a hantzsch condensation reaction / dihydropyridine cascade … · 2018. 7. 3. · a hantzsch...

International Journal of Materials Science

ISSN 0973-4589 Volume 13, Number 3 (2018), pp. 189-204

© Research India Publications

http://www.ripublication.com

A Hantzsch condensation reaction / Dihydropyridine

Cascade Synthesis on Zeolite substrate

Adya Jain*, Shikha Singh, Kautily Rao Tiwari,

Neeraj Kumar and Radha Tomar

S. O. S in Chemistry, Jiwaji University, Gwalior, M.P., 474011, India.

Graphical Abstract:

Fig 1: Graphical Abstract

Abstract

Competence of Nanoporous Modified Zeolite-Beta has been observed at

various parameters (i.e. different solvent, temperature, catalyst concentration

and time interval) on the yield of different derivatives. Synthesis of 9, 10-

Diarylacridine-1, 8-dione was carried out by single-pot Hantzsch condensation

mailto:[email protected],%20Ph

190 Adya Jain et al

reaction, which includes three component reactants i.e. aldehyde, amine and 5,

5-Dimethyl-1, 3- cyclohexanedione (dimedone). Expeditious with excellent

Yield of synthesized drug intermediates from Cr2O3-H-β was found to be

88.75% in ethanol at 90ºC. The synthesized zeolites sample were

characterized by the help of Fourier transform infrared spectroscopy (FTIR),

X-Ray diffraction (XRD), BET Surface Area and Porosity and Scanning

electron microscopy (SEM) while the synthesis of drug derivatives were

confirmed by Fourier transform infrared spectroscopy (FTIR), 1H-Nuclear

Magnetic Resonance Spectroscopy (1H-NMR) and Liquid chromatography-

Mass spectrometer (LC-MS).

Keywords: Zeolite Beta, Hantzsch condensation, 9, 10-Diarylacridine-1, 8-

dione

1. INTRODUCTION

Dihydropyridine (DHP) derivatives (i.e. Acridinediones, Quinolines) displays wide

array of biological activities such as vasodilator, anti-atherosclerotic, antitumor,

antidiabetic [1] calcium β-blockers, antihypertensive activity, α1a-antagonists and

heart defibrillation. Acridine derivatives possess number of biological activities i.e.

antitumor [2], cytotoxic, anticancer [3], antimicrobial, anti multidrug resistant,

fungicidal, antibacterial activity, antiglucoma [4], mutagenic properties etc.

Dihydopyridine molecules are synthesized by one pot multicomponent condensation

reaction i.e. Hantzsch Condensation Reaction which is a catalytic driven reaction. In

the absence of catalyst, the obtained yield percentage is unsatisfactorily in lower

amount and the reaction completes in long duration.

NH

Dihydropyridine

N

O O

CH3CH3

CH3

CH3

R

R1

Acridine-1,8-diones

NH

CH3

OO Ar

OEt

Quinazoline

Fig 2: Structures representing Parent Nucleus Molecule and Drug Derivatives

A number of different derivates of Acridinedione and Quinolines has been

synthesized by different methods in the presence of different catalysts and solvents

such as alumina (neutral or basic) as mineral solid supports using DMF as solvent [5],

p-dodecylbenezenesulfonic acid (DBSA) as a Bronsted acid-surfactant-combined

catalyst [6], Amberlyst-15 in CH3CN [7], 1-butyl-3-methyl-imidazolium

tetrafluoroborate ([bmim][BF4]) [8], tris(pentafluorophenyl) borane [B(C6F5)3] [9], L-

proline [10], sodium 1-dodecanesulfonate (SDS) [11], Brønsted acidic imidazolium

salts containing perfluoroalkyl tails [12] Hf(NPf2)4 [13], nano-Fe3O4 [14], Cross-

dehydrogenative regioselective Csp3–Csp2 coupling of enamino-ketones [15],

A Hantzsch condensation reaction / Dihydropyridine Cascade Synthesis on Zeolite substrate 191

[Bmim]ClO4 [16], aluminium dodecyl sulfate trihydrate [Al(DS)3].3H2O a Lewis

acid-surfactant-combined catalyst[17], magnetite (Fe3O4)/chitosan as a magnetically

recyclable heterogeneous nanocatalyst[18], P2O5 [19], ionic liquid triethylamine

hydrogen sulphate [Et3N]+ [HSO4]- [20], monodisperse platinum nanoparticles

supported with reduced graphene oxide[21] etc. Modified/Simple Zeolite are not used

as catalyst for Hantzsch condensation reaction till date.

Some commercial drugs of 1, 4 Dihydropyridine

NH

OCH3

N+

O-

O

O

O

CH3

O

CH3CH3

NH

OCH3

Cl

O

O

CH3

O

CH3CH3

Cl

NH

OCH3

O

O

CH3

O

CH3CH3

N+

O-

O

Nifadipine(1) Felodipine(2) Nitrendipine(3)

Fig. 3: Structure of Nifadipine(1), Felodipine(2) and Nitrendipine(3)

Calcium Channel Blocker

Dihydropyridines

First Generation

Nifedipine

Short half life

[< 3 hrs]

Second Generation

Nicardipine

Felodipine

Isradipine

Long half life

[< 14 hrs]

Third Generation

Amlodipine

Very long

[> 30 hrs]

192 Adya Jain et al

Zeolites are nanoporous crystalline aluminosilicates containing labyrinth of molecular

dimensions which can be filled by water or other guest molecules. Zeolites are

obtained as natural minerals which can also be artificially engineered. Major

applications of Zeolite are adsorption, catalysis and ion-exchange property. Zeolite

exclusive advantages includes less or noncorrosive nature, no waste or disposal

problem, abundance, low cost, high thermostability, great adaptability to practically

all types of catalysis, heterogeneous i.e. easily separable from reaction mixture, great

acid strength, easier scale up for continuous processes, etc. Hence, we decided to

work on zeolite as catalyst for the synthesis of 1,4-Dihyropyridine drug molecules.

The use of catalyst greatly enhances the yield percentage and purity of drug molecules

therefore fulfills the needs of huge demands for pharmaceutical medicines.

Zeolite Beta is one of the large pore and high synthetic silicate zeolite thus attribute

higher catalytic activity, higher hydrophobicity, high cation concentration and acidic

strength. Therefore we had chosen this zeolite as catalyst due to its remarkable

properties. Zeolite Beta consists of an intergrowth of two distinct structures termed

Polymorphs A and B (hybrid of tetragonal and monoclinic structure). [22] The

polymorphs grow as two-dimensional sheets and the sheets randomly alternate

between the two. Both polymorphs have a three dimensional network of 12-ring

pores. Material formula of zeolite β is Na0.92 K0.62 (TEA)7.6 [Al4.53Si59.47O128] with

Si/Al ratio of 13.1.

The BEA framework topology attracts much attention because of the large available

micropore volume, large-pore channel system and the presence of active sites in

different concentrations that are useful in a number of acid-catalyzed reactions e.g.,

dewaxing, hydroisomerization, hydrocracking, alkane and aromatic alkylation,

disproportionation and other organic synthesis processes [23,24]. Therefore we had

chosen this zeolite for the synthesis of pharmaceutical drug molecules because of

unique exceptional properties.ad chosen this zeolite

To best of our knowledge, these novel drug intermediates are first time synthesized by

using Cr2O3-H-β zeolite as nanoporous catalyst.

Fig 4: Polymorph combination for the formation of Zeolite Beta


2. EXPERIMENTAL

2.1 Synthesis of Zeolite and its derivatives

2.1.1. Synthesis of Zeolite Beta

In a 250 ml round bottomed flask, 29.7 ml distilled water, 44.8 ml Tetramethyl

ammonium hydroxide (template), 0.265 g NaCl, 0.72 g KCl and 14.77 g silica gel was

added to it. Then 10 ml distilled water, 0.165 g NaOH and 0.895 g sodium aluminate

solution was mixed to the above solution (Scheme 1). This mixture was stirred for 10

min and a thick gel was obtained. This thick gel was kept in autoclave at 135ºC for 18

h. Thereafter obtained mixture was centrifuged, washed and filtered by double

distilled water (pH=12). Finally precipitate was dried in oven for an overnight at

77ºC.

2.1.2 Conversion of Na-form zeolites to H-form zeolites

In a 250 ml round bottomed flask, 9 g of zeolite (Na form), 7.230 g NH4Cl and 13.80

ml distilled water mixed with 0.1M HCl solution to reach pH=4. This reaction

mixture was stirred for 30 min at 60ºC. Thereafter obtained material was washed and

filtered by double distilled water. Finally precipitate was dried in oven at 60ºC for 24

h. Further the powdered mixture was calcinated at 200ºC for 60 min (Scheme 2).

2.1.3 Synthesis of Cr2O3-zeolites beta

In a 250 ml round bottomed flask, 1.5 g zeolite and 20 ml of 1M Anhydrous Sr(NO3)2

were mixed and stirred for 5 h. During stirring 50 ml of 0.2 M KMnO4 solution was

added suddenly. Thereafter the reaction mixture was washed with double distilled

water and dried in oven at 100ºC for more than overnight. Finally the powdered form

was calcinated at 550ºC for 4h (Scheme 3).

Scheme 1, 2 and 3: Synthesis and Modification of Zeolite

194 Adya Jain et al

2.2 Synthesis of 1,8-Acridinedione derivatives (3,3,6,6-Tetramethyl-3,4,6,7,9,10-

hexahydro-1,8-acridinedione)

In ethanol (solvent), Primary amine (1 mmol) was added to the mixture of 5, 5-

dimethyl-1,3-cyclohexanedione (dimedone) (2 mmol), an aromatic aldehyde (1 mmol)

and zeolite (0.1 g) at 90 °C (Fig. 5). Reaction completion was realized by Thin Layer

Chromatography. The reaction mixture was filtered and the product was obtained as

filtrate, collected and dried at room temperature. The purification of solid residue was

performed by recrystallizing from ethanol to obtain pure 1, 8-dioxo-

decahydroacridine derivative form. The synthesized compound was characterized by

the help of FTIR, LC-MS and 1H-NMR.

𝐏𝐫𝐨𝐝𝐮𝐜𝐭 𝐲𝐢𝐞𝐥𝐝 (%) =𝐀𝐜𝐭𝐮𝐚𝐥 𝐲𝐢𝐞𝐥𝐝 (𝐠)

𝐓𝐡𝐞𝐨𝐫𝐢𝐭𝐢𝐜𝐚𝐥 𝐲𝐢𝐞𝐥𝐝 (𝐠)× 𝟏𝟎𝟎%

O

O

CH3

CH3

+ RCHO NH2R1

+Refluxing Water

90 °C, 15-20min.N

O O

CH3CH3

CH3

CH3

R1

R

Fig 5: One Pot Hantzsch Condensation Reaction

Table 1: Synthesis of Different derivatives of 1, 8-Acridinedione:

S.No. Benzaldehyde (R) Amine (R’) Product Yield (%)

1. O

Cl

NH2

Cl

Cl

N

O O

CH3CH3

CH3

CH3

Cl

Cl

Cl

86.29

2. O

OH

NH2

Cl N

O O

CH3CH3

CH3

CH3

Cl

OH

90.23


3. O

OH

NH2

Cl

Cl

N

O O

CH3CH3

CH3

CH3

Cl

OH

Cl

89.88

4. O

N+

O-

O

NH2

N

O O

CH3CH3

CH3

CH3

N+ O

-O

88.49

5. O

Cl

NH2

Cl N

O O

CH3CH3

CH3

CH3

Cl

Cl

84.82

O

O

CH3

CH3

ArCHO

aldol

O

O

CH3

CH3

Ar

O

O

Michael

O O

O O

Ar

NH2

O

O O

N

NHO

O O

O O

N

OH

Ar

Ar

Ar

-H2O

O O

N

Ar

Scheme 2: Plausible mechanism for the formation of 1, 8-Acridinedione

196 Adya Jain et al

3.1 Result and Discussion [I]

Melting points were determined in open capillaries from melting point instrument.

Infrared spectra of the synthesized drug intermediates and zeolites were recorded by

“Spectrumto-Perkin Elmer” spectrophotometer in the range of 4000–400 cm-1 by

using KBr pellets. X-Ray diffraction spectra were recorded by using “Miniflex 600”

Diffractometer. 1H-NMR spectra were determined in DMSO-d6 solvent by the help

of JEOL-JNM-ECA Series (Delta V4.3)-400 MHz-FT-NMR. Data for 1H NMR are

reported as follows: chemical shift, integration, multiplicity (s = singlet, d = doublet, t

= triplet, q = quartet, m = multiplet) and coupling constants. BET surface area and

porosity of zeolite samples was determines by using Gemini VII 2390 Surface Area

Analyzer (Micromeritics). Analytical thin layer chromatography was performed using

0.25 mm silica gel plates (Ethyl Acetate: n-Hexane :: 3:1).

3.1.1 Fourier Transform Infrared Spectroscopy

The finger print region of FT-IR determines the formation of zeolite. The absorption

peaks between 750-700 cm-1 (i.e. 743.42, 734.91, 726.83, 712.83 and 702.84)

corresponds to the symmetric stretching vibration of SiO4 groups. The bands around

635.57, 546.81 and 467 cm-1 relates to bending vibration of SiO4 groups or in the

vibration modes of the 4-membered rings of silicate chains. The stretching vibration

of SiO4 are shifted towards lower frequency indicating that the presence of the

internal Si-O···HO-Si bonds.

Fig 6: FT-IR of H-beta and Cr2O3-beta

3.1.2 Scanning Electron Microscope

The SEM micrograph of zeolite shows the interconnection of porous structure by

agglomerating of nanoparticles of Cr2O3 on H-beta with an average particle size less

than 50 μm.

4000 3500 3000 2500 2000 1500 1000 500

0

5

10

15

20

25

% T

rans

mitt

ance

Wavelength (cm-1)

H-Beta

Cr20

3-H-Beta


Fig 7: SEM micrograph of Zeolite Cr2O3-H- β

3.1.3 X-Ray Diffraction

The X-Ray Diffraction pattern is the fingerprint of the crystalline phase of zeolite.

From the diffraction signals, the sharp peaks at 2θ value corresponding to 25.0 for

zeolite-H-β and Cr2O3- H-β are clearly observed. Generally sharp peaks determine the

crystalline nature of material, but here the broadening of peaks determines the

polycrystalline nature of zeolite beta. It is also clearly observed that the X-ray

diffraction patterns of H-forms and metal oxide exchanged forms of zeolites are

similar to the diffraction patterns of their respective parent zeolites. These

observations indicate that zeolite framework has not undergone any significant

structural change during the incorporation of metal ion and crystallinity of the zeolite

was preserved.

Fig 8 and 9: XRD of H-beta and H-beta- Cr2O3 respectively

3.1.4 BET Analysis

The BET surface area of H-BETA zeolite was found to be 310.1525 m²/g, Langmuir

surface area: 446.6285 m²/g, BJH adsorption cumulative surface area of pores

2-theta (deg)

Inte

nsity (

cou

nts

)

20 40 60 80

0

1000

2000

3000

4000

2-theta (deg)

Inte

nsity (

cou

nts

)

20 40 60 80

0

1000

2000

3000

4000

198 Adya Jain et al

between 17.000 A0 and 3000.000 A0 widths: 348.805 m²/g, BJH desorption

cumulative surface area of pores between 17.000 A0 and 3000.000 A0 widths:

408.7747 m²/g.

The BET surface area of Cr2O3-H-BETA zeolite was found to be 139.4775 m²/g,

Langmuir surface area: 202.3463 m²/g, BJH adsorption cumulative surface area of

pores between 17.000 A0 and 3000.000 A0 widths: 166.174 m²/g, BJH desorption

cumulative surface area of pores between 17.000 A0 and 3000.000 A0 widths:

199.1166 m²/g.

Fig 10 and 11: BET analysis representing Relative Pressure v/s Quantity Adsorbed

and Pore width v/s Pore volume

3.2 Result and Discussion [II]

Table 2, Graph 1: Studying the yield of 9-(4-OH C6H5)-10-(3, 4-Cl2 C6H5)-3, 3, 6, 6-

Tetramethyl acridine-1, 8-dione [6] from different zeolites derivatives

S.No. Solvent Catalyst Yield (%)

1. Ethanol H-β 89.88

2. Ethanol Cr2O3-β 85.45

All reactions were carried out at 90ºC from 30-40 min. with catalyst amount of 0.10 g.

0.0 0.2 0.4 0.6 0.8 1.0

0

50

100

150

200

250

300

350

400

450

500

550

600

Qu

an

tity

Ad

so

rbe

d (

cm

³/g

ST

P)

Relative Pressure (P/Po)

Cr2O

3-H-Beta

H-Beta

0 200 400 600 800 1000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

dV

/dlo

g(w

) P

ore

Vo

lum

e (

cm

³/g

·Å)

Pore Width (Å)

Cr2O

3-H-Beta

H-Beta

89.8885.45

80

85

90

95

H-β Cr2O3-β

Yie

ld (

%)

Zeolite

Different Catalyst



Tetramethyl acridine-1, 8-dione [6] from different solvents

S.No. Solvent Yield (%)

1. Ethanol 89.88

2. Acetonitrile 86.60

3. Chloroform 81.23

4. 1,4-Dioxane 76.91

5. Toluene 75.35

All reactions were carried out at 90ºC from 30-40 min. with catalyst H-β amount of 0.10 g .


Tetramethyl acridine-1, 8-dione [6] at different temperature

S.No Temperature Yield (%)

1. 0ºC 31.90

2. 30ºC 53.31

3. 60ºC 64.77

4. 90ºC 89.88

5. 120ºC 47.29


Tetramethyl acridine-1, 8-dione [6] at different time

S.No. Time Yield (%)

1. 15 min 34.16

2. 30 min 52.09

3. 45 min 67.41

4. 60 min 89.88

5. 75 min 80.23

89.8886.6

81.2376.91 75.35

65707580859095

Yie

ld (

%)

Solvents

31.9

53.3164.77

89.88

47.29

0

20

40

60

80

100

0ºC 30ºC 60ºC 90ºC 120ºC

Yie

ld(%

)

Temperature

34.16

52.09

67.41

89.8880.23

0

20

40

60

80

100

15 min 30 min 45 min 60 min 75 min

Yie

ld (

%)

Time

200 Adya Jain et al

Spectroscopic data of some synthesized drugs

9-(4-OH C6H4)-10-(4-Cl C6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione: FT-

IR (KBr in cm-1) 3883.47, 3055.4, 2999.5, 2850.78, 1718.37, 1488.5, 1517.61,

755.12, 724.33; UV-Vis. λ max – 893.2 nm Absorbance at 0.100 Å; m/z = 476.5

(M+H) +.1H NMR (400 MHz, DMSO-d6): d = 0.74 (s, 6 H, 2 CH3), 0.87 (s, 6 H, 2

CH3), 1.75 (d, J = 17.6 Hz, 2 H, 2 CH), 2.03 (d, J = 16.0 Hz, 2 H, 2 CH), 2.18 (d, J =

16.0 Hz, 2 H, 2 CH), 2.18 (d, J = 17.6 Hz, 2 H, 2 CH), 5.00 (s, 1 H, CH), 7.30 –7.49

(m, 6 H, ArH), 7.68 (d, J = 8.8 Hz, 2 H, ArH), 9.05 (s, 1H, -OH ).

9-(4-OH C6H4)-10-(3, 4-Cl2 C6H3)-3, 3, 6, 6-tetramethyl acridine-1, 8-

dione: FT-IR (KBr in cm-1) 3471.47, 3184.5, 2949, 2719.14, 1674.64, 1575, 1460,

1575, 825.5 and 753.56; UV-Vis. λ max – 893.5 nm Absorbance at 0.142 Å; m/z = 511

(M+H) +.1H- NMR (400 MHz, DMSO-d6): d = 0.72 (s, 6 H, 2 CH3), 0.89 (s, 6 H, 2

CH3), 1.78 (d, J = 17.6 Hz, 2 H, 2 CH), 2.01 (d, J = 16.0 Hz, 2 H, 2 CH), 2.19 (d, J =

16.0 Hz, 2 H, 2 CH), 2.20 (d, J = 17.6 Hz, 2 H, 2 CH), 5.01 (s, 1 H, CH), 7.30 –7.49

(m, 6 H, ArH), 7.68 (d, J = 8.8 Hz, 2 H, ArH), 9.05 (s, 1H, - OH ).

9, 10-Bis (4-ClC6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione: FT-IR (KBr

in cm-1) 3051.84, 2960.17, 2873.28, 1688, 1575.18, 1424.78, 852.7, 762.46; UV-Vis.

λ max – 893.5 nm; Absorbance at 0.142 Å; 1H NMR (400 MHz, DMSO-d6): d = 0.72

(s, 6 H, 2 CH3), 0.89 (s, 6 H, 2 CH3), 1.89-2.01 (d, J = 16.0 Hz, 2 H, 2 CH2), 2.42 (d, J

= 17.6 Hz, 2 H, CH2), 5.01 (s, 1 H, CH), 7.30 –7.49 (m, 6 H, ArH), 7.68 (d, J = 8.8

Hz, 2 H, ArH).Anal. Calcd for C29H29Cl2NO2: C, 70.44; H, 5.91; N, 2.83. Found: C,

70.28; H, 6.05; N, 2.90.; m/z = 470 (M+H)+ .

Fig. 12: FT-IR of 9, 10-Bis (4-ClC6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione

4000 3500 3000 2500 2000 1500 1000 500

-5

0

5

10

15

20

25

30

35

40

(%)

Tra

nsm

itta

nce

Wavenumber(cm-1)

9,10-bis-(4-Cl C6H

5) Acridine-1,8-dione


Fig 13: 1H-NMR of 9, 10-Bis (4-ClC6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione

Fig 14: LC-MS of 9, 10-Bis (4-ClC6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione

9-(4-OH C6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione: FT-IR (KBr in

cm-1) 3286.91, 3056.78, 2914.20, 2872.61, 1666.86, 1512.53, 1593.36, 832.62,

805.15; UV-Vis. λ max – 893.5 nm Absorbance at 0.142 Å; m/z = 365 (M+H) +. 1H-

NMR (400 MHz, DMSO-d6): d = 0.75 (s, 6 H, 2 CH3), 0.88 (s, 6 H, 2 CH3), 1.75-1.99

(d, J = 17.6 Hz, 2 H, 2 CH2), 2.14-2.21 (d, J = 16.0 Hz, 2 H, 2 CH2), 4.85 (s, 1 H,

CH), 6.61(m, 2H, ArH), 7.02 (m, 2 H, ArH), 9.02 (s, 1H, NH), 9.25 (s, 1H, OH).

469.5 470.0 470.5 471.0 471.5 472.0 472.5 473.0 m/z

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Inten.(x100)

470.50

202 Adya Jain et al

Fig 15: FT-IR of 9-(4-OH C6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione

Fig 16: 1H-NMR of 9, 10-Bis (4-ClC6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione

4000 3500 3000 2500 2000 1500 1000 500

10

20

30

40

50

60

70

% T

rans

mitt

ance

Wavelength (cm-1)

9(4-OH C6H

6)Acridinedione


Fig 17: LC-MS of 9, 10-Bis (4-ClC6H4)-3, 3, 6, 6-tetramethyl acridine-1, 8-dione

4. CONCLUSION

The foremost merits of this work are significant due to its competency,

environmentally benevolent methodology, recyclable as well as thermally stable

zeolite heterogeneous catalytic applicability. In this study we found that, with

escalating electronegativity, ionization energy decreases consequently reactivity

increases since it uses less energy to lose electrons. The reactivity order H (2.1) > Cr

(1.6) has been confirmed experimentally. The reactivity was found highest in ethanol

with H-β at 90ºC for 60 min. i.e. 89.88%. Further the yield of different derivative is

affected by the presence of electron withdrawing groups (EWG) and electron

donating groups (EDG). Yield of acridine drugs having EWG was found higher than

those for having EDG.

5. ACKNOWLEDGEMENT

I owe to my mentor for supporting and guiding me to make this work possible and

Central Instrumentation Laboratory (CIF), Jiwaji University, Gwalior, M.P. for

providing necessary instrument support (FT-IR, XRD, LC-MS). I am also thankful to

DRDE, Gwalior for providing BET surface area studies and IIT Delhi for 1H-NMR

studies.

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