Med Chem Res (2012) 21:1935–1952
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Isonicotinic acid [1-(2,4-dimethoxy-phenyl)-ethylidene]-
hydrazide (6)
phenyl ring), 7.78–7.91 (d, 2H, CH of C3 and C5 of pyri-
dine ring; J = 12), 8.78–8.81 (d, 2H, CH of C2 and C6 of
pyridine ring; J = 12), and 11.71 (s, 1H, NH); 13CNMR
(d ppm): 11.4, 121.6, 121.9, 125.4, 129.3, 130.5, 130.8,
131.4,141.6, 149.0, 154.2, and 168.4; IR (KBr pellets) m
cm-1: 3186.54 (NH str., amide), 3074.66 (CH str., aro-
matic), 1670.43 (C=O str., amide), 1600.99 (C=C str.,
skeletal phenyl nucleus), 825.57 (CH out-of-plane bending,
4-substituted pyridine), and 597.96 (C–Br str., aromatic);
CHN analysis calc.(found): C, 52.85 (52.19); H, 3.80
(3.65); N, 13.21 (13.32); O, 5.03 (4.91); and Br, 25.11
(24.95).
Mp (ꢁC) 120–123; Yield 59.1%; 1H NMR (400 MHz,
DMSO) d ppm: 2.07 (s, 3H, CH3), 3.79 (s, 6H, OCH3),
6.58 (s, 1H, CH of C3 of phenyl ring), 7.31–7.34 (d, 1H,
CH of C5 of phenyl ring; J = 12), 7.40–7.42 (d, 1H, CH of
C6 of phenyl ring; J = 8), 7.69–7.71 (d, 2H, CH of C3 and
C5 of pyridine ring; J = 8), 8.60–8.63 (d, 2H, CH of C2
and C6 of pyridine ring; J = 12), and 10.72 (s, 1H, NH);
13CNMR (d ppm): 11.8, 55.6, 55.9, 100.3, 106.5, 109.8,
122.2, 122.7, 130.8, 142.0, 149.2, 149.6, 153.5, 163.1,
164.8, and 169.2; IR (KBr pellets) m cm-1: 3105.53 (NH
str., amide), 1683.63 (C=O str., amide), 1307.79 (C–O–C
str., aralkyl ether), and 792.78 (CH out of plane bending,
4-substituted pyridine); CHN analysis calc.(found): C,
64.20 (64.32); H, 5.72 (5.51); N, 14.04 (13.89); and O,
16.04 (16.23).
Isonicotinic acid [1-(2,4-dichloro-phenyl)-ethylidene]-
hydrazide (3)
Mp (ꢁC) 175–178; Yield 55.4%; 1H NMR (400 MHz,
DMSO) d ppm: 2.35 (s, 3H, CH3), 7.25–7.46 (m, 3H, CH
of C3, C5 and C6 of dichloro phenyl ring), 7.74–7.75 (d,
2H, CH of C3 and C5 of pyridine ring; J = 4), 8.70–8.71
(d, 2H, CH of C2 and C6 of pyridine ring; J = 4), and 11.00
(s, 1H, NH); 13CNMR (d ppm): 11.2, 121.3, 121.8,
126.5,128.9, 129.3, 134.2, 136.7, 141.2, 149.5, 154.7, and
169.1; IR (KBr pellets) m cm-1: 3187.51 (NH str., amide),
3031.26 (CH str., aromatic), 1661.75 (C=O str., amide),
1559.51 (C=C str., skeletal phenyl nucleus), 816.89 (CH
out of plane bending, 4-substituted pyridine), and 666.43
(C–Cl str., aromatic); CHN analysis calc.(found): C, 54.57
(54.38); H, 3.60 (3.81); N, 13.64 (13.49); O, 5.19 (5.03);
Cl, and 23.01 (22.87).
Isonicotinic acid [1-(4-hydroxy-phenyl)-ethylidene]-
hydrazide (9)
1
Mp (ꢁC) Above 242; Yield 76.0%; H NMR (400 MHz,
DMSO) d ppm: 2.15 (s, 3H, CH3), 6.75–6.77 (s, 1H, OH),
6.83–6.87 (d, 2H, CH of C3 and C5 of phenyl ring; J = 16),
7.74–7.76 (d, 2H, CH of C2 and C6 of phenyl ring; J = 8),
7.80–7.84 (d, 2H, CH of C3 and C5 of pyridine ring;
J = 16), 8.75–8.76 (d, 2H, CH of C2 and C6 of pyridine
ring; J = 4), and 10.69 (s, 1H, NH); 13CNMR (d ppm):
11.5, 114.2, 114.5,121.4, 121.9, 123.1,129.4, 129.7,
141.5,149.3, 154.1, 159.2, and 168.3; IR (KBr pellets) m
cm-1: 3666.84 (OH str., Phenol), 3279.13 (NH str., amide),
3068.88 (CH str., aromatic), 2795.94 (CH3 str. asymmetric,
ArCH3), 2685.99 (CH3 str. symmetric, ArCH3), 1647.28
(C=O str., amide), and 1532.51 (C=C str., skeletal phenyl
nucleus), 826.53 (CH out of plane bending, 4-substituted
pyridine); CHN analysis calc.(found): C, 65.87 (65.63); H,
5.13 (5.01); N, 16.46 (16.23); and O, 12.54 (12.38).
Isonicotinic acid [1-(4-nitro-phenyl)-ethylidene]-hydrazide
(4)
1
Mp (ꢁC) Above 242; Yield 87.3%; H NMR (400 MHz,
DMSO) d ppm: 2.14 (s, 3H, CH3), 7.62–7.81 (m, 4H,
CH of phenyl ring), 8.24–8.26 (d, 2H, CH of C3 and C5
of pyridine ring; J = 8), 8.68–8.77 (d, 2H, CH of C2 and
C6 of pyridine ring), and 11.15 (s, 1H, NH); 13CNMR (d
ppm): 11.4, 121.4, 121.8, 122.7, 123.2, 128.7, 129.3,
136.9, 141.8, 149.1, 150.2, 154.2, and 168.5; IR (KBr
pellets) m cm-1: 3191.36 (NH str., amide), 3091.06 (CH
str., aromatic), 2937.71 (CH str., aliphatic), 1671.39
(C=O str., amide), 1577.84 (C=C str., skeletal phenyl
nucleus), 1508.40 (NO2 str. asymmetric, aromatic nitro
group), 1350.23 (NO2 str. symmetric, aromatic nitro
group), and 843.89 (CH out of plane bending, 4-substi-
tuted pyridine); CHN analysis calc.(found): C, 59.15
(58.91); H, 4.25 (4.11); N, 19.71 (19.87); O, and 16.88
(16.63).
Evaluation of antimycobacterial activity
All compounds were screened for their in vitro antimyco-
bacterial activity against MTB, in Middlebrook 7H11agar
medium supplemented with OADC by agar dilution
method similar to that recommended by the National
Committee for Clinical Laboratory Standards for the
determination of MIC in triplicate (National Committee for
Clinical Laboratory Standards, 1995). The minimum
inhibitory concentration (MIC) is defined as the minimum
concentration of compound required to give complete
inhibition of bacterial growth.
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