The invention discloses a method for purifying and preparing
sitagliptin free alkali, and belongs to the field of
sitagliptin preparation. The method comprises the following steps: acidifying reaction liquid for preparing
sitagliptin by an
enzyme method, and removing
enzyme; s2, loading a column with a Fe3O4 /
polystyrene magnetic nano
composite material, carrying out dynamic adsorption on the reaction solution subjected to
enzyme removal in the step S1, and sequentially washing with water and eluting with an eluent after saturated adsorption to obtain a sitagliptin eluent; and carrying out vacuum rotary
evaporation and concentration on the eluent until the eluent is dry, standing and filtering at
room temperature, and
drying to obtain sitagliptin free alkali
powder. According to the method, sitagliptin is adsorbed and purified by using the Fe3O4 /
polystyrene magnetic nano
composite material, the separation effect is good, the yield is high, the product quality is high, the sitagliptin can be repeatedly used, a
desorption organic solvent is
ethanol, the usage amount is small, the requirements on equipment and the production environment are low, and the
recovery difficulty is small; the method is simple to operate, low in
toxicity and extremely low in harm to human bodies of operators.