New heterocyclic compounds from 1,2,4-triazole and 1,3,4-thiadiazole class bearing diphenylsulfone moieties. Synthesis, characterization and antimicrobial activity evaluation

Some new 5-(4-(4-X-phenylsulfonyl)phenyl)-4-(R)-2H-1,2,4-triazol-3(4H)-thiones 4a,b; 5a,b and 5-(4-(4-X-phenylsulfonyl)phenyl)-N-(R)-1,3,4-thiadiazol-2-amines 6a,b; 7a,b were obtained by cyclization of new N1-[4-(4-X-phenylsulfonyl)benzoyl]-N4-(R)-thiosemicarbazides 2a,b; 3a,b (X = H, Br). The 1,2,4-triazoles were synthesized by intramolecular cyclization of acylthiosemicarbazides, in basic media. On the other hand, 1,3,4-thiadiazoles were obtained from same acylthiosemicarbazides, in acidic media. These new intermediates from thiosemicarbazide class were afforded by the reaction of 4-(4-X-phenylsulfonyl)benzoic acids hydrazides (X = H, Br) 1a,b with 4-trifluoromethoxyphenyl or 3,4,5-trimethoxyphenyl isothiocyanate. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, MS and elemental analysis. All the new compounds were screened for their antimicrobial activity against some bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 13061, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 49141, Acinetobacter baumannii ATCC 19606 and Pseudomonas aeruginosa ATCC 27853) and yeasts (Candida albicans ATCC 90028 and Candida parapsilosis ATCC 22019).

Graphical abstractNew 1,2,4-triazoles and 1,3,4-thiadiazoles were obtained by cyclization of corresponding acylthiosemicarbazides. The structures of compounds were confirmed by spectral techniques and elemental analysis. The compounds were screened for antimicrobial activity.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New 1,2,4-triazol-3(4H)-thiones and 1,3,4-thiadiazol-2-amines were synthesized. ► The new structures were confirmed by elemental analysis and spectral methods. ► The potential antimicrobial effects of new compounds were investigated. ► The compounds which containing 3,4,5-trimethoxyphenyl showed the best results.