Patent ID: 7091327
Filing Date: 2006-08-15
Classification: A61P,C09B,Y10S

Abstract:
1. A process for the preparation of 3,3′-azo-bis(6-hydroxybenzoic acid) 1 or a salt or derivative thereof, comprising the step of treating a 5-amino salicyclic acid derivative 2a or a salt or derivative thereof, with (i) hydrogen peroxide and acetic acid, followed by (ii) conc. sulphuric acid, to yield a 3,3′-azo-bis(6-hydroxybenzoic acid derivative) 1a or a salt or derivative thereof, wherein X is OR, SR or N(R) when X is OR or SR, R is independently an optionally substituted alkyl alkenyl, alkynyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, alkylaryl, alkenylaryl or alkynylaryl group which may include one or more heteroatoms N, O or S in its carbon skeleton, hydrogen, —Si(alkyl) when X is N(R)