3,4-dihydro-2H-pyran → 6-chloro-2-(tetrahydro-2H-pyran-2-yl)-2H-pyrazolo[4,3-c]pyridine

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Reaction Conditions

Reaction Steps

A mixture of 6-chloro-1H-pyrazolo[4,3-c]pyridine (11.5 g, 0.075 mol) and 3,4-dihydro-2H-pyran (19 g, 0.225 mol) and Tos-OH (0.13 g 0.75 mmol) in 1,4-dioxane (175 mL) was heated at 110° C. overnight. The mixture was cooled to room temperature and concentrated. The crude product was purified by column chromatography on silica gel (petroleum ether/ethyl acetate 20:0˜20:1) to afford a mixture of 6-chloro-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazolo[4,3-c]pyridine and 6-chloro-2-(tetrahydro-2H-pyran-2-yl)-2H-pyrazolo[4,3-c]pyridine (13.5 g, yield 76%) MS (ESI) m/z: m/z: 238 [M+H]+

Provenance & Evidence