Hydrochloric Acid → Spiro[isochroman-4,4'-piperidine]

Participants

Reaction Steps

A mixture of (4-phenyl-piperidin-4-yl)-methanol (0.1 g, 0.5 mmol), paraformaldehyde (0.11 g, 3.7 mmol), 1,4-dioxane (5 ml) and concentrated hydrochloric acid solution (1.3 ml) was heated at reflux for 80 h. The reaction mixture was diluted with ethyl acetate (100 ml) and washed with 0.5 M aqueous sodium hydroxide solution. The aqueous layer was extracted with ethyl acetate (100 ml). The combined organic layers were dried over anhydrous sodium sulfate and concentrated in vacuo. Flash chromatography of the crude product with dichloromethane/methanol as eluent gave the title compound (0.053 g, 50%) as yellow solid. MS m/e: 204 (M+H+).

Provenance & Evidence