[O:1]1[C:5]2=[N:6][CH:7]=[CH:8][CH:9]=[C:4]2[C:3]([CH:10]=[O:11])=[CH:2]1.CC([OH:16])(C)C.CC(=CC)C.[O-]Cl=O.[Na+]>O>[O:1]1[C:5]2=[N:6][CH:7]=[CH:8][CH:9]=[C:4]2[C:3]([C:10]([OH:16])=[O:11])=[CH:2]1To a suspension of furo[2,3-b]pyridine-3-carboxaldehyde (67 mmol) [J. Heterocyclic Chem., 23, 1465 (1986)] in 52 mL H2O were added NaH2PO4 (67 mmol), 260 mL t-BuOH, 71 mL 2-methyl-2-butene followed by portionwise addition of NaClO2 (100 mmol) at 0° C. After 15 min, the cooling bath was removed and the reaction was stirred at RT for 24 h. A solution of sat. aq. NaHCO3 was added and the mixture was extracted with EtOAc. The water phase was acidified with 1N HCl solution and it was then extracted 3 times with EtOAc. The combined organic layers were dried over MgSO4 and concentrated in vacuo to obtain the desired compound as beige solid.
Loading…
