反应详情

Sodium hydroxide (0.21 g, 2.65 mmol, 50% aqueous, 6 equiv) is added to a cold (0-−10° C.) solution of methyl 5-t-butyl-3-nitropyrrole-2-carboxylate (100 mg, 0.44 mmol), benzyltributyl ammonium bromide (158 mg, 0.44 mmol, 1 equiv), and dimethyl sulfate (46 mL, 0.49 mmol, 1.1 equiv) in dichloromethane (1 mL). After 5 min, the cooling bath is removed and the mixture is stirred for 4 h at rt. The reaction mixture is diluted with dichloromethane, washed with water (1×), 10% ammonium acetate (2×), dried (Na2SO4), and concentrated in vacuo to give a bright yellow oil. The residue is purified by flash chromatography (30% hexane in dichloromethane) to give 61 mg of methyl 5-t-butyl-1-methyl-3-nitropyrrole-2-carboxylate as a pale yellow oil which solidifies upon standing (62%). 1H NMR (CDCl3) d 6.47 (s, 1H), 3.92 (s, 3H), 3.80 (s, 3H), 1.38 (s, 9H).

1. customthe cooling bath is removed
2. additionThe reaction mixture is diluted with dichloromethane
3. washwashed with water (1×), 10% ammonium acetate (2×)
4. dry with materialdried (Na2SO4)
5. concentrationconcentrated in vacuo
6. customto give a bright yellow oil
7. customThe residue is purified by flash chromatography (30% hexane in dichloromethane)