Decarbamoylation of N-alkoxy-N-(4-dimethylaminopyridin-1-ium-1-yl)urea chlorides in dimethylsulfoxide as a route to 1-alkoxyamino-4-dimethylaminopyridinium chlorides

Abstract

Decarbamoylation of N-alkoxy-N-(4-dimethylaminopyridin-1-ium-1-yl)urea chlorides in dimethylsulfoxide takes place with the formation of 1-alkoxyaminopyridinium chlorides. The nature of N-alkoxy substituents has a great influence on decarbamoylation efficiency. Decarbamoylation of N-n-butyloxy-N-(4-dimethylaminopyridin-1-ium-1-yl)urea chloride at 20 ºC occurs with the selective formation of 1-n-butyloxyamino-4-dimethylaminopyridinium chloride. N-Methoxy-N-(4-dimethylaminopyridin-1-ium-1-yl)urea chloride is stable in dimethylsulfoxide at 20 ºC, but it forms selectively 1-methoxyamino-4-dimethylaminopyridinium chloride at 82 ºC in 1 h. N-Ethoxy-N-(4-dimethylaminopyridin-1-ium-1-yl)urea chloride is also stable in dimethylsulfoxide at 20 ºC, but it converts into 1-ethoxyamino-4-dimethylaminopyridinium chloride at 100 ºC under heating for 3 h.