反应详情

A mixture of tri-phosgene (Aldrich, St. Louis, Mo.; 0.233 g, 0.784 mmol) and 2-amino-3-bromo-4-fluoro-N-methylbenzamide (720a; 0.57 g, 2.30 mmol) in 23 mL anhydrous DCM was fitted with a water-cooled reflux condenser and drying tube, and heated to reflux overnight. LCMS indicated the reaction was about 85% conversion. Additional triphosgene (0.075 g) was added and heating continued for 5 h. The reaction was cooled and concentrated in vacuo to give 8-bromo-7-fluoro-3-methylquinazoline-2,4(1H,3H)-dione (0.63 g, 2.30 mmol, 100% yield) as a light orange solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 10.89 (1H, s), 8.03 (1H, dd, J=8.8, 5.9 Hz), 7.23 (1H, t, J=8.6 Hz), 3.26 (3H, s). MS (ESI, pos. ion) m/z: 272.9/275.0 (M+1).

1. temperaturecooled
2. temperaturereflux condenser
3. customdrying tube
4. temperatureheated
5. temperatureto reflux overnight
6. additionAdditional triphosgene (0.075 g) was added
7. temperatureheating
8. temperatureThe reaction was cooled
9. concentrationconcentrated in vacuo