Process for the preparation of echinocandin derivatives

A process for the preparation of compounds of formula (I)

• 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 comprising the following stages
• a) a compound of formula (II)
• is subjected to the action of an acid of formula R—CO2H, said acid being, if appropriate, in an isolated or non isolated activated form, in order to obtain the compound of formula (III)
• b) if appropriate, 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 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 (IV)
• 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 such as NaBH3CN in the presence of a Lewis acid, or NaBH(OCOR13), 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 subjected, if appropriate and in any appropriate order, to the one or more of the following operations
• chromatography
• crystallization
• the action of a base
• salification.