反应详情

To a 50 mL round bottom flask equipped with a magnetic stirring bar and nitrogen (N2) inlet was charged 2.13 g (S)-3-hydroxybutyrolactone (Example 2) (95.7% pure by VPC) and 5.0 mL acetic acid. The flask was cooled using an ice bath and 9.0 mL of 33% hydrogen bromide (HBr) in acetic acid was charged dropwise over several minutes upon which the ice bath was removed and the mixture allowed to warm to room temperature and stirred overnight under N2. An additional 1.0 mL of 33% HBr in acetic acid was added when VPC indicated that the reaction was not complete, and the mixture was stirred overnight at room temperature. The reaction was quenched by pouring into ethyl alcohol (85 mL) and heated at reflux until the reaction was complete (8 hours). The solvent was removed and the residue taken up in ethyl acetate (100 mL), washed with dilute aqueous sodium bicarbonate (NaHCO3) solution (25 mL), water (25 mL), and brine (25 mL). The organic layer was distilled and the residue purified by silica gel chromatography to yield 1.74 g (41.5%) of the title compound.

1. customTo a 50 mL round bottom flask equipped with a magnetic stirring bar and nitrogen (N2) inlet
2. temperatureThe flask was cooled
3. customwas removed
4. additionAn additional 1.0 mL of 33% HBr in acetic acid was added when VPC
5. stirringthe mixture was stirred overnight at room temperature
6. customThe reaction was quenched
7. additionby pouring into ethyl alcohol (85 mL)
8. temperatureheated
9. temperatureat reflux until the reaction
10. custom(8 hours)
11. customThe solvent was removed
12. washwashed with dilute aqueous sodium bicarbonate (NaHCO3) solution (25 mL), water (25 mL), and brine (25 mL)
13. distillationThe organic layer was distilled
14. customthe residue purified by silica gel chromatography