反应详情

温度

-78 °C

Oxalyl chloride (231 μL, 2.6 mmol) is combined with CH2Cl2 (10 mL), cooled to −78° C., treated dropwise with DMSO (373 μL, 5.3 mmol) and stirred for 20 min. The cooled solution is treated dropwise with a solution of (3-chlorofuro[2,3-c]pyridin-5-yl)methanol (420 mg, 2.3 mmol) in THF (5 mL)/CH2Cl2 (5 mL), stirred for 1 h, then treated dropwise with Et3N (1.59 mL, 11.45 mmol). The mixture is stirred for 30 min at −78° C., then 30 min at 0° C. The mixture is washed with saturated NaHCO3 (20 mL) and the organics dried over K2CO3 and concentrated in vacuo to a yellow solid (410 mg). The crude material is chromatographed over 20 g slurry-packed silica gel, eluting with 15% EtOAc/hexane. The appropriate fractions are combined and concentrated in vacuo to afford 322 mg (77%) of 3-chlorofuro[2,3-c]pyridine-5-carbaldehyde as a white solid. 1H NMR (CDCl3): δ 7.89, 8.33, 9.02, 10.18 ppm.

1. stirringstirred for 1 h
2. stirringThe mixture is stirred for 30 min at −78° C.
3. custom30 min
4. customat 0° C
5. washThe mixture is washed with saturated NaHCO3 (20 mL)
6. dry with materialthe organics dried over K2CO3
7. concentrationconcentrated in vacuo to a yellow solid (410 mg)
8. customThe crude material is chromatographed over 20 g slurry-packed silica gel
9. washeluting with 15% EtOAc/hexane
10. concentrationconcentrated in vacuo