gummy substance

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58

was washed with dilute s©dlum hydroxide amd water. After

suspending in dilute sulfuric acid, it was steam distilled.

Crude naphthalene, 4.9 g (38.3^ yield) was obtained; m.p.

80-82° after recrystallizatlon from ethanol.

The residue from steam distillation was a pitch-like

black substance which weighed 10,68 g. Sublimation under

reduced pressure yielded n© azonaphthalene but a little red

oil smelling of naphthalene.

NL-NO-II. 2-Naphthyl lithium was prepared as in NL-

NO-I using 6.5 g (0,94 mole) of lithium and 8 g (0.039 mole)

of 2-bromonaphthalene.

Nitrous oxide was passed through the solution of 2-

naphthyl lithium for 4 hours while the flask was immersed

in ice-sodium chloride mixture and one hour at ro©m tempera­

ture. Twenty milliliters ©f methanel foll©wed by 80 ml of

water was added and the mixture was stirred for two hours

until no more gas evolved. The organic layer was separated

amd washed with porti©ns ©f water (A).

The ©rganic s©luti©n was evap©rated t© dryness after

washing with dilute sulfuric acid amd water. The residue

was sublimed at 80-90°, Naphthalene, weighing 1,52 g (30.7^

yield), was obtained, m.p, 78-80 .

The sublimation was continued in vacuo and the tem­

perature was raised to I6O-I7O , A red substance, weighing

1,16 g, was obtained. By the treatment with charcoal and

recrystallizatlon from benzene, colorless flakes with faint

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59

blue fluorescence was ©btained, m.p. 184-186.5° {23,6% yield)

The melting p©int ©f 2,2»-dinaphthyl is 187-188° (48),

The basic s©luti©n (A) was acidified with dilute sul­

furic acid and the precipitate which smelled phen©l-like was

filtered, Dec©l©rizati©n and recrystallizaticn fr©m aque©us-

alcohol gave 26,8 mg ©f 2-naphth©l, m,p, 120-122°, The melt­

ing p©int ©f 2-naphth©l is 123° (^9).

Infra-Red Abs©rpti©n Spectrum ©f the C©mp©und (A)> DNB-KBH-I

Infra-red abs©rpti©n spectrum was ©btained ©n a Perkin-

Elmer Single Beam Infrared Spectrcmeter with D©uble Pass

Itonochrometer, Model 112, using a pressed tablet ©f 400 mg

potassium bromide mixed with ©ne milligram ©f the sample.

Table IV indicates the peaks, their relative intensity and

structural assignment (49) (50) ©f the spectrum reproduced

in Figure 1.

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60

TABLE IV

INFRA-RED ABSORPTION SPECTRUM OF THE COMPOUND (A), DNB-KBH-I

Wave length (microns) Assignment

5.2 (w 6.22(m 6 .3 ( s 6.57(m 6.65(m 6.86(m 7.08(m 7.17(m 7.^6(m 7 .66(s 7.91(w 8.04(m 8.30(s 8,50(w 8.60(w 8 ,79(s 8,85(s 9 . 1 l ( s 9.6l(m 9 .98(s

10,30 10.42 10.89(m 11.03{m 11.64(s 12.9l(ni 13.17(w

w w

a ,b a ,b a a ,b a ,b a ,b

b a a ,b

b a a ,b

a ,b a ,b a ,b

a

a ,b

b

a

C- ' C stretching, phenyl ring vibration, N-H deformati©n. conjugated phenyl ring vibration, NO2 stretching, phenyl ring vibration, N»N stretching. N=N stretching. C-H bending. NO2 stretching. -C-N= bending, not assigned, not assigned, C-H rocking. C-H r©eking, C-H r©cking. -C-N« vibrati©n, C-H wagging. C-H r©eking. C-H r©cking. C-H bending. C-H def©rmati©n. C^^^ stretching. -C-N« vibratl©n. C-H wagging, p-substituted ring vibrati©n, p-substituted ring twisting, substituted ring twisting.

a. Peaks in the spectrum of 4-phenylazo-4»-(p-nitro-phenylaz©)-az©benzene (50),

b. Peaks in the spectrum ©f 4-phenylaz©-4»-(p-amin© phenylaz©)-az©benzene (50).

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61

Page 70: Cha1~~~--tiJ ~ommittee

FIGURE I. INFRA-RED SPECTRUM OF THE COMPOUND (A), DNB-KBH-I

COMPOUND (A), DNB-KBH-I

BACKGROUND

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62

Discussi©n ©f Results

At the ©utset ©f the research pr©Ject described in

the thesis, the aim was t© use metal hydride cemplexes f©r

the reductive ccupling ©f 1-nitr©naphthalene.

The result ©f Br©wn and Nystr©m (3), the reductive

c©upling ©f nitrobenzene to az©benzene with lithium aluminum

hydride, was c©nflrmed. With l-nltr©naphthalene, the pr©-

ducts were mainly an intractable dark brewn s©lid with a

small am©unt ©f 1-naphthylamine; and, ©ccasi©nally an ex­

tremely small ameunt ©f l,l*-az©naphthalene. If the f©rma-

ti©n ©f 1-naphthylamine f©ll©wed the same stepwise c©urse

thr©ugh nltr©s©-, hydr©xylamln©-, az©xy-, az©- aind hydraz©

c©mpound as sh©wn in the electrelytic reductien ©f nitr©ben-

zene in an alkaline medium (l), l,l*-az©naphthalene should

be reduced to 1-naphthylamine with lithium aluminum hydride.

The bright red c©l©rati©n ©bserved during the c©urse ©f m©st

©f the reducti©ns and its subsequent changing int© dark

br©wn was th©ught t© be an indicati©n ©f the f©rmatl©n ©f

the az© c©mp©und as an intermediate which was transf©rmed

int© tar ©r the amine by the further treatment. Repeated

experiments with l,l*-az©naphthalene sh©wed this supp©siti©n

t© be false.

While l-nltr©naphthalene was scarcely reductlvely

ccupled to form the azonaphthalene, a substituted nltronaph­

thalene, 5-br©m©-l-nitr©naphthalene was reductlvely coupled

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63

to give what is believed t© be a mixture of 5,5•-dibrom©-

1,1'-azonaphthalene and 5,5»-dlbr©m©-l,l'-az©xynaphthalene.

•niis result was in accordance with the results of Wacker (8).

With sodium-, potassium- aind lithium b©r©hydrlde, n©

azo compound was isolated. Nevertheless the bright-red col©r-

ati©n was always ©bserved in the ceurse ©f reduction. In all

of the experiments with b©r©hydrides a small am©unt ©f naph­

thalene was formed. With lithium aluminiam hydride, naphtha­

lene was isolated only from the inverse addition method while

its existence was detected in other cases only by ©d©r. The

course of the hydrogenolysis is not clear. The naphthalene

could not have been formed from first-formed naphthylamine,

since experiments with 1-naphthylamine led only to the re­

covery of the naphthylamine. The fact that the light colored

amorph©us s©lid is©lated fr©m the acidic decompositi©n mix­

ture of the lithium b©r©hydride reductions changed into a

dark tar smelling of naphthalene might be an indication that

naphthalene was derived from the decomp©8ition of a metal

hydride organo-complex. Such a c©mplex, if present, did not

have a naphthyl lithium bond, since no naphthoic acid was

isolated from NN-LBH-III in which dry-ice powder was added

to the reaction mixture. It is possible that attack of the

reducing agents at the pelar C-N bond leads to the formatl©n

©f naphthalene, whereas attack which occurs more frequently

at the polar N-0 bond leads to the formation ©f az©- or

aminonaphthalene. There has been no direct evidence for this

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64

speculation, however. The nitro group hydrogen©lyzed was,

perhaps, reduced t© amm©nia as the od©r ©f amm©nia was de­

tected in NN-LBH-III, when the tar derived fr©m the am©rphous

light col©red solid was treated with sodium hydroxide.

The identity of the yellow comp©und ©btained in small

yield in NN-NBH-I is net kn©wn yet. It was m©st likely f©rmed

by the effect ©f high temperature which was accidentally at­

tained by the additi©n ©f s©lid l-nitr©naphthalene t© the

b©rohydride suspensien.

In c©ntrast with an early established fact that the

nitr© group is resistant to attack by potassiiim b©rohydride,

nitr©benzene was reduced to azoxybenzene in 60-70$ yield ©n

pr©l©nged heating in alcoh©lic s©lutl©n.

Pr©m the fact that nitrcbenzene was reduced with b©th

s©dium and p©tassium b©r©hydride t© az©xybenzene (21) and

p-dinitr©benzene was reduced with sedium b©r©hydrlde to p,p'-

diaminoazoxybenzene (DNB-NBH), a simple azoxy c©mp©und was

expected t© be fermed from the reduction of p-dinitrobenzene

with potassium borohydrlde. However, the main product, the

compound (A) ©f DNB-KBH-I, appeared t© be a high molecular

weight compound; it did not have a melting point and was ex­

tremely insoluble in solvents. Because it gave p-phenylene-

diamine on reduction, it was believed t© be a p©lyaz© c©m-

pound. The compoiind C24^ig-^7^2 ^^^^ ^^® structure

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65

0 — ^ — 0 ^ —

and the c©mp©und Cgi^H^^N^O^, with the structure

have compositl©ns agreeing with the analysis ©f the c©mp©und

(A). Nevertheless the similarities in c©mp©siti©n are n©t

c©nclusive evidence. In particular, the tw© az©xy groups

are rather arbitrary. The infra-red spectrum ©f the c©mp©und

(A) resembles that ©f the 4-phenylaz©-4'-(p-nitr©phenylaz©)-

azebenzene, rep©rted by Uen© (50), H©wever there are seme

peaks in the spectrum ©f (A) which are net in the latter,

and Uene's spectrum has seme peaks, 6.4, 7,0, 7.3* 7.6, 9,37,

10.03, and 12,76 mlcrens, which are missing fr©m the former.

The spectrum of the c©mp©und (A) als© has s©me resemblance

to that of the 4-phenylaz©-4»-(p-aminophenylaz©)-azobenzene

(50), However, of the two peaks assigned for amino group in

the latter, 6.22 microns for N-H deformati©n and 7.85 micr©ns

f©r C-N stretching ©f C-NHg b©nd, ©nly the 6.22 mlcrens ap­

pears in the former. Also, 6.22 microns peak is not unique

for N-H b©nd. These facts lead to the obscuration of the

existence ©f amin© group in the c©mp©und (A),

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66

The extent ©f reductive ceupling ©f p-dinitr©benzene

depends ©n the nature ©f the selvents and the temperature.

With N,N-dimethylaniline as the selvent, the reductive c©up-

ling ©f p-dinitr©benzene with petassium b©r©hydride yielded

n© c©mp©xjind resembling the cempound (A) ©f DNB-KBH-I, but

4,4'-dinitr©az©benzene.

Besides the c©mp©und (A), p-nitr©phenet©le was als©

f©rmed in the reductien ©f p-dinitr©benzene with petassium

borohydrlde in ethanol. However, this formation was proved

to be nucleephllic substituticn by the ethexy group as the

same comp©und was als© ©btained in the absence ©f the reduc­

ing agent. The reactien apparently ©ccurred as described

by Antener (33).

As reperted with nitrebenzene (29), the nitr© gr©up

in l-nitr©naphthalene was resistant t© the action of diborane

at ro©m temperature,

nie results ©f the reactlen between nitreus ©xide and

naphthyl lithium differed fr©m the result given previeusly

(30). N© azonaphthalene was isolated but dinaphthyl was ob­

tained in addition to naphthalene.

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CHAPTER IV

CONCLUSION

1, 1,1'-Azonaphthalene was obtained in 5.3^ yield

from the reduction of 1-nitronaphthalene with only lithium

aliiminum hydride. With b©r©hydrides n© az ©naphthalene was

iselated,

2, Up t© 205 1-naphthylamine was always ©btained fr©m

the reaction of 1-nitronaphthalene with all the hydride com­

plexes. The naphthylamine is not f©rmed fr©m first-f©rmed

az©naphthalene.

3, Some hydrogenelytic cleavage ©f the nitr© gr©up

in l-nitr©naphthalene ©ccurred with every hydride cemplex,

4, Nitrebenzene was reduced with petassium b©r©hydride

to give azoxybenzene in 6l% yield.

5, The product from p-dinitrobenzene depends on the

reducing agent, solvent and temperature. 4,4»-Diamin©az©xy-

benzene, 4,4'-dinitr©az©benzene and a compound resembling a

poly azo comp©und were fermed in different cases. p-Nltro-

phenetele, a substitutien product, was also Isolated when

ethanol was used as the solvent.

67

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68

REFERENCES CITED

(1) E. H. Rodd, Chemistry ©f Carb©n C©mpounds, Vgly"" IIIA, Elsevier Publishing Cempany, New Y©rk, 195^. pp. 132, 314-319.

(2) F, Radt, Elsevier's Encyclepedia ©f Organic Chemistry, Series^II, Volume 12B, Elsevier Publishing dempany. New York, 1949. pp. 353> 932.

(3) W. 0. Brown and R. F, Nystrom, "Reductien ©f Organic C©mpounds by Lithium Aluminum Hydride, II. Halides, Quinones, Miscellaneeus Nitr©gen C©mp©unds," Jour­nal ©f the American Chemical Society, 70 (l94tJ), pp. 3758-3740.

(4) W. H, Doer, "Einwirkung von Zinkstaub auf Nitronaphtalin," Berichte der Deutschen Chemischen Gesellschaft, 3 (1870), pp, 291-29^,

(5) W. Kl©buk©wski, "Zur Kenntnisse des Azenaphtalins," Berichte der Deutschen Chemischen Gesellschaft, IC (1877), pp. 570-576.

(6) 0. N. Witt, "iiber die Eurhendine und Laurent's Naphtase," Berichte der Deutschen Chemischen Gesellschaft, 19 (1886), p. 2794.

(7) L. Wacker, "Uber das a-Az©xynaphtalln," Justus Liebigs Annalen der Chemie, 317 U901), pp, 375-3^5.

(8) L, Wacker, "Reducti©npr©ducte der Nitrcnaphtalin," Justus Liebigs Annalen der Chemie, 321 (1902), pp, bl-70,

(9) H. Hepwerth, "The Actien ©f the Grignard Reagent ©n Ar©matlc Nitr© C©mp©unds," J©urnal ©f the Chemical Society, 117 (1920), pp, I004-10l2,

(10) W, M. Cumming and J, K. Steel, "Reduction of Nltro­naphthalene. Part I. Reduction of 0(-Nltronaphtha­lene," JournaloftheCh^^ Society, 123 (1921). pp. 2464-2470. ^' ^ V-^^o;,

(11) R. H, McKee and B. G, Gerapostolon, "Electrolytic Re­duction of Nitr© C©mp©unds in C©ncentrated Aque©us Salt Solution," Transaction ©f the Electrochemical Society, 68 (I93bj, PP. 3^9-373. '

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(12) B, M. Bogoslovskii, "New Method for the Preparation of Symmetrical Azo Comp©unds," J©umal ©f Qg^^ygl Chemistry, U. S. S, R,, l6 (l94b;, pp, 193-190.

(13) N. G, Gaylord, Reduction with Ccmplex Metal Rvdrides, Interscience Publishers, Inc©rp©rated, New Y©rk, 1956. pp, 773-778,

(14) N. G. Gaylord and J. A, Snyder, "Reduction ©f m-Nltro-benzaldehyde," Recueil des Travaux Chimiques des Pays-Bas, 72 (1953), PP. lOOT-lOOti,

(15) G. M. Badger, J. H, Seidler, and B. Th©ms©n, "P©ly-nuclear Heterecycllc Systems. Part III, The 3:4-Benzacridine-5:10-Dlhydr©-3:4-Benzacridine Cemplex, Jeurnal ©f the Chemical Seciety, (1951)^ PP- 3207--mr,

(16) W, Ried and P, Muller, "Uber elnige Reduktlonen mit Llthiumalumini\3mhydrid, " Chemische Berichte, 85 (1952), pp. 470-474,

n

(17) E, Wlberg and A. Jahn, "Uber den Reaktionsmechanismus der H^drierung mit Aluminiumwassersteff," Zeitschrift fur Naturferschung, 7b (1952), p. 58I.

(18) Technical Bulletin 502, Metal I^drides, Inc©rp©rated, 12-24 Cengress Street, Beverly, Massachusetts.

(19) H. C. Brown, E, J, Mead, and B. C. Subba Rao, "A Study ©f Solvents for Sodiiim B©r©hydride and the Effect of Solvent and the Metal Ion on B©r©hydride Reduc-tl©ns," J©urnal ©f the American Chemical Seclety, 77 (1955), pp. 6 09-6 35.

(20) S. W. Chalkin and W. G. Brewn, "Reductien ©f Aldehydes, Ketenes and Acid Chlerldes by Sedium Borohydrlde." Journal of'^he American Chemical Society, 71 (1949), pp. 122-125.

(21) C. E. Weil and G. S. Panson, "The Reduction of Nitro­benzene to Azoxybenzene by Sodium Borohydrlde," Journal of Organic Chemistry^ 21 (1956), p, 803.

(22) Technical Bulletin 402-C, Metal Hydrides, Incorporated, 12-24 Congress Street, Beverly, Massachusetts.

(23) M, D, Banus, R, W, Bragdon, and A. A, Hinckley, "Potas­sium, Plubidivim and Cesium Bor©hydride," Journal of the American Chemical Society^ 76 (1954), p. 3t54i5,

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(24) N. G. Gaylord, "Reduction with Complex Metal Hydrides," Jeurnal ©f Chemical Educatien, 3^ (1957), PP- 3D7-

37,-(25) R. F, Nystr©m, S, W, Chalkin and W, G, Br©wn, "Lithium

B©r©hydride as a Reducing Agent," Jeumal of the American Chemical Society, 71 (19^9), PP. 324!i-J^I^.

(26) L. Friedman, Abstracts of Papers, 122nd Meeting, Ameri­can Chemical Society. Atlantic City, New Jersey, September, 1952, p. 46M,

(27) H. C. Brewn and E, J. Meed, "Additien C©mp©unds ©f Alkali Metal Hydrides. II. Sedium Trlmeth©xyb©r©-^ hydride as a Reducing Agent f©r Organic C©mp©unds," Journal of the American Chemical Society, 75 (1953), pp. 6^3-6265.

(28) G. Hasse and R. Schredel, Natriximtriathexy-Alumlnium-hydrid. Ein Neues Reduktiensmittel in der Organis-chen Chemie," Justus Liebigs Annalen der Chemie, 607 (1957), pp. 24-35.

(29) H. C. Brown and B. C, Subba Rao, "Selective Reductions with Diborane, an Acidic-Type Reducing Agent," Journal ©f Organic Chemistry, 22 (1957), pp. 1135-TT36:

(30) F, M. Beringer, J. A, Farr Jr, and S. Sands, "The Reactions of Nitrous Oxide with Organolithium Com­pounds, " Journal ©f the American Chemical Society, 75 (1953), pp. 39B4-39B7. ^

(31) R, Meier, "Reaktionen metallerganlschen Verbidungen mit Stickexydul," Chemische Berichte^ 86 (1953), PP. 1483-1492.

(32) F. Evans and H. S. Fry, "The Reductien Acticn ©f Magne­sium Amalgam up©n Ar©matic Nitr© C©mp©unds," J©urnal ©f the American Chemical Society. 26 (1904), pp. llbl-1171. ~~

(33) I, Antener, "Uber Reduktions-Reaktionen des P-Dlnltro-benzels," Helvetica Chimica Acta. 21 (1938), pp. 812-8L6.

(34) H. J. Backer, "Hydrelyse des Produits obtenus par Substitutien centrale du Tris-Methylsulf©nyl-methane," Recueil des Travaux Chlmique des Pays-Bas.

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71

(35) R. Adams and W. Moje, "Quinone Imides. XIX. Addition of Active Methylene C©mp©unds t© l,4-Naphth©quinone-dibenzenesulf©nimide," J©urnal of the American Chemical Society, 74 (1952), pp. 5557-55^0.

(36) A, Domow and K, J. Fust, "Reduktlonen mit LiAlH4, XI. Uber Eine Hydrierende Spaltung von C-C-Blndungen, Chemische Berichte, 90 (1957), pp. 1774-1780.

(37) H. Felkin, "Dosage iod©metrique de selutions d'hydrure d'aluminium et de lithium," S©ciet6 Chlmique de France, Bulletin (5), I8 (1951), p. 3^7.

(38) Reference (3), pp. 1008-1010,

(39) Distillatien Pr©ducts Industries, Rechester 3, New Y©rk,

(40) R. L. Shriner, R. C. Fusen and D. Y. Curtin, The Sys­tematic Identificatien ©f Organic C©mp©\m?sl ^ J©hn Wiley & Sens, Inc©rp©rated, New y©rk, 1956.-^ p. 226. I

(41) B. M. B©g©sl©vskii and Z. S. Kazuk©va, "Preparatien ©f Symmetrically Substituted Dibrem©-, Dinitroazonaph-thalenes and Souie Dihydr©xynaplithalenes," Journal of General Chemistry, U. S. S. R., 22 (195^11 pp. 1183-1186.

(42) Private c©mmunicati©n, Mr. R. L, Snell.

(43) Schwarzkopf Microanalytical Lab©rat©ry, 56-I9 37th Avenue, W©©dside 77, New Y©rk.

(44) Matheson, C©leman and Bell Division, The Matheson C©mpany, Inc©rp©rated, N©rw©©d, Ohio,

(45) D. A, Lyttle, E. H, Jensen and W, A. Struck, "A Simple Vclumetric Assay f©r S©di\im Bor©hydride," Analyti­cal Chemistry, 24 (1952), pp, 1843-1844, —

(46) Hellbren, Dicti©nary ©f Organic Compounds. Vol, I, Oxford University Press, New Y©rk, 194b, p, 535,

(47) Heilbron, Dicticnary ©f Organic Compounds, Vol, III. p. 17.

(48) Reference (46), p, 965.

(49) L. J. Bellamy, The Infra-red Spectra ©f C©mplex Mole­cules, John Wiley & Sens, inc©rp©rated. Mew Y©rk T 5 5 ^

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(50) K, Ueno, "P©lyaz©benzenes, III. Infrared Abs©rptl©n Spectra of Some P©lyaz©benzenes," Journal ©f the American Chemical Society, 79 (1957), PP. 32o5-3508: