Patent ID: 6800764
Filing Date: 2004-10-05
Classification: C07B,C07C,C07D

Abstract:
A process for preparing chirally pure S-enantiomers of &agr;-amino acids comprising the steps of:a) preparing an organometallic reagent from an alkyl halide of the formula (R)2CH(CH2)nCH2X; wherein X is Cl, Br or I and n is 0 to about 10; b) adding said organometallic reagent to carbon dioxide to afford a carboxylic acid; c) activating said carboxylic acid with an acid halide, phosphorus trichloride, acid anhydride, or thionyl chloride in the presence of a tertiary amine base; d) reacting the product of step c) with an alkali metal salt of S-4-benzyl-2-oxazolidinone; e) treating the product of step d) with a strong non-nucleophilic base to form an enolate anion; f) trapping said enolate anion with 2,4,6-triisopropylbenzenesulfonyl azide to afford an oxazolidinone azide; g) hydrolyzing said oxazolidinone azide with an aqueous base to afford an &agr;-azido acid; h) reducing said &agr;-azido acid to an &agr;-amino acid; and i) recrystallizing said &agr;-amino acid to form said chirally pure &agr;-amino acid.