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-herteroarylamino-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. J. Heterocyclic Chem., 38, 859 (2001).Recently, substituted 2-acylamino-or 2-hydroxy-3-(dimethylamino)propenoates as masked α-formyl-αamino-or α-formyl-α-hydroxy acid derivatives, and 2-[(2,2-disubstituted ethenyl)amino]-3-(dimethylamino)propenoates and related compounds have been prepared in our laboratory and used as reagents for preparation of various heterocyclic systems, such as 2H-pyran-2-ones and fused pyran-2-ones, fused pyridinones, pyrimidinones [1-10], imidazole-4-carboxylates [11], alkyl 1-acyl-3,4-disubstituted pyrrole-2-carboxylates [12,13], dialkyl 3-aminopyrrole-2,4-dicarboxylates and 5H-pyrrolo[3,2-d]pyrimidine derivatives [14], and (Z)-aplysinopsin analogs in a simple and stereoselektive manner [15]. Alkyl 2-[2cyano-2-(2-pyridinyl)ethenyl]amino-3-dimethylaminopropenoates have been transformed into alkyl 2-[2-cyano-2-(2-pyridinyl)ethenyl]amino-3-[2-methoxycarbonyl-4-(2-pyridinyl)-1H-pyrrol-3-yl]aminopropenoates [16]. Chiral 3-(dimethylamino)propenoate analogs derived from L-glutamic and L-pyroglutamic acid have been used for the preparation of (S)-3-(heteroaryl)alanine and (S)-3-(heteroaryl)lactic acid derivatives, as well as for the preparation of heterocyclic systems with an α-amino acid structural element incorporated into the cyclic system [17][18][19][20][21][22][23].In continuation of our studies in this area, we report the synthesis of alkyl (Z)-2-[(E)-2-alkoxycarbonyl-2-(2pyridinyl)ethenyl]amino-3-dimethylaminopropenoates 7 and 8, and their further transformations with alkyl-, aryl-, and heteroarylamines into β-alkyl (aryl and heteroaryl)aminoα,β-didehydro-α-amino acid derivatives 22-37 as intermediates for preparation of various heterocyclic systems.Alkyl (E)-N-[2-ethoxycarbonyl-2-(2-pyridinyl)ethenyl)glycinates 5 and 6 were prepared by heating a mixture of ethyl 2-pyridinylacetate (1) and N,N-dimethylformamid dimethylacetal (DMFDMA) or (t-butyloxy)bis(dimethylamino)methane (Bredereck's reagent) at 85 °C for 1.5 hours in an argon atmosphere to give ethyl 3-(dimethylamino-2-(2-pyridinyl)propenoate (2) followed, without purification, by treatment with an alkyl glycinate hydrochloride 3, 4 in ethanol by heating at reflux temperature for 1.5 hours in 80-86% yield. They were transformed with (t-butyloxy)-859