反应详情

5-Fluoro-2-methyl-benzoxazole (5.20 g, 0.0344 mol) was added to ice cooled Sulfuric acid (15.0 mL) such as to maintain the temperature below 25° C. After complete addition, a mixture of Sulfuric acid (2.75 mL) and Nitric acid (2.50 mL, 0.0536 mol) was added dropwise, maintaining the temperature below 18° C. After the addition was complete, the cooling bath was removed and the mixture was stirred at ambient temperature for 3 h, then was poured onto 100 mL ice with stirring. The solids were collected and washed with water (3×100 mL) and dried to give 5-Fluoro-2-methyl-6-nitro-benzoxazole as yellow solids. 1H-NMR (DMSO): 8.64 (d, 1H, J=5.4 Hz), 7.97 (d, 1H, J=10.8 Hz), 2.71 (s, 3H).

1. temperatureto maintain the temperature below 25° C
2. additionAfter complete addition
3. additionwas added dropwise
4. temperaturemaintaining the temperature below 18° C
5. additionAfter the addition
6. customthe cooling bath was removed
7. additionwas poured onto 100 mL ice
8. stirringwith stirring
9. customThe solids were collected
10. washwashed with water (3×100 mL)
11. customdried