反应详情

The product from Example 19A (21 mg, 38 μmol) was treated with diazomethane in diethyl ether (˜0.4 M, 1 mL) at ambient temperature. After stirring for 2 days, the solvent was removed under reduced pressure. The residue was dissolved in fresh diazomethane solution and stirred at ambient temperature for an additional 2 days. This process was repeated until TLC (CHCl3:methanol, 19:1) indicated the reaction was complete. The residue was purified by column chromatography on silica gel (CH2Cl2:methanol, 99:1) to provide the title compound as a colorless amorphous solid (17 mg, 77%). 1H NMR (CDCl3) δ 7.09 (d, J=8.9 Hz, 4H), 6.82 (d, J=8.5 Hz, 4H), 4.70 (br s, 1.3H), 4.53 (br s, 0.7H), 3.83-3.78 (m, 2H), 3.78 (s, 6H), 2.85-2.68 (m, 4H), 2.60-2.27 (m, 6H), 1.41 (s, 12H), 1.38 (s, 6H), 0.94-0.84 (m, 3H); MS (APCl+) m/z 572 (M+H)+.

1. customthe solvent was removed under reduced pressure
2. dissolutionThe residue was dissolved in fresh diazomethane solution
3. stirringstirred at ambient temperature for an additional 2 days
4. customThe residue was purified by column chromatography on silica gel (CH2Cl2:methanol, 99:1)