反应详情

To a solution of 2-ethyl-3H-quinazolin-4-one (3.0 g, 17.22 mmol) in glacial acetic acid (50 ml) cooled in an ice bath was added dropwise a solution of bromine (2.75 g, 17.22 mmol) in glacial acetic acid (5 ml). After addition was complete, the reaction was heated to reflux for 18 hours. At which time it was allowed to cool to room temperature. Water was then added to the solution and the mixture was extracted with dichloromethane. The organic layer was then washed with 10% sodium bisulfite solution, and then washed with saturated brine (2×30 ml). The combined organic phase was collected and dried over magnesium sulfate, filtered and concentrated under reduced pressure to yield a brown crude product. The resulting residue was purified by silica gel chromatography with 50% dichloromethane in hexane. The product was collected and was dried under reduced pressure to give 2-(1-Bromo-ethyl)-3H-quinazolin-4-one (Yield 3.02 g, 69.74%). 1H NMR (400 MHz, DMSO-d6): δ 2.22 (d, 3H, J=6.57 Hz), 5.09 (q, 1H, J=14.40, 6.57 Hz), 7.57 (m, 1H), 7.69 (d, 1H, J=8.08 Hz), 7.87-7.80 (m, 1H), 8.12 (d, 1H, J=6.82 Hz), 12.42 (s, 1H). MS m/z calc. 251.99, found (ESI); 253.0 (M+1)+. Retention time 2.60 minutes.

1. additionAfter addition
2. temperaturethe reaction was heated
3. temperatureto reflux for 18 hours
4. extractionthe mixture was extracted with dichloromethane
5. washThe organic layer was then washed with 10% sodium bisulfite solution
6. washwashed with saturated brine (2×30 ml)
7. customThe combined organic phase was collected
8. dry with materialdried over magnesium sulfate
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure
11. customto yield a brown crude product
12. customThe resulting residue was purified by silica gel chromatography with 50% dichloromethane in hexane
13. customThe product was collected
14. customwas dried under reduced pressure