Selective mono-amination of dichlorodiazines

A mild, easy-to-perform, and versatile method for the formation of aminochlorodiazines from reaction of several types of dichlorodiazines (i.e., pyridazines, pyrimidines, and pyrazines) with primary or secondary amines in ethanol in the presence of triethylamine as a base, is described. The methodology is general and efficient despite noticeable difference in reactivity between diazines. While dichloropyridazine and dichloropyrazine require several hours of heating at reflux for the reaction to proceed, dichloropyrimidines reach completion within minutes at room temperature. [Display omitted]