Sodium Bicarbonate → HCID 22495591, compound

Participants

Reaction Steps

A mixture of 5.78 gm (17 mMol) 1-benzyl-3-methyl-4-hydroxy-4-(5-fluorobenzofur-7-yl)piperidine and 10 gm (52.6 mMol) p-toluenesulfonic acid monohydrate in 100 mL toluene was heated at reflux for 24 hours. The reaction mixture was cooled to room temperature and was diluted with 200 mL ethyl acetate followed by 100 mL saturated aqueous sodium bicarbonate and 100 mL IN ammonium hydroxide. The phases were separated and the aqueous phase extracted with 2×100 mL ethyl acetate. The combined organic phases were washed with 100 mL saturated aqueous sodium chloride, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel chromatography, eluting with a gradient of hexane containing from 0-50% ethyl acetate. Recovered starting material (4.38 gm) was subjected again to the dehydration conditions in 200 mL toluene. Fractions containing product from both dehydration runs were combined and concentrated under reduced pressure to provide 4.3 gm (79%) 1-benzyl-3-methyl-4-(5-fluorobenzofur-7-yl)-1,2,3,6-tetrahydropyridine and 0.45 gm (8%) 1-benzyl-3-methyl-4-(5-fluorobenzofur-7-yl)-1,2,5,6-tetrahydropyridine.

Provenance & Evidence