The invention provides a preparation midbody for
Ezetimibe which is shown in a general formula I, wherein PG is an acetyl group, a T-butyloxycarbonyl group, a
benzyl group, a benzyloxycarbonyl group, a trityl group, a
trimethylsilyl group or a diphenylmethyl group
silicon group. The invention further provides a preparation method of the midbody I, and the application for preparing the
medicine Ezetimibe. The method for preparing the
Ezetimibe by adopting the compounds shown in the general formula I is different from the method in the conventional document, the newer
chirality assistant (S)-4-(2-chlorphenyl)-2-
oxazolone is adopted, the productive rate reaches 91%, and the optical purity reaches 100%, so that the productive rate and the optical purity are higher than those of the previously applied (S)-4-phenyl-2-
oxazolone. Besides, the selected
chirality assistant (S)-4-(2-chlorphenyl)-2-
oxazolone can be conveniently prepared by the original commercialized ((S)-2-
chlorobenzene glycine potassium).