Hydroquinone → HCID 9801288, compound

Participants

Reaction Steps

4-[3-(Difluoromethyl)-4,5-dihydro-7-methoxy-1H-benz[g]indazol-1-yl]benzenesulfonamide (Example 1, Step 2) (600 mg, 1.5 mmol) was dissolved in 1,4-dioxane (200 ml), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (341 mg, 1.5 mmol) was added. The reaction was heated to reflux for 16 hours, at which time a second equivalent of DDQ (340 mg, 1.5 mmol) was added and the reaction was heated to reflux for an additional 24 hours. At three successive 24 hour intervals, 1.5 mmol additional DDQ was added and heating continued until no starting material was left (as determined by thin layer chromatography). The reaction was cooled to room temperature, at which time most of the hydroquinone by-product precipitated. The reaction was filtered and concentrated. The residue was chromatographed on silica gel eluting with 50% ethyl acetate in hexane to yield 4-[3-(difluoromethyl)-7-methoxy-1H-benz[g]indazol-1-yl]benzenesulfonamide (514 mg, 85%): 1H NMR (acetone d6) δ=3.9 (s, 3H), 7.05 (m, 1H), 7.2 (t, 1H j=54.0 Hz), 7.5 (m, 2H), 7.7 (m, 1H), 7.9 (m, 3H), 8.2 (d, 2H, j=8.7 Hz); 19F NMR (acetone d6) δ-113.3 ppm (d, 2F).

Provenance & Evidence