SYNTHESIS OF NOVEL [1,2,4]TRIAZOLO[3,4-B][1,3,4]THIADIAZOLE-6(5H)-THIONE, 5,8-DIHYDRO-[1,2,4] TRIAZOLO[4,3-B][1,2,4,5]TETRAZINE AND 5,10-DIHYDRO -[1,2,4]TRIAZOLO[4,3-B][1,2,4] BENZOTRIAZINE DERIVATIVES AND STUDY THEIR BIOLOGICAL ACTIVITY.
International journal of advanced research