反应详情

A solution of 1.0 g (3.18 mmol) of (6aR,10aR)-6a,7,8,10a-tetrahydro-6,6,9-trimethyl-3-pentyl-6H-dibenzo[b,d]pyran-1-ol and 2.32 ml of ethyl bromobutyrate in 10 ml of dimethylsulfoxide was degassed, 1.39 g of potassium carbonate was added, the mixture was degassed and then stirred at room temperature under argon overnight. The reaction was diluted with 250 ml of water and extracted with ether. The extracts were concentrated under vacuum, and the residue was dissolved in benzene and chromatographed over silica gel. The fractions containing the intermediate ester were combined and concentrated under vacuum. The residue was mixed with 60 ml of methanol, 12 ml of water and 1.30 g of sodium carbonate, and the mixture was heated under reflux for 3 hrs. The methanol was evaporated under vacuum, and the residue was acidified with hydrochloric acid and extracted with dichloromethane. The extracts were dried and concentrated, and the residue was dissolved in hexane and chromatographed over silica gel. Elution with from 5 through 20% ethyl acetate in benzene gave fractions containing product which were combined and concentrated to give 1.12 g (88%) of (6aR-trans)-4-[(6a,7,8,10a-Tetrahydro-6,6,9-trimethyl-3-pentyl-6H-dibenzo[b,d]pyran-1-yl)oxy]butanoic acid as a colorless oil: ir (CHCl3) 1740 and 1715 cm-1 ; uv max (C2H5OH) 225 nm (infl) (ε13,000), 275 (2600), and 281 (2700); nmr (CDCl3) δ9.7 (br, CO2H), 6.28 and 6.22 [d, (H-2 and H-4) which includes m~6.25, H-10], 4.02 (t, OCH2C), 3.16 (m, H-10a), 2.63 (t, ArCH2C), 2.47 (t, COCH2C), 1.63 (s, 9-CH3), 1.37 and 1.04 (two s, 6,6-diCH3), and 0.86 (t, ω-CH3); mass mol wt 400; [α]C25° -122.6° (c 1.003, CHCl3).

1. customthe mixture was degassed
2. additionThe reaction was diluted with 250 ml of water
3. extractionextracted with ether
4. concentrationThe extracts were concentrated under vacuum
5. dissolutionthe residue was dissolved in benzene
6. customchromatographed over silica gel
7. additionThe fractions containing the intermediate ester
8. concentrationconcentrated under vacuum
9. additionThe residue was mixed with 60 ml of methanol, 12 ml of water and 1.30 g of sodium carbonate
10. temperaturethe mixture was heated
11. temperatureunder reflux for 3 hrs
12. customThe methanol was evaporated under vacuum
13. extractionextracted with dichloromethane
14. customThe extracts were dried
15. concentrationconcentrated
16. dissolutionthe residue was dissolved in hexane
17. customchromatographed over silica gel
18. washElution with from 5 through 20% ethyl acetate in benzene
19. customgave fractions
20. additioncontaining product which
21. concentrationconcentrated