Trimethylaluminium-Mediated Reaction of Primary Carboxamides with Amines and Indoles: A Convenient Synthesis of Amidines and Indole-3-acylimines

A simple, convenient and general method, exhibiting good functional group tolerance, is described for the synthesis of N- and N,N-disubstituted amidines by the reaction of primary carboxamides with amines mediated by trimethylaluminium (AlMe3). Subsequent reaction of the indole systems with primary carboxamides in the presence of AlMe3 gives exclusively the C-3 substituted imine product.