O1CCOCC1.Cl.C([N:11]([C:16]1[C:32]([O:33][C:34]2[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=2)=[CH:31][C:19]2[C:20](=[O:30])[C:21]([C:25]([O:27]CC)=[O:26])=[C:22]([CH3:24])[O:23][C:18]=2[CH:17]=1)[S:12]([CH3:15])(=[O:14])=[O:13])(=O)C>O>[C:25]([C:21]1[C:20](=[O:30])[C:19]2[CH:31]=[C:32]([O:33][C:34]3[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=3)[C:16]([NH:11][S:12]([CH3:15])(=[O:13])=[O:14])=[CH:17][C:18]=2[O:23][C:22]=1[CH3:24])([OH:27])=[O:26]10 ml of dioxane and 10 ml of 6N hydrochloric acid were added to 500 mg of 7-(N-acetyl-N-methylsulfonylamino)-3-ethoxycarbonyl-2-methyl-6-phenoxy-4H-1-benzopyran-4-one. The mixture was refluxed for 20 minutes. The reaction mixture was cooled to 5°-10° C. 30 ml of water was added thereto. The resulting crystal was collected by filtration and recrystallized from acetic acid to obtain 400 mg (yield: 95.2%) of 3-carboxy-2-methyl-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-one having a melting point of 238°-241° C.
読み込み中…