Triethylamine → tert-Butyl 4-phenyl-3,6-dihydropyridine-1(2H)-carboxylate

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Reaction Steps

To a solution of 4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (354.6 g) in acetonitrile (12 L) was added triethylamine (366.9 g) at 20° C. in a water-bath, and the mixture was stirred for 15 minutes. To the reaction solution was added dropwise a solution of di-t-butyl carbonate (474.5 g) in acetonitrile (700 ml) at 15˜19° C. in a water-bath, and further thereto was added N,N-dimethylamino-pyridine (11.06 g). The mixture was stirred at room temperature for 12 hours, and the solvent was removed by evaporation under reduced pressure. The obtained residue was diluted with methylene chloride (10 L), and washed with 1M hydrochloric acid (×3) and 5% saturated aqueous sodium hydrogen carbonate solution, dried over anhydrous sodium hydrogen sulfate, and the solvent was evaporated under reduced pressure to give a crude product (470.6 g). The obtained crude product was purified by silica gel column chromatography (methylene chloride/methanol=1/0→50/1) to give the title compound (456.8 g).

Provenance & Evidence