Abstract: In this work, a series of new 3-(4' -pyridinoyl)-4-aroyl<-1,2,4-tria-zoline-5-thibne( Ⅱ ) have been synthesized by the cyclization of 1-(4' -pyridinoyl)-4-aroylthiosemicarbazides( Ⅰ ) under the catalysis of alkaline medium in good yields. Having studied the reaction of ( Ⅰ ), we found that in all cases when 4-position substituent of aroyl group in compounds( Ⅰ ) was electron-withdrawing group such as NO₂,halogen and others, or electron-donating group such as Me, MeOand others,3-(4'-pyridinoyl)-4-aroyl-1,2,4-triazoline-5-thione (Ⅱ) could be obtained. The structures of all compounds prepared were characterized by elemental analysis, IRand ¹H NMR. The cyclic orientation of compounds( Ⅰ ) has been comfirmed by the detailed analysis of the fragmentation in mass spectrometry for compounds (Ⅱ ).Preliminary pharmacological examinations show that the new compounds( Ⅱ ) exhibit less antitubercular activity than corresponding parent compounds ( Ⅰ ) except that 3-(4' -pyridinoyl)-4-(2' -fluorine-phenyl)-1, 2, 4-triazoline-5-thione which has a little inhibiting activity.

Key words: Acylthiosemicarbazides, Heterocyclic 1,2,4-triazoline-5-thione