Chemistry
All melting points were recorded on Melt-Temp II melting point apparatus. IR spectra were measured as KBr pellets on a Shimadzu DR-8001 spectrometer. 1H NMR and 13C NMR spectra were recorded on a Bruker at 400 MHz and 100 MHz using TMS as an internal reference, DMSO-d6 as solvent. The elemental analyses were carried out on a Perkin-Elmer 240C Micro analyzer. All compounds were checked for their purity on TLC plates.
General Procedure for the Synthesis of thiazole derivatives 4a-f:
An equimolar mixture of thiosemicarbazide (1) (0.01 mol, 0.91 g) with the appropriate isatin derivative (2a-f) (0.01 mol) was allowed to reflux in ethanol/ TEA until the reaction (TLC) (10 min). Then added 4-(bromoacetyl)-N-(4-methylphenyl)benzenesulfonamide (3) to the reaction mixture, and continued refluxing for 20–30 min., until the reaction completed (TLC) to afford the corresponding thiazole derivatives (4a-f). The reaction mixture was allowed to cool to room temperature and the solid precipitate was filtrated, and recrystallized from ethanol.
4-{2-[2-(2-Oxo-1,2-dihydro-1H-indol-3-ylidene)hydrazino]-1,3-thiazol-4-yl}-N-phenyl-4-tolyl sulfonamide (4a)
Mp 235°C; IR cm− 1: 3363, 3178, 3120 (3NH), 3064 (C–Harom.), 1682 (C = O), 1H NMR δ 13.30 (br,1H, NH), 11.20 ( s, 1H, NH), 10.29 ( s, 1H, NH), 7.76–6.85 (m, 13H, CHarom.), 2.33 (s, 3H, -CH3); 13C NMR; 166.53 (C = O), 150.95, 143.82, 141.71, 137.93, 137.07, 132.53, 130.95, 130.32, 130.20, 130.14, 127.19, 125.03, 122.90, 120.46, 120.28, 120.19, 111.54, 106.41, 21.37; Anal. Calcd. For C24H19N5O3S2 (489.56) C (58.88%), H (3.91%), N (14.31%), S (13.10%); Found C (58.95%), H (3.98%), N (14.26%), S (13.16%).
4-{2-[2-(5-Chloro-2-oxo-1,2-dihydro-3H-indol-3-ylidene)hydrazino]-1,3-thiazol-4-yl}-N-phenyl- tolylsulfonamide (4b)
Mp 241°C; IR cm− 1: 3308, 3124 (3NH), 3061 (CH arom.), 1671 (C = O), 1H NMR δ 13.24 (s,1H, NH), 11.26 ( s, 1H, NH), 10.29 ( s, 1H, NH), 8.39–6.81 (m, 12H, CHarom.), 2.33 (s, 3H, -CH3); 13C NMR δ (ppm): 163.39 (C = O), 150.99, 143.97, 143.82, 141.03, 140.23, 138.72, 137.94, 137.06, 131.30, 130.21, 129.92, 127.19, 127.08, 127.03, 125.87, 121.88, 120.44, 120.11, 119.41, 21.37; Anal. Calcd. For C24H18ClN5O3S2 (524.01) C (55.01%), H (3.46%), N (13.36%), S (12.24%); Found; C (54.98%), H (3.39%), N (13.29%), S (12.18%).
4-{2-[2-(5-Nitro-2-oxo-1,2-dihydro-3H-indol-3-ylidene)hydrazino]-1,3-thiazol-4-yl}-N-phenyl- tolysulfonamide (4c)
Mp 228°C; IR cm− 1: 3247 − 3154 (3NH), 3085 (C–Harom.), 1654 (C = O), 1H NMR δ 10.28 (s,1H, NH), 9.14 ( s, 1H, NH), 8.64–7.11 (m, 13H, CHarom+ NH.), 2.32 (s, 3H, CH3), 13C NMR δ (ppm): 164.76 (C = O), 147.14, 144.84, 142.67, 140.28, 139.36, 138.94, 137.15, 136.03, 135.97, 135.80, 132.56, 128.37, 124.21, 123.98, 120.38, 117.46, 116.09, 112.45, 21.42; Anal. Calcd. For C24H18N6O5S2 (534.56); C (53.92%), H (3.39%), N (15.72%), S (12.00%) Found: C (53.86%), H (3.46%), N (15.65%), S (12.06%)
(4-(2-(2-(1-methyl-2-oxoindolin-3-ylidene)hydrazinyl)thiazol-4-yl)-N-(p-tolyl) benzene sulfonamide (4d)
Mp 268°C; IR cm− 1: 3217, 3161 (2NH), 3078 (C–Harom.), 1658 (C = O), 1H NMR δ 13.16 (br,1H, NH), 10.45 (s, 1H, NH), 7.75–7.02 (m, 13H, CHarom.), 3.73 (s, 3H, N-CH3), 2.30 (s, 3H, CH3); 13C NMR δ (ppm): 160.85 (C = O), 143.84, 141.56, 138.94, 137.04, 135.57, 133.94, 132.06, 131.03, 128.05, 127.20, 123.33, 122.46, 121.55, 121.47, 119.59, 119.37, 115.67, 110.28, 45.66, 21.38; Anal. Calcd. For C25H21N5O3S2 C (59.62%), H (4.20%), N (13.91%), S (12.73%) Found; C (59.69%), H (4.16%), N (13.84%), S (12.85%).
4-{2-[2-(5-Chloro-2-oxo-1,2-dihydro-N-methyl-3H-indol-3-ylidene)hydrazino]-1,3-thiazol-4-yl}-N-phenyl-4 tolylsulfonamide (4e)
Mp 216°C; IR cm− 1: 3190, 3167 (2NH), 3047 (C–Harom.), 1661 (C = O), 1H NMR δ 12.27 (s,1H, NH), 10.33 ( s, 1H, NH), 7.79–6.99 (m, 12H, CHarom.), 3.75 (s, 3H, N-CH3), 2.33 (s, 3H, CH3), 13C NMR δ (ppm): 190.03 (C = O), 143.92, 140.47, 139.93, 137.08, 136.42, 134.57, 132.76, 131.02, 130.81, 127.20, 127.05, 126.14, 124.43, 123.03, 120.43, 120.16, 119.59, 46.40, 21.35; Anal. Calcd. For C25H20ClN5O3S2(538.04) C (55.81%), H (3.75%), N (13.02%), S (11.92%) Found C (55.86%), H (3.83%), N (12.97%), S (11.86%)
4-{2-[2-(5-Nitro-2-oxo- N-methyl − 3-ylidene)hydrazino]-1,3-thiazol-4-yl}-N-phenyl-4-tolyl sulfonamide (4f)
Mp 290°C; IR cm− 1: 3251, 3126 (2NH), 3085 (C–Harom.), 1654 (C = O), 1H NMR δ 9.18 (s,1H, NH), 9.03 (s, 1H, NH), 8.64–7.11 (m, 12H, CHarom.), 3.84 (s, 3H, N-CH3), 2.34 (s, 3H, CH3), 13C NMR δ (ppm): 179.46 (C = O), 147.79, 143.57, 142.90, 140.54, 139.65, 138.82, 134.96, 130.24, 129.31, 128.60, 127.22, 124.42, 121.84, 120.63, 117.36, 116.61, 110.50, 109.25, 35.13, 21.01 ; Anal. Calcd. For C25H20N6O5S2 (548.59); C (54.73%), H (3.67%), N (15.32%), S (11.69%) Found: C (54.69%), H (3.73%), N (15.26%), S (11.78%).
Anti-inflammatory activity
In vivo estimation the anti-inflammatory effects of test compounds on rats via carrageenan-induced paw edema model.
For the in vivo assessment of the test compounds' anti-inflammatory activity, male Wister rats weighing 180 ± 10 grams each were employed, with celecoxib serving as the reference drug. All animals had to acclimate to the criteria set by the Institutional Animals Ethics Committee (IAEC) of the Faculty of Medicine at Sohag University for at least one week prior to the investigations (permit No; ). For this in vivo evaluation, 40 adult male Westar rats (n = 4) were randomly assigned. The selected agents were suspended in 1% newly prepared carboxy methyl cellulose (CMC) prior to being administered orally by gavage. Following a sub plantar injection of 100 µL of freshly prepared carrageenan gel (1% distilled water) into each rat's left hind paw, changes in paw thickness were observed [46]. Rats were administered test compounds orally via gavage one hour before the injection of carrageenan. Paw thickness was measured one, three, and five hours after the development of inflammation. The test compound's effects were quantified as a percentage of edema inhibition. The anti-inflammatory potential is expressed as a percentage suppression of paw edema and quantified [47].
Histopathological analysis of the tissues in the paws
Prior to being embedded in paraffin, the tissues from the paws were stored in a 10% formalin-neutral buffer. Hematoxylin and eosin (H&E) were used to stain the slides after thin sections of 5–6 µm were cut using a microtome. The slides that were made with a light microscope exhibit pathological changes in them.
Docking study
The crystal structure of COX-2 was downloaded from Protein Data Bank (PDB:1CX2) and the molecular docking was performed following our previously reported work [48].
Statistical analysis
The obtained data were statistically analyzed using GraphPad Prism version 9, and the mean values and standard deviations (mean ± SD) were presented as a result. The significance of mean differences was evaluated using the Tukey-Kramer test and one-way analysis of variance (ANOVA), with p-values of less than 0.05 being considered statistically significant.