Patent ID: 8614289

Claim:
A method or process for the preparation of a cyclic depsipeptide compound of the formula I, wherein A 1 is a bivalent moiety of an amino acid with a terminal carboxy or carbamoyl group, and is bound at its right hand side in formula I via a carbonyl to the rest of the molecule; or is C 1-8 -alkanoyl or phosphorylated hydroxy-C 1-8 -alkanoyl; X is bound via an N of A 1 and is acyl, or is absent if A 1 is C 1-8 -alkanoyl or phosphorylated hydroxy-C 1-8 -alkanoyl; R 2 is C 1-8 -alkyl; R 3 is the side chain of leucine, isoleucine or valine; R 5 is the side chain of phenylalanine leucine isoleucine or valine; R 6 is the side chain of a hydroxy amino acid; R 7 is the side chain of the amino acid leucine, isoleucine or valine; and Y is hydrogen or C 1-8 -alkyl; or a salt thereof, said method comprising selectively deprotecting a compound of the formula II wherein Prot is a protecting group, Y is as defined for a compound of the formula I and X*, A 1 *, R 2 *, R 3 *, R 5 *, R 6 *, and R 7 * correspond to X, A 1 , R 2 , R 3 , R 5 , R 6 , and R 7 in formula I, respectively, but with the proviso that reactive functional groups on these moieties are present in protected form at least if they could participate in undesired side reactions, to result in a compound of the formula III, wherein X*, A 1 *, R 2 *, R 3 *, R 5 *, R 6 * and R 7 * have the meanings defined above, reacting the free hydroxyl group under oxidizing conditions to form a compound of the formula IV and removing remaining protecting groups to yield a compound of the formula I, or a salt thereof, and, optionally, converting a free compound of the formula I into a salt, a salt of a compound of the formula I into a different salt of a compound of the formula I or into the free compound of the formula I and/or converting a dehydrated analogue of a compound of the formula I into the corresponding compound of the formula I; and further comprising, for the synthesis of a compound of the formula II, reacting a compound of the formula VI, wherein Prot is a protecting group, Y is as defined for a compound of the formula I and R 2 *, R 3 *, R 5 *, R 6 *, and R 7 * are as defined for a compound of the formula II, with an acid of the formula VII or a reactive derivative thereof, wherein X** is an amino protecting group or is X*, and wherein X* and A 1 * are as defined for a compound of the formula II; and, if X** is an amino protecting group, removing said amino protecting group X** to yield H instead of X* and coupling the resulting amino group with an acyl group X* using the corresponding acid X*—OH wherein C* is as defined for a compound of the formula II, or a reactive derivative thereof.