Solvent free aza-annulation using 4-dimethylamino 2-aza-1,3-dienes as γ-dielectrophiles for a new synthesis of imidazole-4-carboxylates.

Article abstract of DOI:10.1016/S0040-4039(99)01696-2

4-Dimethylamino 2-aza-1,3-dienes 2a,b derived respectively from methyl N-(1-ethoxyethyliden)glycinate 1a and methyl N-[bis-(methylthio)methylene]glycinate 1b react with hydrazines 3a,b and amines 3c,d to give the corresponding new imidazole-4-carboxylates 5(a-f) by a solvent-free aza-annulation.