Metal Complexes of Cyanamides and their Alkylation to Cyanamidium Salts. A General Synthesis of Highly Substituted Ureas, Isoureas, and Guanidines

Abstract

Abstract The complexes 3a – p were prepared from disubstituted cyanamides and Lewis acids. According to a X‐ray structural analysis, the antimony pentachloride complex 3a is neither a s̀ nor a π complex (∡ CN – Sb 133°). The complexes 3 with SbCl 5 and FeCl 3 can be alkylated with tertiary alkyl chlorides, affording crystalline cyanamidium salts ( 5a – m ) which were characterized by reactions with water, primary or secondary alcohols to give ureas ( 11 ) and uronium salts ( 8a – z ), respectively. The guanidinium salts 9a – s were obtained with ammonia, primary and secondary amines.