反应详情

To a solution of 1.35 g (7.1 mmol) of 3-ethyl-1H-indazol-6-yl-carboxylic acid, [Marfat, A., et al., “Indazole Derivatives and Their Use as Inhibitors of Phosphodiesterase Type IV and the Production of Tumor Necrosis Factor TNF, U.S. Pat. No. 6,262,040], 2.9 mL (71 mmol) of methanol, and 0.95 g (7.8 mmol) of DMAP in 60 mL of CH2Cl2 was added 1.5 g (7.8 mmol) of EDCI-HCl. This mixture was stirred at room temperature overnight, concentrated and the residue dissolved in 50 ML of ethyl acetate. The organic layer was successively washed with 40 mL of 1N HCl, 40 mL of water and 40 mL of brine, dried (Na2SO4), and concentrated. The residue was purified by chromatography over silica gel using a gradient of 35% to 50% ethyl acetate in hexanes over 20 minutes as eluant to yield 860 mg (4.2 mmol) of methyl 3-ethyl-1H-indazol-6-yl-carboxylate. 1H-NMR (CDCl3) δ 11.7 (s, 1H), 8.18 (s, 1H), 7.73. (apparent q, 9.0 Hz, 2H), 3.94 (s. 3H), 3.03 (q, 7.5 Hz, 2H), 1.42 (t, 7.5 Hz, 3H).

1. concentrationconcentrated
2. dissolutionthe residue dissolved in 50 ML of ethyl acetate
3. washThe organic layer was successively washed with 40 mL of 1N HCl, 40 mL of water and 40 mL of brine
4. dry with materialdried (Na2SO4)
5. concentrationconcentrated
6. customThe residue was purified by chromatography over silica gel using a gradient of 35% to 50% ethyl acetate in hexanes over 20 minutes as eluant