Patent ID: 7148322

Claim:
A process for the preparation of compounds of formula (I), unsalified forms thereof, and salts thereof in which R represents a linear or branched or cyclic chain containing up to 30 carbon atoms, optionally containing one or more heteroatoms and one or more heterocycles, the process comprising: a) a compound of formula III is provided b) the compound of formula (III) is subjected to an alkylation reaction of the alcohol in position 5 by the action of an alcohol of formula Alk-OH in the presence of pyridinium p-toluenesulfonate (PPTS), Alk representing an alkyl radical containing 1 to 4 carbon atoms, in order to obtain the compound of formula (III′) c) the compound of formula (III) or (III′) is subjected to a dehydration reaction, in order to obtain a compound of formula d) the compound of formula (IV) is subjected to a reducing amination reaction by the action of ethylene diamine in the presence of a reducing agent comprising NaBH 3 CN in the presence of a Lewis acid, or NaBH(OCOR′) 3 , OCOR′ representing Boc-L-Pro, Bzl-L-Pro or any other optically active amino acid as well as any other chiral or non chiral carboxylic acid, in order to obtain the compound of formula (I) as defined above, comprising a majority of one of the active isomers, said compound of formula (I) then being optionally subjected to the one or more of the following operations, chromatography, crystallization, the action of a base to form an unsalified compound, and salification.