The invention belongs to the technical field of pharmaceutical
chemistry, relates to a preparation method of
polymer polypeptide, and discloses a method for preparing
glatiramer acetate. According to the invention, carboxy anhydrides of
alanine, zeta-trifluoro-indole-3-acetyl
lysine, gamma-benzyl glutamate and
tyrosine is used as raw materials;
diethylamine is used as a trigger in dioxane to trigger
polymerization, so as to obtain a
polymer with a
protecting group; the obtained
polymer with a
protecting group experiences debenzylation reaction with 20 to 25% of
acetic acid solution of
hydrogen bromide at the temperature of 18 to 30 DEG C; the reaction liquid is poured into
ice water to separate out solids; the obtained solids are cleaned with
diethyl ether; after being filtered, the solids are collected; water solution of
piperidine is added to remove trifluoroacetyl, so as to obtain coarse product solution of glatiramer, and after purification,
glatiramer acetate is obtained. Compared with the prior art, the preparation method has the advantages of simpleness in operation, little
impact on molecular weight of
glatiramer acetate, and high yield of glatiramer acetate, so as to be suitable for the large-scale industrial production of glatiramer acetate.