Novel dispiro[pyrazolidine-4,3'-pyrrolidine-2',3"-indoline]-2",3,5-triones 5a-j were obtained regioselectively by 1,3-dipolar cycloaddition reaction of 4-arylidene-1-phenylpyrazolidine-3,5-diones 2a-e as dipolarophiles with non-stabilized azomethine ylides, generated in situ via decarboxylative condensation of isatins 3a,b and sarcosine 4 in dry ethanol. The prepared compounds were screened for their anti-inflammatory activity "at a dose of 10 mg/kg body weight", especially 5d, 5f, 5h, and 5j which reveal remarkable activities relative to indomethacin which was used as a reference standard in this study.
Condensation of 4,4'-diacetyldiphenyl sulphide (2) with variable amounts of thiosemicarbazide (3) in refluxing ethanol and in the presence of catalytic amounts of dry piperidine afforded only 4-acetylthiosemicarbazone-4'-acetyldiphenyl sulphide (5). Condensation of 2 with excess semicarbazide hydrochloride (4) in the presence of fused sodium acetate and/or piperidine yielded 4,4'-diacetylsemicarbazone diphenyl sulphide (6), whereas use of equimolar amounts of 2 and 4 afforded 4-acetyl-semicarbazone-4'-acetyldiphenyl sulphide (7). 4-Acetylsemicarbazone-4'-acetylthiosemicarbazone diphenyl sulphide (8) was also obtained via two different routes. The effect of tautomeric structure 5d is discussed. 4-(4"-phenyl-Δ3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl sulphide (9), 4-(5"-carboxyethyl-4"-thiazolidinone-2"-acetylazino)-4'-acetyldiphenyl sulphide (10), 4-(4"-thiazolidinone-2'-acetylazino)-4'-acetyldiphenyl sulphide (11) and 4-(4"-methyl-Δ3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl sulphide (12) were prepared by interaction of 5 with phenacylbromide, bromodiethylmalonate, chloro ethylacetate and chloroacetone, respectively. Sulphides 9-12 were easily condensed with 3 to afford the corresponding 4-(heterocyclic moiety-2"-acetylazino)-4'-acetylthiosemicarbazone diphenyl sulphides 23-26. Oxidation of the prepared sulphides 5-7, 9-12, 23 and 25-26 using H2O2/glacial AcOH mixtures yielded only 4,4'-diacetyldiphenyl sulphone (13) as the main product in every case, besides 3 and 4 in certain cases. Unsymmetrical and symmetrical sulphones 14-22 were obtained starting from 13. The structures of the synthesized compounds are based on IR, 1H-NMR, 13C-NMR and mass spectral data. A theoretical study on some of the prepared compounds using molecular modeling was carried out.
3- 6,7,6]naphthyridine-2(1H)-thione (3a) and 3-cyano-6-methyl-4-(2'-thienyl)-5,6,7,8tetrahydro[1,6]naphthyridine-2(1H)-thione (3b) were reacted with a-halo compounds to give the intermediates 4a-j which upon refluxing in ethanolic sodium ethoxide afforded the thieno [2,3-b][1,6]naphthyridine derivatives 5a-l. Further annellation of pyridine and pyrimidine rings to the remaining free bond of the fused thiophene ring was achieved, providing tetrahydro-pyrido [2',3':4,5]-and -pyrimido[4',5':4,5]-thieno[2,3-b][1,6]naphthyridines. Some of the synthesised compounds were screened against different strains of bacteria.
2-Bromo-4-fluoroaniline (1) was condensed with ethyl 2-cyano-3-ethoxyacrylate (2) in ethanol to afford 3, which upon refluxing in paraffin oil at 250°C gave 8-bromo-3-cyano-6-fluoroquinoline-4(1H)-one (4). Then, compound 4 was taken as a versatile building block that allows the synthesis of thieno[3,2-c]quinoline, pyrrolo[3,2-c]quinoline, and N-methylpyrrolo[3,2-c]quinoline systems. The newly synthesized compounds and their derivatives were characterized by elemental analysis and spectroscopy (IR, (1)H NMR, (13)C NMR, and mass). Furthermore, some of these synthesized compounds were screened for their biological activities against various pathogenic bacterial and fungal strains. Our results demonstrate that most of the synthesized compounds possess a significant broad antibacterial activity against all strains of both gram-positive and gram-negative bacteria. In addition, compound 5 showed remarkable antifungal activity.
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