A Convenient Synthesis of 4-Hydroxy-2-oxo-1,2-dihydro-1,8-naphthyridine-3-carboxamideDerivatives

A simple method for synthesizing 1-aryl-4-hydroxy- N, N-dimethyl-2-oxo-1,2-dihydro-1,8-naphthyridine-3-carboxamideshas been developed. Thus, 3-(2-chloropyridin-3-yl)- N, N-di-methyl-3-oxopropanamide,easily prepared by treating ethyl 2-chloropyridine-3-carboxylatewith lithium enolate of N, N-dimeth-ylacetamide, smoothlyreacts with a range of aryl isocyanates in the presence of two molaramounts of sodium hydride to provide the desired products in moderateyields.