Hydrochloric Acid → 2-Methyl-4-((2-methylbenzoyl)amino)benzoic acid

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Reaction Steps

A toluene solution of a mixture of 2-chloro-2′-methyl-4′-(2-methylbenzoylamino)acetophenone and 2-chloro-4′-methyl-2′-(2-methylbenzoylamino)acetophenone obtained in the above Reference Example 5 is concentrated and to the residue is added isopropyl alcohol (twice volume). To the mixture is added dropwise an aqueous sodium hypochlorite solution (twice molar amount) at 10-20° C. After completion of the reaction (30 minutes to one hour), the reaction mixture is acidified with hydrochloric acid, and the precipitated crystals are separated by filtration to give a crude product of 2-methyl-4-(2-methylbenzoylamino)benzoic acid in a yield of 86-100%. This crude product is recrystallized from methanol to give the desired product (yield 57%, purity by HPLC 99.3%).

Provenance & Evidence