N-Substituted-N', N'-di-(2-cyanoethyl)-guanidines have been cyclized with the elimination of acrylonitrile to 2-imino-3-substituted-4-keto-hexahydropyrimidines. These pyrimidine derivatives also were prepared by treating 1-substituted-3-(2-cyanoethyl)-S-methyl isothiuronium iodide salts with ammonia. 1-(3, 4-Dichlorobenzyl)-3-(2-cyanoethyl)-urea was cyclized in the presence of absolute ethanolic hydrogen chloride to 2, 4-diketo-3-(3, 4- ...
