Acetic Anhydride → HCID 86703444, compound

Participants

Reaction Steps

(1R,2R,3aS,9aS)-2,3,3a,4,9,9a-hexahydro-2-(tert-butyldimethylsilyoxy)-1-((S,E)-3-(tert-butyldimethylsilyoxy)oct-1-enyl)-1H-cyclopenta[b]naphthalen-5-ol (0.5 g, 0.89 mmol) in toluene (5 ml) was treated with acetic anhydride (0.1 ml, 1.07 mmol) and DMAP (1.1 mg, 0.09 mmol) at room temperature for 30 minutes. The reaction was diluted with saturated sodium bicarbonate aqueous (10 ml) and extracted with ethyl acetate (10 ml). The reaction mixture was phase separated and the aqueous layer was extracted with ethyl acetate. The organic layers were combined and dried over anhydrous magnesium sulfate. The solid was filtered off. The solvent was evaporated off under vacuum. The crude product was purified by chromatography on silica gel using a mixture of hexane and ethyl acetate as a gradient eluent. 0.45 g (1R,2R,3aS,9aS)-2,3,3a,4,9,9a-hexahydro-2-(tert-butyldimethylsilyoxy)-1-((S,E)-3-(tert-butyldimethylsilyoxy)oct-1-enyl)-1H-cyclopenta[b]naphthalen-5-yl acetate was obtained. The product was then dissolved in tetrahydrofuran (0.9 ml), and treated with acetic acid (2.7 ml) and distilled water (0.9 ml) overnight at room temperature. The reaction was then diluted with saturated sodium bicarbonate aqueous (12 ml) and extracted with ethyl acetate (15 ml). The reaction mixture was phase separated and the aqueous layer was extracted with ethyl acetate. The organic layers were combined and dried over anhydrous magnesium sulfate. The solid was filtered off. The solvent was evaporated off under vacuum. The crude product was purified by chromatography on silica gel using a mixture of hexane and ethyl acetate as a gradient eluent. The titled compound was obtained in a crystalline form. Melting range was 54˜65° C. Yield: 65%.

Provenance & Evidence