Recrystallization method of mirabegron alpha crystal form raw material

The invention provides a recrystallization method of a mirabegron alpha crystal form raw material. The method is characterized in that by adopting a single solvent for recrystallization, a target alpha crystal form raw material can be rapidly obtained only by adopting a simple heating and cooling procedure without adding of a seed crystal; by further adding activated carbon for purification, the content of an impurity A can be reduced to 0.1% or below, so that the product quality is greatly improved; and the solvent is easy to recycle, the consumed time is short, the production cost is reduced, the operation is simple, the product purity is high, and industrial production is more facilitated. 本发明提供一种米拉贝隆α晶型原料的重结晶方法，该方法采用单一溶剂重结晶，不需要加入晶种，仅采用简单的升降温程序，即可快速获得目标α晶型原料。另外，还可以通过进一步加入活性炭纯化，将杂质A的含量降至0.1％以下，大大提高了产品的质量。该方法容易回收利用溶剂、耗时较短，降低了生产成本，操作简单，产品纯度较高，更加利于工业化生产。