反应详情

Compound 1 (108.6 mg, 0.3 mmol) was dissolved to a mixture of MeOH (4 mL) and THF (8 mL). Trimethylsilyldiazomethane (2 M in hexanes, 1.0 mL, 2.0 mmol) was added to the solution. The mixture was stirred for 12 h at room temperature, and then concentrated in vacuo. The residue was purified by chromatography on silica gel using n-hexane/EtOAc (2:1, v/v) to afford 30 (67 mg, 55%) as a pale yellow powder. mp 157-159° C.; 1H NMR (CDCl3) δ 8.53 (s, 1H, H4), 7.58 (d, 1H, H5, J=8.7 Hz), 7.27 (d, 1H, H6, J=8.7 Hz), 6.79-6.82 (m, 3H, H2′+H5′+H6′), 6.03 (AB, 2H, 3′,4′-OCH2O—, Δδ=10.2 Hz, J=1.5 Hz), 5.89 (AB, 2H, 7,8-OCH2O—, Δδ=7.2 Hz, J=1.5 Hz), 3.94, 3.66 (each s, 2×3H, 2×OCH3); MS (EI) m/z 408 [M]+.

1. concentrationconcentrated in vacuo
2. customThe residue was purified by chromatography on silica gel