2,3,4,5-Tetrahydropyridine → Diphenyl piperidin-2-ylphosphonate

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Reaction Conditions

Reaction Steps

This compound was prepared from the trimer of 2,3,4,5-tetrahydropyridine and diphenyl phosphite using the procedure previously described for the synthesis of the diethyl ester (Solodenko, V. A., Kukhar, V. P., Synthesis of DL-(2-Piperidyl) Phosphonic Acid, Zh. Obsh. Khim. 1987, 57, 2392). A mixture of the trimer (10 mmol, 2.5 g) and diphenyl phosphite (30 mmol, 7.0 g) was heated for 1.5 h at 100° C. under argon. The resulted crude diphenyl piperidine-2-phosphonate was dissolved in 100 mL of dry ether, undisolved material was removed by filtration, and the solution was saturated with gaseous HCl. The precipitated hydrochloride 2 was collected by filtration, washed with ether, dried and recrystallized from acetone to give a white solid in 41% yield: top. 172°-174° C.; 1H-NMR (D2O), δ (ppm) 1.5-2.4 (m, 6H), 3.05 (m, 1H), 3.45 (m, 1H), 4.10 (m, 1H), 6.9-7.4 (m, 10H); MS (FAB) m/e 318 (M-Cl)+. Anal. (C17H21NO3PCl): C, H, N, Cl.

Provenance & Evidence