Reactions of Alkylbiguanides with Benzoin at the pH of the Biguanide Bases

Article abstract of DOI:10.1007/BF00811115

Alkylbiguanides 2a-e react with benzoin (1) at the pH of the base in different ways. 1 undergoes in presence of 2a, c oxidation to benzoic acid which reacts with the bases 2a, c to yield 4-phenyl-1,3,5-triazinamines 3c, 4c; in presence of 2b 1 is transformed to benzil, which reacts with 2b under rearrangement to yield 1-(4-oxo-5,5-diphenyl-2-imidazolin-2-yl)-3,3-dimethylguanidine (5b).However, the cycloalkylbiguanides 2d, e react in presence of nitrogen as well as oxygen with 1 to yield piperidine-1- (7d), resp. morpholine-4- (7e).The structure of 7e was established by means of an X-ray structure analysis.All proton- and carbon resonances were assigned on the basis of 2-dimensional NMR data.Keywords: Benzoin, reaction with alkylbiguanides; Imidazoles , 1-(4-oxo-5,5-diphenyl-2-imidazolin-2-yl)-3,3,-dimethyl-guanidine>; Triazines ; NMR; X-ray analysis.