The stereoselective synthesis of nitrile amino acids using a chiral Schiff base complex.

摘要

This thesis focuses on the synthesis of (S)- and ( R)-Schiff base complexes of Ni2+, glycine, and 2-[ N-(N'-benzylprolyl)amino]benzophenone (BPB) and their use in the stereoselective synthesis of a series of nitrile amino acids, a class of non-protein amino acids. Optimized reaction conditions are presented for the alkylation of (S)- and (R )-BPB complexes with alkylcyano bromides (Br(CH2) nCN, n = 2--4). Enantiomerically enriched (S)- and (R)-nitrile amino acids (84--96% e.e.) obtained by acid hydrolysis of the alkylated complexes were recrystallized to yield enantiomerically pure nitrile amino acids (>99% e.e.). The diastereoselectivity of the alkylation reaction and enantiomeric purity of the nitrile amino acids was determined by HPLC analysis of diastereomeric, fluorescent derivatives. Optical rotations were used to assign stereochemical configurations.;The corresponding (S)- and (R)-diamino acids were produced in a single step by reducing the nitrile group of the nitrile amino acids.