反应详情

A mixture of the product (2.0 g, 8.51 mmol) from Step A above in triethyl orthoformate (100 mL) was warmed at reflux for 18 h. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure. The residue was dissolved in 250 mL of dichloromethane and was filtered through a pad of silica gel. The pad was washed with 20% methanol/dichloromethane to elute the compound from the silica gel, and this filtrate was concentrated to dryness and then redissolved in dichloromethane. Addition of hexanes afforded a precipitate, which was collected. The filtrate was concentrated to half volume, and was then diluted with additional hexanes to yield a second crop of product. The combined solids were dried in vacuo to afford the title compound as a pale yellow solid. LC/MS 246.0 (M+1)

1. temperaturewas warmed
2. temperatureat reflux for 18 h
3. concentrationthe reaction mixture was concentrated under reduced pressure
4. dissolutionThe residue was dissolved in 250 mL of dichloromethane
5. filtrationwas filtered through a pad of silica gel
6. washThe pad was washed with 20% methanol/dichloromethane
7. washto elute the compound from the silica gel
8. concentrationthis filtrate was concentrated to dryness
9. dissolutionredissolved in dichloromethane
10. additionAddition of hexanes
11. customafforded a precipitate, which
12. customwas collected
13. concentrationThe filtrate was concentrated to half volume
14. additionwas then diluted with additional hexanes
15. customto yield a second crop of product
16. customThe combined solids were dried in vacuo