Synthesis and antimicrobial studies of new N,N′-[5,5′-{2,2′-(bis-alkoxy) bis(2,1-phenylene)]bis(4-acetyl-4,5-dihydro-1,3,4-thiadiazole-5, 2-diyl)]diacetamide

The bisthiadiazolines 4a(a ′ -f ′ ) and 4b(a ′ -f ′ ) built around the various rigid chains have been synthesized in good yields by refluxing bisthiosemicarbazones 3a(a ′ -f ′ ) and 3b(a ′ -f ′ ) in acetic anhydride medium. The reaction of bisaldehydes 2a(a ′ -f ′ ) and 2b(a ′ -f ′ ) with thiosemicarbazide under alcoholic medium yielded 3a(a ′ -f ′ ) and 3b(a ′ -f ′ ) and the former were obtained from the reaction of 2/4-hydroxybenzaldehyde with suitable alkylating agent in the presence of anhydrous K 2 CO 3 /dry acetone and Bu 4 N + I − (PTC). The intermediates and final compounds have been characterized from the rigorous analysis of their IR, 1 H-NMR, 13 C-NMR, ESI-Mass and elemental analysis. The antibacterial and antifungal activities of the prepared compounds were also evaluated against the Klubsellia pneumoniae , Pseudomonas aeruginosa , Escherichia coli , Staphylococcus aureus , Bacillius subtilis and Aspergillius janus and Pencillium glabrum strains, respectively. The formation and antimicrobial behaviour of the bisthiadiazolines 4a(a ′ -f ′ ) and 4b(a ′ -f ′ ) are found to be independent of nature of the internal spacer unit. Graphical Abstract The synthesis and antimicrobial behaviour of new 1,3,4-bisthiadiazolines built around the five rigid chains have been described. The formation and antimicrobial behaviour of bisthiadiazoline derivatives are found to be independent of the nature of internal spacer unit.