The invention belongs to preparation of antibiotic, in particular to preparation method of
Valnemulin and
hydrochloride thereof.D-hydroxy
valine Dane salt is added into more than ten weight of
tetrahydrofuran and is suspended by stirring at 0-20 DEG C, and
triethylamine, N, N-
dimethyl formamide (
acetamide) and N-methyl
morpholine are added until reaction liquid is clear; methyl (ethyl)
chloroformate molar weight of which is not more than that of D-hydroxy
valine Dane salt is added; (2-amino-1, 1-dimethyl ethyl)
mercaptoacetic acid, (3aS, 4R, 5S, 6S, 8R, 9R, 9aR, 10R)-octohydrogen-5, 8-dyhydroxy-4, 6, 9,10-tetramethyl-6-ethenyl-3a, 9-
propane-3aH-
cyclopentene (
cyclooctene)-1(4H)-keto-8-ester the
molar weight of which is not more than that of D-hydroxy
valine Dane salt is dissolved in equal
mass of
tetrahydrofuran, the reaction liquid is dripped in and stirred at 0-10 DEG C, and reaction is carried out for 2-5h at 0-20 DEG C; the
organic solvent is removed, the residue is added with water and
hydrochloric acid is used for adjusting pH value, heating up, stirring and decontaminating are carried out, and the
filtration is freeze dried to obtain
Valnemulin hydrochloride. The invention solves the problems of low purity and high reaction condition of the existing product and has the advantages of simple technology and high product purity.