Sulfuric Acid → Xanthone-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 29.9 g (0.11 mol) of 2-(4-carboxyphenoxy)benzoic acid (Example 10e) and 250 ml of concentrated sulfuric acid is heated at 80° C. for one hour. The resulting solution is then poured onto about 2.5 litres of water and the mixture is stirred vigorously for 30 minutes. The product which has precipitated is filtered off, washed with water and dried under a high vacuum. 23.15 g (85%) of 9-oxo-9H-xanthene-2-carboxylic acid, melting point >280° C., result as a beige powder.

Provenance & Evidence