Reaktion #7989

Reaktionsgleichung

9a-butyl-4-ethyl-6-fluoro-7-methoxy-8-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one

boron tribromide

→

9a-butyl-4-ethyl-6-fluoro-7-hydroxy-8-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one

Lösungsmittel

dichloromethane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe cooling bath was removed
2. 2
   SonstigeThe mixture was partitioned between EtOAc (20 mL) and water (20 mL)
3. 3
   workup.ADDITIONcontaining 2N HCl (2 mL)
4. 4
   WaschenThe organic phase was washed with brine (10 mL)
5. 5
   Trocknendried over MgSO4
6. 6
   Filtrationfiltered
7. 7
   Sonstigeevaporated under vacuum
8. 8
   SonstigeThe residue was purified by preparative layer chromatography on two 0.05×20×20 cm silica gel GF plates
9. 9
   WaschenThe product bands were eluted with EtOAc
10. 10
    Sonstigethe eluent evaporated under vacuum

Vorschrift

A solution of 9a-butyl-4-ethyl-6-fluoro-7-methoxy-8-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one (93 mg, 0.28 mmol) in anhydrous dichloromethane (1.4 mL) was cooled in a dry ice-acetone bath (−78° C.) and the solution treated with 1M boron tribromide in dichloromethane (1.4 mL, 1.4 mmol). The cooling bath was removed and the mixture was stirred at room temperature for 90 minutes. The mixture was partitioned between EtOAc (20 mL) and water (20 mL) containing 2N HCl (2 mL). The organic phase was washed with brine (10 mL), dried over MgSO4, filtered, and evaporated under vacuum. The residue was purified by preparative layer chromatography on two 0.05×20×20 cm silica gel GF plates, developing with 5% EtOAc in CH2Cl2. The product bands were eluted with EtOAc, the eluent evaporated under vacuum, and the residue lyophilized from benzene to afford 9a-butyl-4-ethyl-6-fluoro-7-hydroxy-8-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one as an amorphous solid.

Quelle