反应详情

N,N-Dimethylformamide (0.3 mL) was added dropwise to a suspension of oxalyl chloride (6.6 mL, 76 mmol) and 4-chloropicolinic acid (10.0 g, 63.5 mmol) in dichloromethane (200 mL). The reaction mixture was stirred for 1 hour and additional oxalyl chloride (4 mL) and N,N-dimethylformamide (0.2 mL) was added. After a further 30 minutes, isopropanol (100 mL) was slowly added, followed by, after a further 15 minutes, solid sodium bicarbonate (12 g). The reaction mixture was diluted with 1:1 saturated sodium bicarbonate solution and water, the aqueous phase extracted with dichloromethane (3×100 mL), and solvent removed from the extract under reduced pressure. The residue was purified by by flash chromatography (rf: 0.48 in 2:1 hexanes:ethyl acetate) to give 4-chloropicolinic acid isopropyl ester (11.0 g, 87% yield). 200.1 (M+1).

1. waitAfter a further 30 minutes
2. customafter a further 15 minutes
3. extractionthe aqueous phase extracted with dichloromethane (3×100 mL), and solvent
4. customremoved from the
5. extractionextract under reduced pressure
6. customThe residue was purified by by flash chromatography (rf: 0.48 in 2:1 hexanes:ethyl acetate)