Compound A14
(1'S,2'R,10'S,11'S,15'S)-2',15'- Dimethyldispiro[1,3-dioxolane-2,5'- tetracyclo[8.7.0.02,7.011,15]heptadecane- 14',2''-[1,3]dioxolan]-7'-en-17'-one
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InChIKey RETKBEOWDBJXFZ-WJRACZLCSA-N
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
Adrenosterone (2.95 g, 9.83 mmol) was dissolved in toluene (250 mL). A catalytic amount of p-toluenesulfonic acid (129 mg, 0.678 mmol) was added to the reaction solution followed by ethylene glycol (25 mL). A Dean-Stark trap was fitted to the reaction flask and the reaction was heated at 145 °C for 6 hours. At this time, the reaction was cooled to room temperature, concentrated under reduced pressure to a third of its original volume and transferred to a separatory funnel. A saturated solution of sodium bicarbonate was added to the separatory funnel and the crude product was extracted with chloroform (3x). The organic layers were then combined, dried with magnesium sulfate and concentrated under reduced pressure to give a crude solid. This product was then purified via recrystallization using petroleum ether and ether to give 3.29 g (86% yield) of the desired ketone A14 as a white crystalline solid. M.p. 180-182 °C. 1H NMR (CDCl3, 500 MHz): δ 5.34 (dt, J = 5.4, 2.0 Hz, 1H), 4.01 - 3.89 (m, 6H), 3.85 - 3.76 (m, 2H), 2.68 - 2.53 (m, 3H), 2.17 - 1.75 (m, 11H), 1.64 (dq, J = 13.8, 3.5 Hz, 1H), 1.43 - 1.29 (m, 1H), 1.25 - 1.19 (m, 1H), 1.22 (s, 3H), 0.82 (s, 3H). 13C NMR (CDCl3, 125 MHz): δ 211.3, 141.4, 120.8, 118.2, 109.3, 65.6, 64.8, 64.6, 64.4, 60.6, 50.4, 49.1, 48.8, 41.8, 37.3, 35.3, 34.6, 34.1, 32.1, 31.0, 22.8, 18.2, 15.1. HRMS(ESI): m/z calc. for C23H33O5 [M+H]+: 389.2328, found: 389.2327.
