Patent ID: 6977311

Claim:
A process for synthesizing greater than 99% enantiomerically pure 4-methylene-L-glutamic acid or an ester thereof having the formula wherein R 1 and R 2 are individually hydrogen or C 1 -C 6 alkyl, said process comprising the steps of: a. providing a protected (2S)-pyroglutamic acid or ester thereof as a starting material; b. reacting the starting material with an amide or an acetal at a temperature ranging from 70° C to 130° C to form a protected 4-enamine pyroglutamic acid intermediate or ester thereof; c. hydrolyzing the protected 4-enamine derivative to form a protected 4-hydroxymethylidene pyroglutamic acid intermediate or ester thereof; d. reducing in a basic solution the protected 4-hydroxymethylidene intermediate to form a protected 4-methylene pyroglutamic acid or an ester thereof; and e. reacting the protected 4-methylene pyroglutamic acid with a base to form linear 4-methylene glutamic acid, or an ester or salt thereof.