Darstellung von Guanidosäuren und Guanidopeptiden

Abstract

Creatine was prepared by treating 0.1 mol of o-methylisourea in absolute methyl alc. with 0.05 mol sar-cosine, and allowing the soln. to stand about 2 wks. Guanidine derivatives were not formed by treating iminodi-acetic acid with s-methylisothiourea sulfate in conc. NH3, nor by treating the free o-methylisourea base with iminodi-acetic acid in methanol. Asymmetric guanidineanhydrodi-acetic acid monomethyl ester was prepared by mixing 5 g. of diglycolamid acid dimethyl ester in absolute ether with a great excess of cyanamide in absolute ether. By the reaction of 12.6 g. iminodiacetic acid dimethyl ester in 200 ml. absolute ether, with an ether soln. of 4.15 g. cyanogen bromide, cyanamidodiacetic acid dimethyl ester was formed. When this compound was treated with NH3, guanidinedi-acetic acid monomethyl ester was obtained. It was shown that the method of preparing guanidine derivatives with alkylisothiourea salts in conc. NH3 was of general application for by it guanidinepropionic acid was prepared from alanine, guanidineacetic acid from glycine, guanidine-acetylglycine from glycylglycine and guanidineacetyltyrosine from glycyltyrosine.