[NH2:1][C:2]1[C:7]([CH3:8])=[CH:6][C:5]([OH:9])=[C:4]([CH:10]([CH3:12])[CH3:11])[C:3]=1[OH:13].O[C:15]1C=C(C(C)C)C=C(O)[C:20]=1C.C1(C)CC(=O)C(C(C)C)C(=O)C1.C(OC(OCC)OCC)C.OS(O)(=O)=O>CO.[Cl-].[Ti+4].[Cl-].[Cl-].[Cl-]>[CH:10]([C:4]1[C:3]2[O:13][C:15]([CH3:20])=[N:1][C:2]=2[C:7]([CH3:8])=[CH:6][C:5]=1[OH:9])([CH3:11])[CH3:12]To a flask charged with 4-amino-2-isopropyl-5-methyl-benzene-1,3-diol (250 mg, 1.4 mmol) (Treibs and Albrecht, “The dihydroxycymenes. IV. Isocymorcin (3,5-dihydroxycymene) from 3,5-menthanedione by dehydrogenation and total synthesis,” Journal fuer Praktische Chemie (1961), 13, 291-305), purged with argon, and cooled to 0° C., was sequentially added triethylorthoformate (0.53 mL, 4.2 mmol), MeOH (2.5 mL), and a 10% v/v solution of H2SO4 in MeOH (25 μL). The reaction was allowed to warm to room temperature slowly, stirred overnight, quenched with saturated NaHCO3, and concentrated. The residue was partitioned between water and methylene chloride. The combined organic phases were dried with Na2SO4 and concentrated. Purification via flash chromatography afforded 175 mg of 7-isopropyl-2,4-dimethyl-benzooxazol-6-ol.
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