Synthesis and Antitumor Activity Evaluation of Some Novel-Fused and Spiro Heterocycles Derived from a 2(3H)-Furanone Derivative

2(3H)-furanone 1 was fused with methyl-4-aminobenzoate followed by hydrazinolysis to give the acid hydrazide derivative 3. Treatment of 3 with carbon disulfide gave 4-amino-5-mercapto-3-substituted triazole derivative 5. The presence of mercapto and amino groups adjacent to each other in compound 5 made it valuable key precursor for the formation of fused and spiro heterocycles. Ring transformation of 5 into triazolothiadiazole and triazolothiadiazine derivatives is investigated. The antitumor and antimicrobial activities of the synthesized compounds were evaluated. Some of the tested compounds showed promising activities.