反应详情

温度

-15 °C

To a suspension of methyl 8-acetyl-2-morpholino-4-oxo-4H-chromene-6-carboxylate (193 mg, 0.41 mmol, as described in Example 2.00) in methanol (2 mL) was added at −15° C. sodium tetrahydroborate (15.4 mg, 0.41 mmol). The resulting suspension was stirred at −15° C. for 20 minutes. The reaction mixture was quenched with a 2N aqueous NaOH solution (0.408 mL, 0.82 mmol) and allowed to warm to room temperature for 1 hr. More NaOH (0.408 mL, 0.82 mmol) was added and stirring was maintained for another 15 min. HCl (0.917 mL, 1.83 mmol) was added to adjust pH to 2-3. The resulting precipitate was diluted with a about 1 mL of water, collected by filtration, washed with ethyl acetate, diethyl ether and dried to a constant weight to afford 8-(1-hydroxyethyl)-2-morpholino-4-oxo-4H-chromene-6-carboxylic acid (122 mg, 94%) as a orange solid which was used without further purification. Mass Spectrum: M+H+ 320.

1. temperatureto warm to room temperature for 1 hr
2. stirringstirring
3. temperaturewas maintained for another 15 min
4. filtrationcollected by filtration
5. washwashed with ethyl acetate, diethyl ether
6. customdried to a constant weight