反应详情

A stirred solution of 2-(3-pyridylmethylsulphinyl)ethanol (0.25 g, 1.35 mmol) in dimethylformamide (25 ml) at 0° C. was treated portionwise with potassium tert-butoxide (0.15 g, 1.35 mmol) and stirred for 10 mins. Formaldehyde gas [generated by heating paraformaldehyde (45 mg, 1.5 mmol) at 150° C.] was passed into the reaction mixture in a rapid stream of argon whilst cooling in an ice bath. When addition of the formaldehyde was completed the cooling bath was removed and the mixture allowed to warm to room temperature over 15 mins. The solution was poured into ethanol (30 ml), neutralised with concentrated hydrochloric acid and filtered to give a clear solution which was evaporated in vacuo and the residue was purified by flash chromatography on silica, eluting with 7% methanol in dichloromethane, to give 3-(3-pyridyl)-1,4-oxathiane 4-oxide (900 mg), as a colourless crystalline solid, m.p. 74°-76° C.

1. temperaturewhilst cooling in an ice bath
2. customwas removed
3. additionThe solution was poured into ethanol (30 ml), neutralised with concentrated hydrochloric acid
4. filtrationfiltered
5. customto give a clear solution which
6. customwas evaporated in vacuo
7. customthe residue was purified by flash chromatography on silica
8. washeluting with 7% methanol in dichloromethane