反应详情

A solution of 1,1-bis(methyloxy)-2-propanone (40.1 mL, 339 mmol) in 5% (v/v) methanol/acetonitrile (200 mL) was cooled to <5° C. while stirring. A 1 mL portion of a solution of bromine (17.44 mL, 339 mmol) in acetonitrile (30 mL) was added and the mixture was stirred until the solution was decolorized. The remainder of the bromine solution was added to the reaction mixture over 6-8 hrs while maintaining an internal temperature of <10° C. The mixture was stirred at RT overnight. Sodium bicarbonate (30.2 g, 360 mmol) was added and the mixture was stirred for 1 hr, then filtered. The filtrate was concentrated and t-butyl methyl ether (30 mL) and heptane (15 mL) were added. The mixture was washed with aqueous sodium bicarbonate (6.0 g in 60 mL water) and the organic layer was dried over sodium sulfate. The solvent was evaporated to give the title compound (47.03 g, 70%) as a yellow oil. 1H NMR (400 MHz, chloroform-d) δ ppm 4.64 (s, 1H), 4.13 (s, 2H), 3.35 (s, 6H).

1. stirringthe mixture was stirred until the solution
2. temperaturewhile maintaining an internal temperature of <10° C
3. stirringThe mixture was stirred at RT overnight
4. stirringthe mixture was stirred for 1 hr
5. filtrationfiltered
6. concentrationThe filtrate was concentrated
7. additiont-butyl methyl ether (30 mL) and heptane (15 mL) were added
8. washThe mixture was washed with aqueous sodium bicarbonate (6.0 g in 60 mL water)
9. dry with materialthe organic layer was dried over sodium sulfate
10. customThe solvent was evaporated