Patent ID: 9670176
Date: 2017-06-06
CPC Classifications: C07D

Claim:
1. A process for preparing Zileuton of formula-I comprising the steps of: (i) reacting 1-benzo[b]thiophen-2-yl-ethanol compound of formula II  with anhydride of general formula (RCO)  in presence of a base and solvent (ii) reacting 1-benzo[b]thiophen-2-yl-ethyl-ester compound of formula-III obtained in step (i) with phenyl-N-hydroxy carbamate of formula-IV  in the presence of a Lewis acid to obtain phenyl-1-(benzo[b]thiophen-2-yl)ethyl(hydroxyl)carbamate of formula V; (iii) optionally, purifying the compound of formula V using a solvent to provide pure phenyl-1-(benzo[b]thiophen-2-yl)ethyl(hydroxyl)carbamate of formula V; and (iv) treating phenyl-1-(benzo[b]thiophen-2-yl)ethyl(hydroxyl)carbamate compound of formula-V with ammonia to obtain Zileuton of formula I.