[Br:1][C:2]1[CH:13]=[CH:12][C:5]2[CH2:6][CH2:7][CH2:8][CH2:9][C:10](=[O:11])[C:4]=2[CH:3]=1.[C:14](=O)([O:17]C)[O:15][CH3:16].[H-].[Na+]>Cl>[Br:1][C:2]1[CH:13]=[CH:12][C:5]2[CH2:6][CH2:7][CH2:8][CH:9]([C:14]([O:15][CH3:16])=[O:17])[C:10](=[O:11])[C:4]=2[CH:3]=1To a solution of 3-bromo-6,7,8,9-tetrahydro-5H-benzo[7]annulen-5-one from step A1 (600 mg, 2.51 mmol) in neat dimethyl carbonate (2.81 mL, 33.3 mmol) was slowly added 60% NaH dispersed in mineral oil (251 mg, 6.27 mmol). The mixture was stirred at 85° C. for 3 h, then cooled to rt, treated with 1 N HCl (40 mL), and extracted with EtOAc (2×50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to afford crude methyl 3-bromo-5-oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulene-6-carboxylate (800 mg, 2.69 mmol, 107% yield), which was used for the next step without purification. LCMS (M+H)+=297.2. 1H NMR (500 MHz, chloroform-d) δ 12.56 (s, 1H), 7.78 (d, J=2.1 Hz, 1H), 7.47 (dd, J=8.2, 2.1 Hz, 1H), 7.12 (d, J=7.9 Hz, 1H), 3.86 (s, 3H), 2.61 (t, J=6.9 Hz, 2H), 2.18-2.05 (m, 4H).
Wird geladen…
