The reaction of <i>N,N</i>‐dimethyldichloromethyleniminium chloride (phosgeniminium chloride) with 6‐<i>N</i>‐arylaminouracils. A new and convenient “one pot” synthesis of l,3‐dimethyl‐5‐ dimethylaminopyrimido[4,5‐<i>b</i>]quinoline‐(1<i>H</i>,3<i>H</i>)‐2,4‐diones, 1,3‐dimethyl‐5‐chloropyrimido[4,5‐<i>b</i>]quinoline‐(1<i>H</i>,3<i>H</i>)‐2,4‐diones and 3‐methyl‐10‐alkyl‐5‐chloropyrimido[4,5‐<i>b</i>]quinoline‐(3<i>H</i>,10<i>H</i>)‐2,4‐diones (3‐methyl‐10‐alkyl‐5‐chloro‐5‐deazaflavins)

Abstract

Abstract The 1,1,1‐tricondensation of N,N ‐dimethyldichloromethyleniminium chloride (phosgeniminium chloride) with various 1,3‐dimethyl‐6‐ N ‐arylaminouracils and 3‐methyl‐6‐ N ‐(alkylaryl)aminouracils, which gives only 5‐dimethylaminopyrimido[4,5‐ b ]quinoline‐2,4‐diones when performed in the presence of triethylamine, affords also the corresponding 5‐chloropyrimido[4,5‐ b ]quinoline‐2,4‐diones, including 3‐methyl‐10‐alkyl‐5‐chloro‐5‐deazaflavins, when carried out in the absence of a base and under appropriate solvent and temperature reaction conditions. With regard to the selectivity of the transformation, these reaction conditions have been found to be especially dependent on the nature and the position of the starting arylaminouracil substituents.