Purification process of N-[3-(3-cyanopyrazolo[1,5-a]pyrimidin-7-yl)phenyl]-N-ethyl-acetamide (zaleplon) and zaleplon crystalline forms prepared in such a manner

摘要

Zaleplon can be separated from a regioisomer impurity by crystallization from selected solvents or by adding an anti-solvent to a solution of zaleplon and the regioisomer. Zaleplon crystalline Forms II, III, IV, and V are useful for the treatment of insomnia. These crystalline Forms are described along with processes for making them v crystallize from selected solvents.