Synthesis of novel bis-1,3,4-thiadiazoles, bis-1,2,4-triazoles and their antimicrobial activity

Condensation of sebacic acid dihydrazide (1) with aryl/alkyl isothiocyanates (2a-g) gives bis-(N-aryl/alkyl-thiocarbamido)-sebacic acid diamides (3a-g), which on reaction with o-phosphoric acid yields 1,8-bis-(2-aryl/alkylamino-1,3.4-thiadiazol-5-yl)-octanes (4a-g). 1,8-Bis-(3-mercapto-4-aryl/alkyl-1,2,4-triazol-5-yl)-octanes (5a-g) were obtained by a similar condensation of compounds (3a-g) with aqueous KOH, which on reaction with ethyl iodide in the form of dihydroiodides have been isolated (6a-g). These on basification with aq. ammonia solution afforded free bases (7a-g). Compounds (4a-g) on benzoylation with benzoyl chloride and NaOH affords benzoyl derivatives (8a-g). The structures of all these compounds were confirmed on the basis of elemental analysis and spectral data and evaluated for their antimicrobial activity against gram positive and gram negative bacteria.