Acetic Acid → 2-Diethoxyphosphoryl-1-[1-(4-methyl-2-pyridyl)-4-piperidyl]ethanone

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Reaction Steps

Diethyl methylphosphonate (1.27 g, 8.36 mmol) was dissolved in anhydrous THF (7 ml), the solution was purged with argon and cooled to −78° C. n-Butyllithium (2M in hexane, 2.67 ml, 5.34 mmol) was added at such a rate that the temperature remained below −65° C. After addition was complete, stirring was continued for 20 minutes, then a solution of ethyl 1-(4-methyl-2-pyridyl)piperidine-4-carboxylate (626 mg, 2.52 mmol) in anhydrous THF (1 ml) was added dropwise so that the temperature remained below −70° C. Stirring was continued overnight while the temperature was allowed to reach room temperature. The mixture was neutralized with glacial acetic acid, concentrated under reduced pressure, water was added and the mixture was extracted with DCM (3×). The combined organic phases were dried (sodium sulfate), and concentrated under reduced pressure to give a brown oil that was used directly in the next step MS (multi-mode) m/z=355.1 [M+1]+.

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