反应详情

5,6-Dichloronicotinic acid ethyl ester (5.33 g, 24.2 mmol) is added to a solution of KOtBu (2.72 g, 24.2 mmol) in isopropanol (50 mL). The mixture is heated at 80° C. for 15 h before another portion of KOtBu (272 mg, 2.42 mmol) is added. Stirring is continued at 80° C. for 24 h. The mixture is diluted with sat. aq. NaHCO3 solution, extracted with diethyl ether, and the combined org. extracts are dried (Na2SO4), filtered and concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 9:1 to give 5-chloro-6-isopropoxy-nicotinic acid isopropyl ester; LC-MS: tR=1.10 min, [M+1]+=258.05.

1. additionis added
2. extractionextracted with diethyl ether
3. dry with materialextracts are dried (Na2SO4)
4. filtrationfiltered
5. concentrationconcentrated
6. customThe crude product is purified by CC on silica gel eluting with heptane:EA 9:1