Sulfuric Acid → HCID 71332292, compound

The mixture of the tetraester compound (B) (9.4 g, 23.5 mmol) and KOH (26.4 g, 47.0 mmol) in H2O (200 mL) was heated to reflux for 2 d. The reaction mixture was cooled to room temperature, and acidified to pH 1 by adding concentrated H2SO4. The resulting mixture was heated to reflux for 3 d, and then cooled to room temperature. The mixture was extracted with EtOAc, dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product (5.8 g) was dissolved in MeOH (80 mL), and treated with concentrated H2SO4 (3.5 mL). The mixture was then stirred at room temperature for 12 h. Most of the solvent was removed under reduced pressure. The concentrate was dissolved in EtOAc, washed with H2O, dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by SiO2 flash column chromatography (hexanes:EtOAc=4:1) to give the dimethyl ester (C) (4.75 g, 20.9 mmol) in 89% yield.

1. temperaturewas heated
2. temperatureto reflux for 2 d
3. temperatureThe resulting mixture was heated
4. temperatureto reflux for 3 d
5. temperaturecooled to room temperature
6. extractionThe mixture was extracted with EtOAc
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. dissolutionThe crude product (5.8 g) was dissolved in MeOH (80 mL)
11. additiontreated with concentrated H2SO4 (3.5 mL)
12. customMost of the solvent was removed under reduced pressure
13. dissolutionThe concentrate was dissolved in EtOAc
14. washwashed with H2O
15. dry with materialdried over Na2SO4
16. filtrationfiltered
17. concentrationconcentrated under reduced pressure
18. customThe crude product was purified by SiO2 flash column chromatography (hexanes:EtOAc=4:1)

ORD record

ord-e262424eb7b04200a57873bae0037654

Source dataset

uspto-grants-2008_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07470822B2