Dimethylformamide → HCID 71721408, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,3-dibromo-5-chloropyridine (60 g, 221 mmol) in THF (500 mL) was added a solution of isopropylmagnesium chloride lithium chloride solution in THF (1.3M, 185 mL) at −40° C. over about 30 min. The solution was stirred for 30 min at −40° C. and DMF (50 mL) was added. The resulting solution was warmed up to room temperature and stirred for 30 min. The reaction was quenched with 1 N HCl (400 mL) and MTBE (200 mL) was added. Organic layer was separated and washed twice with 5% aqueous NaHCO3 (200 mL). The solvent was removed under vacuum at 50° C. The resulting solids (aldehyde intermediate) were dissolved in methanol (400 mL). The solution was cooled to 5° C. under an ice bath. NaBH4 (3.6 g) was added slowly over 30 min while maintaining the reaction temperature below room temperature. The reaction mixture was stirred for another 30 min followed by addition of water (125 mL). The resulting mixture was concentrated under vacuum to approximately 150 ml. Solids precipitated during the concentration. The suspension was stirred vigorously at room temperature for 1 h and solids were collected by filtration. The wet cake was dried in a vacuum oven over night at 60° C. to give 52 (45.6 g, 93%) as a solid. 1H NMR (CDCl3, 400 MHz): δ 8.26 (d, J=2.5 Hz, 1H), 7.88 (d, J=2.5 Hz, 1H), 4.73 (d, J=5.8 Hz, 2H), 2.33 (t, J=11.4 Hz, 1H); 13C NMR (CDCl3, 100 MHz): δ 147.12, 138.48, 138.39, 136.14, 132.06, 62.76.

Provenance & Evidence