ACCELERATION OF THE N(ALPHA)-DEPROTECTION RATE BY THE ADDITION OF M-CRESOL TO DILUTED METHANESULFONIC-ACID AND ITS APPLICATION TO THE Z(OME)-BASED SOLID-PHASE SYNTHESES OF HUMAN PANCREASTATIN-29 AND MAGAININ-1

In solid-phase peptide synthesis, the addition of m-cresol to diluted methanesulfonic acid (MSA) in dichloromethane accelerated the deprotec tion rate of the acid-labile alpha-amino protecting group, the p-metho xybenzyloxycarbonyl (Z(OMe)) group. Further, 0.1 m MSA, 20% m-Cresol/C H2Cl2 was found to be a practically useful N(alpha)-deprotecting reage nt system, since the deprotection of the Z(OMe) group occurred selecti vely within 30min at room temperature, leaving intact the other side c hain protecting groups, such as benzyloxycarbonyl, benzyl ester, S-p-m ethoxybenzyl and N(G)-mesitylene-2-sulfonyl groups. This reagent syste m was applied to the Z(OMe)-based solid phase syntheses of human pancr eastatin-29 and magainin 1.