Patent ID: 9278908
Filing Date: 2016-03-08
CPC Classification: A61P,C07C,C07D

Claim Text:
1. A process for preparing N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid ethyl ester, or a salt thereof, or the compound N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid comprising i) reacting a compound of formula (3), or salt thereof, wherein R1 is hydrogen or a nitrogen protecting group; first with a base and then with a compound of the formula CO wherein R1 is hydrogen or a nitrogen protecting group; and R4 is selected from hydroxyl, alkyl, aryl and arylalkyl; and ii) reacting the obtained compound of formula (4), or salt thereof, with a base and formaldehyde, optionally in the presence of a phase transfer catalyst, to obtain a compound of formula (1), or salt thereof, wherein R1 is hydrogen or a nitrogen protecting group; and iii) subsequently converting the obtained compound of formula (1) to the compound N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid ethyl ester, or a salt thereof, or the compound N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid or a salt thereof.