Synthesis of 1,2,4-Triazole Thioketone Schiff-bases Under Microwave Irradiation and Its Characterization

3-(4-Amino-3-phenyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-1,3-diphenylpropanal(Ⅳ) was synthesized by nucleophilic substitution of 4-amino-3-phenyl-5-mercapto-1,2,4-triazole and chalcone under microwave irradiation.The product then reacted with aryl aldehydes to give seven novel triazolethione Schiff-base derivatives(Ⅴa~Ⅴg),namely,3-[4-(arylideneamino)-3-phenyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenylpropanal.The influence of mole ratio of substrate,the amount of catalyst,solvent,reaction time and radiant power upon the product yield was discussed.The optimal conditions for preparation were ascertained as follows:n(aromatic aldehyde)∶n(amino substituted triazolethione)=1∶1.1,the amount of acetic acid was 2 mL,the time 5～7 min,microwave power 500 W,the solvent DMF,and the yields were 71%～87%.The structures of the intermediate and the target compounds were characterized by means of IR,MS,1HNMR spectra and elemental analysis.