STUDIES ON THE SYNTHESIS AND RESOLUTION OF GAMMA-CARBOXYGLUTAMIC ACID-DERIVATIVES

The synthesis and resolution of N-(benzyloxycarbonyl)-γ,γ-di-tert-butyl-d, l-γ-carboxyglutamie acid (5a) is described. Resolution using quinine allowed separation of the D enantiomer from the racemic mixture in 15% yield from N-(benzyloxycarbonyl)-O-tosyl-d, l-serine methyl ester (1a). Liberation of the L enantiomer from the remaining oily quinine salt followed by purification of the L-tyrosine hydrazide salt of 5a provided an overall yield of 13% of the L enantiomer from la. The synthesis of N-(benzyloxycarbonyl)-γ,γ-di-tert-butyl-D-γ-carboxyglutamyl-γ,γ-di-tert-butyl-D-γ-carboxyglutamic acid (19) is described. © 1979, American Chemical Society. All rights reserved.