ITEM No. 24FILE No. XXVI-75

COPY No. 5

INSECTICIDES, INSECT REPELLENTS,RODENTICIDES AND FUNGICIDES

1.6. FARBENINDUSTRIE A.G.,ELBERFELD AND LEVERHUSEN

COMBINED INTELLIGENCE OBJECTIVESSUB-COMMITTEE

CONFIDENTIAL

INSECTICIDES, INSECT REPELLENTS, RODENTICIDES AND FUNGICIDES

OFI. G. BWKBENINDÜSTRIB A. G.

ELBERFELD AND LEVERKUSEN, GERMANY

19-30 May 1945

Reported by

Dr. STANLEY A. HALL, Ü.S. CivilianOffice of the Chief Surgeon, Hq.USFET

CIOS Target Nos, 2k/3Medital

COMBINED INTELLIGENCE OBJECTIVES SUB-COMMITTEE0-2 Division, SHAJEF (Rear) APO lp-3

CONFIDENTIAL

CONFIDENTIAL

TABLE OF CONTENTS

Subject Page No»I • INTRODUCTION. .'

. 3II. INSECTICIDES... ........ §

a* *m 1700n| *DDD* or l,l-dichloro-2,2

bis(p-chlorophenyl)-ethane**.•••••••*. 5b* "Mg 1748*, "Gix", "Fluorgesarol" or

1-triehloro-2,2-bix{p-chlorophe nyl)-ethane ****•••••••••••••*••«••••«•.••*. 6

c. *Lauseto-neu* or phenyl chior ome thylsulfone and p-chlorphenylchloro-methyl sulfone. * • « 7

d. Compounds prepared by Dr* Melsershowing insecticidal activity*•....... 9

e* p-chlorophenyl-trichloromethylcarbinol*... ••...««••• 9

f* *Bladan* or hexaethyl ester of tetra-phosphoric acid** •«•.••.•••••••••••••. 10

III. MOSQUITO REPELLENTS. 10a. Testing at Elberfeld. *•*...•*••••••••• 10b. *PTesinol" or "Mipax*................. 11e. Effect of calcium chloride to enhance

repellency. 11d. Simplified *Mipax* formula***...*••••� 12e. Esters of phthalic acid*.* ••«•••• • •••* 12f. "Repellent 50/181* or trichloroace-

tylchlorethylamide* *•••••••••••*•••••* 12g. Impregnation of cloth with repellents 12

Comment on repellent testing.• •*•••••• 13IV. RODENTICIDES* 13

a. "Castrix* or 2-chioro-4-methyl-6-dimethylaminopyridine ••**•*«••«••*..*• 13

b. p-dimethylaminobenzene diazoniumsulfonic acid, sodium salt...**.«***.* 13

V. FUNGICIDES. * . * * 14VI. A COMPOUND FOR TESTING SEED GERMINATION.. 16

a. Triphenyltretrazolium chloride........ 16Appendix 1. "Preparation of l,l-dichloro-2,2-

b i s(p-chlorophenyl)-ethane *•*...*•« 17* 2. "Substances tested against body

lice*. Dr. StBtter.«».. 19* 3. Results of testing repellents and

mosquitocides. Dr. Mudrow.*•*••••.. 24* 4. "Preparation of triphenyltetra-

zolium chloride*.o................. 45

CONFIDENTIALI« INTRODUCTION

The undersigned, an investigator attached to thefifedical Intelligence Branch, Office of the ChiefSurgeon, was ordered to proceed by aircraft, on 19 May1945 to Wiesbaden and thence to Elberfeld (Target 24/l)and Leverkusen (Target 24/3), Germany, for the purposeof investigating plants of the I# G# FarbehiMustrie,A* G# at these two locations# The subjects covered inthis investigation comprise primarily insecticides andmosquito repellents, but also include rodenticides,fungicides and one organic miscellaneous chemical#

On arrival at Elberfeld the undersigned joined ateam composed of Drs# Rice, Kleiderer, and Conquestwho were investigating other phases of the research ofthe I# G# Farbenindustrie# Since much of the researchat the Elberfeld and Leverkusen Laboratories has beenclosely interlocking, the results of investigations ofthese two places have been combined and are presentedin this single report#

The German scientists at the I# G# Farbenindustriehave had an active interest in the field of insecti-cides and insect-repellents, but have carried outresearch on a considerably smaller seals than we havein the United States# In general, it can be said thatthe German advances are behind our own in this field#

It is especially difficult to evaluate the resultsof their entomological testing since it has beencarried out, for the most part, in a rather haphazardfashion, not at all conducive to drawing reliableconclusions#

It is, therefore, difficult to evaluate their claimsshort of subjecting them to our own experimental tests#This applies to some of their chemical as well as to allof their entomological work# They claim, for example,that the insecticide which we-know as DDD (their desig-nation, MS 1700) or l«l-dichloro-2,2-bls(p-chloro-phenyl>-ethane can be produced, in good yield fromethanol, chlorine and chlorobenzene by the Bayer Con-densation without the formation of any DDT in the reac-tion# If our own experiments should confirm this,

CONFIDENTIAL

then this information would be of value to us, sincewe already know that DDD is as effective as a larvi-cide. as DDT and presumably the DDD could be producedby this method more cheaply and not subject to theGeigy patent*

The German claims as to the superior insectici-dal action of their MS 1748 ("Gix" or "Fluorgesarol")l-trichloro-2,E-bix(p-fluorophenyl)-ethane, in com-parison to DDT, are not clearly supported by theirmeager and inadequate tests against houseflies* More-over, the Germans who tested it differ sharply amongthemselves as to their conclusions*

Likewise, the German claims of a superior insec-ticide against body lice and bedbugs called "Lauseto-neu" (a mixture of phenyl-chloromethyl sulfone andp-chlorophenyl chloromethyl sulfone) must be treatedwith skepticism until confirmed by sound testingmethods*

Their testing of mosquito repellents was especiallypoor and inadequate*

It may prove that their repellent designated as50/181 or trichloroacetylchlorethylamide will holdsome value for us; but, in general, the Germans havelagged far behind us in the development of mosquitorepellents*

"Bladan" or the hexaethyl ester of tetraphosphoripacid is an insecticide claimed to be an excellent sub-stitute for nicotine for use against aphids*

Two organic fungicides were turned up which mayhave some value to us#

Two new organic rodenticides were uncovered whichmay prove of value*

Finally, a new non-toxic organic compound fortesting the germination of seeds was uncovered* Thismay be of use to seed specialists#

CONFIDENTIAL

II* INSECTICIDES1# MS 1700.

a* At Elberfeld»

l,l-Dichloro-8 ,2-bix(p-chlorophenyl) -ethane ,

known as M DDD" in the United States and designated asMS 1700 at Elberfeld, was prepared by Dr# Meiser# Ofthe DDT analogs (approximately 50) made by Meiser, thebest from the standpoint of both cost and insecticidalactivity as MB 1700 or DDD# That its insecticidalproperties approach those of DDT against certain in-sects is not new since the Bureau of Entomology andPlant Quarantine of the ü# S# Department of Agriculturehas reported similar findings# Only one other analogof DDT prepared by Dr# Meiser, namely, l-trichloro-2,2-bix(p-fluorophenyl)-ethane or «Gix" possesses theactivity of DDT# DDD or MB 1700 is less toxic to warm?*blooded animals than DDT according to a statement madeby Dr# SchOnhöfer.

Dr# Meiser prepared DDD by passing chlorineinto ethanol (96$) at a reaction temperature of 25-30°C# The products formed are CloGHCHtOCoHR)©,ClgCHCHCllOCgHs), and a small amount of ClgCHGHlOHig#No chloral or chloral acetal is formed at this reac-tion temperature# The mixture of products from thechlorination of the alcohol is condensed directly,without further isolation, with chlorobenzene usingoleum (Sp#G# T#900 to 1#915) at 0 to 5°C# A goodyield of DDD is obtained containing about 80$ of thep,p f compound and about 17$ of the o,p* compound whichis quite analagous to the isomers obtained from theBayer Condensation with chloral in commercial DDTmanufacture# (See Appendix !•)•

Both Dr# Meiser and Dr# Sehönhöfer have statedunequivocally that not a trace of chloral is formedwhen the first step of the reaction is carried out atthe temperatures described# Hence no DDT is formed inthe Bayer Condensation# If this statement is true,then the insecticide DDD would not be subject to theGeigy patent, and should also be simpler and cheaperto manufacture than DDT#

CONFIDENTIAL'■ ■ 1

b« At Leverkusen»

This compound (DDD or MS 1700) was not pro-duced at Leverkusen according to Dr* Rösch« Dr«Meiser at Elberfeld prepared it, but it was testedat Leverkusen« Dr« Bonrath at Leverkusen tested itagainst several species of caterpillars (Lepidoptera)and found it almost as affective as DDT« Againsthouseflies, mosquitoes (adults) and certain speciesof beetles it was as effective as DDT« Fed to ratsand to cats. Dr« Bonrath found it no more toxic thanDDT which he considers "non-toxic to warm-bloodedanimals

On the other hand, Dr« Stötter and Dr«Laiboch tested this compound against moths, bodylice and bedbugs in comparison with DDT and foundDDD not sufficiently effective to warrant their fur-ther interest in it«

2« MB 1748

a« At Elberfeld«

1-trichloro-2,2-bix(p-fluorophenyl)-ethane,known as Fluorgesarol or "Gii" which is a liquid atroom temperature, has been produced at Höchst« Thefluorobenzene is obtained by diazotization of anilinein liquid HF« The insecticide is considerably morecostly to produce than DDT« Dr« Meiser first pre-pared "Gix" in the laboratory, and Dr« Schönhöferclaims that it possesses a more rapid knock-downagainst flies than does DDT«

b« At Leverkusen«w Gixn or Fluorgesarol was tested by Dr*

Bonrath against houseflies« He impregnated filterpaper with 0*5$ "Gix" in acetone and placed the driedpapers in dishes# Flies confined over the dishes weredown after 30 minutes« He obtained the same resultswith DDT and found no essential difference betweenthe action of "Gix" and of DDT against houseflies*Questioned as to why he did not use a Peet-Gradychamber with sub-lethal sprays of "Gix" and of DDT,he replied that these compounds are foot-poisons,(Fussgifte) and should not be used as fly-sprays«

CONFIDENTIAL

Drs* Rttsoh, Stötter, and Laibooh did not agreewith Dr* Bonrath f s conclusion that "Gix" is no betterthan DDT against houseflies* They said that n Gix" isfaster-acting than DDT against flies* Dr* Laiboch, inrunning comparative tests, used a ventilated woodenbox 20 x 25 cm square (inside dimensions]* Sheets ofwhite paper 20 x 25 cm were impregnated with 2$, 1%and of the substance to be tested* This impregnatedpaper was placed on the wall opposite to the window inthe box» Twenty houseflies (2-3 weeks old, males andfemales) were introduced» The light shining on thepaper through the window attracted all flies to walkon the paper* The flies were observed after 3 hoursand counted:

The above is a typical run# quite a numberof such tests were made# From this type of testingit is difficult to see how one can conclude that "Gix”is superior to DDT# The compounds were not tried assprays in a Peet-Grady chamber#

3* Lauseto-neu»

a* At Elberfeld,

This product, p-Cl-CßBii-SOgOBoCl, made atLeverkusen is described by Dr* Schönhöfer as limitedin its action to moths, mosquitoes and lice: but noteffective against many insects including flies« Dr»SchOnhSfer also stated that the chlorine in the ben»•zene ring is not essential for insecticidal activity,i*e*, is just as effective*

b* At Leverkusen»Phenylchlqromsthyl sulfone, CgEgSOgCEgCl, as

well as p-chlorophenyl-chloromethyl suifone,P-CI-G5B4SO2GB2CI* are loosely termed «Lauseto-neu»*

Gix DDT Gix""il)T Gll^DT Number of Flies17 5 9 � • 4 1 •• * Down

• • • • � • • • • * • i • 3 Badly effected3 9 10 11 6 11 Affected

• 6 1 9 13 6 Slightly affected

CONFIDENTIAL

Prof# Bayer described its preparation asfollows:

Ma2s°|» p-Cl-C6H4-S0 2Na 75-80%Yield

ClpCHOOOMey (p-Cl-C 6H4-SOgCHClCOONa) Not isolated

Acidified C02 � p-Cl-C6H4-S02CH2Cl 75% fieldand heated'

Dr# StOtter has tested both the p-chlorophenylsulfone and the phenyl sulfone against body lice andagainst bedbugs# He used pieces of bloth (in Petriedishes) treated with a powder containing 0#3$ end also1$ of active ingredient# Twenty insects were placedupon each piece of bloth and observed at definite tineintervals under varying conditions to count the licethat were (l) unaffected, (2) slightly affected, (3)affected, (4) badly affected, and (5} dead# Comparedin this manner to DDT, Dr# StOtter coneluded thatp-chlorophenylchloromethyl sulfone is 4 to 5 timesmore effective* The tests against bedbugs were runin much the same manner* Dr* StOtter stated that,while both the p-chlorophenyl sulfone and the phenylsulfone were both much more effective than DDT againstbedbugs, he found the phenyl sulfone better than thep-chlorophenyl sulfone against bedbugs* The reversewas found against body lice, i*e#, the p-chlorophenylsulfone was superior* (See Appendix 2)#

Dr* Bonrath, who ran tests independently ofDr# StOtter against bedbugs (but not against bodylice) stated that he found both thesulfone and the phenyl sulfone about equally effec**tive against bedbugs but definitely superior to DDT#Dr* Bonrath found both sulfones ineffective againstcaterpillars (4 species of Lepidoptera), beetles andhouseflies#

Dr* Rttoofc stated that the sulfones (Lauset o«*neu) were used successfully against body lice andbedbugs in concentration camps# Tablets containing44$ of active ingredient compounded with bentoniteand wetting agent were manufactured for making wateremulsions of the preparation# Trichloroethylene hasbeen found the best solvent for the sulfones*

CONFIDENTIAL

4« Compounds Prepared by Dr« Melser ShowingInsecticidal Activity«

a. At Elberfeld.U) ä-ä ME 1491 where R-CH3-

JWfcO““ 1517 " BaC2H5-

R MS 1565 " • H= (CH3 ) 2CH-

The above 3 compounds are described asfairly good stomach poisons, but are also toxic towarm-blooded animals« Higher homologs above isopropylshowed a rapid decrease In insecticidal activity«

(2) . . ME 1503 where R=CH 3-

ME 1504 - HrCaHs-The above 2 compounds are described as

stomach poisons not so toxic to warm-blooded animalsas the diphenyl analogs«

(3) MB 1548 where RrCgHg-\=S \ Me 1549 " RaCH 3-

The above 2 compounds are also stomachpoisons« No data given on their toxicity to warm-blooded animals«

(4) p-C1“C 6E4CH0ECC13 Me 1664

The above compound is wall known to us«Dr« Melser stated that It has been found rather effec-tive against flies«

b« At Leverkusen

p-Chlorophenyl-trichloromethyl carbinol(MS 1664) was tasted by Br« Bonrath who stated that Ithad no action against houseflies, but was effectiveonly against adult mosquitoes« This Is a flat contra*diction of Dr« Melser Y s statement that It was effec*tive against houseflies«

CONFIDENTIAL

5» "Bladan*

a* At Elberfeld»

Hexaethvl ester of tetraphosphorio acid#((CgHgOjgPÖbKi, tnown as was first preparedby Dr. Schrader#

b, At Leverkusen,

Dr, Podschus made it on a larger scale:

POCl 3 � 3 (C 2H5 ) 3P0 4 140°t hour

3 C2H5CI 4 ( (CoHgO) gPO Yield almostquantitative.

It is a high-boiling liquid which does notdistil without decomposition at atmos, press. Thereaction product is used as an insecticide withoutany further purification.

It is bottled as 60$ active ingredient plus80$ toluene plus 20$ wetting agent. This concentrateis stirred into water (1 part in 1000 by vol,) givingah emulsion containing 0,06$ active ester. The esteris almost completely hydrolyzed on standing in thewater emulsion for 24 hours. Hence, the emulsion mustbe made up Just before it is to be used as a spray.Dr, Bonrath claims that it is extremely effectiveagainst plant lice (aphids), and acts so rapidly thatthe subsequent hydrolysis to non-toxic phosphoric acidand alcohol is a definite advantage. No foliage injuryhas been found at concentrations up to 0,2$« Accordingto Dr, Bonrath it is an excellent substitute for nico-tine preparations against aphids.

Ill# MOSQUITO HEIELLSISTS

1# Testing Repellents at Elberfeld#a« Comparatively, little work has been done

at Elberfeld in the field of mosquito repellents#What work has been done is not especially new nor wasthe testing done in a way to give reliable results#

CONFIDENTIALApproximately 50 substances and mixtures (mostly)mixtures) were tested by Dr* Mudrow against Aedesae&ypti and Culex fatigans* The latter species oftencould not be" Induced to bite the untreated arm of thesubject«

b * "Presinol* or "Mipax" •

This concoction contains the followingingredients:

100 g Cinnamyl alcohol 106 g Water894 g Ethanol (96$) 1 g Melissen Oil60 g« Calcium chloride (90-93$) £ g Geraniol40 g« Magnesium chlorideThe essential oils in this mixture, according to Dr*Dörr* who concocted it* are not necessary»

o* Effect of Calcium Chloride to EnhanceRepellency*

Dr* Dörr stressed the action of calciumchloride in extending the repellent time of substancespossessing repellency such as cinnamyl alcohol,coumarin, esters of phthalic acid, etc* None of theapproximately 30 pure compounds that were tested arenew to us, i*e*, they have also been tested by theBureau of Entomology and Plant quarantine, U* 3* Dept*of Agriculture who also tested the addition of CaClgto repellent mixtures and found it of small value*Dr* Dörr emphasized that the addition of CaClg has adefinite effect in extending repellency although Dr*Mudrow 1 b testing data were somewhat stager to supporthis assertion* Dr* Dörr, when questioned about theMgClg in the "Mipax" formula, seemed to think that itwas not particularly necessary but that someonethought it had an astringent effect on the skin*Without CaClg in the formula, "Mipax” or "Presinol"was found not very effective* With CaClg in theformula, the repellent gave 3 to 5 hours protectionagainst Aedes aegypti in a cage test when the arm ofthe subject had Seen saturated with repellent appliedwith a sponge and the test started one hour afterapplication*

CONFIDENTIAL

Illustrative of the effect of CaClg in arepellent mixture, the following data were obtained asthe result of only a few tests;

10 g Cinnamyl alcohol90 g Ethanol (96$) 3 hours

10 g Cinnamyl alcohol90 g Ethanol (96$) 9 hours10 g CaClgd* "Simplified Mipax"

A simplified "Mipax" recipe which is just aseffective as the more elaborate one was given by Dr*Dörr as follows;

100 g Ginnamyl alcohol60 g Calcium chloride

900 g Ethanol (96$)100 g Water

e* Esters of Phthalic Acid*

Dr* Mudrow, who conducted the repellent testsfound that diethyl phthalate as well as dimethylphthalate as alcoholic solutions protected againstAedes aegypti for approximately the same length oftime, i*e*, about 2- to 3 hours* Dibutyl phthalatewas found to give no protection*

f* Repellent 50/181** Trichloroacetylchlorethylamide,

ClgCGONHCHgGHgCl, was made at Leverkusen by Dr*Schweitzer* Dr* Mudrow at Elberfeld used a 7*5$alcoholic solution of this compound, and in a fewtests it protected for about 7 hours* Dr* Mudrowstated that* at the concentration used, it was not atall irritating to the skin*

g* Impregnation of Cloth with Repellents»

Rayon sleeves were Impregnated with variousrepellents in alcoholic solution* The longest protec-tion time obtained was about two weeks , which is con-siderably inferior to results obtained in the U*S«JL*

CONFIDENTIAL

2* Comment on Repellent Testing At Elberfeld* .

The repellent values obtained must be ratherdrastically discounted because the small cages housingthe mosquitoes were not designed to allow sufficientventilation, especially when volatile and odorous sub-stances were used on the arm» No attempt was made toascertain the biting-rate of the mosquitoes at anytime on the untreated arm# Moreover, insufficientmosquitoes and test subjects were used» (See Appendix.3)*

IV* RODSNTICIDSS

1# "Cestrix*

a* At Elberfeld

"Castrix" or 2-chloro-4-methyl-6-dimethyl-aminopyrimidine f is a rodent leide claimed by Dr*Schönhöfer to be approximately l/4 as toxic to rateas Strychnine* Dr* Westphal prepared it as follows:

CO(NH}g 4 CEaCOOHgCOOSt

InactiveIsomer2.0% Yield

ActiveIscoer"Castrix"60% Yield

2* p-lGH3 ) 2N-C6H4-NsN-S03Ha

a* At Biberfeld*

This rodenticide* prepared by Dr« Schönhöfer

CONFIDENTIALis easily made by treating the diazonium salt fromprdimethylaminoaniline with NaHSOg# This compoundis not as toxic to rats as "Castrix" but it killsquickly and does not make the rats ferocious beforedeath as does "Castrix"# Either compound, accordingto Dr* Schönhöfer, when mixed with grain, is readilyeaten by rats* *Castrixw has been used at 0*1$ con-centration in grain*

3• Comparison of 2 Rodenticides*a* At Leverkusen#

•

Dr* Bonrath found "Castrix" more affectiveagainst mice; it is not quite as toiic against rats#The main objection to "Castrix" is its toxicity tohigher animals* However, it has been found non-toxicto chickens, and other fowl at the concentration used#Grain is impregnated with 0*1# in water solution#The diazo compound is used at a higher concentration,namely, 0#6$ and is better against rats* It is alsotoxic to larger animals and has not been testedagainst fowl#

No attempts were made to determine the LD/50of either compound# Dr# Bonrath stated, however, thatapproximately 60 mg/kilo of the diazo compound waslethal for mice, rats and cats# For "Gastrix" hereckoned that approximately 6 mg/kilo was the lethaldose#

V* FUNGICIDES

L. P 1258

a# At Elberfeld»

Dr* Pöhls made a series of compounds all con-taining the structure•

:iU ■

This structure! he claims, is essential to fungicidalactivity* The meta and para position isomers werefound inactive# The best compound of about 20 in thisseries is:

CONFIDENTIAL

Dr» Pöhla prepared It as follows:

Quant» YieldM*P» -620

B»P. S5*170-172OInsol» ln water

The compound was tested in the laboratory againstPenicilllum« Goniphora and Fusicladium« In fieldtests it did not workas well» Although the com-pound can cause skin irritation it is described asotherwise harmless to humans and it causes nofoliage injury»

2» 5-ohloro-4-hydroxyphenyl-dlazosulfonlc acid.Sodium Salt«

a» At Leverkusen»This compound was made by Dr» Urbschat and

tested by Dr» Bonrath» Against a fungus disease ofoats (Flugbrand) end against Fusarium nivale on rye,it has been found completely effective as a seed dis-infectant» The seeds are soaked in a 0»1$ water solu-tion of the compound for 30 minutes»

CONFIDENTIAL

Yl. A COMPOUND FOR TESTING THE GERMINATION OF SS3DS»

1# "Tetrazolium Salt”

a« At Biberfeld»

"Tatrazolium Salt" c n n-h~c6h5Cl

or triphenyltetrazolium chloride is a compound pre-pared by Dr* Lauchs as follows:

CgHgCHO «• C6H5MH2 C6H50»N-HH-C6H5 83$ Yield

80$ Yield

67-68$ Yield

The compound is colorless. Seeds that will germinateare colored red. (See Appendix 4) »

b. At Leverkusen®

The compound is used as a 1 to 2$ watersolution« Cereal seeds (wheat, oats, corn, rye,barley, etc«) are soaked in the solution for 6 to 8hours except in the case of oats which require S4hours« The embryos of the seeds that will germinateturn red. Its chief advantage over the use of sodiumselenide reagent in a germination assay is the non-toxicity of the tetrazolium salt«

APPENDIX 1Preparation of l»l-Di-chlorphenyl-2*2-dlchlorÖthan

I# Chlorierung des Xthylalkohols*Jn 1000 ccm denat* Alkohol wird unter anfänglicher

Kühlung mit Leitungswasser Chlor eingeleitet derart, dassdie Temperatur nicht höher als 30° ansteigt; beste Reak-tionstemperatur: 25-300# pi© zunächst klare Lösung trenntsich allmählich in zwei Schichten; es entsteht eine untereSchicht, die allmihlioh an Volumen zunimmt auf Kosten derzunöchst grossen oberen Schicht* Man leitet so lange Chlorein, bis die obere Schicht nicht weiter abnimmt, was nach4 1/2-tÄgigem Einleiten von insgesamt 3360 g Chlor eintritt#Die untere Schicht, die im wesentlichen aus einem Gemischvon TrichlorSther9 Dichloracetal und wenig Dichlorace-taldehydhydrat besteht (vergl* A# 279,2941, wird alsdannabgatrennt und ohne weitere Nachbehandlung direkt zurKondensation eingesetzt; die obere Schicht besteht imwesentlichen aus wössriger Salzsaure* Man erhört:

untere Schicht; 985 ccm; d z 1,330; mithin s 1310 gobere Schicht ; 250 ccm; d m 1,255#

Bei zwei in gleicher Weise mit je 5 Ltr# Alkohol durch-geführten Versuchen wurden folgend© Ergebnisse erhalten:

II* Kondensation*

Zu 200 ccm conc# Schwefelsäure wird unter Kühlung beieiner Temperatur von 0 bis 5° ein Gemisch von 200 gr# Chlor-benzol und 160 gr# chlorierter Alkohol (d-1,315; bei 30°chloriert) allmählich zugetropft unter stetem kräftigemRöhren* Danach-werden bei der gleichen Temperatur allmäh-lich 200 ccm Oleum (d-1,900 bis 1,915) tropfenweiseeingetragen# Danach wird ohne die Kühlung zu erneuernweiter geröhrt, sodass die Mischung sich allmählich wiederauf Zimmertemperatur erwärmt# Es wird mindestens 12Stunden nachgeröhrt* Danach trögt man den ganzen Ansatzauf Bis aus, dekantiert die wössrige Schwefelsöure von demkrümelig abgeschiedenen Reaktionsprodukt und wöscht diesesalsdann söurefrei durch 5 bis 6 maliges Dekantieren mitWasser* Nach der Neutralisation der letzten Schwefel-söurereste mit Natriumacetat wird zur Entfernung nicht

untere Schicht d ; obere Schicht d

a) 4500 ccm 1,330 : '1550 ccm 1,8X0b) 5040 ccm 1,335 ; 1375 com 1,252

umgesetzten Chlorbenzols eine Stunde mit Wasserdampf destill-iert, eventuell erneut aufgetretene Mineralsäure noch heissmit Hatriumacetat neutralisiert und alsdann unter kräftigemHShren erkalten gelassen# Das zu kleinen kugeligen Aggre-gaten erstarrte Produkt wird alsdann abgesaugt mit etwasWasser gewaschen und an der Luft getrocknet#

Ausbeute: 240 bis 245 gr#Analyse: p-Verbindung 79,0$

o-Verbindung 17,3$mithin wirks# Subst# 96,3$Paradichloraldehyd; 0,7$Wasser : 3,0$

I# G« FARBENINDÜSTRIE AKTISNGBSSLL-SCHAFT Werk Elberfeld

APPENDIX 2

Substances Tested against Body Lice: Dr» Stötter

In den Tabellen sind die Eigenschaften von verschiedenenPräparaten, die sich gegen Kleiderläuse als besonders Wirksamerwiesen haben, in Bezug auf Wirkung und bei den besten inFrage kommenden Typen auf Dauer der Wirkung dargestellt*

Was in den Tabellen für Puderwirkung gezeigt wird, gilt ingleicher Weise bei Prüfung der Wirkstoffe angewandt inorganischen Lösungsmitteln nach Art der chemischen Wäscheund auch bei Anwendung der Wirkstoffe aus Wasser, sei esals Emulsion oder als Dispersion*

In jeder der Anwendungsweise ergab sieh die Überlegenheitdes Chlorphenylchlormethylsulfon gegenüber den Vergleichs-produkten unter gleichen Versuchsbedingungen*

5 Beilagen

Die Bewertung in den Tabellen ist:schwarz s Versuchstiere ungeschfidigt s

blau s « leicht krank s

grün B krank

gelb S» schwerkrank = 11

rot s « tot s ■

Puderversuohe gegen KleiderläusePrufungsergebnis bei Einwirkungsdauer von:

Blindversuoh; Talkum - Kreide /2;I1 Std.2 "

3 "

6 tt

18 “

Puder von Dich!ordlphenyltri-eb!ormethylmethan (Gesarol)

X Std.2 ■

3 "

6 "

18 "

Puder von 4 Ghloiphenyltrichlor-methyl-Caibinol

X Std.2 "

3 "

6 11

18 "

Puder von Pentachl oräthyIbens ol(Lucex)

1 Std.2 H

3 «

6 "

18 "

3$iger Puder von Butyroanisol

1 Std.2 "

3 H

6 "

lö "

Puder von Trichloracetylchloräthyl-aroid (50/181)

1 Std.2 11

3 "

6 ”

18 “

0. jfeger Puder von 2f~Chlorphenylchlor-methylsulfon (Lauseto-neu)

1 Std.2 "

3 "

6 "

18 «

Puderbasis; 2 Teile Talkum, 1 Teil Kreide.Versuchsanordnung; je 20 Versuchstiere in

Petrischalen auf Stoffproben, auf diegleiche Mengen Puder dünn aufgetragen

■waren.

Prüfung gegen Kleiderläuse.(Belüftungsversuchy

ttDie eingepuderten Proben wurden vor der Prüfung gegen Klei-derläuse einen, zwei, vier und acht Tage belüftet und dann5m üblichen 18 Std.-Versuch geprüft.

i$iger Puder aus 4*4* DiohlordL-richlomethyImethan

■belüftet:1 Ta2 "

4 M

8 "

4&Lger Puder aus Pentachl orathyl-benzol

1 "

2 “

4 “

8 "

Puder aus 4-öhlorphenQrl-ohlomethylsulfon.

1 «

2 “

4 w

8 n

Die Versuche wurden wie stets unter ganz gleichenBedingungen mit gewichtsn&ssig gleichen Pudemengenausgefuhrt.

Prüfung gegen Kleiderläuse.Vergleich von Pentachlorathylbenaol, 4,4*triohl omethylmethan und 4~Ghlorphenylclilormeth^lsulfon

bei zeitlich beschrankter Einwirkungsdauer*I* l$> iger Puder von Pentachlorathylbenzol

Zustand der Larven;direkt nach Pudeiberuhr, nach 24 Stdn. nach 48 Std.

Pudeifoerubjunp;; (top to bottom) 1, 4, 30 Minuten;1« 3? 4, 6 Stunden«

II. Puder von 4>4 f Diehlordiphenyltfi-"aBomethylmethon

Pudeiberuhrung: (top to bottom) 1, 4> 30 Minuten;1» 3f 4» Stunden.

III« ffiiger Puder von 4-02x1orphei^ylchlor-methylsulfon

Pudeiberuhrung; (top to bottom) 1, 4» 30 Minuten;I, 3, 4* 6 Stunden*

Die Versuchstiere wurden 1 - 4 - 30 Minuten, 1 - 3 - 4 - 6Stunden auf eingepuderten Stoffproben gehalten und dannabgenommen und ihr Zustand -sofort, nach 24 Stunden und nach48 Stunden beobachtet. p*

_

APPENDIX 3

Insecticides and Repellents Produced and Tested by I. G.Farbehindustrie » Leverkusen#

Note: It should be noted that the "Pb” numbers representthe number assigned to a test specimen and not necessarilya new and different substance« New substances aredesignated by other letters and/or numbers* This shouldbe borne in mind when reading the correspondence*

H. Horlein

I* Lists of Preparations Tested

A* Anti-mosquito preparations from Leverkusen, relatedto Gesarol, that were tested in Wuppertal-Slberfeld.

Pb 460 r Lauseto (Gesarol) was effective for 122 months inthe contact experiment (2); after that time,testing was discontinued®

Pb 461462463 See correspondence of 17 Feb. end 3 April 1944»464465 Formulas in part in latdr correspondence466

Pb 544545 See correspondence of 24 April and 19 May 1944546

Pb 637638639640641642643 See correspondence of 15 June, 26 July, 10 Aug.

* 644 1944645646647 Formulas in Section II648649650651652

B* Other Mosquito-preparationsPb 756

757

Pb 758759 See correspondence of 24 Aug« and 83 Oct» 1944760761 Formulas also to be found there762763764

Pb 805806807808809 See correspondence of 5 Sept* 1944 and 10 Jan# 1945810811 Formulas also to be found there812813814 '

815816

II« Testing Methods » Correspondence, and Reports of Tests

A« Testing of the Anti-Mosquito Preparations

1« Repellent effect* Designation of experiment M&»a» On bare skin (arm)»b» On cloth drawn over the arm (stocking-

knitting)•2» Mosquitoci (contact effect, corresponding

to that of Gesarol)« Designation of experiment Ge«a» The uncovered arm of the experimental persons

is rubbed with the liquid (i»e* dissolved in a solvent)preparation; after on© hour the first test is made in themosquito cage* If an effect is found, the tests arecontinued hourly, 7-8 hrs« in all« The substance usedfor comparison is Mipax (Presinol) vfoich has a standardeffect of 3 - 5 hrs» The mosquitoes are in gauze-coveredwire cages of a base of approx» 30 x 40 cm and a heightof 30 cm« A full cage contains about 300 mosquitoes(males and females in about equal proportions)• Thepreparation is considered as having effect if within a5 min» period of exposure no mosquito bites» If, up to4 mosquitoes bitewithin the 5 min» period, this isconsidered a trace effect; if more than 5 mosquitoes bitewithin 5 minutes or even a shorter period, the preparationis designated as ineffective» The "landing" of themosquitoes without biting is not counted in the evaluation«

b» The cloth test is performed in the same manner«In certain instances the effect was examined also immediatelyafter the saturation of the cloth with the preparation«

o* In the test for aosquitocide effect of theGesarol type, 10 mosquitoes are placed in cages whosemuslin walls have been saturated with the substance inquestion* An hourly record ins kept of the behavior ofthe mosquitoes* The cages consist of a cube shaped wireframe whose sides are 10 cm long; they are covered withremovable muslin tubes* These muslin tubes are soakedwith the substance to be tested which is dissolved inether, acetone, or a similar solvent, and then they aredried in air* The first test takes place the followingmorning, about 16 hours after the muslin tubes weretreated* If the preparation possesses a mosquitocideeffect, it.is examined again after 14 days, 1 month,and later, as long as the efficacy lasts* The cagesare stored away in the meantime, without renewed treatmentof the muslin*

Evaluation of the efficacy:W m Wirkung (effect)(80-100$ of the mosquitoes in the

cages are dead)*Sp«W* • Spur Wirkung (Trace Effect) (40-70$ of the

mosquitoes in the cages are dead; the others maybe injured)«

g*Sp*W* s geringe Spur Wirkung (Slight Trace Effect)(20-30$ of the mosquitoes are dead, while theothers may display injuries)*

B* Correspondence and Reports of Tests

Chemotherapeutic LaboratoryTO; Dr* We gier, Leverkusen, Wissenschaft Hohes

Hauptlaboratorium (Principal ScientificLaboratory)•

Prof* Md*/F* 10 Jan*1945Anti-mosQulto substances*

Since our investigation of the substances whichyou sent with a letter of 5 Sept* 1944 for testing inregard to their anti-mosquito effect, have reached acertain finishing point, and since at present due to thelack of insect material we are able to perform only alimited number of tests, I should like to present to youthe results obtained until now* This is most simplyaccomplished by means of a tabulated survey chart, fromwhich you are able to read off the efficacy or lack thereofof the individual compounds with the various testingmethods* The preparations which you numbered 1-12received with us, in continuous numbering, the designationsPB 805-816*

In the tests for the mosquito repellent qualitythe undiluted solutions were used* in testing in contactexperiments, on the other hand, the substances were diluted

for reasons of economy to their three-fold amount bymeans of acetone: the mosquito cages were thus impregnatedwith a solution. After drying, the mosquitoes wereplaced in the cages only 16 hrs# later, and the effectwas then tested hourly for 8 or 9 hrs. If the limit ofthe efficacy of a substance is not reached by this point,the investigations of the contact effect are then contin-ued even beyond this point«

The long duration of the tests is explained inpart by the necessity of repetitions when the results werenot clear, and in part also by a high mortality rate inthe mosquito cages after tests for the repellent effect«Those mosquitoes vfoioh did not bite, but which at timesflew against the arm of the experimental persons, alsocome into contact with the preparation and die becauseof the contact effect, so that the mosquitoes in the testcages had to be replenished much more frequently from ournone-too-extensive mosquito cultures than in the case ofpreparations without this effect«

Since Director Dr« Schönhöfer of the Scientific-Chemical Laboratory here is also participating in thetesting of anti-mosquito substances, I should like to askyou to send him also copies of your letters#

Chemotherapeutic Laboratory/s/ Dr, Mudrow

TableI:

Testsperformedon

thearmsof

experimentalpersonsin

regardto

mosquitorepellenteffect*I»G»

Wuppertal-Elberfelöl

Chemo�-Labor*

After •

•

• hoursPb805Pb806Pb807Pb808Pb809Pb810Pb811

813

Pb812Pb814 815Pb816

1i

Sp00WWW

Sp0WWWWWWWWWSpW0

SpV

0SpSp00

Sp0

2

W

WSpSpSp

Sp

3p00W

SpSpWWWW

0

WSpSpSp

Sp

3

Sp

W000

00

sp0spwarwSp

V000

0

4

0

0

Sp0

WWW0

w

5

0

Sp0

0

6

Spw

•

7

0

Sp

W•*

Wirkung(Effect);

nomosquito

biteswithini3

min#

Sps»Spurwirkung

(Traceeffect);upto4

mosquitoesbit©within5min.

0/aNoeffect;

morethan5

mosquitoesbitewithin5min#or

less#

I. G. Tüfappertal-SlberfeldChemo .-Labor.

To the Coloristic Dept*, Attn: Dr. Drapal, Leverkusen*

Dr*Dr*/G* 29 Sept* 44: Dr*Md*/B* 20 Sept* X944

Anti-mosquito substance Schweitzer 50/181»Preparation Schweitzer 50/181* heated in a reflux

condenser, was examined several times by means of themosquito tests, in which with various experimental per-sons it displayed a period of efficacy of 3 to 7 hours*Thus in comparison to the fresh preparation it showed nodecrease of effect, since in biological tests one mustalways calculate with certain fluctuations*

The testing of the 9 solutions which you sent withyour letter of 24 Aug* has been possible only on 9 days,and I should like to repeat the tests before sending youmy findings*

Chemotherapeutic Laboratory

/s/ Dr. Mudrow

I» G* LeverkusenPrincipal Scientific Lab*

To: Dr* Mudrow

I* G. Werk Hf«-Elberfeld Dr. Wg/0e* 5 St».* 1944

He: I am glad to accept your kind offer, made recentlyvia long-distance telephone call, of examining some furthersubstances for their effect against mosquitoes, and I amsending you a number of compounds for testing* The majorityof these compounds belongs to the Benzyl alcohol series* ofwhich you have already examined 3,4-dichiorbenzyl alcoholwhich you found quite effective.

1* (Pb 805) benzyl alcohol (omit this if you have alreadytested it),

2* (Pb 806) 4-methozybenzyl alcohol,3* (Pb 807) 4-isoprobylbenzyl alcohol (smelling substance),4* (Pb 808) F 97 n dimethylbenzyl alcohol,5* (Pb 809) F 141 - ethylbenzyl alcohol,6* (Pb 810) F 163 = menaphtyl alcohol.

7* (Fb 811) phenozyethanol,8* (Fb 812) F 146 m benzylacetoacetic ester,9* (Fb 813) F 160 & di(p-ohlorbenzyl)-acetoacetic ester,10* (Fb 814] F 163 s 3*4-dichlorbenzylacetoacetic ester,11* (Fb 815) F 167 - 0

HO p'a:>CC13

18. (Pb 816) J 168 s 0«

-<x}>cci3

all products are solutions in acetone or methanol.Regler,

I« G« Whppertal-ElberfeldChemo«-Labor*

Coloristic Department, attn, Dr. Drapal, Leverkusen#

Dr«Dra#/F# 24«Aug. 1944 Letter No« 8488 Dr«Md«/B 23 Oct#1944Test for mosquito-repellent effect:

As the result of difficulties in the breeding ofmosquitoes it was not possible for me to undertake theintended 2nd repetition test of all preparations you sentus in August* So that you will have to wait no longer. Iwish to send you today the results obtained on the variousdays of the first tests* The solutions were applied tothe arms of the experimental persons* In the 2nd mosquitoexperiment the test of the 5th hour had to be omittedbecause of air-raid alarm*

Pb 765-M/29 1.)8.) 3&W.4-8& Sp.W.

Pb 757-11/30 1,1 3bW,4hp8.)

Pb 758-H/31 1,18.) 3&ir,4b0

Fb 761-M/34 1.) ltW.2hSp,W.S~ep9.7*Sp»V2.) 6*1». 7h0

Fb 762-M/35 1.) 1&02.) lhsp.«,2h0•3.) lMFb 763-M/36 1.) 1&0

Pb 759-M/32 1.)2.J 3hW.4hSp.W.6

Fb 760-M/33 1*) 4&W.5&jj2.)

2.) lhSp.W.2-3*iW.4h3p.W.6h03e ) l£0

Pb 764-M/37 1.) 2hW#3hSp<

W.4^jÖ2«) 6hW.7hSp.W*

The findings show that preparations Pb 762 and 763 are une-quivocally the poorest: however, in regard to the bettereffect it is more difficult to make gradations* Neverthelessit appears that none of the preparations is effective enoughto warrant testing in a higher dilution*

The above-mentioned difficulties in our mosquito»breeding wore largely caused by the testing of thesepreparations* The repellent effect frequently becomesapparent in the fact that the mosquitoes fly against thearm of the test person but do not bite* In flying againstthe arm they come into contact with the preparation andsooner or later they come victim to its killing effect*In any case, after such a mosquito test we always observedan especially high mortality rate in our mosquito cages*In order to convince ourselves of the mosquitocide effectof the substance tested, another test was conducted on theorder of a Gesarol test (insertion of 10 mosquitoes intocages impregnated with the substance» hourly observationsof the effect)* In order to save substance, the solutionswere diluted to one-third by means of alcohol, resp* acetone,i*e* were tasted as solutions* The results were thefollowing;

Pb 756 after lhW* (all mosquitoes dead) Pb Pb758:lhw*. Pb 759; 1Pb 760; lhW*, Pb 762; 3%*,Pb 763:3%., Pb 764; 1%.

From these results you will observe that the contacteffect of these substances, as we already know it, is sostrong that it interferes with the tests of the repellenteffect of the substances, especially since we do not haveunlimited numbers of mosquitoes at our disposal* I shouldlike to ask you therefore, to have patience until I am ableto send you the results of the further testing*

Chemotherapeutic LaboratorySlberfeld

/s/ Dr* Mudrow*

I«G»

Wuppertal-Elberfeld Chemo»-Labor.

Table2:Testfortoxic

contacteffect•

Effect after:Pb805806807808809810811312813814815816

16hrs«7h

g.Sp.3&Wihsr

lhW

2%4hW

6hW

6hW

6hW

5&Wah0

6h

14days9

Sp,

8h0

8h0

9&W2hW

8%6hW

8&08hW

8&W

1month

8h0

(05fS11»

•

•

#

••

1-|months

•

8h

g.Sp�

:

*0)•

P*iP

CD

2

months

**

7h*f

8^Sp.7hW

3

months

8%S^g.Sp.

S^Sp•

W•

Wirkung(Effect):80-

100$ofthemosquitoesdied«

Spm

SpurWirkung

(TraceEffect):

40-

70$ofthe:

mosquitoesdied«

g«Sp«n

geringeSpur

Wirkung(Slight

traceEffect)

•

20«•

30%ofthemosquitoesdied«

I# Om Leverkusen

Coloristic Department

TO: Chemotherapeutic Laboratory 0 Dir#Dr#Sch5nhöfern Prof »Dr»Bayer

Dr.Dra/G 29 Aug# 1944Anti-mosquito substance Schweitzer 50/181»

To determine the storage ability of the anti-mosquitosubstance, dissolved in alcohol, we have heated the inclosedsubstance for several days in a reflux condenser and werequest you to examine this solution in comparison with thefresh solution of Schweitzer 50/181, recently sent to you,for their anti-mosquito action#sent •

1 sampleEulan tech/s/ Drapal

I« Go LeverkusenColoristic Department

Eulan Technisch ConfidentialVia; Director's Section 0 Dir#Dr# SchönhöferTO: Chemotherapeutic Labor#, Elberfeld n Prof#Dr «Bayer

Dr#Dra/P# • 24 Aug# 1944Test for mosquito-repellent effect#

In the quest for mosquito-repellent substances of last-ing effect and of a certain distance effect we have prepareda series of preparations which we hope will have the sought-for effects#

W© ask you therefore to test the 9 100cc samples ofsolutions, sent to you under separate cover, according tothese points of view by direct rubbing upon the skin, andto determine the most suitable product by investigatingdegrees of dilution#

All of these solutions contain 7#5$ active ingredientsand, with exception of M/36 which is dissolved in acetone,they are alcoholic (denatured) solutions# Designations ofthe products, whose compositions are sent to you separately,are as follows; __

1« (Fb 756) M/29; Schweitzer 50/181 (for comparison)2. (Fb 757) M/30; Schweitzer 50/181 4 Meiser 1700 (l;l)3« (Fb 758) M/31; Schweitzer 50/181 4 Muth 2567 (ijl)4« (Fb 759) M/32; Lobar F/95 4 Meiser 1700 (l : l),5« (Fb 760) M/33; Lobar F/95 4 Math 2567 (l:l)6» (Fb 761) M/34; Lober F/1697* (Fb 762) M/35; Meiser 17008* (Fb 7631 M/36: Wegler 248449* (Fb 764) M/37: Schweitzer 50/181 � 15$ Tylose TWA 25,

It is requested that the 5 substances, M/29, M/30, M/31,M/33, and M/37 be given preferred treatment, if possible«

Incl; 1 list compositions9 Solutions (separate)

Incl;

Bulan techn«/&/ Drapal

Compositions of the products named in the letter#

Schweitzor 50/181} C.Clg.CO.HH-CgH^Ol-/CßH^ClMeiser 1700; CHClc.CEC^Cl

Huthi 2567; GgHg^SOgoCHg^ClLober F/95; 2,6 • dichlorbenzyl alcoholLobar E/iegs

#

Wagler 24844; 01<^-*S-s02-N.CH2 »CH2.CNCl ce3

1. G, t.-ElberfoldChemo««Labor«

TO; Coloristie Dept#,Leverkusen, attn; Dr* Drapal Dr*Md*/Felg# 10 Aug#1944

Mosquito repellents»

According to our agreement via telephone with Dr«Wegler,.of 31 July, we have tested 4 of your mosquito repel-lents as to their mosquitocide effect« The mosquito cages

were impregnated with the 7#5$ alcoholic solutions; as inother experinients f the mosquitoes were inserted in the cages16 hrs® later® The result was the following;

Fb 643 after 1 hr®, effect®Pb 644 after 2 hr»®, effect.Fb 745 after 4 hrs®, effect.Fb 649 after 2 hrs®, effect®

Chenjotherapeutic Laboratory

/s/ Dr® Mudrow

- I.a® W®-Blberfeld -

Chemo tLabor®

TO: Coloristic Dept®, Leverkusen, attn; Dr. Drapal.

Dr®Dra/P 15 June, 19 June, 10 July® Dr.Md./Felg® 26 July 44Test for mosquito-repellent effect.

In extensive experimental series we have examined the16 substances, sent to us in June, for their mosquito-,repellent effect, and in comparison with MLpax we haveobtained the results shown in the inclosed tables® Thepreparations were tested in the order shown in your letter;they were given the numbers Fb 637 - 658® According tothe results of the tests, the most effective substancesware Fb 637 s Schweitzer 50/181, which also in the test onthe bare skin in its original concentration remainedeffective for 7 hrs®, and Fb 644 - Lober V/752 whoseeffect was somewhat poorer i&en tested upon the arm(1-3 hrs®. trace effect; 5 hrs®, without effect)® Thegroup Fb 640, 641, 642, 646-650 was almost equally effectivein the form of a 7 «5$ solution, but differences becameevident in the 10-fold dilution. Also Pb 638, 639, 643 hadrelatively good effect, whereas Fb 645, 651, and 652 hadconsiderably poorer results *so that tests for thesesubstances were discontinued®

With the values obtained it must be stressed that, withthe exception of a preliminary test, we are dealing in eachcase with the results of only one mosquito test, since moredetailed investigations could not be performed for reasonsof time, personnel, and material (limited number ofmosquitoes)® Thus it may be that.in individual casescertain shifts of value occur (e®g® between affect and brace

effect, or between trace effect and no effect, as is alwaysthe case in biological tests) or that differences appearbetween the individual experimental persons# But on thewhole it is assumed that the results give a correct picture#

The5$ solution of Schweitzer 50/181 » Pb 544 has notyet undergone testing, but in agreement with your wisheswe have undertaken a rinsing test on the arm and are thusable to confirm your observations# After the arm wasrinsed with water even for several minutes and thenpermitted to dry in the open air, the effect was retained;to be sure it disappeared when warm water was used or whenthe arm was rubbed energetically with a towel#

Chemotherapeutic Laboratory

/s/ Dr* Mudrow

Table1*

Mosquitorepellents

fromLeverkusen7*5$

methanolsolution#

Np.1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1*17

Sub-637638639640641642643644645646647648649650651652Mipax

stance immed.W

W

wW

W

wW

W

V

W

W

W

W

W

Sp.W.w

w ■tr

1hr#W

wwW

ww

www

W

w

W

w

w

w

w

wttf

3hrs.W

wwwwwwwSp.Wow

V

w

w w

wSp«Wow

w

v***

p

Fhrs*V

V

wwwnrww0

¥

w

w

wSp

aWo0

Sp.W*w

7hrs.W

W

24hrs.WW

72hrs.W0

14daysSpW

sp.w.wWWW 0wwSpW0

V w w SpWwJw w w w

¥ V ww

w w w SpWw w w SpWw w w0

wwJ

bp.HfoP

SpaW.W

Sp.W.w

w.-

nomosnuito

biteinthecourseof5min.

SvAt*aunto4mosnuitoes

biti

inthecourseof5min.

f)i5ormore

mosquitoesbitinthecourseof5min»

Table2#

Mosquitorepellents

fromLeverkusep0.75$methanolsolution.

Nr#1

2

3

4

5

6

7

8

10

11

1213

14

17

Sub-637638639640641642643644

646647648649

650Mipax

stance imnted.V

0

V

W

W

wW

V

0

W M»

W mm

w

W

W w

1hr#W

3hrs.V

5hrs.W

7hrs.W

24hrs.0

j

Wj

V

W

ww

SpWSpW0

0

10

w w w J

w ¥0

W w SpW SpW SpWJ

wsp^ww

•

W SpW0

72hrs.

Coloristic Department

0 Dir# Dr# Sohönhöfer

Dr.Dra*/P* 10 July 1944

Chemotherapeutic InstituteW*-Elberfeld

He: Mosquito Repellents#

In connection with our letter of 15 .June 1944 we informyou that in a practical test with preparation M/X2 (» Schwei*tzer 50/181) we observed a remarkable resistance againstrinsing away of the mosquito-repellent effect, upon theskin« Since this property m? be of significance forbathers, for example (in an open sun bath), we shouldappreciate if you would check on our observation#

Eulan technic*

for Dr* Drapal

I* G« Leverkusen

Coloristic Department

TO: Chemotherapeutic Laboratory 0 Dir* Dr* SohönhöferW#-Elberfeld Dr*Dra#/P 19 June 1944

Re; Test for mosquito-repellent,effect *

In reference to our letter of 15 June 1944 we shouldlike to ask you to include also the following products inthe test series;

12, (648) U/i - Schmelzer 196/3313, (649) U/25 s Lober F/8714, (650) 14/26 s SchrBter R/10815, (6511 14/27 = Retter 69416, (652) 14/28 s Schrader 11/61The concentration is the same as in the 11 substances

sent to you 15 June, i*e® 7*5$ in alcohol#Incl®: Coloristic Department

5 preparations @ 50 cc# -s- Dr# Christ

I. G. Leverkusen

Coloristic Department

TO: Chemotherapeutic Laboratory 0 Dir.Dr.Schönhöfer

W.-Elberfeld Dr.Dra./P« 15 June 1944

Test for mosquito-repellent effect»

W© thank you for the test findings on the preparationsSchweitzer 50/181 (Pb 544) andLober 3/340 b (Pb 546)

in which you judge very favorably on the-mosquito-repellenteffect of these two products« Since with this result wenaturally are greatly interested in testing other substancesof similar composition, we gladly make use of your willing»ness to perform further investigations for us. Thus we aresending you under separate cover 11 additional preparations,which, like Mipax, are 7«5$ and were dissolved in alcohol«In each instance we send'50 cc of:

We request you to perform the tests again, to the extent as thequantities sent permit it, on the inclosed stocking-weaveand•also on the bare skin, and to determine in this boththe intensity of the initial effect and also that of a•permanent effect»

We also request you to compare the most effectiveproductsappearing from this test in an additional seriesof tests, comparing them with each other and with Mipax,by changing both concentrations and time, until it becomesunequivocally apparent which of the products is the mosteffective. In this it is recommended to include in the testseries also.substance P 544, as this received especiallyfavorable mention in the first tests. A gradation inconcentration, as might be required, may be undertaken bysuitable dilution with alcohol«

1« (Pb 637! Schweitzer 50/181 (Numerical sequence LesM/122* (Pb 638, i it 52/lS0a t» it lä/163« IPb 639, tt 52/l21b n tt M/174« (Pb 640 t 53/52 tt tt M/185« (Pb 641 tt 53/53 n tt M/196. (Pb 642, t n 53/4b tt tt U/207. (Pb 643; Lober F/95 tt « M/218. (Pb 644 tt 7/762 tt tt M/159» (Pb 645, tt 748/2 tt tt M/22

10. (Pb 646, Schommer 1439 tt tt M/2311. (Pb 64?; Math 2597/II tt tt . M/24

To give the product with the greatest initial effect agreater permanent effect, we also request you to carry outa test in which this product is mixed with parts of thatproduct which in itself has the greatest permanent effect*

Coloristie Department

/s/ Dr* Christ

I* Go Wo-ElberfeldChemo•-Labor *

TO; Coloristic Department, Leverkusen, attn* Dr* Drapal

Dr*Dra*/P# 24 April Dr*Md*/Br* 19 May 1944

Test for mosquito-re pel lent effect»

The 5$ alcoholic solutions sent to us at the end ofthe past month of 1*) Schweitzer 50/181 (- our No* Pb 544),2« ) Schweitzer 50/181 � Y 762 (1*1) (» Pb 545), and 3*)V 762 (purified Lober 3/340 b) (- Pb 546) were.sprayed uponthe.stocking-knit weaves Bemberg/Cotton and Silk/Cotton (sentwith the solutions) and tested for their mosouito-repellenteffect* First a preliminary experiment had been performedwith a small number of mosquitoes in order that not toomany mosquitoes would be lost by the mosquitocidal effectwhich is also present in the substances* Already thispreliminary showed a certain mosquito-repellent effectimmediately after spraying, and an hour later; after 5 hrs*isolated mosquitoes began to bite in the cases of Pb 545 and546* The subsequent test with full mosquito cages (severalhundreds of female mosquitoes) yielded the surprising resultthat at all times (Immediately, after 1, 3, 5* and 7 hrs*)occasionally, or with every sample, the mosquitoes flewagainst the arms of the experimental persons, covered withsprayed weaves, but that not one single bite took place*Their desire to bite, on the other hand, was shown by thefact that they settled upon the uncovered arms in largequantities, and bit, but only those areas of skin Trtiichhad not been in contact with the treated material. Thisresult induced me to test the various solutions alsowithout cloth directly on the arm, on the order of Mipax*In this the mosquito-repellent effect was confirmed, whichwith Pb 544 lasted for 6 hrs* and with the two othersubstances for 4 hrs* each, as also in the case of Mipaxwhich was tested simultaneously, for the sake of comparison*To be sure, the mosquitoes again flew against the arm (whichhappens more rarely in the case of Mipax, but they did, notbite* It- is now my intention to test the solutions once

more in connection with the cloth materials, in comparisonwith materials sprayed with Mipax; 1 shall infoim you onthis fition the experiments are completed»

It is extremely disagreeable for me to have to informyou that the flaoon which you sent for spraying arrivedhere in a damaged and useless condition» By whom and howthis accident happened was no longer to be determined»I regret this especially since in present conditions weare not in the position to repair the damage# We shall •

at least attempt to have one of our fine mechanics repairat least the spraying mechanism#

For spraying the materials we used at first for thetime being a flower spray# Butsince this method appearedtoo complicated and since in spraying from nearby the thinweaves were nevertheless soaked, we have in the main experi-ment, soaked the cloth completely with the solution inquestion, which always dried relatively rajidly, and thiswe also intend to do with Mipax#

As an addendum I should like to give you the resultof the recent tests with the mosquitocide substances#

Pb 460 - Lauseto Pb 461-Muth 2509/1 Pb 465-Pie penbrink

30841 month 4 hrs #f effect 6 hrs., effect no effect2 months 3 hrs»$ effect 8 hrs#, trace effect

Chemotherapeutic Laboratory

0 Dr# Schönhöfer /s/ Dr# Mudrow* Dr# Dörr

I« G« LeverkusenColoristic Department

TO: I#G# Sfuppertal-ElberfeldChemotherapeutic Laboratory Dr*Dra*/P# 24 April 1944

Dr*Md#/B* 3 April 1944

Test fox* mosquito-repellent effect#

in your report of 3 April 1944 we are especiallyinterested in the test results on the preparations:

Pb 463 b Schweitzer 50/181Pb 466 r Lober 3/340 b*

as these substances, to be sure, do not display a lasting,but a very rajid effect and thus might possibly be used asspraying substances as. for example, on stockings« Fordetermining such possibilities we sent you 200 cc of 5$alcoholic solutions of each of the following:

1« (Fb 544) Schweitzer 50/1812* (Fb 545) Schweitzer 50/181 � V/762 (Isl)3» (Fb 546) V/762 (a purified Lober 3/340 b), and also:4# 6m stocking weave Bemberg/Cotton5# *6 m stocking weave Silk/Cotton6« 1 30-cc-flacon for spraying*

To approximate the conditions of practice, we proposethat the tests be performed in such a manner that in eachcase a type of stocking weave be drawn over the arms ofsuitable test persons and that immediately after the sprayingof the individual preparations their mosquito-repellenteffect be tested at once, after 1 hr*, and after 5 hrs«.If the spray should fail temporarily in the fla con, whichmay occur when air is punned in, one unscrews the pressbutton with the valve, shakes it out, and again screws iton«

If for the execution of the tests you should requireadditional quantities of the substances and of the knitmaterials we can furnish you with them« After completionof the tests ma request you to return the spraying flaconto us, as it was borrowed from a private owner«sent under separata cover;2 knit materials and chem*

substances1 spraying flacon3 bottles

Eulan techn»/a/ Dr« Drapal

I« Gr« LeverkusenColor ist ic Department

TO: Chemotherapeutic Laboratory

Elberfeld Ör«Dra*/F« 17 Feb« 1944

Test for mosquito-repellent effect«

We request you to test the following preparations fortheir mosquito-repellent, resp« mosquitocide effect* Allpreparations are soluble in acetone; with exception of the50$ solution of Lauseto, they are all 100$ (full strength):

1* Lauset o 5« Piepenbrink 30832# Math 2509/1 6« Piepenbrink 30843* Math 2567/1 7# Lob#» 3/340 b#

Eulan techn#Under separate cover j /s/ Dr« Drapal7 small bottles

TO; Coleristic Department, attn; Dr# Drapal, Leverkusen17 Feb# 1944 Dr.Md#/B. 3 April 1944

Re: Test for mosquito-repellent effect#

The 7 preparations mentioned in your letter have beentested in comparison to Gesarol for their mosquitooideeffect» All substances were dissolved like Gesarol at 1$in ether, and they were used in this 1$ solution in theimpregnation of muslin for mosquito cages* 16 hrs# afterthis treatment the same number of mosquitoes (efitlex pipiens)was placed in each cage and observed during the followinghours* "Effect" signifies that at a certain point of time70-100$ of the mosquitoes were dead, while "slight traceeffect" signifies that a number of the insects 170-80$)survived* 15-16 days later the same cages were.examinedonce more in the same manner* Since the effect of Gesarolpersisted still after 2 months, we shall test these sub-stances which still show a mosquitocide effect after 2weeks again after 1-2 months, and we shall inform you onthe results* In the following I quote the results thatwere obtained until now:Preparation 1st Test 2nd Test

(16 hrs* after treatm»)(15-16 days after treatm*)

Pb 460sLauseto after 5 hrs#, effect after 5 hrs., effectPb 461sMuth 2509/1 after 5 hr#.,effect after 6 hrs# f effectPb 462»Muth 2567/1 after 4 hrs#,effect after 8 hrs#, sl#tr#

eff#-0Pb 463*Schweitzer

50/l81 after 2 hrs., effect after 8 hrs#, 0Pb 464=Piepenbrink

3083 after 3 hrs#, effect aft#r 8 hrs#, 0Pb 465-Piepenbrink

3084 after 5 hrs#, effect after 6 hrs#, effectPb 466sLober 3/340 b

after 2 hrs#, effect after 8 hrs#, sl#tT#eff.-0

Thus tlie preparations Pb 462, 463, 464, and 466 areeliminated from the tests#

Heil HitlerICnemotherapeutio Laboratory

/s/ Dr® Lutter /s/ Dr* Mudrow! Dir. Dr. Schönliöffer

I» Gt9 FARBENINUJSTRIE AKTIENGESELLSCHAFTWERK ELBERFELD

/s/ Dr* Sch9nfc8fer ppa# Kikuth*

APPENDIX 4Preparation of Triphenyltetrazoliumchlorid (Tetrazollumsalz)

,'fjafc-C6H5Cl

y N-HH C.Hcc h5 -c 6 5,b vMsK-CgH5

Zu 400 g Triphenylformazan 1,7 Ltr»Trockensprit

und 330 Amylnitrit 11sst man in einem 3 Ltr.-Kolben unterRöhren 185 g 37$ alkoholische Salzslur© zutropfen» Durchdie Reaktionswlrm© steigt die Temperatur im Innern desKolbens auf 50-55°• Wenn die alkoholisch© Sakzslure zuge-tropft ist. wird noch 1 l/2 - 2 Stunden nachgeföhrt, dann,ohne zu rönren, noch 4 Stunden stehen ©Lassen, bis keineBlasenentwicklung (Stickstoff) mehr zu bemerken ist» Dierote Farbe des Triphenylformazans ist verschwunden undeine tiefbraun© Lösung entstanden» Diese Lösung wird daraufSolange mit Le itungswasser versetzt, bis sich deutlich eineIschicht (in der Hauptsache. Amylalkohol) abscheidet, wozu

ungeflhr 6r8 Ltr» Wasser erforderlich sind» Die wtssrig-alkohol» Lösung wird durch Ablassen von der 01Schichtgetrennt und im Vakuum oder auf dem Wasserbad bis auf 1 -

1 l/2 ltr» eingeengt» Zur KLlrung behandelt man noch heissmit Tierkohle und saugt ab» Das gelbliche Filtrat' wird jetztauf dem Wasserbad bis zur beginnenden Kfystallisation weitereingedampft, auf Eis gestellt, wodurch das wasserhaltig©Rohprodukt des Triphenyltetrazoliumschlor ids in fester Formerhalten wird« Zwecks Reinigung wird das Rohprodukt inheissem Wasser gelöst (auf 1 Teil Rohprodukt höchstens 1Teil Wasser)» Die..Lösung reagiert meist kongosauer, deshalbmuss mit 20$ Ammoniaklösung bis zum Verschwinden der kongo«*

säuren Reaktion (aber noch deutlich lackmussäuert) abgestumpftwerden, wozu ca» 30-40 ccm Ammoniaklösung erforderlich sind»Ausserdem wird nochmals etwas Tierkohle zugegeben und nochwarm abgesaugt» Das Filtrat wird in Eiswasser gestellt undunter ümröhren zur Krystallisation gebracht* Man erhält dannein fast farbloses Triphenyltetrazoliumchlorid, das abgesaugtzunöchst 2 Tage lang bei gewöhnlicher Temperatur unterAusschluss von Licht und dann erst im Dampf schrank getroclo&etwird» Triphenyltetrazoliumchlorid stellt ©in schwach gelb-bräunliches Krystallpulver dar, das bei 241° sich zersetztund die erforderlichen Reinheitspröfungen erfüllen muss»Ausbeute gegen 300 g a 67-68$ d»Th»Darstellung von Benzyllden-phenylhydrazon»

Zu 108 g Phenylhydrazin und 200 ccm Trockensprit lässt

men in einem 1 Ltr •-Kolben unter Röhren 106 g Benzaldehydzutropfen# Wenn der Benzaldyhd zugetropft ist, wird 30 Min#lang gekocht; hierauf wird mit Eiswasser abgekühlt, dasgebildete Benzyliden-phenylhydrazon abgesaugt und mit kaltemTrockensprit und etwas Aether nachgewaschen# Die Trocknungdes Benzyliden-phenylhydrazons erfolgt im lichtgeschätzenExiccator überChlorkalzium, wobei man am besten im Wasser-strahlvakuum trocknet« Ausbeute 162 g gleich 83$ der Th#Die getrocknete Substanz wird in braunen Flaschen aufgehoben*

Darstellung von Trlphenylformazan»

77 g Anilin und 207 ccm Salzsäure conc* werden bei einerTemperatur, die � 10° nicht übersteigen soll, mit einerwässrigen Lösung„von 59 g Natriumnitrit diazotiert# DieDiazolösung.wird rasch filtriert* Während des Filtrierensoder schon vorher, hat man sich eine Lösung von 162 g Benzy-

in 350 ccm Pyridinfraktion II und 350ccm Trockensprit bereitet und diese Lösung in einem grossenBecherglas unter Röhren auf 15-20° heruntergekühlt# Dannlässt man bei dieser Temperatur die filtrierte. Diazolösungunter Rühren zutropfen# Die Temperatur steigt bei demZutropfen der Diazolösung auf ca* 25°, was nicht schadet#Höhere Temperaturen sind jedoch durch Aussenkühlung mitFis zu vermeiden. Um eine Zeradbzung der Diazolösunghintanzuhalten, ste'llt man sie bis zur Verwendung inEiswasser# Nach dem Zutropfen der Diazolösung wird nochmindestens 2-3 Stunden weiter gut durchgerührt• hieraufwird der entstandene rote Niederschlag, der das roheTriphenylforaazan darstellt# Formel:

/ N-NH CaHrCeHg-onn-:i-c6h5

abg©saugt und mehrmals mit Wasser gewaschen# Ausbeute205 g* Zum Zweck der Weiterverarbeitung auf Triphenyl-tetrazoliumChlorid genügt es, das lufttrocken© Triphenyl-formazan mit 15 Raumteilen Trockensprit auszukochen# Zudiesem Zweck werden beispielsweise 205 g des Triphenyl-formazans mit 3075 ccm Trockensprit 30-40 Min# langgekocht, kalt über Nacht stehen lassen und schliesslichabgesaugt. Man.erhält ©in violettrot schimmerndeskrystallislertes Produkt, das den Sm*170-173° aufweist undfür die Weiterverarbeitung geeignet ist# Ausbeute:80$ des Rohproduktes s 164 g#

Darstellung von Trlphenyltetrazoliumchlorid (Tetrazoliumsalz)> N-N-CßHg

CeHg-c6h5

ci

Zu 400 g Triphenylformazan f X f 7 Ltr*Trockensprit

und 330 Amylnitrit lösst man in einem 3 Ltr«-Kolben unterRöhren 185 g 37$ alkoholische SalzsBure zutropfen. Durch dieReaktionswÄrme steigt die Temperatur Im Innern des Kolbensauf 50-55°. Wenn die alkoholisch© SaiisSure zugetropft ist,wird noch 1 l/2 - 2 Stunden nachgeröhrt, dann, ohne zu röhren,noch 4 Stunden stehen gelassen, bis-keine Blasenentwicklung(Stickstoff) mehr zu bemerken ist. Die rote Farbe des Tri-phenylformazans ist verschwunden und eine tiefbraune Lösungentstanden. Dies© Lösung wird darauf solange mit Leitungs-wasser versetzt, bis sich deutlich eine Olschicht (in derHauptsache Amylakohol) abscheidet, wozu ungefähr 6-8 Ltr#Wasser erforderlich sind* Di© wössrig-alkohol. Lösung wirddurch Ablassen von der ölschicht getrennt und im Vakuum oderauf dem Wasserbad bis auf 1-11/2 Ltr. eingeengt. ZurKlftrung behandelt man noch heiss mit Tierkohle und saugt ab.Das gelbliche Filtrat wird jetzt auf dem Wasserbad bis zurbeginnenden Kfystallisation weiter eingedampft, auf Eisgestellt, wodurch das wasserhaltige Rohprodukt des Tri-phenyltetfazoliumschlqrids in fester Form erhalten wird.Zwecks Reinigung wird das Rohprodukt in heissem Wasser gelöst(auf 1 Teil Rohprodukt höchstens 1 Teil Wasser). Die Lösungreagiert meist kongosauer, deshalb muss mit 20$ Ammoniak-lösung bis zum Verschwinden der kongosluren Reaktion (abernoch deutlich 1ackmussauert) abgestumpft werden, wozu ca.30-40 ccm Ammoniaklösung erforderlich sind. Ausserdem wirdnochmals etwas Dierkohle zugegeben und noch warm abgesaugt.Das Filtrat wird in Eiswasser gestellt und unter ümröhrenzur Kfystallisation gebracht. Man erh&lt dann ein fastfarbloses Triphehyltetrazoliumchlorid, das abgesaugtzunächst 2 Tage lang bei gewöhnlicher Temperatur unterAusschluss von Licht und dann erst im Dampfschrankgetrocknet wird. Triphenyltetra-zoliumchlorid stellt einschwach gelb-bröunliches Krystallpulver dar, das bei 241°sich zersetzt und die erforderlichen Reinheitspröfungenerföllen muss. Ausbeute gegen 300 g s 67-68$ d.Th*

/K-HH CfiH_C 6 5

6 36h5

Darstellung von Benzyllden-phenvlhydrazon.

Zu 108 g Phenylhydrazin und 200 ccm Trockensprit iBsstman in einem 1 Ltr.-Kolben unter Röhren 106 g Benaaldehydzutropfen. Wenn der Benzaldyhd zugetropft ist, wird 30 Min#lang gekocht; hierauf wird mit Biswasser abgeköhlt, dasgebildete Benzyliden-phenylhydrazon abgesaugt und mit kaltemTrockensprit und etwas Aether nachgewaschen. Die Trocknungdes Benzyliden-nhenylhydrazons erfolgt im lichtgeschötztenExiccator OberChlorkalzium, wobei man am besten im Wesser-strahlvakuum trocknet. Ausbeute 162 g gleich 83$ der Th. Die

getrocknete Substanz wird in braunen Flaschen aufgehoben*

Darstellung von Triphenylformazan*

77 g Arflin und 207 ccm Salzsäure conc* werden bei einerTemperatur, die � 10° nicht übersteigen soll, mit einerwässrigen Lösung,.von 59 g Natriumnitrit diazotiert* DieDiazolösung.wird rasch filtriert* Während des Filtrierensoder schon vorher, hat man sich eine Lösung von 162 gBenzyliden-phenylhydrazon in 350 ccm PyridinfraktionII und 350 ccm Trockensprit bereitet und diese Lösung ineinem grossen Becherglas unter Röhren auf 15-20°heruntergekühlt• Dann lässt man bei dieser Temperatur diefiltrierte Diazolösung unter Röhren zutropfen* DieTemperatur dem Zutropfen der Diazolösung aufca* 25°, was nicht schadet* Höhere Temperaturen sind Jedochdurch Aussenkühlung mit Eis zu vermelden* Um eine Zersetzungder Diazolösung hintanzuhalten, stellt man sie bis zurVerwendung ..in Eiswasser* Nach dem Zutropfen der Diazolösungwird noch mindestens 2-3 Stauden weiter gut durchgeröhrt;hierauf wird der entstandene rote Niederschlag, der dasrohe Triphenylformazan darstellt* Formel:

/N-NE CRHqC,H5-Cf 6 5

5 s nn=k-c 6h5abgesaugt und mehrmals mit Wasser gewaschen* Ausbeute 205 g*Zum Zweck der Weiterverarbeitung auf Triphenyltetrazolium-ohlorid genügt es, das lufttrockene Triphenylformazan mit15 Raumteilen Trockensprit auszukochen» Zu diesem Zweck werdenbeispielsweise 205 g des Triphenylsformazans mit 3075 ccmTrockensprit 30-40 Min* lang gekocht, kalt über Nacht stehenlassen und schliesslich abgesaugt* Man erhört ein violettrotschimmerndes krystallisiertes Produkt, das den Sm* 170-173° ausweist und für die Weiterverarbeitung geeignet ist*Ausbeute: 80$ des Rohproduktes « 164 g*