The synthesis and transformations of 2-[2-ethoxycarbonyl-2-(2-pyridinyl)ethenyl]amino-3-dimethylaminopropenoates. the synthesis of substituted β-amino-α,β-didehydro-a-amino acid derivatives

Alkyl (Z)-2-[(E)-2-ethoxycarbonyl-2-(2-pyridinyl)ethenyl]amino-3-dimethylaminopropenoates 7 and 8 were prepared from ethyl 2-pyridinylacetate (1) in two steps. Substitution of the dimethylamino group with alkyl-, aryl-, or heteroarylamines afforded the corresponding β-alkyl- 22–24, β-aryl- 25–35, and β-herteroaryl-amino-α,β-didehydro-α-amino acid 36 and 37 derivatives, intermediates for further preparation of various heterocyclic systems. The orientation around both double bonds were determined by various nmr techniques.