Vranicar L, Pozgan F, Polanc S, Kocevar M
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, SI-1000 Ljubljana, Slovenia.
Amino Acids. 2003 Apr;24(3):273-80. doi: 10.1007/s00726-002-0406-5.
2H-Pyran-2-ones 1 were transformed with various hydrazines into (E)- or (Z)-alpha, beta-didehydro-alpha-amino acid (DDAA) derivatives 4 (and 7) containing a highly substituted pyrazolyl moiety attached at the beta-position. With heterocyclic hydrazines, the products 4 were accompanied also by decarboxylated enamines E-6. In order to separate (E/Z)-mixtures of acids, they were transformed to the corresponding methyl esters 9 and 10 by the application of diazomethane. Catalytic hydrogenation under high pressures with Pd/C as a catalyst resulted in the formation of racemic alanine derivatives 11.
2H-吡喃-2-酮1与各种肼反应，转化为（E）-或（Z）-α，β-二脱氢-α-氨基酸（DDAA）衍生物4（和7），这些衍生物在β位带有高度取代的吡唑基部分。使用杂环肼时，产物4还伴有脱羧烯胺E-6。为了分离酸的（E/Z）混合物，通过应用重氮甲烷将它们转化为相应的甲酯9和10。以Pd/C为催化剂在高压下进行催化氢化，得到外消旋丙氨酸衍生物11。
