| 主权项 |
1. A method for making a precursor of an HMO core structure comprising a step of reacting a disaccharide glucosamine donor of formula 1 wherein X is a halogen atom selected from the group consisting of F, Cl, Br and I, n is 0, 1, 2 or 3, and one of the R1-groups is a residue of formula A and the other R1-group is acyl, and R2 and R3 are independently acyl, with an acceptor of formula 2 wherein R4 is acyl, R5 is selected from the group consisting of H, a peracylated N-acetyllactosaminyl residue and a peracylated lacto-N-biosyl residue, R6 is H or acyl, R7 is selected from the group consisting of H, acyl, acetal type groups, silyl and a peracylated N-acetyllactosaminyl residue optionally substituted with 1 or 2 moieties selected from a peracylated N-acetyllactosaminyl group and a lacto-N-biosyl group, R8 is a group removable by hydrogenolysis, Y is —OR4 or acetylamino optionally substituted by a halogen atom, Q is a bond when Y is —R4 and Q is a carbohydrate linker comprising a peracylated lactose moiety optionally substituted either with a peracylated N-acetyllactosaminyl residue or a peracylated lacto-N-biosyl residue when Y is an acetylamino optionally substituted by a halogen atom, provided that at least one of R5 and R7 is H, in the presence of a boron halogenide promoter. |
