Benzyl Bromide → HCID 10787419, compound

Participants

Reaction Steps

Benzyl bromide (4.5 g, 38 mmol) was added under argon atmosphere at 0° C. to a suspension of 2-ethoxy-β-estradiol (2) (4.5 g, 13 mmol) and potassium carbonate (8.6 g, 62 mmol) in anhydrous ethanol (100 mL). The resulting mixture was stirred at reflux for 7.5 h. The solvent was evaporated under reduced pressure, the residue was diluted with water, and the mixture was extracted with ethyl acetate (3×200 mL). The combined organic extract was washed with water (100 mL), sodium bicarbonate (120 mL), brine (100 mL) and dried over sodium sulfate. Evaporation of the ethyl acetate under reduced pressure gave a viscous oil containing (17), which was used without further purification. Activated MnO2 (3 g) was added under an arcon atmosphere to a solution of crude alcohol (17) (1.6 g, 3.9 mmol) in anhydrous dichloromethane (50 mL). After 7 h, an additional amount of MnO2 (5 g) was added and the reaction mixture was left over night at room temperature. MnO2 (4 g) was added again and stirring was continued for 7 h. The mixture was filtered through a celite pad and the filtrate was evaporated under reduced pressure to give crude product, which was purified by column chromatography on silica gel using hexane, followed by hexane-CH2C2 (2:8) to afford pure ketone (18) (0.42 g, 8%): IR (neat) 3065, 2929, 2869, 2825, 1727, 1607, 1504, 1450 cm-1 ; 1H NMR (CDCl3) δ 0.92 (s, 3 H), 1.30-2.60 (m, 16 H), 2.83 (m, 2 H), 4.07 (q, J=8.5 Hz, 2 H), 5.10 (s, 2 H), 6.68 (s, 1 H), 6.88 (s, 1 H), 7.20-7.60 (m, 5 H).

Provenance & Evidence