SYNTHESIS OF 1,2,4-TRIAZOLO[4,3-A] [1,8]NAPHTHYRIDINES

2-Hydroxy-3-phenyl-1,8-naphthyridine (2) on treatment with POCl3 gives 2-chloro-3-phenyl-1,8-naphthyridine (3) which on hydrazinolysis yield s 2-hydrazino-3-pheny1- 1,8-naphthyridine (4). The hydrazine 4 on cond ensation with aromatic aldehydes in ethanol containing a catalytic amo unt of gl. acetic acid affords 3-phenyl-1,8-naphthyridin-2-yl hydrazon es (5), which on oxidative cyclization with nitrobenzene under reflux results in the formation of henyl-1,2,4-triazolo[4,3-alpha][1,8]naphth yridines (6). Further, 4 when treated with formic acid and gl. acetic acid yields the respective 1,2,4-triazolo[4,3-alpha][1,8]naphthyridine s (7 and 8). The structures of the compounds 3-8 have been established on the basis of their elemental analyses and spectral (IR,H-1 NMR and mass) data and are evaluated for their antimicrobial activities.