Abstract

SYNTHESIS, IDENTIFICATION AND ANTIBACTERIAL EVALUATION OF SOME 1,3,4- OXADIAZOLES DERIVATIVE ON 1,8-NAPHTHYRIDINE RING

Ala I. Ayoub and Mohanad Y. Saleh*

ABSTRACT

Several 1,8-naphthyridine derivative were prepared using Vilsmeier-Haack synthization. 2-chloro-3-formyl-1,8-naphthyridine was synthesized by reacting N-(pyridin-2-yl) acetamide with POCl3 in dimethylformamide. 1,8-naphthyridine group was oxidized with NIS-K2CO3 in methanol at room temperature to yield 2-chloro-3-methoxy carbonyl -1,8-naphthyridine (2), acid hydrazide was then prepared by treating the methyl ester with hydrazine hydrate in ethanol (3), the synthesis of 2-chloro-3[2(1,3,4-oxadiazol-5-thiol-1,8-naphthyridine (4) was obtained from compound(3) reaction with CS2 in basic medium, acid hydrazide was then converted to the corresponding carbothioamide (5) by treating with benzyl isothiocyanate respectively. Thiosemicarbazide (5) was reacted with mercuric oxide in methanol to produce 1,3,4-oxadiazole (6). 2-chloro-3-[2(1,3,4-oxadiazole)]-1,8-naphthyridine (8) was yielded from acid hydrazide reaction with formic acid followed by PbO2. Acid hydrazide (3) was treated with benzaldehyde to formhydrazone (9) which then reacted with PbO2 to give 1,3,4-oxadiazole (10). Finally. The structures of synthesized compounds were confirmed spectroscopically using IR and1HNMR in addition to another physical data. The newly synthesized compounds (4,6,8,10) show a significant antibacterial activity.

Keywords: heterocyclic compounds, Vilsmeier-Haack, 1,8-naphthyridine, 1,3,4-oxadiazole, 1,3,4-thiadiazole, 1,2,4-trazole.