Enzymatic resolution of (±)-5-phenyl-4,5-dihydroisoxazole-3-carboxylic acid ethyl ester and its transformations into polyfunctionalised amino acids and dipeptides
作者:Giuseppe Cremonesi、Piero Dalla Croce、Alessandra Forni、Maddalena Gallanti、Raffaella Gandolfi、Concetta La Rosa
DOI:10.1016/j.tetasy.2009.07.025
日期:2009.8
via enzymatic resolution of the corresponding racemic mixture using a lipase from hog pancreas (PPL). The following reduction of the ester group to the corresponding alcohol and the oxidation of the latter led to (5R)-(−)-5-phenyl-4,5-dihydroisoxazole-3-carbaldehyde, and the reaction between this and Schöllkopf’s reagent, (2R)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine, gave mixtures of adducts
使用猪胰脏(PPL)中的脂肪酶,通过酶促拆分相应的外消旋混合物,获得对映体纯的(5 R)-(-)-5-苯基-4,5-二氢异恶唑-3-羧酸乙酯。随后将酯基还原为相应的醇,然后将其氧化,生成(5 R)-(-)-5-苯基-4,5-二氢异恶唑-3-甲醛,其与Schöllkopf '的反应试剂,(2 - [R )- (+) - 2,5-二氢-3,6-二甲氧基-2-异丙基吡嗪,得到的加合物的混合物具有良好的顺式/反比率。主要的非对映异构体的空间构型是根据光谱数据和X射线分析确定的。随后吡嗪环的受控水解导致β-(5-苯基-4,5-二氢异恶唑-3-基)-丝氨酸甲酯和具有(R)-缬氨酸的相应二肽。最后,在水解条件下4,5-二氢异恶唑环的还原裂解使得可以获得相应的多官能化二肽成为可能。