Compound A1

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InChIKey STGCVRDHDZZYEE-PMNYKWLYSA-N

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

Alcohol A10 (41.9 mg, 0.133 mmol) was taken up in anhydrous pyridine (500 µL) and catalytic 4-(dimethylamino)-pyridine (2 mg, 0.016 mmol) was added. After 2 minutes of stirring at room temperature, all solids were completely dissolved. Acetic anhydride (500 µL, 5.29 mmol) was then added to the stirring solution and allowed to run overnight at room temperature. After 25 hours, the reaction was quenched with a saturated solution of sodium bicarbonate and extracted with dichloromethane (3x). The organic layer was then washed with a 5% solution of aqueous hydrochloric acid followed by brine (1x each). The organic layer was then collected, dried with magnesium sulfate and concentrated under reduced pressure. The desired target compound A1 was purified via flash chromatography using 1:1 hexanes/ethyl acetate to yield 48.5 mg (91% yield) as a white foam. M.p. 57-58 °C. ¹H NMR (CDCl₃, 500 MHz): δ 5.90 (s, 1H), 5.33 (m, 1H), 5.32 (m, 1H), 3.98 (dd, J = 15.0, 8.4 Hz, 1H), 3.68 (dd, J = 14.9, 8.5 Hz, 1H), 2.53 - 2.47 (m, 1H), 2.51 (s, 3H), 2.29 - 2.06 (m, 4H), 2.05 (s, 3H), 2.02 (m, 3H), 1.90 (dd, J = 15.4, 8.7 Hz, 1H), 1.77 (dd, J = 15.0, 8.0 Hz, 1H), 1.68 (m, 2H), 1.65 (s, 3H), 1.22 (m, 1H), 1.14 (s, 3H). ¹³C NMR (CDCl₃, 125 MHz): δ 172.6, 170.6, 168.7, 159.8, 136.4, 126.1, 121.1, 119.9, 70.2, 49.7, 44.5, 44.1, 41.1, 36.4, 35.1, 34.2, 32.9, 27.7, 24.1, 21.9, 21.8, 20.8, 12.2. HRMS(ESI): m/z calc. for C₂₃H₃₁N₂O₄ [M+H]⁺: 399.2284, found: 399.2288.