Used in peptide synthesis as a fully protected glutamic acid derivative. The Boc group protects the α-amino group, while methyl esters protect both the α-carboxylic acid (as -OMe) and the side chain carboxylic acid (as OMe). This configuration allows selective deprotection of the Boc group under mild acidic conditions for coupling at the α-amino group, preventing side reactions at either carboxylic acid. After incorporation into the peptide chain, the methyl esters remain intact for subsequent selective deprotection (e.g., basic hydrolysis of the α-ester) or modification. Commonly applied in solution-phase synthesis of bioactive peptides and pharmaceutical intermediates; adaptable for solid-phase methods with additional steps.