Spiro-heterocyclics: A convenient synthesis and antimicrobial activity of 3-(5-substituted phenyl-1,3,4-thiadiazole-2-yl)-5,8-dithiaspiro[3,4]octan-2-ones and 1,4-dithia-6-azaspiro[4,4]-nonan-7-ones

A new series of novel 3-(5-substituted phenyl-1,3,4-thiadiazole-2-yl)-5,8-dithiaspiro[3,4]octan-2-ones and 1,4-dithia-6-azaspiro[4,4]nonan-7-ones have been synthesized from a common intermediate, in good yields. These compounds have been screened for their antibacterial and antifungal activity against different pathogenic strains of bacteria and fungi. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been determined for the test compounds as well as for reference standards. Compounds 4b, 4c, 4d, 5b, 5c, and 5d have shown good antibacterial activity whereas compounds 4b, 4d, 5b, and 5d have displayed better antifungal activity.