The application discloses a preparation method of an intermediate N-methyl-2-hydroxyethyl
pyrrolidine of clemastine, relates to the technical field of
medicine intermediate synthesis, and comprises the following steps:
triphenylphosphine is added into an
organic solvent,
ethyl bromoacetate is added, stirring reaction is carried out,
filtration is carried out, the obtained precipitate is washed with the above-mentioned
organic solvent,
vacuum drying is carried out, and an intermediate one is obtained; N-methyl pyrrolidone is added into a
benzene solvent, the intermediate one is added under stirring, stirring reaction is carried out,
solid is removed through
filtration, the filtrate is distilled under reduced pressure, and an intermediate two is obtained; the intermediate two is added into an
alcohol solvent, hydrogenation is carried out through
palladium-carbon,
sodium borohydride is added in three batches, stirring reaction is carried out, pH is adjusted, extraction is carried out with
dichloromethane, the obtained aqueous phase is extracted with
dichloromethane again, organic phases are combined,
drying is carried out, and N-methyl-2-hydroxyethyl
pyrrolidine is obtained through reduced pressure
distillation; the preparation method is high in yield, convenient in separation and purification, low in cost, simple and convenient to operate, and small in danger.