Carbon Tetrachloride → Methyl 3-chloro-1H-pyrrole-2-carboxylate

温度

0 °C

To a solution of 5-methyl-3,4-dihydro-2H-pyrrole (2.50 g, 30.0 mmol) in CCl4 (100 mL) was added N-chlorosuccinimide (32.00 g, 240 mmol), and the mixture was then heated to reflux for 72 hours. The reaction mixture was cooled to 0° C. The formed precipitate was filtered off, and the filtrate was concentrated under reduced pressure. The residue was dissolved in methanol (100 mL), followed by the addition of sodium methoxide (9.80 g, 180 mmol). The resulting suspension was heated to reflux and stirred for 1.5 h. The solvent was evaporated, and the residue was suspended in ether. The solid was filtered off, and the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (100 mL) and 2 M HCl (100 mL). The biphasic solution was stirred for 10 min. The organic layer was separated, dried over MgSO4, filtered and evaporated. The crude oil was subjected to chromatography purification on silica gel eluting with EtOAc and Hexanes to afford the title compound (2.5 g, 52%) as an orange solid. MS (ES+) C6H6ClNO2 requires: 159. found: 160 [M+H]+.