The invention relates to the field of preparation of medicaments and specifically relates to a preparation method of
alogliptin benzoate. The preparation method comprises the following steps of: taking 6-chlorouracil as a starting
raw material, reacting with o-cyanobenzyl
bromide to obtain 2-((6-chloro-2, 4-dioxo-3, 4-dihydro-2H-pyrimidin-1-yl) methyl)
benzonitrile, further performing
methylation with iodomethane to obtain 2-((6-chloro-3-methyl-2, 4-dioxo-3, 4-dihydro-2H-pyrimidin-1-yl) methyl)
benzonitrile, then reacting with (3R)-3-tert-butoxycarbonylamino-
piperidine to obtain N-(3-(2-cyano-benzyl)-1-methyl-2, 6-dioxo-1, 2, 3, 6-tetrahydro-pyrimidin-4-yl)
piperidine-(3R)-3-tert-
butyl carbamate, performing deprotection by
hydrogen chloride gas, and further forming a salt with
benzoic acid to obtain the
alogliptin benzoate. According to the preparation method of the
alogliptin benzoate, disclosed by the invention, the raw materials which are low in cost and easy to purchase are selected, an
alogliptin benzoate product is finally generated by reaction, and the overall manufacturing cost is low; and the temperature is strictly controlled in the steps, byproducts are few, the yield is high, and no
toxicity is generated.