Stereoselective synthesis of (2E) 3-amino-2-(1H-benzimidazol-2-yl)acrylateand symmetric bisacrylates by transamination reactions

A range of various amines 2(a-i) was tested in transamination reactions usi ng ethyl 2-(1H-benzimidazol-2-yl)-3-dimethylamino-acrylate la. The (E)-s-ci s/trans confirmation of some representative products 4 was analyzed by H-1 and C-13 NMR spectra. The C-2/C-3 bond of the compounds 3(a-i) is strongly polarized by a push-pull effect. In the same manner, reactions of ethyl 2-( benzoxazol-2-yl)-3-dimethylamino-acrylate Ic with I,rt-diaminobenzene 21, e thylenediamine 21, and 1,5-diaminomaphthalene 2k have been investigated and gave directly the corresponding symmetric bis-acrylates 4(a-c) in good yie lds. (C) 1999 John Wiley & Sons, Inc.