Patent ID: 7361757

Claim:
A process for the synthesis of compounds of formula (I) wherein R represents a linear or branched (C 1 -C 6 )alkyl group, wherein a morpholinone of formula (III): wherein P represents a protecting group for the amino function, is reacted either with allyl bromide or allyl triflate, in the presence of a base, to yield a compound of formula (IV) having the (3S,5S) configuration: which is hydrogenated in the presence of palladium-on-carbon, or with iodopropane, to yield a compound of formula (V): which is subjected to the action of LiOH, then to the action of an esterification reagent, to yield a compound of formula (VI): which is reacted with an oxidizing agent to yield, after deprotection of the amino function, the compound of formula (I).