Patent ID: 7385072
Filing Date: 2008-06-10
Classification: C07C

Abstract:
1. A method for preparing a compound of formula I: comprising: (i) contacting a 3-alkoxy-4-hydroxy-5-nitrobenzadehyde where the alkyl group of the alkoxy is a methyl or an ethyl group, with N,N-diethylamino-cyanoacetamide in the presence of a mild acid catalyst and a solvent at a temperature of about 50° C. to about 115° C., to provide a 3-O-alkylated entacapone of formula (4): wherein R is methyl or ethyl; (ii) treating the 3-O-alkylated entacapone with an acid catalyst in the presence of an organic base and one or more solvents at a temperature of about 20° C. to about 60° C., to provide the crude compound of formula I; and (iii) optionally purifying the compound of formula I using a solvent or a mixture of solvents to provide a purified entacapone.