Compound G19
(4bR,7S,9aS,10R)-N-Isobutyl-1,7-dimethyl-8-oxo-5,6,7,8,9,10-hexahydro-4bH-7,9a-methanobenzo[a]azulene-10-carboxamide
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InChIKey ZZCSACDTEFWVRR-UHVFKWDWSA-N
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
In an oven-dried round bottom flask, G11 (799.5 mg, 2.81 mmol) was dissolved in tetrahydrofuran (60 mL). Thionyl chloride (450 µL, 6.20 mmol) was added, and the reaction was refluxed for 50 minutes. The reaction was then cooled in an ice bath, at which point triethylamine (900 µL, 6.46 mmol) and isobutylamine (950 µL, 9.47 mmol) were added and the reaction was allowed to warm to room temperature for 1 hour. The reaction was quenched with water, extracted with ethyl acetate (3x), and purified by flash silica chromatography using 4:1 to 3:1 hexanes/ethyl acetate to afford pure G19 as a white solid (569.6 mg, 60% yield). 1H NMR (CDCl3, 500 MHz): δ 7.22 (t, J = 7.5 Hz, 1H), 7.07 (d, J = 7.5 Hz, 1H), 7.01 (d, J = 7.5 Hz, 1H), 5.55 (br s, 1H), 4.01 (s, 1H), 3.12 (t, J = 6.4 Hz, 2H), 2.94 (t, J = 8.0 Hz, 1H), 2.71 (d, J = 17.7 Hz, 1H), 2.43 (dd, J = 17.7, 3.7 Hz, 1H), 2.23 (s, 3H), 2.10 (dq, J = 9.0, 7.8 Hz, 1H), 1.96 (dd, J = 12.0, 3.7 Hz, 1H), 1.87 - 1.71 (m, 3H), 1.68 - 1.59 (m, 1H), 1.47 (d, J = 12.0 Hz, 1H), 1.05 (s, 3H), 0.90 (d, J = 2.2 Hz, 3H), 0.88 (d, J = 2.2 Hz, 3H). 13C NMR (CDCl3, 125 MHz): δ 222.0, 171.4, 147.2, 137.9, 135.6, 129.4, 128.7, 121.1, 58.5, 52.0, 51.6, 49.4, 48.1, 47.3, 38.6, 34.5, 29.9, 28.6, 23.5, 21.8, 20.5, 19.5. HRMS(ESI): m/z calc. for C22H30NO2 [M+H]+: 340.2277, found: 340.2267. M.p. 168-170 °C.
