反应详情

4-oxo-3,4-dihydroquinazoline-8-carboxylic acid (5.0 g, 26.3 mmol) was treated with a solution of sulfuric acid ((1.2 equivalents) in anhydrous MeOH (100 mL) under refluxing for 2 days. After cooling to rt, 2N NaOH solution was added to the reaction mixture to adjust pH˜8. After removal of MeOH, methyl ester was collected by filtration, and washing with water and ethyl acetate as pale yellow solid in 94% yield. 1HNMR (in DMSO): 3.84 (s, 3H), 7.42 (t, J=7.6 Hz, 1H), 7.85 (d, J=6.9 Hz, 1H), 8.16 (s, 1H), 8.20 (d, J=7.8 Hz, 1H). Mass: M+H+: 205.

1. temperatureunder refluxing for 2 days
2. customAfter removal of MeOH, methyl ester
3. filtrationwas collected by filtration
4. washwashing with water and ethyl acetate as pale yellow solid in 94% yield