α,β-Didehydroamino acid derivatives with an isoxazolyl or a pyrazolyl moiety: The effect of substituents and reaction conditions on their stereoselective formation from 2H-pyran-2-ones
作者:Lidija Vranic̆ar、Anton Meden、Slovenko Polanc、Marijan Koc̆evar
DOI:10.1039/b107624h
日期:2002.2.22
2H-Pyran-2-ones 1 and 2 and hydroxylamine or hydrazines are used as synthons for the synthesis of E- or Z-α,β-didehydroamino acid derivatives 4 and 5 containing an isoxazolyl or a pyrazolyl ring attached at the β-position. The emphasis of our study is on the effect of substituents on both reagents as well as on the reaction conditions (solvent, catalyst, and temperature) influencing the ratio between (E)- and (Z)-isomers and, in some cases, decarboxylated analogues 6.
2H-Pyran-2-ones 1 和 2 与羟胺或肼(hydrazines)用作合成 E- 或 Z-δ,δ²-二羟基氨基酸衍生物 4 和 5 的合成催化剂,这些衍生物含有一个连接在 δ² 位上的异恶唑基或吡唑环。我们研究的重点是取代基对两种试剂以及反应条件(溶剂、催化剂和温度)的影响,这些因素会影响(E)-和(Z)-异构体之间的比例,在某些情况下还会影响脱羧类似物 6。