反应详情

温度

60 °C

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet was charged with 101 (2.50 g, 4.72 mmol), methanol (30 mL) and a 37% solution of formaldehyde in methanol (30 mL, 100 mmol). A reflux condenser was attached to the flask, and the reaction mixture was heated at 60° C. for 3 h under nitrogen atmosphere. After this time, the mixture was stirred at room temperature for 1 h and filtered through a Buchner funnel. The filter cake was washed with methanol (3×5 mL) and dried under vacuum at 40° C. for 12 h to afford 108a in a 93% yield (2.45 g) as a white solid: mp 185-187° C.; 1H NMR (300 MHz, DMSO-d6) δ 9.33 (s, 1H), 7.79 (s, 1H), 7.47 (m, 1H), 7.39 (s, 1H), 7.38 (s, 1H), 7.14 (s, 1H), 6.77 (t, J=7.8 Hz, 1H), 5.99 (s, 1H), 5.43 (d, J=7.5 Hz, 2H), 4.78 (s, 2H), 3.97 (t, J=5.0 Hz, 2H), 3.51 (s, 2H), 2.79 (t, J=5.0 Hz, 2H), 2.35 (s, 3H), 2.13 (s, 3H), 1.41 (s, 9H); MS (ESI+) m/z 530.2 (M+H).

1. customA 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet
2. customA reflux condenser was attached to the flask
3. filtrationfiltered through a Buchner funnel
4. washThe filter cake was washed with methanol (3×5 mL)
5. customdried under vacuum at 40° C. for 12 h