PREPARATION OF PEPTIDE AMIDE SULFATE ESTER TERMINATED WITH CHOLECYSTOKININ-PANCREOZYMIN C

摘要

PURPOSE:To obtain the titled compound useful as a contracting agent for a cholecyst, in high yield, by converting a protected peptide amide sulfate ester into a bivalent metallic salt, and removing the unreacted sulfur trioxide-pyridine complex as a sulfate in the form of a precipitate. CONSTITUTION:A protected peptide amide of formula I [R2 is formula II or III (X is protecting group of the amino group; Y is protecting group of the carboxyl group] is dissolved in an inert solvent, e.g. DMF, and sulfur trioxide-pyridine complex in an amount of 10 times that of the protected peptide amide is added thereto to give a sulfate ester. The solvent is then distilled from the reaction mixture, and a solvent, e.g. methanol, and a water-soluble bivalent metallic salt, preferably Ca salt, are added to the residue to convert the peptide amide sulfate ester in the reaction mixture into a bivalent metallic salt thereof. The resultant solution is then purified by the column chromatography. The protecting groups are removed, and the resultant product is desalted to give the aimed compound of formula IV (R1 is Asp-or formula V) industrially and advantageously.