THE TETRABENZYLGLUCOSYLOXYCARBONYL(BGLOC)-GROUP-A CARBOHYDRATE-DERIVED ENZYME-LABILE URETHANE PROTECTING GROUP

The development of the tetrabenzylglucosyloxycarbonyl (BGloc)-protecti ng group as an enzymatically removable urethane protecting function fo r peptide synthesis is described. BGloc-protected amino acids are read ily synthesized by conversion of amino acid allyl esters into the resp ective isocyanates, subsequent treatment with 2,3,4,6-tetrabenzylgluco se and C-terminal allyl ester cleavage. From BGloc masked dipeptide es ters, which are accessible by standard methods of peptide chemistry, t he N-terminal urethane is selectively cleaved off in high yield via re moval of the benzyl ethers by hydrogenation followed by hydrolysis of the urethane by means of alpha- and beta-glucosidase under very mild r eaction conditions. (C) 1998 Elsevier Science Ltd.