N,N,N',N'-Tetramethylethylenediamine → 2-Pyridinecarboxaldehyde, 3,4-difluoro-

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Reaction Conditions

Reaction Steps

Butyllithium (ALDRICH, 1.529 mL, 3.82 mmol) was added dropwise over 10 min at −20° C. (CCl4/acetone) to a solution of N,N,N′,N′-tetramethylethylendiamine (ALDRICH, 0.521 mL, 3.48 mmol) in diethyl ether (anh) (15 mL). Reaction mixture was stirred at −20° C. for 1 h and cooled to −78° C. (acetone/CO2(s)). A solution of 3,4-difluoropyridine (CHEMCOLLECT, 400 mg, 3.48 mmol) in diethyl ether (1 mL) was added dropwise over 15 min at −78° C. Mixture was stirred at −78° C. temperature for 1 hour. N,N-Dimethylformamide (300 μl), previously dissolved in diethyl ether (1 mL), was added dropwise over 10 min at −78° C. Reaction mixture was stirred for 2 hours and was poured carefully onto a rapidly stirring ice/water mixture. Mixture was stirred for 20 min and diluted with ethyl acetate (15 mL). Aqueous layer was further extracted with DCM (4×15 ml). Organic layers were combined, dried over MgSO4(anh) and concentrated. Residue was purified by silica chromatography using Hexane-AcOEt (1:3) as eluents to yield the title compound (148 mg, 1.034 mmol, 30% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm: 10.02-10.03 (m, 1H), 8.63-8.66 (m, 1H), 7.87-7.93 (m, 1H). [ES+MS] m/z 144 (MH+).

Provenance & Evidence