Syntheses of New Unsymmetrical and Symmetrical Diarylsulphides and Diarylsulphones Containing Thiazolinyl and Thiazolidinonyl Moieties Using 4,4'-Diacetyldiphenylsulphide

Abstract: 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.