反応手順
Methanesulfonic acid 5-bromo-2-propionyl-phenyl ester (5.00 g, 16.3 mmol) was combined with 4-methoxyphenylhydrazine hydrochloride (4.00 g, 22.9 mmol) and sodium acetate (4.01 g, 48.9 mmol) in xylenes (30 mL). The reaction mixture was heated to 135° C. for 36 hours using a Dean Stark apparatus. The reaction was cooled to room temperature, diluted with dichloromethane (50 mL), and washed with water (50 mL) and 1N aqueous hydrochloric acid (50 mL). The organic extract were dried over magnesium sulfate and concentrated. The crude product was purified by chromatography on silica gel eluting with 4:1 hexanes/ethyl acetate to yield 2.14 g of 6-bromo-3-ethyl-1-(4-methoxy-phenyl)-1H-indazole (40% yield). 1H NMR (400 MHz, CDCl3) δ 1.43 (t, 3, J=7.7), 3.00 (q, 2, J=7.7), 3.86 (s, 3), 7.03 (d, 2, J=8.9), 7.25 (dd, 1, J=8.5, 1.5), 7.53 (d, 2, J=9.1), 7.58 (d, 1, J=8.5), 7.73 (d, 1, J=1.5). 13C NMR (100 MHz, CDCl3) δ 13.53, 20.34, 55.61, 113.02, 114.70, 121.33, 121.70, 122.45, 123.93, 124.50, 132.90, 140.67, 148.83, 158.42. IR 2970, 2934, 1604, 1519, 1461, 1442, 1300, 1250, 1050, 1035, 945, 832 cm-1. Analysis calculated for C16H15BrN2O: C, 58.02; H, 4.56; N, 8.46. Found: C, 58.39; H, 4.69; N, 8.13.
