1,6- and 1,7-naphthyridines.II. Synthesis from acyclic precursors

Autor:	Isabel A. Perillo, M. Mercedes Blanco, Celia B. Schapira
Rok vydání:	1999
Předmět:	chemistry.chemical_classification chemistry.chemical_compound Sarcosine chemistry Oxalyl chloride Diazomethane Sodium Organic Chemistry Proton NMR chemistry.chemical_element Organic chemistry Ethyl ester Alkyl
Zdroj:	Journal of Heterocyclic Chemistry. 36:979-984
ISSN:	1943-5193 0022-152X
DOI:	10.1002/jhet.5570360425
Popis:	A number of 8-hydroxy-6-methyl-1,6-naphthyridin-5(6H)-one-7-carboxylic acid alkyl esters 3 and the isomeric 5-hydroxy-7-methyl-1,7-naphthyridin-8(7H)-one-6-carboxylic acid alkyl esters 4 were synthesized from acyclic precursors obtained starting from quinolinic anhydride 5. Thus, methanolysis of 5 afforded the hemiester 6 which treated with oxalyl chloride and sarcosine ethyl ester gave 3-(N-ethoxycarbonylmethyl-N-methylcarbamoyl)pyridine-2-carboxylic acid methyl ester 8. Compound 8 was cyclized to naphthyridines 3a-e with sodium alkoxides. The isomeric naphthyridines 4a-c were obtained by cyclization of the open intermediary 2-(N-ethoxycarbonylmethyl-N-methylcarbamoyl)pyridine-3-carboxylic acid methyl ester 9 obtained by a route that involves treatment of 5 with sarcosine ethyl ester and esterification with diazomethane. Spectroscopic properties (1H nmr, uv, ir) of compounds 3 and 4 are discussed and confirmed the proposed structures.
Databáze:	OpenAIRE
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