反应详情

1 g of tert-butyl 4-{[(trifluoromethyl)sulfonyl]oxy}-3,6-dihydropyridine-1(2H)-carboxylate, 0.256 g of lithium chloride, 1.418 g of potassium carbonate, 1.05 g of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine and 0.209 g of tetrakis(triphenylphosphine)palladium are introduced into 15 ml of 1,2-dimethoxyethane in a 100 ml three-necked flask under nitrogen; the mixture is brought to reflux for 1 h 30. The mixture is allowed to return to ambient temperature, 100 ml of water are added and the aqueous phase is extracted with 3 times 80 ml of ethyl acetate. The organic phases are combined and dried over sodium sulfate and the solvent is evaporated under reduced pressure. The residue is chromatographed on silica gel with a dichloromethane to dichloromethane/methanol/aqueous ammonia 90/10/1 elution gradient. 0.821 g of tert-butyl 3,6-dihydro-4,4′-bipyridine-1(2H)-carboxylate is obtained.

1. temperatureto reflux for 1 h 30
2. customto return to ambient temperature
3. extractionthe aqueous phase is extracted with 3 times 80 ml of ethyl acetate
4. dry with materialdried over sodium sulfate
5. customthe solvent is evaporated under reduced pressure
6. customThe residue is chromatographed on silica gel with a dichloromethane to dichloromethane/methanol/aqueous ammonia 90/10/1 elution gradient