反应详情

A 1 N aqueous LiOH solution (3.3 ml, 3.3 mmol) was added to a solution of 2-chloro-5-ethyl-nicotinic acid methyl ester (325 mg, 1.6 mmol; T. Y. Zhang, E. F. V. Scriven, WO 9318005 A2) in THF (3.3 ml). The reaction mixture was stirred for 3 h at ambient temperature, poured onto ice water/isopropyl acetate 1/1 and acidified with 1 N aqueous HCl solution. The layers were separated and the aqueous layer was extracted two times with isopropyl acetate. The combined extracts were washed with brine, dried over sodium sulfate and the solvent was removed under reduced pressure to give 2-chloro-5-ethyl-nicotinic acid as white solid (292 mg, 1.57 mmol; 97%) which was used in the next step without further purification. MS: m/e=184.1 [M−H−].

1. customThe layers were separated
2. extractionthe aqueous layer was extracted two times with isopropyl acetate
3. washThe combined extracts were washed with brine
4. dry with materialdried over sodium sulfate
5. customthe solvent was removed under reduced pressure