反应详情

The benzophenone intermediate was then stirred in EtOH (400 ml) at room temperature and treated with a solution of NaOMe in MeOH (25 wt. %, 45.72 ml, 0.2 mole). The color of the reaction mixture changed to burgundy right away. The reaction mixture was brought to reflux for 1 hr and 20 min, TLC showed that the reaction was complete. After brief cooling, water (500 ml) was added while the mixture was still warm and a yellow powder precipitated. The suspension was stored in refrigerator overnight. The solid was filtered on a Buchner funnel and washed with cold water. 2-Methoxy-9H-xanthen-9-one 1 (20.7 g, 91.6%) was obtained as a light yellow powder: m.p. 128-130° C.; 1H NMR (CDCl3): delta 8.33 (1H, dd, J=7.9, 1.8 Hz), 7.67-7.72 (2H, m), 7.47 (1H, d, J=8.6 Hz), 7.42 (1H, d, J=9.2 Hz), 7.35 (1H, m), 7.31 (1H, dd, J=9.2, 3.1 Hz) and 3.90 (3H, s); 1R (CHCl3): 2998, 1635, 1610, 1480, 1463, 1430, 1313, 1266, 1140, 1108, 1038, 852 and 823 cm-1.

1. temperatureto reflux for 1 hr and 20 min
2. temperaturewas still warm
3. customa yellow powder precipitated
4. customwas stored in refrigerator overnight
5. filtrationThe solid was filtered on a Buchner funnel
6. washwashed with cold water