ABSTRACT A series of substituted pyridinyl 1, 3, 4 oxadiazole derivatives were synthesized from Schiff bases of nicotinic acid derivatives through chlorination followed by reaction with hydrazine hydrate and with the use various aldehydes. The synthesized compounds were characterized by elemental analysis, IR, 1 H NMR and Mass Spectra. All the compounds were screened for in vitro antioxidant activity by DPPH and Nitric oxide scavenging assay. Compounds substituted with electron donating groups like methoxy and hydroxyl showed higher antioxidant activity

M Vijey Aanandhi

Mohammed Hashim Mansoori

P Shanmugasundaram

S Shanmugapriya

Shiny George

CiteSeerX

          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1083 
 
Research Journal of Pharmaceutical, Biological and Chemical 
Sciences 
 
Synthesis and In- vitro antioxidant activity of substituted Pyridinyl 1, 3, 4 
oxadiazole derivatives 
 
M Vijey Aanandhi*, Mohammed Hashim Mansoori, S Shanmugapriya, Shiny George,  
P Shanmugasundaram 
 
Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, VELS University, Chennai-600117, 
Tamilnadu, India. 
 
 
 
 
 
ABSTRACT 
 
A series of substituted pyridinyl 1, 3, 4 oxadiazole derivatives were synthesized from Schiff bases of 
nicotinic acid derivatives through chlorination followed by reaction with hydrazine hydrate and with the use 
various aldehydes. The synthesized compounds were characterized by elemental analysis, IR, 
1
H NMR and Mass 
Spectra. All the compounds were screened for in vitro antioxidant activity by DPPH and Nitric oxide scavenging 
assay. Compounds substituted with electron donating groups like methoxy and hydroxyl showed higher 
antioxidant activity. 
Keywords: Nicotinic acid, Schiff base, oxadiazole and antioxidant activity. 
 
 
 
 
 
 
 
 
 
 
 
*Corresponding author 
Email: mvaanandhi@gmail.com 
 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1084 
 
INTRODUCTION 
 
From the past few decades the research on nicotinic acid derivative revealed that the 
derivative had wide range of therapeutic application such as antimicrobial[1], antimycobial [2], 
anti-inflammatory [3], anticancer [4], antiviral [5], anticonvulsant [6] and antioxidant activity 
[7]. The versatile applications of nicotinic acid have given zeal to design and synthesize the 
novel derivatives with the aim to achieve antioxidant activity. Oxadiazole derivatives also found 
to possess anthelmintic [8], antibacterial [9], anti-inflammatory [10] and antioxidant [11] 
activities. 
 
In the present study nicotinic acid was converted to nicotinoyl chloride in the presence 
of phosphorous pentachloride and carbon tetrachloride. This was converted to nicotino 
hydrazide in presence of hydrazine hydrate and this was converted to Schiff base derivatives  in 
presence of different aromatic aldehydes and further acetylation of schiff base in presence of 
acetic anhydride yielded 1,3,4 oxadiazole derivatives respectively (Scheme 1). 
 
MATERIALS AND METHODS 
 
Melting points were determined by open capillary method and were uncorrected. The 
reaction was monitored by TLC using solvent Chloroform: Methanol (50:50 ratio). FT-IR spectra 
was recorded on Shimadzu FT 8300, 1H NMR were recorded at JEOL GSX400 and Mass spectra 
an JEOL GC Mate spectrometer. The elemental analysis was obtained on a CHN Rapid analyser 
and all compounds showed satisfactory elemental analysis. 
 
EXPERIMENTAL 
 
Synthesis of Nicotinoyl chloride (2) 
 
A mixture of nicotinic acid (0.03 mol) and phosphorus pentachloride (0.05 ml) in 
anhydrous carbon tetra chloride (20 ml) was refluxed for two hours at 100°C. Solvent was 
distilled off and the acid chloride thus obtained was used for further reaction. 
 
Synthesis of Nicotino Hydrazide (3) 
 
In the acid chloride (0.03 mol) hydrazine hydrate was added (0.1 mol) drop wise at 0°C 
and the resultant mixture was separated out was washed with aqueous sodium carbonate 
(10%) and dried vaccum. It was recrystalized from methanol. 
 
Synthesis of Schiff bases (4) 
 
The nicotino hydrazide (0.01 mol) and aromatic aldehyde (0.01 mol) in tetra hydrofuran 
(25 ml) was heated gently for two hours at a temperature of 60°C. The reaction mixture was 
then poured into ice cold water and it was filtered. The pure compound recrystalized was from 
methanol. 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1085 
 
Acetylation of Schiff base derivatives (5) 
 
The mixture of Schiff base (0.01 mol) and acetic anhydride (10 ml) was dissolved in 
ethanol (25 ml) and the reaction mixture was refluxed for two hours at 100°C. The reaction 
mixture was then concentrated, allowed to cool, the solid product obtained was filtered, 
washed with water and recrystallized using methanol. The physical data of synthesized 
compounds are given in Table 1. 
 
Spectral Analysis 
 
1-(2-phenyl-5-(pyridin-3-yl)-1,3,4-oxadiazole-3 (2H)-yl) ethanone (A): IR (KBr): 3009, 1686, 
2901, 1602, 1323, 1584, 1329 cm-1; 1H NMR (DMSO d6): δ 7.3-9.2 (M, 9H),  8.1 (S, 1H),  2.4 (S, 
3H); MS (relative intensity): m/z value 267.17 (10%), 103.41 (100%), 75.63 (75%), 84.18 (12%), 
92.58 (14%), 109.40 (13%), 120.26 (87%), 126.85 (15%), 135.09 (16%), 147.39 (17%), 163.54 
(16%), 171.15 (14%), 178.88 (10%), 186.44 (11%), 199.12 (14%), 207.31 (12%), 214.63 (14%), 
232.20 (17%), 243.77 (11%),249.30 (25%), 255.35 (18%). 
 
1-(2-(4-dimethylamino)phenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl ethanone (B): IR 
(KBr): 3080, 1701, 2924, 1632, 1361, 1597, 1421 cm-1; 1H NMR (DMSO d6): δ 6.6-9.2 (M, 8H), 8.1 
(S, 1H), 2.4 (S, 3H), 2.9 (S, 6H); MS (relative intensity): m/z value 310.25 (24%), 249.10 (100%), 
75.60 (40%), 88.76 (16%), 103.30 (55%), 112.85 (21%), 120.32 (46%), 135.68 (20%), 143.56 
(22%), 158.31 (18%), 167.98 (21%), 175.87 (14%), 200.74 (28%), 216.36 (44%), 232.34  (60%), 
242.55 (13%), 272.12 (18%), 297 (16%). 
 
1-(2-(2-chlorophenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl) ethanone (C): IR (KBr): 3058, 
1673, 2885, 1638, 1360, 1594, 1419, 762 cm-1; 1H NMR (DMSO d6): δ 7.2-9.2 (M, 8H), 8.1 (S, 
1H), 2.4 (S, 3H); MS (relative intensity): m/z value 301.51 (29%), 249 (100%), 89.26 (33%), 
103.22 (56%), 119.78 (54%), 127.70 (36%), 135.06 (48%), 147.29 (33%), 157.17 (34%), 165.89 
(23%), 178.54 (30%), 191.29 (28%), 199.10 (31%), 216 (40%), 223.47 (33%), 232.15 (64%), 
260.77 (30%), 266.31 (26%), 285.77 (28%), 295.77 (24%). 
 
1-(2-(2-Nitrophenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl) ethanone (D): IR (KBr): 3029, 
1669, 2849, 1651, 1343, 1593, 1420, 1420 cm-1; 1H NMR (DMSO d6): δ 7.6-9.2 (M, 8H), 8.1 (S, 
1H), 2.4 (S, 3H); MS (relative intensity): m/z value 312.71 (40%), 247.65 (100%), 80.21 (48%), 
86.64 (39%), 102.94 (54%), 108.92 (41%), 120.60 (44%), 135.59 (36%), 146.93 (40%), 155.80 
(28%), 172.39 (32%), 185.89 (28%), 200.65 (49%), 232.28 (69%), 259.77 (33%), 271.58 (37%), 
280.81 (29%), 300 (28%). 
 
1-(2-(4-Methoxyphenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl) ethanone (E): IR (KBr): 
3072, 1701, 2924, 1632, 1361, 1597, 1421, 1293 cm-1; 1H NMR (DMSO d6): δ 6.8-9.2 (M, 8H), 8.1 
(S, 1H), 2.4 (S, 3H), 3.7 (S, 3H); MS (relative intensity): m/z value 297.33 (43%), 247.28 (100%), 
76.65 (65%), 81.54 (60%), 85.20 (53%), 103.14 (79%), 111.11 (52%), 121.21 (49%), 137.93 
(55%), 165.50 (56%), 177.86 (48%), 198.57 (58%), 207.59 (50%), 219.86 (44%), 231.37 (92%), 
258.57 (40%), 272.54 (45%), 280.21 (52%). 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1086 
 
1-(2-(3-Chloro-4-nitrophenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl)ethanone (F): IR 
(KBr): 3000, 1700, 2900, 1640, 1375, 1596, 1423, 1468, 738 cm-1; 1H NMR (DMSO d6): δ 7.6-9.2 
(M, 7H), 8.1 (S, 1H), 2.4 (S, 3H); MS (relative intensity): m/z value 346.22 (56%), 120.99 (100%), 
76.42 (96%), 86.36 (56%), 103.34 (84%), 135.42 (64%), 142.80 (36%), 164.42 (50%), 174.53 
(48%), 187.34 (37%), 195.42 (68%), 216.27 (49%), 232.62 (61%), 247.28 (63%), 256.19 (40%), 
265.56 (60%), 277.74 (32%), 293.11 (34%), 305.23 (44%), 321.77 (40%), 329 (34%). 
 
1-(2-(3-nitrophenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl)ethanone (G): IR (KBr): 3195, 
1682, 2923, 1651, 1387, 15962, 1475 cm-1; 1H NMR (DMSO d6): δ 7.2-9.2 (M, 8H), 8.1 (S, 1H), 
2.4 (S, 3H); MS (relative intensity): m/z value 312.88 (14%), 58.38 (100%), 76.17 (12%), 
103.76(15%), 115.75 (10%), 148.38 (8%), 208.82 (4%), 235.59 (6%), 249.62 (2%), 262.86 (4%), 
277.32 (10%), 291.07 (8%), 302.05 (12%). 
 
 1-(2-(4-Hydroxy-3-methoxyphenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl) ethanone (H): 
IR (KBr): 3063, 1698, 2957, 1651, 1374, 1596, 1475, 1202, 3383, 130 cm-1; 
1H NMR (DMSO d6): δ 7.6-9.2 (M, 7H), 8.1 (S, 1H), 2.4 (S, 3H), 2.1(S, 1H), 3.8(S, 3H); MS (relative 
intensity): m/z value 313.09 (8%), 120.68 (100%), 76.17 (40%), 102.86 (55%), 58.40 (20%), 
134.62 (2%), 233.57 (3%), 279.36 (6%), 296.44 (4%), 306.74 (10%). 
 
 1-(5-pyridine-3-yl)-2-p-tolyl-1,3,4-oxadiazole-3(2H)-yl) ethanone (I): IR (KBr): 3212, 1699, 
3010, 1636, 1361, 1574, 1418, 1293 cm-1; 1H NMR (DMSO d6): δ 7.3-9.2 (M, 8H), 8.1 (S, 1H), 2.3 
(S, 3H), 2.4 (S, 3H); MS (relative intensity): m/z value 281.42 (2%), 103.69 (100%), 76.17 (80%), 
120.70 (55%), 58.38 (18%), 89.03 (12%), 130.59 (14%), 145.44 (16%), 206.03 (3%), 219.92(10%), 
238.81 (30%), 245.74 (6%). 
 
1-(2-(3,4-Dimethoxyphenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl)ethanone (J): 
 IR (KBr): 3210, 1698, 2915, 1652, 1373, 1596, 1417, 1301 cm-1; 1H NMR (DMSO d6): δ 7.5-9.2 
(M,7H), 8.1 (S,1H), 2.4 (S,3H), 3.6 (S,6H); MS (relative intensity): m/z value 327.92 (12%), 103.85 
(100%), 76.15 (48%), 84.18 (8%), 119.65 (16%), 129.43 (10%), 154.19 (6%), 194.82 (10%), 
208.78 (20%), 221.58 (16%), 235.63 (18%), 249.54 (12%), 279.33 (30%), 300.14 (35%), 313.09 
(32%). 
 
ANTIOXIDANT ACTIVITY 
 
In the present study DPPH scavenging and Nitric oxide scavenging assay are two in vitro 
methods used for screening the antioxidant activity. The antioxidant activity of the synthesized 
compounds was expressed as IC50 values.  
 
DPPH Assay method 
 
The antioxidant activity using the DPPH assay was assessed by the method of Tagashira 
and Ohtake [12]. Test sample solution (200 µL) was added to 4 mL of 100 mmol L–1 ethanolic 
DPPH. After vortexing, the mixture was incubated for 10 minutes at room temperature and the 
absorbance at 517 nm was measured. The difference in absorbance between a test sample and 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1087 
 
a control was considered as activity. The activity was shown as IC50 value (50% of inhibitory 
concentration in mg mL–1). BHT was used as reference substance. The antioxidant activity data 
is given in Table 2. 
 
Nitric oxide scavenging activity assay 
 
Nitric oxide radical scavenging activity was determined according to the method 
reported by Garrat [13]. Sodium nitroprusside in aqueous solution at physiological pH 
spontaneously generates nitric oxide, which interacts with oxygen to produce nitrite ions. 2 mL 
of 10 mM sodium nitroprusside in 0.5 mL phosphate buffer saline (pH 7.4) was mixed with 0.5 
mL of test solution at various concentrations and the mixture incubated at 25oC for 150 min. 
From the incubated mixture 0.5 mL was taken out and added into 1.0 mL sulfanilic acid reagent 
(33% in 20% glacial acetic acid) and incubated at room temperature for 5 min. finally, 1.0 mL 
naphthylethylene diamine dihydrochloride (0.1% w/v) was mixed and incubated at room 
temperature for 30 min before measuring the absorbance at 540 nm was measured with a 
spectrophotometer. The nitric oxide radicals scavenging activity was calculated and data is 
given in Table 3. 
 
RESULTS AND DISCUSSION 
 
All the targeted compounds were synthesized in good yield. The melting points of all 
synthesized compounds were found in open capillary tubes and readings were uncorrected. 
The synthesized compounds were screened for their in vitro antioxidant activity by DPPH, Nitric 
oxide scavenging method shows good antioxidant activity, out of all the synthesized 
compounds 1-(2-(4-Methoxyphenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl) ethanone (E), 
1-(2-(4-Hydroxy-3-methoxyphenyl)-5-(pyridine-3-yl)-1,3,4-oxadiazole-3(2H)-yl) ethanone (H) 
followed by I and J showed significant antioxidant activity, in these two methods except the 
compound F and G which showed less when compared to that of the standard butylated 
hydroxyl toluene. The compounds (E, H, I and J) substituted with electron donating groups like 
Methoxy and hydroxyl showed higher antioxidant activity compared to others.  
 
CONCLUSION 
 
A series of pyridyl 1,3,4 oxadiazole derivatives were synthesized by reaction of 
nicotinoyl chloride with various aromatic aldehydes and further acetylation. Synthesized 
compounds were screened for in vitro antioxidant assay and possess significant activity. The 
results revealed that the test compound is electron donor and could react with free radical 
chain reaction. 
 
ACKNOWLEDGEMENT 
 
The authors are thankful to the Head of School of Pharmaceutical Sciences, Vels 
University for providing necessary facilities for this research work. 
 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1088 
 
 
N
COOH
PCl5,CCl4
N
COCl
N
NHNH2
O
NH2NH2.H2O
N
NH
O
N C
R
R1
R2
R4 R3
RCHO
NN
O
CH3
O
Ethanol, Acetic anhydride
THF
R1
R2
R3R4
(A-J)  
Scheme 
 
 
 
 
 
Table 1 Physical data of synthesized compounds 
 
 
Compound R1 R2 R3 R4 Mol. Formula M.P 
(ºC) 
Yield  
 (%) 
Elemental analysis (%) 
found 
C H N 
A H H H H C15H13N3O2 145 62 67.40 4.90 15.72 
B H N(CH3)2 H H C17H18N4O2 170 65 65.79 5.85 18.05 
C H H H Cl C15H12ClN3O2 180 63 59.71 4.01 13.93 
D H H H NO2 C15H12N4O4 190 67 57.69 3.87 17.94 
E H OCH3 H H C16H15N3O3 173 61 64.64 5.09 14.13 
F Cl NO2 H H C15H11ClN3NO2O2 182 68 22.01 1.35 5.13 
G H H NO2 H C15H12N4O4 193 66 57.69 3.87 17.94 
H H OH OCH3 H C16H15N3O4 150 64 61.34 4.83 13.41 
I H CH3 H H C16H15N3O2 157 65 68.31 5.37 14.94 
J OCH3 OCH3 H H C17H17N3O4 140 63 62.38 5.23 12.84 
 
 
 
 
 
 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1089 
 
 
Table 2 Antioxidant activity by DPPH radical scavenging method 
 
S. No. Compounds 
%RSC 
IC50 
25 µg/ml 50 µg/ml 75 µg/ml 100 µg/ml 
1.  A 15.50±0.213 33.72±0.477 51.46±0.450 63.80±0.531 73 
2.  B 19.72±0.603 34.25±0.567 41.25±0.458 58.30±0.558 88 
3.  C 16.20±0.580 28.16±0.492 38.50±0.406 51.14±0.693 99 
4.  D 19.25±0.219 35.30±0.350 45.35±0.262 59.31±0.641 84 
5.  E 24.91±0.608 63.18±0.529 73.26±0.542 82.10±0.726 42 
6.  F 12.86±0.437 24.92±0.609 36.21±0.814 53.12±0.832 96 
7.  G 15.50±0.144 30.85±0.298 43.51±0.403 54.69±0..249 91 
8.  H 17.50±0.393 31.07±0.430 45.97±0.393 61.59±0.572 83 
9.  I 35.06±0.684 67.19±0.510 82.13±0.457 90.16±0.593 37 
10.  J 38.23±0.606 71.15±0.433 86.26±0.524 91.86±0.588 34 
11.  BHT 12.35±0.360 25.72±0.079 58.81±0.303 97.32±0.553 <50 
 
 
 
Table 3 Antioxidant activity by Nitric oxide radical scavenging assay 
 
S. No. Compounds 
%RSC 
IC50 25 µg/ml 50 µg/ml 75 µg/ml 100 µg/ml 
1.  A 9.21±0.17 15.69±0.21 24.81±0.29 41.06±0.06 >100 
2.  B 20.91±0.28 31.15±0.41 42.28±0.18 53.02±0.07 93 
3.  C 16.91±0.34 30.58±0.19 41.58±0.22 52.63±0.27 95 
4.  D 21.46±0.18 32.44±0.13 45.12±0.42 56.42±0.31 89 
5.  E 28.49±0.19 54.81±0.21 74.48±0.28 84.19±0.15 41 
6.  F 12.49±0.06 19.96±0.09 35.82±0.05 59.96±0.03 91 
7.  G 17.90±0..08 32.10±0.18 44.08±0.13 67.15±0.11 82 
8.  H 32.71±0.07 51.65±0.16 68.92±0.22 82.15±0.26 46 
9.  I 36.24±0.09 60.81±0.21 74.39±0.25 85.56±0.17 40 
10.  J 41.43±0.23 66.28±0.16 79.80±0.09 91.73±0.25 44 
11.  BHT 13.30±0.04 27.65±0.17 59.61±0.32 96.98±0.61 <50 
 
 
REFERENCES 
 
[1] Yeong Woo Jo, Weon Bin Im, Jae Keol Rhee, Mi Ja Shim, Won Bae Kim and Eung Chil Choi. 
Bioorganic Med Chem  2004; 12(22): 5909-5915. 
[2] Gabriel Navarrete-Vazquez, Gloria Marıa Molina-Salinas, Zetel Vahi Duarte-Fajardo, Javier 
Vargas-Villarreal, Samuel Estrada-Soto, Bioorganic Med Chem 2007; 15 (16): 5502-5508. 
[3] Kalia R, Rao CM, Kutty NG.  Arzneimittel-Forschung-Drug Research 2007; 57(9): 616-22. 
[4] Shanthaveerappa Boovanahalli K, Xuejun Jin, Yinglan Jin, Jin Hwan Kim, Nguyen Tien Dat, 
Young Soo Hong, Jeong Hyung Lee, Sang Hum Jung, Kyeong Lee, Jung Joon Lee. Bioorg 
Med Chem Lett 2007; 17: 6305-10. 
          ISSN: 0975-8585 
 
October – December       2010             RJPBCS              1(4)    Page No. 1090 
 
[5] Pandey VK, Gupta VD, Mrinalini Upadhyay, Mridula Upadhyay, Singh VK, Meenal Tandon. 
Ind J  Chem 2005; 44B: 158-62. 
[6] Mrunmayee Toraskar P, Vithal Kulkarni M, Vilasrao Kadam. Int J Chem Tech Res 2009; 3: 
696-701. 
[7] Chrysoula Spanou, Stella Manta, Dimitri Komiotis, Albiona Dervishi and Demetrios 
Kouretas. Int J Mol Sci 2009; 8: 695-704. 
[8] Gugila Sandhyarani, Kantham Srinivas, Kusuma Praveen Kumar. Int J Biopharm 2010; 1: 
14-19. 
[9] Desai NC, Bhavsar AM, Shah MD, Anil Saxena K. Indian J Chem 2008; 47B: 579-589. 
[10] Asif Hussain, Mohammed Ajmal. Acta Pharm 2009; 59: 223-233. 
[11] Padmavathi V, Nagi Reddy S,  Dinneswara Reddy G, Padmaja A. European J Med Chem 
2010;  45 (9): 4246-4251. 
[12] Tagashira M, Ohtake Y. Planta Med 1998; 64: 555–558. 
[13] Garrat DC. The Quantitative Analysis of Drugs, Japan, Chapman and Hall, 1964, 456. 
 
 
 
 
 
 
 
 
 
 
 
 


Synthesis and In-vitro antioxidant activity of substituted Pyridinyl 1, 3, 4 oxadiazole derivatives

http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=2BF0F395F299010292317847D2CEA950?doi=10.1.1.1075.1722&rep=rep1&type=pdf

Synthesis and In-vitro antioxidant activity of substituted Pyridinyl 1, 3, 4 oxadiazole derivatives

Abstract

Similar works

Full text

Available Versions

CiteSeerX