CPC C07H 19/06 (2013.01) | 19 Claims |
1. A method for preparing a compound of formula II, wherein a compound of formula III and a compound of formula IV are reacted in a first solvent in the presence of an acid to obtain the compound of formula II,
wherein, X is a halogen atom;
R1 and R2 are each independently hydrogen, methyl or halogen atoms;
R3 and R4 are hydroxyl protecting groups; and
the acid is one or a mixture of two or more of HCl, formic acid, acetic acid, or acetic anhydride.
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