The invention discloses a preparation method for improving the purity of
terbinafine hydrochloride, and the method comprises the following steps: 1) adding an acid binding agent into water, stirring and dissolving, adding N-methylnaphthylamine and 1-
chlorine-6,6-dimethyl-2-
heptene-4-
alkyne, and cooling to
room temperature; adding
ethyl acetate for extraction, filtering, adding a hydrochloric acidaqueous solution, stirring, and filtering to obtain crude
terbinafine hydrochloride; and 2) purifying the
terbinafine hydrochloride, namely adding the crude
terbinafine hydrochloride in the step 1) and
purified water into a reaction kettle, heating and refluxing to dissolve, cooling to
room temperature, and filtering to obtain a finished product of the
terbinafine hydrochloride. According to the preparation method of the
terbinafine hydrochloride, only water is used as a
crystallization solvent and no toxic
solvent is used in the final step reaction of the
bulk drug, so that
potential harm oftoxic organic solvents to human bodies is avoided; moreover, the
solvent amount is extremely small, the cost is low, the generated waste liquid is less, the
pollution to the environment is reduced, the product purity and yield are high, the reaction operation is simple, the control is easy, the production period is short, and commercial production is facilitated.