METHOD FOR PREPARING ANHYDROUS CRYSTAL FORM I OF SITAGLIPTIN PHOSPHATE

摘要

The present invention relates to a method for preparing an anhydrous crystal form I of sitagliptin phosphate. The method comprises: crystallizing by stirring a suspension of sitagliptin phosphate solid at a crystallization temperature, then separating the crystallized crystals, washing, and drying so as to obtain an anhydrous crystal form I of the sitagliptin phosphate, wherein the solvent for the suspension of the sitagliptin phosphate solid is selected from acetone or acetonitrile, or the solvent for the suspension of the sitagliptin phosphate solid is selected from a mixture of a C1-4 alkanol and water, a mixture of ethylene glycol and water, a mixture of acetone and water, or a mixture of acetonitrile and water. A single crystal form of sitagliptin phosphate in an anhydrous crystal form I can be prepared by the method of the present invention. The method facilitates the control of product quality and the establishment of a quality standard, and has advantages such as a simple and convenient crystallization process, mild reaction conditions, and a high product yield without a high temperature reaction for a long time.