Microwave Assisted Knoevenagel Condensation - Scientific Journals

M.M.H. Bhuiyan et al / Chemistry Journal (2012), Vol. 02, Issue 01, pp. 30-36 ISSN 2049-954X 

Research Paper 

Microwave Assisted Knoevenagel Condensation: 

Synthesis and Antimicrobial Activities of Some 

Arylidene-malononitriles 

M.M.H. Bhuiyan*, M.I. Hossain, M. Ashraful Alam and M.M. Mahmud 

Department of Chemistry, University of Chittagong, Chittagong 4331, Bangladesh 

* E-Mail: mosharef65@yahoo.com 

Abstract 

Eleven arylidene-malononitriles, viz. 2-(1-naphthylidene)-malononitrile (1), 2-(4-N,N-dimethylaminobenzylidene)- 

malononitrile (2), 2-(4-hydroxy-3-methoxybenzylidene)-malononitrile (3), 2-(3-methoxybenzylidene)-malononitrile (4), 2- 

(2-methylbenzylidene)-malononitrile(5), 2-(4-hydroxybenzylidene)-malononitrile (6), 2-(3-methylbenzylidene)- 

malononitrile (7), 2-(2,4-dimethoxybenzylidene)-malononitrile (8), 2-(3-nitrobenzylidene)-malononitrile (9), 2-(9- 

anthracenylidene)-malononitrile (10) and 2-[3-(4-dimethylaminophenyl)-allylidene]-malononitrile (11) were prepared by 

Knoevenagel condensation reaction of malononitrile with corresponding aromatic aldehydes in presence of ammonium 

acetate (NH 4 OAc), using microwave irradiation under solvent free condition. The reaction is clean with shorter reaction 

time, mild reaction condition, eco-friendly, excellent yields as compared to conventional methods and reduces the use of 

volatile organic compounds (VOCs). Variety of functional groups such as nitro, chloro, amino and ether survived under the 

reaction conditions. The structures of the arylidene-malononitriles have been established on the basis of their IR, NMR 

spectral data and elemental analyses. These compounds were screened for their antibacterial activities against five 

pathogenic organisms: Bacillus cereus (BTCC 19), Staphylococcus aureus (ATCC 6538), Vibrio choloriae, Shigella 

dysenteriae (AE 14396) and Salmonella typhi (AE 14612) (Table 1) and antifungal activities against two organisms: 

Aspargilllus flavus and Saccharomyces cerevisiae (Table 2) using disc diffusion method and poisoned-food technique 

respectively. Some of them were found to possess significant activity, when compared to standard drugs. 

Keywords: Arylidene-malononitriles, Microwave Irradiation, Antimicrobial Activity 

1. Introduction 

Organic reactions under solvent-free conditions (Tanaka et 

al, 2000 & Knochel, 1999) have increasingly attracted 

chemists’ interests, particularly from the viewpoint of 

green chemistry (Anastas et al, 1998). The Knoevenagel 

condensation is one of the most important, useful and 

widely employed methods for the formation of carboncarbon 

bonds (Tietze et al, 1991). It has been used for the 

preparation of a range of substituted alkenes and bioactive 

molecules, and as a key step in natural product synthesis. 

The reagent malononitrile is a methylene active compound 

largely used in the Knoevenagel condensation. The 

arylidenemalononitriles thus obtained have found 

increasing applications in industry, agriculture, medicine, 

biological science and in the elegant 

synthesis of fine chemicals (Fatiadi, 1978 & Freeman, 

1980). They are important intermediates for the synthesis 

of various organic compounds, mainly by 

cyclization reactions (Campaigne et al, 1976). Moreover, 

benzylidenemalononitriles were reported to be effective 

anti-fouling agents, fungicides, insecticides and used as 

cytotoxic agents against tumours or as riot control agents 

(Jones, 1972). 

Available online at www.scientific-journals.co.uk 30


In general, the Knoevenagel condensation is catalyzed 

by organic bases such as aliphatic amines, ethylenediamine 

and piperidine or their corresponding ammonium 

salts, Lewis bases and acids including ZnCl 2 , CdI 2 , 

TiCl 4 , Al 2 O 3 , MgO, ZnO, AlPO 4 –Al 2 O 3 , KF–Al 2 O 3 , 

natural hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) (Mallouk et al, 

2010) and ammonium acetate (NH 4 OAc)-basic alumina 

(Balalaie et al, 2000). However, this employs hazardous 

benzene and requires prolonged heating with continuous 

water removal. The use of such bases/acids and solvents 

has led to environmental problems, i.e. the necessity to 

dispose huge amount of organic waste due to the formation 

of undesirable side products. Electrochemical, microwave 

and ultrasound activation methods have also been reported 

(Wang et al, 2002; Li et al, 2004; Feroci et al, 2007). 

Recently microwave radiation a non-conventional energy 

source for the activation of reactions has gained the 

attention of chemists due to its unique advantages, such as 

shorter reaction times, cleaner reaction products, higher 

yields and better selectivities (Kappe, 2004; Kappe et al, 

2009 & Bougrin et al, 2006). Moreover, the combination 

of MW activation and solvent-free conditions lead to 

enhanced conversion rates, higher yields, easier work-up 

and in general, cleaner reactions confirming therefore the 

real advantages of this approach in the framework of green 

chemistry. 

In continuation of our earlier studies directed at the 

development of practical and efficient chemical processes 

(Basu et al, 2003; Bhuiyan et al, 2011 & 2012), we report 

herein a sustainable Knoevenagel condensation protocol 

using microwave irradiation (MWI) and ammonium 

acetate (NH 4 OAc) catalysis under solvent-free conditions. 

2. Experimental 

2.1. Physical Measurements 

Melting points were recorded with electro thermal melting 

point apparatus and were uncorrected. Thin layer 

chromatography was performed on Kieselgel GF 254 and 

visualization was accomplished by iodine vapour or UV 

Flame. The infrared (IR) spectra were recorded by FTIR 

spectrophotometer (Model-8900, Shimadzu, Japan) using 

KBr matrix in the range 4000-200 cm -1 . 1 H-NMR (400 

MHz and 500 MHz) and 13 C-NMR (100 MHz and 125 

MHz) spectra were recorded on JEOL GS×400, GEOL 

JNM-AL 400 (400 MHz) and JEOL GS×400, GEOL JNM- 

AL 400 (100 MHz) spectrometer in CDCl 3 , CD 3 OD and 

DMSO-d 6 at solvent. Chemical shifts were reported in δ 

unit (ppm) with reference to TMS as an internal standard 

and J values were given in Hz. The carbon, hydrogen and 

nitrogen percentages in synthesized products were 

analyzed according to the approved method ASTM D- 

5291 by employing Leco-CHNS-932 analyzer. All 

reactions were carried out in a commercially available LG 

microwave oven (MB – 3947C) having a maximum power 

output of 800 W operating at 2450 MHz. 

2.2. General Procedure for the Synthesis of Arylidenemalononitriles 

To an equimolar mixture of aromatic aldehyde and 

malononitrile catalytic amount of ammonium acetate was 

added and the reaction mixture irradiated under microwave 

condition at 160 watt for 20-60 sec. After complete 

conversion of the reaction (TLC; ethyl acetate: n-hexane; 

1:5, v/v), the obtained solid mass was recrystallized from 

ethyl acetate and n-hexane solvent mixture. 

2.2.1. Spectral Data 

2-(1-naphthylidene)-malononitrile (1): yellow crystals, 

IR (KBr) υ max (cm -1 ): 3028.03 (=C-H), 2223.77 (C≡N), 

1564.16 (s, C=C), 1506.3 (s, C=C, Ar). 1 H-NMR (400 

MHz, CDCl 3 ): δ H (ppm): 8.67 (s, 1H, =CH), 8.29 (d, 1H, 

H-8, J = 7.32 Hz), 8.12 (d, 1H, H-5, J = 8.72 Hz), 7.96 (d, 

2H, H-2, H-4, J = 8.72 Hz), 7.66 (m, 3H, H-3, H-6, H-7). 

13 C-NMR (100.40 MHz, CDCl 3 ): δ C (ppm): 157.70, 

134.91, 133.49, 131.02, 129.40, 128.55, 128.49, 127.46, 

127.27, 125.36, 122.26, 113.69, 112.48, 85.10. DEPT – 90 

(100.40 MHz, CDCl 3 ): δ C (ppm): 157.71, 134.92, 129.41, 

128.56, 128.50, 127.28, 125.37, 122.26. DEPT – 135 

(100.40 MHz, CDCl 3 ): δ C (ppm): 157.71, 134.92, 129.41, 

128.56, 128.50, 127.28, 125.37, 122.26. Analysis 

calculated for C 14 H 8 N 2 (204.23): C, 82.34%; H, 3.95%; N, 

13.72%; Found: C, 81.44%; H, 4.55%; N, 14.52%. 

2-(4-N,N-dimethylaminobenzylidene)-malononitrile (2): 

orange red crystals, IR (KBr) υ max (cm -1 ): 2925.81 (C-H), 

2206.41 (s, C≡N), 1612.36 (s, C=C), 1566.09 (s, C=C, Ph). 

1 H-NMR (400 MHz, CDCl 3 ): δ H (ppm): 7.82 (d, 2H, H-2, 

H-6 J = 9.16 Hz,), 7.47 (s, 1H, =CH), 6.69 (d, 2H, H-3, H- 

5, J =9.16 Hz), 3.14 (s, 6H, 2×CH 3 ). 13 C-NMR (100.40 

MHz, CDCl 3 ): δ C (ppm): 158.05, 154.17, 133.76, 119.20, 

115.98, 114.90, 111.54, 40.08. DEPT – 90 (100.40 MHz, 

CDCl 3 ): δ C (ppm): 158.05, 133.77, 111.54. DEPT – 135 

(100.40 MHz, CDCl 3 ): δ C (ppm): 158.05, 133.77, 111.54, 

40.08 (CH 3 ). Analysis calculated for C 12 H 11 N 3 (197.24): C, 

73.07%; H, 5.62%; N, 21.30%; Found : C, 72.57%; H, 

6.12%; N, 20.91%. 

2-(4-hydroxy-3-methoxybenzylidene)-malononitrile (3): 

reddish yellow crystals, IR (KBr) υ max (cm -1 ): 3309.62 (b, 

OH), 3024.16 (C-H), 2231.40 (s, C≡N), 1604.66 (s, C=C), 

1564.16 (s, C=C, Ph), 1191.93 (s, C-O str, ether). 1 H-NMR 

(400 MHz, CD 3 OD): δ H (ppm): 7.95 (d, 1H, J = 9.12 Hz), 

7.70 (s, 1H, =CH), 7.44 (s, 1H,), 6.91 (d, 1H, J = 8.68 Hz), 

3.89 (s, 3H, OCH 3 ). 13 C-NMR (100.40 MHz, CD 3 OD): δ C 

(ppm): 161.09, 154.99, 149.30, 129.42, 124.85, 116.89, 

115.92, 115.10, 113.05, 77.09, 56.32. DEPT – 90 (100.40 



MHz, CD 3 OD): δ C (ppm): 161.10, 129.42, 116.89, 113.07. 

DEPT – 135 (100.40 MHz, CDCl 3 ): δ C (ppm): 161.10, 

129.42, 116.89, 113.07, 56.32 (OCH 3 ). Analysis calculated 

for C 11 H 8 N 2 O 2 (200.20): C, 66.00%; H, 4.03%; N, 

13.99%; Found: C, 65.34%; H, 3.84%; N, 14.26%. 

2-(3-methoxybenzylidene)-malononitrile (4): deep 

yellow crystals, IR (KBr) υ max (cm -1 ): 3089.75-2941.24 (C- 

H), 2227.63 (s, C≡N), 1595.02 (s, C=C), 1569.95 (s, C=C, 

Ph), 1161.07 (s, C-O str, ether). 1 H-NMR (400 MHz, 

CD 3 OD): δ H (ppm): 8.17 (s, 1H, =CH), 7.55 (s, 1H, H-2), 

7.50 (t, 1H, H-5, J = 7.32 Hz), 7.46 (d, 1H, H-6, J = 6.84 

Hz), 7.22 (d, 1H, H-4, J = 8.24 Hz), 3.85 (s, 3H, OCH 3 ). 

13 C-NMR (100.40 MHz, CDCl 3 ): δ C (ppm): 161.92, 

161.57, 133.96, 131.59, 124.58, 121.73, 115.67, 115.01, 

114.09, 83.53, 56.01. DEPT – 135 (125 MHz, CD 3 OD): δ C 

(ppm): 161.92, 131.59, 124.58, 121.74, 115.67, 56.01 

(OCH 3 ). Analysis calculated for C 11 H 8 N 2 O (184.20): C, 

71.73%; H, 4.38%; N, 15.21%; Found: C, 72.24%; H, 

5.36%; N, 15.71%. 

2-(2-methylbenzylidene)-malononitrile (5): gray crystals 

IR (KBr) υ max (cm -1 ): 3045.39-22927.74 (C-H), 2221.84 (s, 

C≡N), 1573.81 (s, C=C). 1 H-NMR (400 MHz, CD 3 OD): δ H 

(ppm): 8.47 (s, 1H, =CH), 8.00 (d, 1H, H-6 J = 7.76 Hz), 

7.49 (d, 1H, H-3, J = 7.92 Hz), 7.36 (t, 2H, H-4, H-5, J = 

7.32 Hz), 2.44 (s, 3H, CH 3 ). 13 C-NMR (100.40 MHz, 

CD 3 OD): δ C (ppm): 160.73, 141.30, 134.77, 132.32, 

131.83, 129.23, 127.66, 114.93, 113.88, 85.22, 19.65. 


134.77, 132.31, 129.23, 127.66. DEPT – 135 (100.40 

MHz, CDCl 3 ): δ C (ppm): 160.73, 134.77, 132.32, 129.23, 

127.66, 19.66 (CH 3 ). Analysis calculated for C 11 H 8 N 2 

(168.20): C, 78.55%; H, 4.79%; N, 16.65%; Found: C, 

79.25%; H, 5.04%; N, 16.37%. 

2-(4-hydroxybenzylidene)-malononitrile (6): gray 

crystalline solid, IR (KBr) υ max (cm -1 ): 3350.12 (b, OH), 

3026.10 (C-H), 2223.77 (s, C≡N), 1569.95 (s, C=C), 

1511.16 (s, C=C, Ph). 1 H-NMR (400 MHz, CD 3 OD): δ H 

(ppm): 7.97(s, 1H, =CH), 7.89 (s, 2H), 6.91 (d, 2H, J = 6.4 

Hz). 13 C-NMR (100.40 MHz, CD 3 OD): δ C (ppm): 165.34, 

160.98, 134.99, 124.51, 117.46, 115.90, 114.95, 77.31. 

DEPT–90 (100.40 MHz, CD 3 OD): δ C (ppm): 160.99, 

134.99, 117.46. DEPT – 135 (100.40 MHz, CD 3 OD): δ C 

(ppm): 160.99, 134.98, 117.46. Analysis calculated for 

C 10 H 6 N 2 O (170.17): C, 70.58%; H, 3.55%; N, 16.46%; 

Found: C, 71.16%; H, 3.3%; N, 15.86%. 

2-(3-methylbenzylidene)-malononitrile (7): light gray 

crystalline solid, IR (KBr) υ max (cm -1 ): 3093.39-2925.81 

(C-H), 2225.70 (s, C≡N), 1596.95 (s, C=C). 

1 H-NMR 

(400 MHz, CDCl 3 ): δ H (ppm): 7.73 (d, 2H, J = 5.52 Hz), 

7.69 (s, 1H, =CH), 7.44 (s, 1H), 7.42 (t, 1H, J = 7.80 Hz), 

2.43 (s, 3H, CH 3 ). 13 C-NMR (100.40 MHz, CDCl 3 ): δ C 

(ppm): 160.17, 139.59, 135.55, 131.26, 130.89, 129.47, 

127.88, 113.81, 112.62, 82.31, 21.24. DEPT – 90 (100.40 

MHz, CDCl 3 ): δ C (ppm): 160.16, 135.56, 131.26, 129.47, 

127.88. DEPT – 135 (100.40 MHz, CDCl 3 ): δ C (ppm): 

160.16, 135.56, 131.25, 129.47, 127.87 , 21.24 (CH 3 ). 

Analysis calculated for C 11 H 8 N 2 (168.20): C, 78.55%; H, 

4.79%; N, 16.65%; Found: C, 78.30%; H, 4.05%; N, 

17.82%. 

2-(2,4-dimethoxybenzylidene)-malononitrile (8): yellow 

crystals, IR (KBr) υ max (cm -1 ): 3122-2975 (C-H), 2219.91 

(s, C≡N), 1610.45 (s, C=C), 1562.23(s, C=C, Ph), 1120.56 

(s, C-O str, ether). 1 H-NMR (400 MHz, CDCl 3 ): δ H (ppm): 

8.28 (d, 1H, J = 7.32 Hz, H-6’), 8.19 (s, 1H, =CH), 6.61 

(d, 1H, J = 7.32, H-5’), 6.44 (s, 1H, H-3’), 3.91 (s, 3H, 

OCH 3 ), 3.90 (s, 3H, OCH 3 ). 13 C-NMR (100.40 MHz, 

CDCl 3 ): δ C (ppm): 167.18, 161.50, 153.22, 130.96, 

115.47, 114.29, 114.06, 107.04, 98.24, 77.64, 56.26, 56.16. 


130.97, 107.04, 98.24. DEPT – 135 (100.40 MHz, CDCl 3 ): 

δ C (ppm): 153.21, 130.97, 107.04, 98.24, 56.26 (OCH 3 ), 

56.15 (OCH 3 ). Analysis calculated for C 12 H 10 N 2 O 2 

(214.23): C, 67.28%; H, 4.71%; N, 13.08%; Found: C, 

66.17%; H, 5.11%; N, 12.74%. 

2-(3-nitrobenzylidene)-malononitrile (9): off-white 


(s, C≡N), 1610.45 (s, C=C), 1595.02 (s, C=C), 1529.45 

(NO 2 , sym. str.), 1479.30 (NO 2 , asym. str.). 1 H-NMR (400 

MHz, CD 3 OD): δ H (ppm): 8.31 (s, 1H, =CH), 8.45-8.33 

(m, 3H, H-4, H-5, H-6), 7.86 (s, 1H, H-2). 13 C-NMR 

(100.40 MHz, CD 3 OD): δ C (ppm): 159.74, 149.81, 

136.96, 133.99, 132.00, 128.89, 125.99, 114.53, 113.52, 

86.78. DEPT – 90 (100.40 MHz, CD 3 OD): δ C (ppm): 

159.74, 136.96, 132.00, 128.90, 126.00. DEPT – 135 

(100.40 MHz, CD 3 OD): δ C (ppm): 159.74, 136.96, 132.00, 

128.90, 126.00. Analysis calculated for C 10 H 5 N 3 O 2 

(199.17): C, 60.31%; H, 2.53%; N, 21.10%; Found: C, 

60.17%; H, 2.69%; N, 20.75%. 

2-(9-anthracenylidene)-malononitrile (10): orange 


(s, C≡N), 1573.81 (C=C), 1550.66 (s, C=C). 1 H-NMR 

(500 MHz, CDCl 3 ): δ H (ppm): 8.97 (s, 1H, H-10), 8.67 (s, 

1H, =CH), 8.11 (d, 2H, J = 8.60 Hz), 7.94 (d, 2H, J = 9.15 

Hz), 7.69 (t, 2H, J = 6.85 Hz), 7.59 (t, 2H, J = 7.45 Hz). 

13 C-NMR (125 MHz, CDCl 3 ): δ C (ppm): 161.93, 133.83, 

132.19, 130.84, 130.38, 129.66, 127.36, 125.17, 124.66, 

114.31, 112.69, 93.59. DEPT – 90 (125 MHz, CDCl 3 ): δ C 

(ppm): 161.93, 133.83, 130.85, 129.66, 127.36, 125.17. 

DEPT – 135 (125 MHz, CDCl 3 ): δ C (ppm): 161.93, 

133.83, 130.85, 129.66, 127.36, 125.17. Analysis 

calculated for C 18 H 10 N 2 (254.29): C, 85.02%; H, 3.96%; N, 

11.02%; Found: C, 84.81%; H, 4.66%; N, 10.13%. 

2-[3-(4-dimethylaminophenyl)-allylidene]-malononitrile 



(11): deep violet crystals, IR (KBr) υ max (cm -1 ): 3087-2815 

(C-H), 2208.34 (s, C≡N), 1585.38 (s, C=C), 1544.88 (s, 

C=C, Ph). 1 H-NMR (500 MHz, DMSO-d 6 ): δ H (ppm): 8.06 

(d, 1H, J = 11.85 Hz), 7.58 (d, 2H, H-2, H-6, J = 8.60 Hz), 

7.47 (d, 1H, J = 14.9 Hz), 6.94 (dd, 1H, J = 12.05 Hz, 2.85 

Hz), 6.75 (d, 2H, H-3, H-5, J = 6.80 Hz), 3.04 (s, 6H, 

2×CH 3 ). 13 C-NMR (125 MHz, CDCl 3 ): δ C (ppm): 162.03, 

153.02, 131.94, 121.38, 116.64, 115.49, 113.51, 112.02, 

73.13, 39.67, 39.65. DEPT – 135 (125 MHz, DMSO-d 6 ): 

δ C (ppm): 162.03, 153.02, 131.94, 116.65, 112.02, 39.67 

(CH 3 ), 39.65 (CH 3 ). Analysis calculated for C 14 H 13 N 3 

(223.28): C, 75.31%; H, 5.87%; N, 18.82%; Found: C, 

74.71%; H, 6.27%; N, 19.31%. 

2.3. Antimicrobial Screening 

The synthesized compounds (1-11) were screened for 

antibacterial activity against five pathogenic organisms: 

Bacillus cereus (BTCC 19), Staphylococcus aureus 

(ATCC 6538), Vibrio choloriae, Shigella dysenteriae (AE 

14396) and Salmonella typhi (AE 14612 (Table 1) and 

antifungal activity against two organisms: Aspargilllus 

flavus and Saccharomyces cerevisiae (Table 2). The disc 

diffusion method (Bauer et al, 1966) and poisoned-food 

technique (Grover et al, 1962) were used for antibacterial 

and antifungal activities, respectively. 

eleven ylidene-malononitrile derivatives from several 

aromatic aldehydes and active methylene compound 

malononitrile in the presence of catalytic amount of 

NH 4 OAc by modified Knoevenagel reaction using 

microwave irradiation, as indicated in Scheme 1 and Table 

3. The corresponding reactions proceeded smoothly and in 

excellent yields (85-99%). 

An important feature of this procedure is the survival of 

variety of functional groups such as nitro, chloro, amino 

and ether under the reaction conditions. The structures of 

the products were established from their IR, 1 H NMR, 13 C 

NMR and elemental analyses. For example, the IR 

spectrum of compound 11 displayed a band absorption 

2208.34 cm -1 for C≡N group. The absorption bands at 

1585.38 cm -1 and 1544.88 cm -1 were due to C=C and 

aromatic ring. The 1 H NMR spectrum of 11 exhibited two 

doublet signals resonated at δ 7.58 ppm and at δ 6.75 ppm 

with J values 8.60 Hz and 6.80 Hz were designated to four 

aromatic protons of H-2’, H-6’, H-3’ and H-5’. A doublet 

signal at a lower field, δ 8.06 ppm (J= 11.85 Hz) was 

attributed to H-3 of allylidene which was coupled with H-4 

in a trans-relationship. Another doublet at δ 7.47 ppm (J = 

14.9 Hz) attributed to H-5 of the conjugated system which 

was coupled with H-4 in a trans-relationship. H-4 of the 

conjugated system appeared as a doublet of doublet 

Ar 

H 

O 

+ 

CN 

CN 

NH 4 

OAc 

MWI 

Ar 

H 

(1-11) 

CN 

CN 

Scheme 1 

Scheme 1 

The tested compounds were dissolved in N,Ndimethylformamide 

(DMF) to get a solution of 1 mg ml –1 . 

The inhibition zones were measured in millimeters at the 

end of an incubation period of 48 hours at (35±2) °C. DMF 

alone showed no inhibition. Nutrient agar (NA) and potato 

dextrose agar (PDA) were used as basal media to test the 

bacteria and fungi, respectively. Commercial antibacterial 

Ampicillin and antifungal Nystatin were also tested under 

similar conditions for comparison. 

3. Results and Discussion 

As already mentioned in the introduction various methods 

for the synthesis of ylidene-malononitrile have been 

developed and employed successfully on the light of green 

chemistry aspects. In the present work, we synthesized 

centered at δ 6.94 ppm (J = 12.05 Hz, 2.85 Hz) coupled 

with H-3 and H-5. A six-proton singlet displayed at δ 3.04 

ppm attributed to –N(CH 3 ) 2 group. The 13 C NMR spectrum 

of compound 11 showed the presence of eleven signals 

attributed to fourteen carbons corresponding molecular 

formula C 14 H 13 N 3 . The spectrum displayed a downfield 

peak at δ 162.03 ppm was assigned for C-3 of the 

allylidene group (=CH). CN and =C< appeared at δ 113.51 

and 73.13 ppm. Two methyl (CH 3 ) carbons appeared at δ 

39.67 ppm and 39.65 ppm slightly downfield due to 

electron withdrawing nitrogen atom. The peaks at δ (ppm) 

153.02, 131.94, 121.38, 116.64, 115.49, 112.02 were for 

the remaining carbons. The DEPT–135 spectrum of 

compound 11 showed peaks at δ (ppm) 162.03, 153.02, 

131.94, 116.65, 112.02 attributed to seven methine carbons 

(CH). The microanalytical data of the compound 11 is also 



Table 1. Antibacterial Activity of the Synthesized Compounds (1-11) 

Compound 

No. 

Diameter of zone of inhibition in mm(100 mg (dw)/ disc) 

B. cereus S. aureus V. choloriae S. dysenteriae S. typhi 

1 -- -- 7 -- -- 

2 7 -- 7 -- -- 

3 7 -- 6 -- 7 

4 8 6 9 6 7 

5 9 8 8.5 -- 8 

6 9 8 8.5 -- 8 

7 6.5 6.5 7 6.5 7 

8 7 6 -- -- 7 

9 -- 6.5 8 -- 6 

10 -- 6.5 6.5 -- -- 

11 -- -- 7 -- -- 

Ampicillin 20 12 17 30 24 

N.B :-‘(--)’ Means no inhibition; dw: Denotes dry weight 

Table 2. 

Compound 

No. 

Antifungal Activity of The Synthesized Compounds 

(1-11) 

% Inhibition of Mycelial Growth 

(100 µg(dw)/ml PDA) 

Aspargillus 

flavus 

Saccharromyces 

cerevisiae 

1 87* 87* 

2 85* 90* 

3 82* 75 

4 87* 87* 

5 69 67 

6 82* 87 * 

7 87* 62 

8 69 84 

9 75 92* 

10 78 87* 

11 75 85* 

Nystatin 90 80 

N.B :- ‘*’ Means good inhibition; dw: Denotes dry weight 

in good agreement with the assigned structure. Similarly 

the peaks in 1 H-NMR and 13 C-NMR spectra of rest of the 

compounds were accordance with assigned structures. 

Most of the compounds showed good to moderate 

antimicrobial activities and a few of them were unable to 

show inhibition for some pathogens. For the antifungal 

activity, all compounds showed excellent results against all 

fungi and are comparable to that of the standard antibiotic, 

Nystatin. 

4. Conclusion 

In this work, we have demonstrated the synthesis of 

ylidene-malononitrile by microwave irradiation using 

NH 4 OAc under and solvent free condition. The advantages 

of this method are high yields, relatively short reaction 

times, low cost, simple experimental and as isolation 

procedures, and finally, it is in agreement with the green 

chemistry protocols. The activity data obtained during the 

study will be certainly useful to go for further research for 

drug designing and synthesizing new ylidene-malononitrile 

derivatives. 



Table 3. Microwave Assisted Knoevenagel Reaction Between Various Aldehydes and Malononitrile 

Comp. No. Substrate Product 

Watt/ 

Time(sec) 

Yield 

(%) 

M. P. °C 

1 

C N 

160/30 96 167-168 

C H O 

H 

C N 

2 

C H 3 

CH 3 

N 

C H 3 

N 

H 3 

C 

C N 160/30 95 190-191 

3 

CHO 

H C N 

HO 

HO 

CN 

160/20 98 135-136 

H C O 

H 3 

C O CHO 

3 

H CN 

4 

C N 

160/50 99 107-108 

H C O 

H 3 

C O 

C H O 

3 

H C N 

5 

6 

HO 

CH 3 

CHO 

CHO 

HO 

C H 3 

C N 

160/50 97 106-107 

H C N 

CN 

160/40 85 185-186 

H CN 

C H 3 

7 

C H 3 

C N 160/40 94 74-75 

8 

C H 3 

O 

C H O 

O CH 3 

CHO 

H C N 

H 3 

C O 

O CH 3 

CN 

160/60 93 141-142 

H CN 

N O 2 

N O 2 

160/30 96 107-108 

9 

C N 

C H O 

H 

C N 

10 

C H O 

H 

C N 

C N 

160/30 94 204-206 

11 

C 

C H 3 

N 

C H 3 

CH 3 

N 

C N 

CN 

160/30 95 147-148 

H 3 

C H O H 

H 



Acknowledgments 

The authors wish to thank Dr. A. Rahman, Department of 

Biochemistry and Molecular Biology, University of 

Chittagong, Bangladesh, for his cooperation in 

determining the antimicrobial activity of the synthesized 

compounds. We also wish to thank Dr. M. Al-Amin, JSPS 

Postdoctoral Fellow, Department of Chemistry, Hokkaido 

University, Japan for recording the spectral data. 

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