Acetic Acid → [1-(3,5-Diethoxy-4-fluoro-benzyl)-piperidin-4-yl]-(5-methanesulfonyl-pyridin-2-yl)-amine

Participants

Reaction Conditions

Reaction Steps

To a solution of (5-methanesulfonyl-pyridin-2-yl)-piperidin-4-yl-amine (0.12 g, 0.5 mmol, 1.0 equiv; intermediate B16) and 3,5-diethoxy-4-fluoro-benzaldehyde (0.11 g, 0.5 mmol, 1.0 equiv; intermediate E5) in ethanol (5 mL) under an atmosphere of Ar was added N-ethyl diisopropylamine (0.19 mL, 0.15 g, 1.2 mmol, 2.3 equiv) and glacial acetic acid (0.05 mL, 0.06 g, 1.0 mmol, 2.0 equiv) and the mixture heated to 50° C. for 2 h. After cooling down to 35° C., sodium cyanoborohydride (0.16 g, 2.5 mmol, 5.1 equiv) was added and the reaction mixture heated again to 50° C. for 1.5 h. It was then poured into crashed ice, the pH of the water phase adjusted to ˜10 by addition of a sat. solution of sodium carbonate and the mixture extracted twice with dichloromethane. The combined organic phases were washed with water, dried over MgSO4, filtered and concentrated by evaporation under reduced pressure. The crude product was purified by column chromatography on silica eluting with a gradient of dichloromethane/methanol to give 0.16 g (71%) of the title compound as colorless foam. MS (ISP): 452.1 [M+H]+.

Provenance & Evidence