Dimethylformamide → tert-Butyl (2-chloro-3-formylpyridin-4-yl)carbamate

Beteiligte Stoffe

Reaktionsschritte

A solution of tert-butyl (2-chloropyridin-4-yl)carbamate (1.14 gm, 5 mmol) in dry THF (20 mL) was cooled to −70° C. under an inert atmosphere and 1.7 M t-butyl lithium/pentane (8 mL, 13.5 mmol) was slowly added. The reaction was stirred for two hours and then dry DMF (1.2 mL, 15.5 mmol) was added. The reaction was allowed to slowly warm to room temperature over a three hour period. The reaction mixture was quenched with 3 N HCl (12 mL) and diluted with diethyl ether. The ether layer was washed with aqueous NaHCO3, dried (over Na2SO4), filtered and evaporated. The residue was triturated with cold diethyl ether to give pure t-butyl (2-chloro-3-formylpyridin-4-yl)carbamate. The mother liquors were chromatographed on silica gel eluting with 15-20% ethyl acetate/hexane to give additional product. 1H-NMR (500 MHz, CDCl3): δ11.0 (1H, br s), 10.52 (1H, s), 8.38 (1H, d, J=6 Hz), 8.31 (1H, d, J=6 Hz), 1.54 (9H, s); m/e (m+1): 257.2.

Herkunft & Nachweise