摘要
A simple and regioselective synthesis of 2-chloro-3-formyl-l,8-naphthyridine （1） through V ilsmeier-Haack cyclization of N-（pyridine-2-yl） acetamide has been reported. The reaction of compound （1） with sodium sulphide gives thione （2） and the reaction of compound （1） with Na2S/DMF followed by reaction with alkyl halide in one pot afforded thioether （3 and 4）. New naphthyridone （5） was synthesized from the action of acetic acid and POCI3 in compound （1）. The condensation of compounds （1 and 8） with hydroxylamine and aniline leads to the formation of compounds （6, 7 and 9）. The 2-chloro-3-formyl-l,8-naphthyridine was treated with sodium azide underwent cyclization to afford tetrazolo （l,5-a） （l,8-naphthyridine-4-carbaldehyde （8）. The azitidinone （10 and 12） and thioazolidinone （11 and 13） were synthesized from shift base intermediates by using chloroacetyl chloride and thioglycolic acid. The formyl group in compound （1） is subjected to cyano （14） and 3-alkoxycarbonyl （15）, respectively. The ester （15） was treated with hydrazine hydrate in ethanol to give acid hydrazide （16） then converted to thio semicarbazide （17） by their reaction with ammonium thiocyanate. New thiadiazolo （18）, triazolo （19） and oxadiazolo （20） have been prepared. The structures of synthesized compounds have been confirmed by suitable spectroscopic techniques such as IR （infrared spectrometry） and ^1H NMR （proton nuclear magnetic resonance）.
