反应详情

A toluene solution of a mixture of 2-chloro-2′-methyl-4′-(2-methyl-benzoylamino)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%).

1. customobtained in the above Reference Example 5
2. concentrationis concentrated and to the residue
3. additionis added isopropyl alcohol (twice volume)
4. additionTo the mixture is added dropwise an aqueous sodium hypochlorite solution (twice molar amount) at 10-20° C
5. customAfter completion of the reaction (30 minutes to one hour)
6. customthe precipitated crystals are separated by filtration