Preparation and antimicrobial activity evaluation of some quinoline derivatives containing an azole nucleus

摘要

Quinoline-2-carbohydrazide (2) obtained from quinaldic acid(1) was converted to the corresponding carbothioamide 3 andcarboxamide 6 by treatment with benzyliso(thio)cyanate. The basictreatment of 3 and 6 yielded the corresponding 1,2,4-triazolederivatives 4 and 7. The synthesis of 5-(quinolin-2-yl)-1,3,4-oxadiazol-2-thiol (9) was performed from the reaction of 1 with CS_2in basic media. The Mannich reaction of compounds 4, 7, and 9resulted in the formation of aminoalkylated derivatives 5a-c, 8, and10a,b. The condensation of 1 with thiosemicarbazide, carbohydrazide,or thiocarbohydrazide gave the corresponding 1,2,4-triazolederivatives (11-13). The treatment of 4-amino-5-(quinolin-2-yl)-4H-1,2,4-triazole-3-thiol (13) with 4-chlorophenacyl bromide causedthe formation of fused triazolothiadiazine 14. The condensation of 13with 4-methoxybenzaldehyde generated the corresponding Schiff base 15.The newly synthesized compounds were characterized by elemental analyses, IR, ^1H-NMR, ^{13}C-NMR, and mass spectra. The antimicrobial activity study revealed that some of the newly synthesized compounds showed good to moderate activity against a variety of microorganisms.