反应详情

To a solution of 5-chloro-2,3-dihydro-1-benzofuran-2-carboxylic acid (1 g, 5 mmol) in N,N-dimethylformamide (10 ml) was added EDAC.HCl (1.45 g, 7.56 mmol, 1.5 eq), HOBt (1.02 g, 7.55 mmol, 1.5 eq), triethylamine (1.52 g, 15.0 mmol, 3 eq) and tert-butyl piperazine-1-carboxylate (935 mg, 5.02 mmol, 1 eq). The resulting solution was stirred overnight at room temperature, quenched with water (200 ml), and then extracted with ethyl acetate (3×200 ml). The combined organic layer was washed with brine (3×100 ml), dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The crude material was purified by silica gel chromatography using 10%-20% ethyl acetate in petroleum ether to elute. The product-containing fractions were combined and concentrated under vacuum to afford tert-butyl 4-[(5-chloro-2,3-dihydro-1-benzofuran-2-yl)carbonyl]piperazine-1-carboxylate as a off-white solid (1.2 g, 65%). (ES, m/z): [M+H]+ 367; 1H NMR (300 MHz, CDCl3): δ 7.05-7.22 (m, 2H), 6.72 (d, J=8.4 Hz, 1H), 5.38-5.45 (m, 1H), 3.75-3.90 (m, 3H), 3.25-3.70 (m, 7H), 1.50 (s, 9H).

1. customquenched with water (200 ml)
2. extractionextracted with ethyl acetate (3×200 ml)
3. washThe combined organic layer was washed with brine (3×100 ml)
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated under vacuum
7. customThe crude material was purified by silica gel chromatography
8. washto elute
9. concentrationconcentrated under vacuum