Abstract:
The present invention relates to pyrrolidin-2-ones according to the formula (1), or salts thereof, wherein R1 is hydrogen or a nitrogen protecting group, methods for their preparation and their use in the preparation of NEP-inhibitors, particularly in the preparation of N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid ethyl ester or salt thereof.
Abstract:
An improved process for preparing 1,4,8,11-tetraazacyclotetradecane comprising the tetratosylation of an acyclic tetraamine to obtain a tetratoluenesulfonamide compound in a first step, the cyclization of said sulfonamide compound to obtain tetratosyl cyclam in a second step, and the detosylation of tetratosyl cyclam in a third step followed by basification to obtain the desired 1,4,8,11-tetraazacyclotetradecane.