N-Carbobenzoxy-α-alkoxyglycine esters were synthesized by H2SO4-catalyzed O-alkylation of N-carbobenzoxy-α-hydroxyglycine and also by base treatment of N-carbobenzoxy-N-chloroglycine methyl ester in the corresponding alcohol. Saponification of the protected α-alkoxyglycines gave free acids which can be used for the synthesis of α-alkoxyglycine residue-containing peptides.
Preparation of Protected α-Methoxyglycine and Its Incorporation into Peptide Synthesis
A protected α-methoxyglycine Cbz-DL-Gly(OMe)-OMe (1) was prepared from the N-chloro derivative of Cbz-Gly-OMe.Catalytic hydrogenolysis of 1 in the presence of a mixed anhydride prepared from a Boc-amino acid and ClCO2Bui gave a diastereomeric p