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In diethyl ether; for 2h; |
2-METHYL-1 H-PYRROLE (Intermediate 22,10 g, 0.123 mmol) in anhydrous diethyl ether (30 MI) was added dropwise over 1 h to a stirred solution of triacetyl chloride (29 g, 0.16 mmol) in anhydrous ET20 (100 ML). The mixture was stirred for a further 1 h then K2CO3 (10 g/30 ML) was added slowly through a dropping funnel. The organic phase was dried over NA2SO4 and treated with decolourizing charcoal (3 g) for 30 minutes at room temperature. The resulting purple solution was concentrated and triturated with n-hexanes to give the title compound as a purple solid. (16. 72 G). 'H NMR (CDCL3) No.: 2. 36 (s, 3H); 6.04 (DD, 1H) ; 7.45 (dd, 1H) ; 10.344 (s, 1H). |
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Intermediate 30; 2,2,2-Trichloro-l-(5-methyl-lH-pyrrol-2-yl)ethanone; 2-Methyl-lH-pyrrole (Intermediate 31, 1O g, 0.123 mmol) in anhydrous diethyl ether (30 ml) was added dropwise over 1 h to a stirred solution of trichloroacetyl chloride (29 g, 0.16 mmol) in anhydrous Et2O (100 ml). The mixture was stirred for a further 1 h then K2CO3 (10 g/30 ml) was added slowly through a dropping funnel. The organic phase was dried over Na2SO4 and treated with decolorizing charcoal (3 g) for 30 min at room temperature. The resulting purple solution was concentrated and triturated with n-hexanes to give the title compound as a purple solid. (16.72 g). NMR (CDCl3): 2.36 (s, 3H), 6.04 (dd, IH), 7.45 (dd, IH), 10.344 (s, IH). |
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In diethyl ether; for 2h; |
2-Methyl-lH-pyrrole (Intermediate 46; 10 g, 0.123 mmol) in anhydrous diethyl ether (30 ml) was added dropwise over 1 h to a stirred solution of triacetyl chloride (29 g, 0.16 mmol) in anhydrous Et2O (100 ml). The mixture was stirred for a further 1 h then K2CO3 (10 g/30 ml) was added slowly through a dropping funnel. The organic phase was dried over Na2SO4 and treated with decolourizing charcoal (3 g) for 30 minutes at room temperature. The resulting purple solution was concentrated and triturated with n-hexanes to give the title compound as a purple solid. (16.72 g). NMR (CDCl3): 2.36 (s, 3H); 6.04 (dd, IH); 7.45 (dd, IH); 10.344 (s, IH). |
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In tetrahydrofuran; at 0 - 20℃; for 16h; |
To a solution of 2-methyl-lH-pyrrole (10 g, 123.3 mmol) in THF (100 mL) was added 2,2,2-trichloroacetyl chloride (26.9 g, 148 mmol) at 0C. The mixture was then stirred at rt for 16 hrs. The mixture was poured into H20 (500 mL), then extracted with EtOAc (500 mL x 2), dried, and concentrated to give residue of 2,2,2-trichloro-l-(5-methyl-lH-pyrrol-2-yl) ethanone (26.6 g, 95%) as a yellow solid which was used in the next step without further purification. ESI-MS (EI+, m/z): 226.0 [M+H]+. |
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In tetrahydrofuran; at 0 - 20℃; for 16h; |
To a solution of <strong>[636-41-9]2-methyl-1H-pyrrole</strong> (10 g, 123.3 mmol) in THF (100 mL) was added 2,2,2-trichloroacetyl chloride (26.9 g, 148 mmol) at 0 C. The mixture was then stirred at rt for 16 hrs. The mixture was poured into H2O (500 mL), then extracted with EtOAc (500 mL×2), dried, and concentrated to give residue of 2,2,2-trichloro-1-(5-methyl-1H-pyrrol-2-yl) ethanone (26.6 g, 95%) as a yellow solid which was used in the next step without further purification. ESI-MS (EI+, m/z): 226.0 [M+H]+. |