PROCESS FOR THE PREPARATION OF N2 -(1(S)-CARBOXY-3-PHENYLPROPYL)-L-LYSYL-L-PROLINE

摘要

The process for producing N<2>-(1(S)-carboxy-3-phenylpropyl)-L-lysyl-L-proline in a simple, efficient and industrially advantageous manner, which comprises: the first step of subjecting the N<2>-(1(S)-alkoxycarbonyl-3-phenylpropyl)-N<6>-trifluoroacetyl-L-lysyl -L-proline (1) to alkali hydrolysis in a mixed solution composed of water and a hydrophilic organic solvent using an inorganic base in an amount of n molar equivalents (n >/= 3) per mole of the above compound (1), the second step of neutralizing the hydrolysis product using an inorganic acid in an amount of (n - 1) to n molar equivalents (n >/= 3) and removing the inorganic salt formed by causing the same to precipitate out from a solvent system suited for decreasing the solubility of the inorganic salt, and the third step of causing the compound (2) existing in the mixture after removal of the inorganic salt to crystallize out at the isoelectric point thereof and thereby recovering the compound (2) in the form of crystals while retaining the salts comprising the trifluoroacetic acid-derived organic acid salt in a state dissolved in the mother liquor.