Process for the production of N-[3-(3-cyanopyrazolo[1,5-a]pyrimidin-7-yl)phenyl]-N-ethylacetamide (zaleplon)

Abstract

The present invention provides a process for the production of N-[3-(3-cyanopyrazolo[1,5-a]pyrimidin-7-yl)phenyl]-N-ethylacetamide (zaleplon), an active ingredient that is approved for the treatment of insomnia. The process involves reacting N-[3-[3-(dimethylamino)-1-oxo-2-propenyl]phenyl]-N-ethylacetamide or a salt thereof with 3-amino-4-cyanopyrazole or a salt thereof under acidic conditions in a reaction medium comprising a mixture of water and a water-miscible organic compound.

1 - 24 . (canceled)  
     
     
         25 . N-[3-(3-cyanopyrazolo[1,5-a]pyrimidin-5-yl]-N-ethylacetamide.  
     
     
         26 - 29 . (canceled)  
     
     
         30 . A method for assaying zaleplon comprising the steps of: 
 a. providing a sample solution of a zaleplon sample in acetonitrile:water (1:1) diluent,    b. loading the sample solution onto an RP-18, 3 mm, HPLC column,    c. eluting the column using a mixture of ammonium-format buffer and acetonitrile with determined flow rate, and    d. measuring the zaleplon content of the relevant sample at 245 nm wavelength with a UV detector and appropriate recording apparatus.