反应详情

A stirred solution of piperazine (1.15 g, 13.4 mmol) and triethylamine (4.7 ml, 46.5 mmol) in dichloromethane (30 ml) was cooled to −5° C., and a solution of 5-chlorobenzofuran-2-sulphonyl chloride (1.69 g, 7.8 mmol) in dichloromethane (10 ml) was added. Stirring was continued for 15 mins, and the reaction mixture then allowed to warm to ambient temperature over 2 hrs with stirring. Water was added to the reaction mixture, and the organic layer separated; this was washed with water (twice), brine (once), then dried (MgSO4), filtered and evaporated to give a yellow gum. This was chromatographed (Merck Art 9385 silica, eluting with dichloromethane containing increasing amounts of methanol, up to 10% v/v) to give a yellow solid; trituration with diethyl ether gave 5-chlorobenzofuran-2-ylsulphonyl piperazine as a colourless solid (1.11 g) which was used without further purification, 1H NMR (CDCl3) δ=2.8-3.0 ppm (t, 4H), δ=3.2-3.4 ppm (t, 4H), δ=7.3 ppm (s, 1H), δ=7.45 ppm (dd, 2H), δ=7.7 ppm (s, 1H); MS (M+H)+ 301/303.

1. stirringwith stirring
2. customthe organic layer separated
3. washthis was washed with water (twice), brine (once),
4. dry with materialthen dried (MgSO4)
5. filtrationfiltered
6. customevaporated
7. customto give a yellow gum
8. customThis was chromatographed (Merck Art 9385 silica
9. washeluting with dichloromethane containing
10. temperatureincreasing amounts of methanol
11. customup to 10% v/v) to give a yellow solid