Regiospecific synthesis of N,N’-disubstituted-2-imino-hydantoins derived from cyanamides

The present work developed a new simple method and convenient procedure to synthesize a novel series of 1-(4,6-dimethylpyrimidin-2-yl)-2-imino-3-arylimidazolidin-4-ones 3. The sodium salt of N-(4,6-dimethylpyrimidin-2-yl)cyanamide (1) was selected to use as the starting material to undergo intramolecular cyclization reaction with 2-chloro-N-arylacetamides in boiling acetone for about 12–18 hours. According to this new synthetic route, eleven imino-hydantoins were readily separated in moderate to excellent yields as single products after cooling the reaction without any purification technique. Also, on the basis of the experimental results and analysis data (IR, NMR, elemental analyses, and GC-MS spectra), the reaction is regiospecific as well as a plausible mechanism to form the target products 3 instead of di-imino-oxazolidines 4 and/or 2-imino-2,3-dihydro-oxazoles 5 is proposed.