反应详情

6-nitro-4-oxo-3,4-dihydroquinazoline-8-carboxylic acid (500 mg, 2.13 mmol) was treated with a solution of sulfuric acid ((1.2 equiv.) in anhydrous MeOH (10 mL) under refluxing overnight. 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 as yellow solid in 84% yield. 1HNMR (in DMSO): 3.91 (s, 3H), 8.38 (s, 1H), 8.74 (d, J=2.6 Hz, 1H), 8.88 (d, J=2.6 Hz, 1H). Mass: M+H+: 250.

1. temperatureunder refluxing overnight
2. customAfter removal of MeOH, methyl ester
3. filtrationwas collected by filtration
4. washwashing with water and as yellow solid in 84% yield