Dimethylformamide → 3-Fluoro-2-pyridinecarboxaldehyde

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of DABCO (262.4 g, 2342 mmol) in anhydrous Et2O (2.1 L) at −25° C. in a 10 L 3-neck round bottom flask was added n-BuLi (2.5 M in hexane, 938 mL, 2342 mmol). The mixture was stirred between −25° C. to −10° C. for 45 min. and then cooled to −70° C. To the above solution, was added 3-fluoropyridine (206.7 g, 2129 mmol) dropwise, and the reaction mixture was stirred between −70° C. to −60° C. for 1.5 h before DMF (344 mL, 4258 mmol) was added. The progress of reaction was monitored by TLC (5% EtOAc in Petroleum ether). After 1 h stirring at −70° C., water (800 mL) was added and the reaction was allowed to warm to rt. The layers were separated, and the aqueous layer was extracted with DCM (5×1 L). The combined organic layers were washed with brine and dried over sodium sulphate. After removal of solvent, the residue was purified by silica gel chromatography using a gradient of EtOAc in hexane to give 3-fluoropicolinaldehyde as a pale yellow oil. 1H-NMR (400 MHz, CDCl3): δ ppm 10.21 (s, 1H), 8.63 (t, J=2.2 Hz, 1H), 7.54-7.57 (m, 2H). MS (ESI pos. ion) m/z: 126.0 (M+H).

Provenance & Evidence