Patent ID: 7262169

Claim:
A process for the preparation of a compound of formula B: or a salt thereof; wherein AA 4 , AA 5 , AA 6 and AA 7 are independently selected from a natural or unnatural amino acid; Fm is 9-fluorenylmethyl; 4-Hyp is and r is 2 or 3, that comprises the steps of: a) reacting the diester of the formula E: with the tripeptide D: or a salt thereof; to provide an intermediate of the formula C-1: or a salt thereof; b) reacting the intermediate of the formula C-1 with a tetrapeptide of the formula F: wherein Prot is a carboxylic acid protecting group, to provide the following compound of the formula: and c) deprotecting the C-terminus of the following compound of the formula: