Synthesis, lipophilicity and biological evaluation of indole-containing derivatives of 1,3,4-thiadiazole and 1,2,4-triazole

3-[(2-Methyl-1 H-3-indolyl)methyl]-4-aryl-4,5-dihydro-1 H-1,2,4-triazole-5-thiones 6a-c and their respective N-{5-[(2-methyl-1 H-3-indolyl) methyl]-1,3,4-thiadiazol-2-yl}- N-arylamines 7a,b have been prepared. The antidepressant profile of 6a,c and 7a was studied on mice with respect to that of the analogous 3-(1 H-1-indolylmethyl)-4-aryl-4,5-dihydro-1 H-1,2,4-triazole-5-thiones 1a-c and the respective N-15{(2-methyl-1 H-3-indolyl)methyl]-1,3,4-thiadiazol-2-yl}- N-arylamines 2a-c, the synthesis and antimicrobial potency of which we have recently reported. Behavioral effects, induced by the members of both series, in conjunction with their activity in some specific tests (forced swim, pentetrazole convulsions) on mice, show that these derivatives cross the blood-brain barrier and could develop an antidepressant activity comparable to that of imipramine. Blood-brain barrier penetration is also supported by the lipophilicity data obtained for all analogs.