3-Hydroxyanthranilic Acid → Acetate

Participants

Reaction Steps

To a suspension of 3-hydroxyanthranilic acid (0.153 g, 1.0 mmol) in toluene (10 mL) was added 4-chlorobenzoyl chloride (0.525 g, 3.0 mmol) followed by pyridine (0.275 g, 3.5 mmol) at room temperature. The resulting mixture was stirred at room temperature for 30 minutes then heated to 80° C. for 1 hr. After this time the reaction was cooled and poured into a mixture of ethyl acetate (50 mL) and 5% aqueous hydrochloric acid (20 mL). Subsequent separation of the layers, drying the organic over anhydrous magnesium sulfate and filtration afforded a solution. After removal of the solvent, the residue was dissolved in toluene (20 mL) and the solution treated with 4-methylbenzenesulfonic acid (0.4 g, 2.1 mmol). The reaction mixture was then heated to reflux overnight. After this time the reaction was cooled and poured into water (100 mL), the organic layer separated then washed with water (100 mL). The organic was dried over anhydrous magnesium sulfate, filtered and concentrated to a solid. Re-crystallization of this solid from acetate gave 2-(4-chlorophenyl)benzo[d]oxazole-4-carboxylic acid as a white solid product (0.068 g, 24.9% yield). MS (ESI) m/z 274 [M+1]+.

Provenance & Evidence