5657-51-2

699-98-9

5657-51-2

General procedure for the synthesis of furan[3,4-B]pyridin-5(7H)-one from 2,3-pyridinedicarboxylic anhydride: NaBH4 (1.14 g, 33.5 mmol) was slowly added to a solution of tetrahydrofuran (THF, 35 mL) of 2,3-pyridinedicarboxylic anhydride (5.0 g, 33.5 mmol) under argon gas protection and the temperature of the reaction was kept at 15 °C. Subsequently, acetic acid (4 g, 67 mmol) was added dropwise and the reaction mixture was stirred continuously at 15 °C for 4 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was dissolved in a mixture of acetic acid (13.5 mL) and acetic anhydride (13.5 mL) and stirred at 100 °C for 3 hours. The reaction mixture was concentrated under reduced pressure and the residue was dissolved in a mixed solution of water (35 mL) and sodium chloride (6.7 g). The aqueous phase was extracted with chloroform (3 x 40 mL) and the organic layers were combined and concentrated. Finally, recrystallization by isopropanol (z'-PrOH) afforded the target compound furan[3,4-B]pyridin-5(7H)-one (2.5 g, 55% yield) as a light yellow solid with a melting point of 123-125°C. The product was detected by IR (KBr), showing characteristic absorption peaks located at 1778, 1567, 1423, 1355, 1000, 743 cm^-1 ; 1H NMR (300 MHz, CDCl3) spectrum showed δ 8.87 (dd, J = 1.5, 4.9 Hz, 1H), 8.22 (dd, J = 1.5, 7.7 Hz, 1H), and 7.50 (dd, J = 5.0, 7.8 Hz, 1H), 5.33 (s, 2H); ESIMS analysis showed m/z 136 (MH+, relative intensity 100).