Orthoamides and iminium salts, LXXV [1]. Contribution to the formation of 2-formyl-1,1,3,3-tetramethylguanidine and the isomeric 1,1-Dimethyl-3- dimethylaminomethylene-urea

摘要

2-Formyl-1,1,3,3-tetramethylguanidine (1) could be prepared from tris(dimethylamino)ethoxy-methane (3a) and formamide (4). Surprisingly, guanidine 1 does not result from the reaction of 1,1,3,3-tetramethylguanidine with formylating reagents such as dimethylamino-methoxy-acetonitrile (8) or the N,N-dimethylformamide-dimethylsulfate adduct (9), rather the isomeric 1,1-dimethyl-3-dimethylaminomethylene-urea (2) is formed. The structure of 2 was confirmed by NMR spectroscopy and crystal structure analysis.