SYNTHESIS AND REACTIONS OF 3-(3'-THIONE)-1',2',4'-TRIAZOL-5'-YLCOUMARIN

3-(3'-Thione)-1',2',4'-triazol-5'-ylcoumarin (1) was prepared via condensation of 3-ethoxycarbonylcoumarin with thiosemicarbazide in boiling pyridine. The reaction of coumarin (1) with primary amines and hydrazines takes place by nucleophilic attack on the thione group to give 3-(3'-amino)-1',2',4'-triazol-5'-ylcoumarins (2a or 2b) and 3-(3'-hydrazinyl)-1',2',4'-triazol-5-ylcoumarins (2c-d). Condensation of 2c with aromatic aldehydes gave the corresponding 3-(3'-arylidenehydrazonyl)-1',2',4'-triazol-5'-ylcoumarins (3a-g). Alkylation of coumarin (1) with methyl iodide and ethyl chloroacetate gave 3-(1'-methyl-3'-methylthio)-1',2',4'-triazol-5'-ylcoumarin (8) and 3-(3'-ethoxycarbonylmethylthio)-1',2',4'-triazol-5'-ylcoumarin (9) respectively. Addition of compound (1) to acrylonitrile or methyl vinyl ketone under Michael addition conditions afforded the 3-{[}3'-(2''-cyanoethylthio)]-1',2',4'-triazol-5'-ylcoumarin (11a) and 3{[}3'-(3-oxobutylthio)]-1',2',4'-triazol-5'-ylcoumarin (11b) and addition of (1) to Schiff bases afforded 3-{[}3'-(alpha-arylaminobenzylthio)]-1',2',4'-triazol-5'-ylcoumarins (12a-c). The antibacterial and antifungal activities of some compounds have been described.