One-Carbon Compounds as Synthetic Intermediates. The Synthesis of Hydropyrimidines and Hydroquinazolines by Sequential Nucleophilic Addition to Diphenyl Cyanocarbonimidate with Concomitant Cyclization

Article abstract of DOI:10.1021/jo00266a013

Diphenyl cyanocarbonimidate (1) undergoes nucleophilic addition with ω-amino esters and amines in a sequential manner to give guanidine derivatives that, for the most part, spontaneously cyclize to give hydropyrimidines or hydroquinazolines.The hydropyrimidines could be dehydrogenated to dihydropyrimidines, and the NCN group could be hydrolyzed to a carbonyl or amine group in the pyrimidine and to an amine group in the quinazoline series.The regiospecificity of the cyclization was determined by a combination of spectroscopic methods and comparison of compounds synthesized by standard routes.The scope of the synthetic route is indicated.Some of the acyclic N-cyano-O-phenylisoureas formed by the first nucleophilic addition exist as mixtures of isomers, and the barriers to interconversion have been determined by NMR spectroscopy.