AMINO-ACIDS .8. A NOVEL SYNTHESIS OF GAMMA-CARBOXY-L-GLUTAMIC ACID FROM L-5-OXOPROLINE ESTERS

N-Alkyl-L-5-oxoproline esters l-5 react with phosgene to form primarily the α-chloro enamines 6, which then react further to give the 4-carboxylated compounds 7. Solvolysis of the latter with an alcohol furnishes the alkyl N-alkyl-4-(alkoxycarbonyl)-L-5-oxoprolinates 2l,4dl-8 in good yields. The dibenzyl N-benzhydryl ester 2l,4l-8c can be converted simply to γ-carboxyglutamic acid (L-Gla) by way of the N-Boc-protected dibenzyl ester 2l,4dl-10. © 1990, American Chemical Society. All rights reserved.