ASYMMETRIC-SYNTHESIS OF THREONINE AND PARTIAL RESOLUTION AND RETRORACEMIZATION OF ALPHA-AMINO-ACIDS VIA COPPER(II) COMPLEXES OF THEIR SCHIFF-BASES WITH (S)-2-N-(N'-BENZYLPROLYL)AMINOBENZALDEHYDE AND (S)-2-N-(N'-BENZYLPROLYL)AMINOACETOPHENONE - CRYSTAL AND MOLECULAR-STRUCTURE OF A COPPER(II) COMPLEX OF GLYCINE SCHIFF-BASE WITH (S)-2-N-(N'-BENZYLPROLYL)AMINOACETOPHENONE(S
ASYMMETRIC-SYNTHESIS OF THREONINE AND PARTIAL RESOLUTION AND RETRORACEMIZATION OF ALPHA-AMINO-ACIDS VIA COPPER(II) COMPLEXES OF THEIR SCHIFF-BASES WITH (S)-2-N-(N'-BENZYLPROLYL)AMINOBENZALDEHYDE AND (S)-2-N-(N'-BENZYLPROLYL)AMINOACETOPHENONE - CRYSTAL AND MOLECULAR-STRUCTURE OF A COPPER(II) COMPLEX OF GLYCINE SCHIFF-BASE WITH (S)-2-N-(N'-BENZYLPROLYL)AMINOACETOPHENONE(S
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DOI：
10.1021/ja00345a057
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发表时间：
1983-01-01
影响因子：
15
通讯作者：
BELIKOV, VM
中科院分区：
文献类型：
--
作者：
BELOKON, YN;ZELTZER, IE;BELIKOV, VM
本文的工作涉及寻找用于氨基酸的不对称合成、拆分和反消旋化的通用手性试剂。N-苄基-（S）-脯氨酸与邻氨基苯甲醛或邻氨基苯乙酮反应，得到（S ′）-2-7-（Ar '-苄基脯氨酰基）氨基苯甲醛（（S）-BPAB）或（5'）-2-7-（7V-苄基脯氨酰基）氨基苯乙酮（（S ′）-BPAAPh）。这些手性试剂与-氨基酸（aa）和Cu（II）离子相互作用形成配合物[（S）-BPAB-aa] Cun和[（S）-BPAAPh-aa] Cu-，其中席夫碱（S）-BPAB-aa或（S）-BPAAPh-aa作为四齿配体，并通过吡咯烷片段的氮原子、去质子化的酰胺基团、和氨基酸片段以及羧酸根的氧原子。元素分析、分子量测定、电子光谱、红外光谱和圆二色光谱数据均支持这种结构。最后通过[（S）-BPAAPh-Gly] Cun的X射线衍射分析证实了这一点。1当量的（S）-BPAB与2当量的（R，5）-aa和2当量的Cu（II）反应，优先形成席夫碱与（S）-aa的铜配合物。用氯仿萃取后，富含R对映体的氨基酸保留在水溶液中。以这种方式，外消旋氨基酸（Ala、Nva、Phe、瓦尔、Thr）的部分拆分已经进行，对映体纯度为4- 50%。（S）-BPAB或（S）-BPAAPh在Cu（II）离子（试剂比1：1：1）和CH_（30）离子存在下处理外消旋氨基酸通过将R转化为5对映体（反外消旋化）而实现对映体富集。因此（从外消旋样品中获得对映体纯度分别为36、12、22、54、42和35%的1-Ala、（S）-Nva、（S）-Leu、（S）-瓦尔、（S）-Phe和（S）-PhGly。[（S）-BPAB-Gly] Cun或[（S）-BPAAPh-Gly] Cu 11与乙醛的CH_（30）_催化反应产生了非对映配合物的混合物，其在用H_2S除去Cu（II）后得到（7 R）- 60%或97-100%对映体的苏氨酸
The work describedhere is concerned with the search for universal chiral reagents for the asymmetric synthesis, resolution, and retroracemizationof amino acids. Reaction of 7V-benzyl-(S)-proline with o-aminobenzaldehyde or o-aminoacetophenone has given (S')-2-7V-(Ar'-benzylprolyl) aminobenzaldehyde ((S)-BPAB) or (5')-2-7V-(7V-benzylprolyl) amino-acetophenone ((S')-BPAAPh). These chiral reagents have interacted with-amino acids (aa) and Cu (II) ions to form complexes [(5)-BPAB-aa] Cun and [(S)-BPAAPh-aa] Cu" in which Schiff bases (S)-BPAB-aa or (S)-BPAAPh-aa act as tetradentate ligands and coordinate the copper ion by the nitrogen atoms of the pyrrolidine fragment, the deprotonated amide group, and the amino acid fragment and by the oxygen atom of the carboxylate. Such a structure was supported by data on elemental analysis, the molecular weight measurements, and electron, IR, and CD spectra. It was finally confirmedby an X-ray diffraction analysis of [(S)-BPAAPh-Gly] Cun. One equivalent of (S)-BPAB has reacted with 2 equiv of (R, 5)-aa and 2 equiv of Cu (II), having given preferential formation of copper complexes of Schiff bases with (S)-aa. After their extraction with chloroform the amino acid enriched with the R enantiomer remained in the aqueous solution. In this manner partial resolution of racemic amino acids (Ala, Nva, Phe, Val, Thr) has been carried out with enantiomeric purity 4-50%.(S)-BPAB or (S)-BPAAPh treatment of a racemic amino acid in the presence of Cu (II) ions (reagents ratio 1: 1: 1) andCH30~ ions permitsenantiomeric enrichment via conversion of the R into the 5 enantiomer (retroracemization). Thus (¿/-Ala,(S)-Nva,(S)-Leu,(5)-Val,(S)-Phe, and (S)-PhGly of enantiomeric purity 36, 12, 22, 54, 42, and 35%, respectively, were obtained from racemic samples. CH30 “-catalyzed reaction of [(S)-BPAB-Gly] Cun or [(5)-BPAAPh-Gly 1 Cu11 with acetaldehyde has given rise to a mixture of diastereometric complexes, which upon removal of Cu (II) by H2S gave (7?)-threonine of 60% or 97-100% enantiomeric