RAMBABU et al., Orient. J. Chem., Vol. 33(1), 226-234 (2017)
232
(400 MHz, DMSO-d6): d 3.73 (s, 3H), 3.85 (s, 6H),
Biology
7.22 (s, 2H), 8.28 (s, 1H), 8.32 (s, 1H), 8.46 (brs,
1H), 11.78 (s, 1H); MS (ESI) m/z: 366.27 [M+H]+.
Antimicrobial activity test
The antibacterial and antifungal screening
test of hydrazones 4a-l was done as per the
standard agar diffusion method23. The microbial
strains utilized for the study are (a) Aspergillus
niger (MTCC 282), Candida albicans (MTCC 227)
categorized under fungal strain (b) Escherichia coli
(MTCC 443), Pseudomonas auriginosa (MTCC 424),
Staphylococcus aureus (MTCC 96), Streptococcus
pyogenes (MTCC 442) categorized under bacterial
strains. Ampicillin(for antibacterial study) and
Greseofulvin (for fungal study) are used as the
standard reference drugs respectively under alike
conditions for assessment. 1% Dimethyl sulphoxide
was used as a blank reading. The MIC (minimum
inhibitory concentration) was found at 50 µg/mL
(using dimethyl sulfoxide as solvent) for the both
fungal and bacterial study. The culture strains of
fungi was maintained on potato dextrose agar (PDA)
slant at 27 0.2°C for 24-48 hrs (till sporulation)
while the bacteria was maintained on nutrient agar
slant at 37 0.5°C for 24 h.The antimicrobial activity
was assessed as follows (i) in case of antibacterial
study: nutrient agar plate seeded with 0.1 mL of
the respective bacterial culture strain suspension
prepared in sterile saline (0.85%) of 105 CFU/mL
dilutions (ii) in case of antifungal study: Sterile PDA
plate was prepared containing 2% agar; 0.1 mL of
each fungal spore suspension was spread on each
plate and incubated at 27 0.2 °C for 12 hrs. Target
compounds viz., synthesized hydrazone derivatives
(0.1 mL), dilution ranging from 25 to 1000 ¼g/mL
was poured into wells (6 mm diameter) separately for
individual bacteria and fungi strains. All the plates
were incubated at 37 0.5°C for 24 h (for bacterial
study) and 27 0.2 °C for 12 hrs (for fungal study)
and respective MIC values were determined for all
the compounds.
(E)-N’-(4-(methylsulfonyl)benzylidene)-3,4,5-
trimethoxybenzohydrazide 4j
White solid;Yield: 86%; M.p.: 137-138 °C;
IR (KBr): umax cm-1 3443, 3170, 3067, 3005, 2983,
2941, 2925, 2889, 2836, 2631, 1955, 1701, 1638,
1583, 1560, 1503, 1463, 1454, 1411, 1367, 1337,
1313, 1292, 1277, 1235, 1198, 1181, 1169, 1153,
1130, 1083, 1069, 993, 969, 851, 839, 820, 778,
1
767, 745, 729, 696, 666, 567, 544, 530, 486; H
NMR (400 MHz, DMSO-d6): d 3.30 (s, 3H), 3.74 (s,
3H), 3.87 (s, 6H), 7.25 (s, 2H), 8.00 (s, 4H), 8.55 (s,
1H), 11.92 (s, 1H); 13C NMR (100 MHz, DMSO-d6)
´: 162.7, 152.7, 145.7, 145.2, 141.4, 140.6, 139.2,
139.0, 130.2, 128.2, 127.7 (3C), 105.3, 60.1, 56.1,
43.4, 43.1; MS (ESI) m/z: 390.9 [M+H]+
(E)-N’-(4-(dimethylamino)benzylidene)-3,4,5-
trimethoxybenzohydrazide 4k
White solid;Yield: 82%; M.p.: 123-124 °C;
IR (KBr): umax cm-1 3444, 3205, 3077, 3035, 2994,
2963, 2936, 2838, 2632, 2103, 1636, 1610, 1593,
1583, 1566, 1552, 1524, 1500, 1463, 1448, 1413,
1362, 1331, 1285, 1229, 1182, 1170, 1123, 1103,
1060, 1001, 971, 944, 858, 717, 761, 738, 630,
526, 494; 1H NMR (400 MHz, DMSO-d6): d 2.98 (s,
6H), 3.72 (s, 3H), 3.86 (s, 6H), 6.76 (d, J = 7.2 Hz,
2H), 7.21 (s, 2H), 7.54 (d, J = 6.8 Hz, 2H), 8.32 (s,
1H), 11.39 (s, 1H); 13C NMR (100 MHz, DMSO-d6) ´:
162.0, 152.6 (2C), 151.5 (2C), 148.6, 128.9, 128.3
(3C), 121.5, 111.8, 105.0 (2C), 60.0, 56.0(3C), 40.1,
39.9; MS (ESI) m/z: 358.1 [M+H]+.
(E)-N’-(2-methoxy-6-pentadecylbenzylidene)-
3,4,5-trimethoxybenzohydrazide 4l
Off white solid; Yield: 86%; M.p.: 132-133
°C; IR (KBr): umax cm-1 3427, 3276, 3158, 3071,
2957, 2919, 2848, 1646, 1590, 1514, 1474, 1406,
1372, 1301, 1254, 1179, 1152, 1071, 1010, 973,
836, 813, 770, 734, 724, 672, 653, 593, 570, 478;
1H NMR (400 MHz, DMSO-d6): d 11.63 (s, 1H), 8.77
(s, 1H), 7.27 (s, 3H), 6.92 (d, J = 7.2 Hz, 1H), 6.85
(d, J = 5.6 Hz, 1H), 3.86 (s, 9H), 3.73 (s, 3H), 2.97
(brs, 2H), 1.52 (brs, 2H), 1.34 (brs, 2H), 1.18 (m,
22H), 0.85 (s, 3H); MS (ESI) m/z: 555.1 [M+H]+.
By measuring the diameter of the inhibition
zone around the well (in mm, including the well
diameter), the zone of inhibition was calculated.
The readings were recorded three times and the
average values were tabulated (data are expressed
in the form of mean of inhibition zone diameter for
test compound performed in triplicate SD).