Patent ID: 8193342

Claim:
A method for the preparation of a compound of Formula (3) comprising: (i) sulfonating a compound of Formula (6) with a sulfonating agent and a base to form a sulfonyl substituted compound of Formula (7) wherein R is an alkyl or aryl optionally substituted by 1-5 substituents selected from —OH, halo, —CN, C 1 -C 6 alkyl, arylalkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkenyl, C 1 -C 6 hydroxyalkyl, amino, C 1 -C 6 alkylamine, and C 1 -C 6 dialkylamine, wherein the alkyl groups can be further substituted with one or more halogens; (ii) reducing the sulfonyl substituted compound of Formula (7) with a reducing agent to form a compound of Formula (8) (iii) hydrolyzing the compound of Formula (8) with an acid to form a compound of Formula (9) (iv) oxidizing the compound of Formula (9) with an oxidizing agent followed by reduction with a reducing agent to form a compound of Formula (10) (v) acetylating the compound of Formula (10) with an acetylating agent in the presence of an acid catalyst to form the compound of Formula (3)