Patent ID: 6242565
Filing Date: 2001-06-05
Classification: C07K,Y02P

Abstract:
A method for preparing a peptide derivative of formula (I) or a salt thereof: ##STR21##including the steps of:removing two MBzl groups from a compound of formula (II) or a salt thereof: wherein the compound (II) or the salt thereof is reacted with a mixture of phenols, trifluoroacetic acid, and methane-sulfonic acid at a temperature between 0 and 30.degree. C., ##STR22##and MBzl represents a 4-methoxybenzyl group which serves as a protective group for a thiol group, R.sup.1 represents a hydrogen atom or a protective group for an indolyl group of D-Trp;and subsequently oxidizing in an aqueous buffer solution having a pH from 4.0 to 5.0 to form an intramolecular disulphide bond.