Transformations of conjugated enamines of the imidazolidine 1-oxide series in the Vilsmeier-Haack reaction

摘要

In some cases,the reactions of enaminones of the imidazolidine 1-oxide series with the Vilsmeier reagent afford electrophilic substitution products containing the dimethyl-aminomethylene group.In an acidic medium,these products undergo either hydrolytic elimi-nation of the dimethylaminomethylene moiety or hydrolysis of the latter to form the aldehyde group.The reaction of nitroenamine,which is a derivative of imidazolidine 1-oxide,with the Vilsmeier reagent produces furoxane,viz.,the nitroxyl biradical.Reduction of the latter affords the dioxime biradical.