反应详情

温度

100 °C

A solution of 5-benzyl-3-methyl-6-propyl-5H-isoxazolo[5,4-d]pyrimidin-4-one (method 18) (3.167 g, 11.2 mmol) and sodium acetate (4.59 g, 56 mmol, 5 eq) in glacial acetic acid (26 ml) was treated with a preformed bromine solution (0.7 ml bromine in 10 ml of glacial acetic acid) (8.64 ml, 22.4 mmol, 2 eq). The mixture was stirred at 100° C. for 24 hrs. Excess bromine (8.64 ml, 22.4 mmol, 2 eq) was added to the mixture. The mixture was then stirred at 100° C. for another 24 hrs. Water was added to the reaction mixture, followed by aq. potassium carbonate. The mixture was extracted with DCM (50 ml×3), the combined organic phases were washed with water and dried, then concentrated to give the crude product which was purified by flash chromatography (elute: hexane-EtOAc). 2.5 g product was furnished as a white solid. 1H NMR (DMSO-d6): 0.79 (t, 3H), 2.18 (m, 1H), 2.35 (m, 1H), 2.58 (s, 3H), 5.12 (t, 1H), 5.25 (d, 1H), 5.80 (d, 1H), 7.27-7.42 (m, 5H).

1. stirringThe mixture was then stirred at 100° C. for another 24 hrs
2. extractionThe mixture was extracted with DCM (50 ml×3)
3. washthe combined organic phases were washed with water
4. customdried
5. concentrationconcentrated
6. customto give the crude product which
7. customwas purified by flash chromatography (elute: hexane-EtOAc)