Synthesis and antibacterial activities of 1,3,4-oxadiazole and pyrazoline derivatives containing 1,8-naphthyridine moiety

Condensation of 2-trifluoromethyl-1,8-naphthyridine-3-carboxylic acid hydrazide 2 with different acetophenones affords the corresponding acetophenone 2-trifluoromethyl-1,8-naphthyridine-3-carbonylhydrazones 3, which on cyclization with acetic anhydride yield 4-acetyl-2-(2-trifluoromethyl-1,8-naphthyridin-3-yl)-5-aryl-5-methyl-1,3,4-oxadiazoles 4. Treatment of 2 with arylideneacetophenones furnishes 3,5-diaryl-1-(2-trifluoromethyl-1,8-naphthyridine-3-carbonyl)-2-pyrazolines 5. The compounds synthesized have been characterized by means of their elemental analyses, IR H-1 NMR and MS data. Their antibacterial activities have also been evaluated.