The invention relates to the technical field of purification of chemical drugs, in particular to a recrystallization method of
mirabegron and a preparation method thereof. The recrystallization methodof
mirabegron comprises the following steps: dissolving a
mirabegron crude product in a mixed
solvent under a
reflux temperature condition, cooling for
crystallization, and collecting a
solid; wherein the mixed
solvent comprises an
alcohol solvent and
dichloromethane. According to the recrystallization method disclosed by the invention, by regulating and controlling the mixed solvent, the mirabegron in the beta
crystal form can be rapidly converted into the alpha
crystal form after being dissolved in the specific mixed solvent, the
solubility of the mirabegron in the specific mixed
solvent system is reduced after
crystal transformation, and the mirabegron is slowly separated out, so that other
impurity components are separated from the mirabegron, and the purification purpose is achieved;the method has the advantages of simple operation process, low production cost, reduction of the
impurity imA content in the product especially for the imA
impurity in the mirabegron crude product, simple
crystallization and purification of the crude product obtained on the basis of the original process
route, and important meaning for the research, development and application of mirabegron medicines.