Synthesis of Trifluoroalkyl- and Fluoroaryl-Substituted 4,5-Dihydro-1H-1,2,4-triazole-5-thiones

Reactions of 4-(4-fluorophenyl)-, 4-(4-trifluoromethoxyphenyl)-, 4-(3,4-difluorophenyl)-, 4-(4-trifluoromethylphenyl)-, 4-piperidino-, and 4-(3-pyridyl)thiosemicarbazides with esters gave the corresponding 3,4-disubstituted 4,5-dihydro-1H-1,2,4-triazole-5-thiones and their S-alkyl derivatives. Analogous reactions with methyl 2,2,3,3,4,4,5,5-octafluoropentanoate and 2,2,3,3,4,4,5,5-octafluoropentanenitrile afforded, respectively, the acylation and addition products.