Journal of Chemistry
3
3H, -CH(CH ) + -CH ), 4.66-4.67 (m, 1H, -NH-CH-CO),
10.97 (s, 1H, D O exchangeable, NH isatin), 11.40 (s, 1H,
3 2
2
2
5.54-5.55 (m, 1H, -NH-CH-CO), 6.94–7.56 (m, 4H, Ar-H),
D O exchangeable, NH hydrazide), 11.70 (s, 1H, D O
2
2
8.29 (s, 1H, Ar-H), 8.76 (s, 1H, D O exchangeable, NH amide),
exchangeable, NH hydrazide); HR-MS: 447.4478. Anal.
Calcd. for C H ClN O (447.87): C (61.68), H (4.05), N
2
3
9.00–9.26 (m, 2H, Ar-H), 11.41 (s, 1H, D O exchangeable, NH
2
23 18
5
3
isatin), 12.45 (s, 1H, D O exchangeable, NH hydrazide), 13.52
(15.64). Found: C (61.69), H (4.02), N (15.67).
2
(s, 1H, D O exchangeable, NH hydrazide); HR-MS: 458.1546.
2
Anal. Calcd. for C H BrN O (458.31): C (52.41), H (4.40),
20 20
5
2.2. Biological Study
N (15.28). Found: C (52.39), H (4.43), N (15.26).
2.2.1. Samples Preparation. All samples were dissolved in
dimethyl sulfoxide (RFCL Limited, New Delhi, India)
(DMSO) at 10 mg/mL concentration, in comparison with
different standard antibiotics as shown in Table 1. Antibiotic
discs of streptomycin (S) (10 ꢀg) and tetracycline (TE) (30 ꢀg)
were used as positive control for bacteria, neomycin (N)
(30 ꢀg) and nystatin (NY) (100 ꢀg) were used for fungi, and
sterilized paper discs without compounds or antibiotics were
used as negative controls for both bacteria and fungi. e
experiment was performed in triplicate.
N-(1-(2-(5-Chloro-2-oxoindolin-3-ylidene)hydrazinyl)-4-meth-
yl-1-oxopentan-2-yl)nicotinamide (6d). Yield (90%); m. p.
194–196∘C; −[ꢅꢆ = −70 (ꢇ = 0.01, MeOH); IR (KBr)
25
D
1
]
max/cm−1 3413–3232 (NH), 1700 (C=O), 1641 (C=N); H
NMR (DMSO-ꢂ6) ꢃ 0.93–1.10 (m, 6H, 2CH ), 1.62–1.92 (m,
3
3H, -CH(CH ) + -CH ), 4.66-4.67 (m, 1H, -NH-CH-CO),
3 2
2
5.54–4.55 (m, 1H, -NH-CH-CO), 6.90–7.68 (m, 4H, Ar-H),
8.30 (s, 1H, Ar-H), 8.78 (s, 1H, D O exchangeable, NH amide),
2
9.00–9.26 (m, 2H, Ar-H), 11.42 (s, 1H, D O exchangeable,
2
NH isatin), 12.43 (s, 1H, D O exchangeable, NH hydrazide),
2
13.51 (s, 1H, D O exchangeable, NH hydrazide); HR-MS:
2.2.2. Antimicrobial Activity. e ability to inhibit the growth
of Gram-positive and Gram-negative bacteria, yeasts, and
filamentous fungi was observed using an overlay method
[29].
2
413.0183. Anal. Calcd. for C H ClN O (413.86): C (58.04),
20 20
5
3
H (4.87), N (16.92). Found: C (58.01), H (4.83), N (16.95).
N-(1-Oxo-1-(2-(2-oxoindolin-3-ylidene)hydrazinyl)-3-phenyl-
propan-2-yl)nicotinamide (6e). Yield (84%); m. p. 218–220∘C;
2.2.3. Antimicrobial Assay
−[ꢅꢆ = −110 (ꢇ = 0.03, MeOH); IR (KBr) ]max/cm−1 3413–
25
D
1
(1) Strains Used. e common pathogenic and food spoilage
microorganisms were selected for their relevance in bakery
products and other foods: the Gram-positive bacteria were
Bacillus subtilis and Staphylococcus aureus, Gram-negative
bacteria was Escherichia coli, yeasts such as Candida albicans,
and fungi was Aspergillus niger.
3228 (NH), 1702 (C=O), 1621 (C=N); H NMR (DMSO-ꢂ6)
ꢃ 3.08–3.33 (m, 2H, -CH ), 4.90-4.91 (m, 1H, -NH-CH-CO),
2
5.67–4.68 (m, 1H, -NH-CH-CO), 7.11–7.58 (m, 10H, Ar-H),
8.19 (s, 1H, Ar-H), 8.72 (s, 1H, D O exchangeable, NH amide),
2
9.01–9.60 (m, 2H, Ar-H), 11.35 (s, 1H, D O exchangeable, NH
2
isatin), 12.61 (s, 1H, D O exchangeable, NH hydrazide), 13.55
2
(s, 1H, D O exchangeable, NH hydrazide); HR-MS: 413.1841.
2
(2) Media Used. e bacteria were slanted on nutrient agar
(Merck, Darmstadt, Germany), yeast was slanted and men-
tioned onSabaroud’s agar medium (Lab M., Bury, Lancashire,
UK), and the fungi were slanted and mentioned on the Potato
Dextrose Agar medium (Lab M Limited, Bury, Lancashire,
UK). Mueller-Hinton agar (Lab M., Bury, Lancashire, UK)
following the manufacturer’s instructions was used for the
assay.
Anal. Calcd. for C H N OS (413.43): C (66.82), H (4.63),
16 15
5
N (16.96). Found: C (66.78), H (4.61), N (16.99).
N-(1-(2-(5-Bromo-2-oxoindolin-3-ylidene)hydrazinyl)-1-oxo-
3-phenylpropan-2-yl)nicotinamide (6f ). Yield (81%); m. p.
200–204∘C; −[ꢅꢆ = −105 (ꢇ = 0.01, MeOH); IR (KBr)
25
D
1
]
max/cm−1 3410–3230 (NH), 1700 (C=O), 1630 (C=N); H
NMR (DMSO-ꢂ6) ꢃ 3.07–3.39 (m, 2H, -CH ), 4.90-4.91
2
(m, 1H, -NH-CH-CO), 5.64–4.65 (m, 1H, -NH-CH-CO),
6.86–7.96 (m, 9H, Ar-H), 8.17 (s, 1H, Ar-H), 8.76 (s, 1H,
(3) Bioassay. e antibacterial screening was performed by
the well diffusion agar method described by Moosdeen
et al. [30]. e organisms were streaked in radial patterns
on the agar plates. Plates were incubated under aerobic
conditions at 37∘C and 28∘C for 24 h and 48 h for bacteria and
fungi, respectively. In order to obtain comparable results, all
prepared solutions were treated under the same conditions.
All tests were performed for three replicates. Plates were
examined for evidence of antimicrobial activities, represented
by a zone of inhibition of microorganism’s growth around
the holes, and diameters of clear zones were expressed in
millimeters [31].
D O exchangeable, NH amide), 9.04–9.41 (m, 2H, Ar-H),
2
11.48 (s, 1H, D O exchangeable, NH isatin), 12.47 (s, 1H,
2
D O exchangeable, NH hydrazide), 13.48 (s, 1H, D O
2
2
exchangeable, NH hydrazide); HR-MS: 491.0701. Anal.
Calcd. for C H N OS (492.32): C (56.11), H (3.69), N
16 15
5
(14.23). Found: C (56.10), H (3.65), N (14.26).
N-(1-(2-(5-Chloro-2-oxoindolin-3-ylidene)hydrazinyl)-1-oxo-
3-phenylpropan-2-yl)nicotinamide (6g). Yield (80%); m. p.
226–230∘C; −[ꢅꢆ = −20 (ꢇ = 0.01, MeOH); IR (KBr)
25
D
]
max/cm−1 3413–3280 (NH), 1741–1692 (C=O), 1620 (C=N);
1H NMR (DMSO-ꢂ6) ꢃ 3.07–3.39 (m, 2H, -CH ), 4.90-4.91
(4) Determination of Minimum Inhibitory Concentration
(MIC). e in vitro minimum inhibitory concentration
(MIC) of the synthesized compounds was determined by agar
well diffusion method. Nutrient broth medium was used to
2
(m, 1H, -NH-CH-CO), 5.64–4.65 (m, 1H, -NH-CH-CO),
6.93–7.54 (m, 9H, Ar-H), 8.18 (s, 1H, Ar-H), 8.73 (s, 1H,
D O exchangeable, NH amide), 9.0–9.40 (m, 2H, Ar-H),
2