反应详情

To a solution of 4.0 g (22.5 mmol) 2,6-dichloro-4-methoxy-pyridine in THF (20 ml) was added 10.0 ml (2.47 M in hexane, 24.7 mmol) n-butyllithium at −78° C. After stirring for 1 h at −78° C. excess dry ice was added and the mixture was allowed to warm to RT. Then the mixture was acidified with 6N aqueous hydrochlorid acid to pH 3-4 followed by extraction with EtOAc. The organic layer was dried over Na2SO4 and concentrated in vacuo. Purification of the residue by CC (hexane/EtOAc 4:1) provided 3.5 g (15.8 mmol, 70%) 2,6-dichloro-4-methoxy-pyridine-3-carboxylic acid.

1. additionwas added
2. extractionfollowed by extraction with EtOAc
3. dry with materialThe organic layer was dried over Na2SO4
4. concentrationconcentrated in vacuo
5. customPurification of the residue by CC (hexane/EtOAc 4:1)