1,3‐Diacyl derivatives of imidazolidine and hexahydropyrimidine: I. Preparation by novel method and characterization

The reaction of formaldehyde and diamides of 1,2‐diamines in acetic acid containing a trace of hydrochloric acid was found to give 1,3‐diacyl derivatives of imidazolidine in high yield. The similar reaction of formaldehyde and diamides of 1,3‐propylenediamine gave high yields of 1,3‐diacylhexahydropyrimidines. Attempts to extend this reaction to other aldehydes than formaldehyde failed, as did attempts to condense formaldehyde with a diamide which would give a four‐membered or seven‐membered ring system, the diamide being recovered unchanged in each instance. Twenty‐two new compounds were prepared and characterized.