Hydrochloric Acid → 3-carboxy-7-methylsulfonylamino-6-phenoxy4H-1-benzopyran-4-one

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Reaction Steps

80 ml of dioxane and 40 ml of 6N hydrochloric acid were added to 4.03 g of 3-ethoxycarbonyl-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-one. The mixture was refluxed for 30 minutes. The reaction mixture was cooled. 200 ml of water was added thereto. The resulting crystal was collected by filtration, washed with water and recrystallized from acetic acid to obtain 3.41 g (yield: 91%) of 3-carboxy-7-methylsulfonylamino-6-phenoxy4H-1-benzopyran-4-one having a melting point of >250° C.

Provenance & Evidence