反应详情

To a solution of ethyl 5-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (Preparation B, Step A; 2.0 g, 9.65 mmol) in a 2:1 mixture of THF:MeOH, (40 mL) was added lithium hydroxide monohydrate (29 mL, 29.0 mmol, 1.0 M in water). The solution was stirred at reflux for 16 hours then cooled and concentrated. The residue was dissolved in water (100 mL) and acidified with 6M HCl. The resulting white precipitate was collected by filtration and washed with water and Et2O, then dried under reduced pressure to afford 5-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid (1.18 g, 68% yield) as a white solid. 1H NMR (d6-DMSO) δ 8.50 (d, 2H, J=7.7 Hz), 8.02 (s, 2H), 6.07 (d, 2H, J=8.2 Hz)

1. temperatureat reflux for 16 hours
2. temperaturethen cooled
3. concentrationconcentrated
4. dissolutionThe residue was dissolved in water (100 mL)
5. filtrationThe resulting white precipitate was collected by filtration
6. washwashed with water and Et2O
7. customdried under reduced pressure