Potassium Carbonate → HCID 22826055, compound

Participants

Reaction Steps

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).

Provenance & Evidence