Synthesis and biological evaluation of indole containing derivatives of thiosemicarbazide and their cyclic 1,2,4-triazole and 1,3,4-thiadiazole analogs

New indolic derivatives of thiosemicarbazides and some cyclic 1,2,4-triazol -5-thione analogs were synthesized. The newly synthesized compounds as well as some indole containing thiosemicarbazides. 1,2,4-triazoles and 1,3,4- t hiadiazoles, which have been reported previously, were investigated for ant imicrobial, antifungal and antiphage activity. Certain thiosemicarbazide de rivatives and the corresponding cyclic 1,2,4-triazole analogs showed select ive antimicrobial or antifungal activity, while they lack any antiphage act ivity. Antiphage activity was detected for one compound, bearing the 1,3,3- thiadiazole nucleus. The selectively active compounds cover a wide range li pophilicity. Structure-activity relations show a remarkably similarity in t he antimicrobial and antifungal behav lour of the thiosemicarbazides and th eir cyclic triazo-thien-5-yl analogs, while alpha-naphtyl substitution in t he non indolic portion of the molecule is favorable. C5 substitution on the indolic nucleus may also be critical for selective activity.