Preparation of both enantiomers of β2-(3,4-dihydroxybenzyl)-β-alanine, higher homologues of Dopa
作者:Claudia G. Avila-Ortiz、Gloria Reyes-Rangel、Eusebio Juaristi
DOI:10.1016/j.tet.2005.06.094
日期:2005.8
and the desired β-amino acids were purified by silica gel chromatography. Alternatively, enantioenriched (R)- and (S)-1 were prepared by means of the highly diastereoselective alkylation (3,4-dimethoxybenzyl iodide) of open-chain β-aminopropionic acid derivatives (R,R,S)-8 and (S,S,R)-8 containing the chiral auxiliary α-phenylethylamine. Finally, nearly enantiopure (R)- and (S)-1 were obtained by resolution
β 2 - (3,4-二羟基苄基)-β-丙氨酸[β 2 -Homo多巴,1 ]是一种新型的β氨基酸多巴,在帕金森氏病的治疗中最成功的治疗剂的同源物。通过对映纯的β-丙氨酸手性衍生物对映体纯嘧啶酮(R)-和(S)-3的非对映选择性烷基化,与藜芦基碘化物得到对映体富集的(R)-1和(S)-1。主要的非对映异构产物(2 S,5 R)-4和(2 R,5 S)-4将其用57%HBr水解,并通过硅胶色谱法纯化所需的β-氨基酸。或者,通过开链β-氨基丙酸衍生物(R,R,S)-8和(R)的高度非对映选择性烷基化(3,4-二甲氧基苄基碘)制备对映体富集的(R)-和(S)-1。S,S,R)-8包含手性辅助α-苯基乙胺。最后,通过外消旋N的拆分获得了近对映纯(R)-和(S)-1。-苄氧基羰基-2-(3,4-二苄氧基苄基)-3-氨基丙酸rac - 12,与(R)-或(S)-α-苯基乙胺,然后催化氢解。