Patent ID: 9611217
Date: 2017-04-04
CPC Classifications: C07C,C07D

Claim:
1. A process for preparing carprofen comprising the steps of: (1) reacting an enamine of formula 3 with an α-substituted carboxylic acid ester of formula 4 in a first organic solvent followed by treatment with a base to afford an enamine of formula 12; (2) reacting the enamine of formula 12 in a second organic solvent with an aqueous solution of a substituted phenyldiazonium salt of formula 9′ to give a compound of formula 14″; (3) heating a mixture of the compound of formula 14″ in a third organic solvent system to form a compound of formula 11; or, heating a mixture of formula 14″ in a fourth organic solvent system to form a compound of formula 15″; and (4) heating a mixture of the compound of formula 11 or 15″ in the presence of an organic salt to yield carprofen.