Process for purifying N-3-(3-cyanopyrazolo1,5-apyrimidin-7-yl)phenyl-N-ethylacetamide (zaleplon) and crystalline forms of zaleplon accessible with the process

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 crystallization from selected solvents.