Dimethyl Sulfoxide → HCID 86743551, compound

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Reaction Steps

3,4,5,6-Tetrafluoro-1,2-benzenedicarboxylic acid, dimethyl ester (Example 1), 2.66 g, is treated with 8 g of dimethylsulfoxide and the mixture is warmed to dissolve the solid. The solution is cooled in an ice bath and 2.65 g of tertiary-pentylamine is added. The resulting solution is then stirred at room temperature for three hours, 50 ml of water added, and the solution extracted with heptanes (2×30 ml). The combined heptane extract is extracted with a 5% aqueous solution of hydrochloric acid (2×4 ml) and concentrated to give 4-[(1,1-dimethylpropyl)amino]-3,5,6-trifluoro-1,2-benzenedicarboxylic acid, dimethyl ester as an oil. Hydrochloric acid (36% aqueous solution), 20 ml, is added to this oil and the resulting mixture is heated at reflux for 20 hours. The solution is concentrated to 4-5 ml and then diluted with water (20 ml). Cooling gave crystals which are collected and vacuum dried to give 1.2 g of 3-amino-2,4,5-trifluorobenzoic acid (63%); mp 133° -136° C.; GC (97.9%); HPLC (94%).

Provenance & Evidence