A simple and general synthesis of symmetrical and unsymmetrical bis(arylamino)methanes. Reactions of N,O‐acetals with nitrogen bases

Bis(arylamino)methanes 4 free of amine contamination have been efficiently synthesized from N,O‐acetals 1 following three different methodologies. The first two are useful for symmetrical aminals and involve the decomposition of an N,O‐acetal by a base (phenyllithium or a lithium arylamide) and trapping of the resulting methyleneamine 2 by the equimolar amount of the corresponding arylamine. The third method allows the preparation of either symmetrical or unsymmetrical aminals and consists of decomposing the starting N,O‐acetal 1 by heating in vacuo in the presence of the desired arylamine.