Synthesis of highly 1,3-proton shift transferable N-benzyl imines of trifluoroacetophenone under the "low-basicity" reaction conditions

The standard reaction conditions commonly used for the condensation of carbonyl compounds with amines were found to be synthetically inefficient for preparation of the imines derived from trifluoroacetophenone and benzylamines owing to the susceptibility of these imines to 1,3-proton shift. Application of a "low-basicity" method, using instead of free benzylamines their salts formed from acetic acid (AA), allowed synthesis of the target compounds in chemically pure form and excellent chemical yields. (C) 2004 Elsevier B.V. All rights reserved.