A New Route for the Preparation of 5-Hydroxyisophthalic Acid

Abstract

A new, simple and practical, two-stage process for the preparation of 5-hydroxyisophthalic acid (5-HIPA) from isophthalic acid is described. In the first stage, isophthalic acid is brominated by bromine in oleum, in the presence of an iodine catalyst, to give crude 5-bromoisophthalic acid (5-BIPA). In the second stage the crude 5-BIPA is hydrolyzed with aqueous NaOH, in the presence of a copper catalyst, to give crude 5-HIPA, with a purity of ca. 98%. Both stages of the process were optimized. A single crystallization of the crude 5-HIPA from water gives the product in a purity of more than 99%. The overall yield of pure 5-HIPA is 65-70%.

Aromatic Bromination in Concentrated Nitric Acid

“…The main method for its preparation is bromination of isophthalic acid 5 in oleum at a heat. For example acid 5 is heated with bromine in 10% oleum in sealed tube at 130˚C for 22 hours [10] or in 20% oleum at 102˚C -107˚C for 6 h in the presence of 2% -3% of iodine as catalyst [11]. That strongly contrasts with described above process in concentrated nitric acid at room temperature.…”

Bromination of Deactivated Aromatics: A Simple and Efficient Method

“…Bromoaromatic compounds find application in the synthesis of dendrimers . Several procedures are available for the synthesis of deactivated bromoarenes. − However, most of these methods involve the use of moisture-sensitive Lewis acid, long reaction time, , and poor yields. ,,, …”

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] However, most of these methods involve the use of moisture-sensitive Lewis acid, 24 long reaction time, 26,28 and poor yields. 14,25,26,28 In one of our programs in medicinal chemistry wherein we need to synthesize a highly deactivated brominated aromatic compound, we came across the report of Lambert et al 27 H 2 SO 4 medium. But bromination of 1,3-dideactivated aromatic compounds has not been studied under these conditions.…”