Compound A2

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InChIKey ZBDNNXMKEMYSQQ-CKPORNQBSA-N

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

Enamide A7 (77.0 mg, 0.246 mmol dissolved in 0.8 mL tetrahydrofuran) was added dropwise to a stirring suspension of sodium hydride (50 mg, 0.986 mmol) in tetrahydrofuran (1.2 mL) at 0 °C. The resulting mixture was allowed to stir for 30 minutes before benzyl bromide (59 µL, 0.493 mmol) was added to the reaction. The reaction was allowed to stir at 0 °C for an additional 20 minutes before the ice bath was removed and the reaction stirred at room temperature for 16 hours. Upon completion of the reaction (monitored by TLC) a saturated solution of ammonium chloride was added to quench the reaction and ethyl acetate was used to extract the product. The ethyl acetate layer was then washed with brine (2x), dried with magnesium sulfate and concentrated under reduced pressure. The crude material was purified by column chromatography using 10:1 to 2:1 hexanes/ethyl acetate to afford 27.4 mg enamide A2 (26% yield) as a white foam. ¹H NMR (CDCl₃, 500 MHz): δ 7.43 - 7.13 (m, 8H), 7.12 - 7.02 (m, 2H), 5.61 (s, 1H), 4.71 (d, J = 15.0 Hz, 1H), 4.58 (d, J = 15.0 Hz, 1H), 3.74 (d, J = 14.9 Hz, 1H), 3.56 (d, J = 14.9 Hz, 1H), 2.58 - 2.42 (m, 3H), 2.39 - 2.22 (m, 2H), 2.21 - 1.83 (m, 9H), 1.85 (s, 3H), 1.31 (s, 3H), 1.15 (m, 1H). ¹³C NMR (CDCl₃, 125 MHz): δ 198.6, 174.8, 149.3, 140.0, 139.2, 137.7, 130.9, 128.8 (2), 128.7 (2), 128.2 (2), 127.8 (2), 127.5, 126.3, 121.6, 119.6, 56.3, 51.3, 47.5, 41.2, 35.4, 34.3, 34.0, 32.5, 32.4, 32.2, 25.6, 21.1, 18.5, 12.7. HRMS(ESI): m/z calc. for C₃₃H₃₇N₂O₂ [M+H]⁺: 493.2855, found: 493.2859.