Piperidine, 3-cyclopentyl- (9CI) synthesis

Yield:794533-53-2 87%

Reaction Conditions:

with hydrogenchloride;palladium 10% on activated carbon;hydrogen in methanol;water at 85; under 30003 Torr; for 64 h;Autoclave;

Steps:

Representative procedure for the preparation of 1:

3-cyclopenlylpiperidine(1a). A mixture of 10% Pd/C (5.0 g, 50% wet with H2O for safety, unreduced),MeOH (400 mL), pyridine 2a (25.1 g, 0.103 mol), and concentrated aq HCl (2.5mL, 0.03 mol), was placed in an autoclave and hydrogenated at 40 bar of H2 and 85 C for 64 h. The catalyst was filtered off, and the filtrate was evaporated under reduced pressure to give 24.6 g of the residue. It was dissolved in H2O (150 mL),20% aq NaOH (50 mL) was added, and the mixture was extracted with hexanes(2×80 mL). The combined organic phases were dried over NaOH and evaporatedin vacuo. The crude product was distilled in vacuo to give the product 1a. Yield13.8 g (87%). Colorless liquid. Bp 94-96 °C / 10 mbar. MS (m/z, ESI): 154 (MH+).Anal. calc. for C10H19N C 78.37 H 12.50 N 9.14. Found C 78.03 H 12.71 N 8.96.1H NMR (400 MHz, CDCl3) δ 3.07 - 2.99 (m, 1H), 2.97 - 2.89 (m, 1H), 2.46 (td, J = 11.9, 2.9 Hz, 1H), 2.21 (dd, J = 11.9, 10.4 Hz, 1H), 2.04 (br s, 1H), 1.85 - 1.77(m, 1H), 1.75 - 1.63 (m, 2H), 1.63 - 1.48 (m, 3H), 1.48 - 1.31 (m, 4H), 1.20 -1.10 (m, 1H), 1.10 - 0.93 (m, 3H). 13C NMR (101 MHz, CDCl3) δ 51.9 (CH2), 46.7(CH2), 44.0 (CH), 42.9 (CH), 30.2 (CH2), 30.1 (CH2), 30.0 (CH2), 26.5 (CH2), 24.9(CH2), 24.7 (CH2).

References:

Subota, Andrii I.;Grygorenko, Oleksandr O.;Valter, Yevheniia B.;Tairov, Maxim A.;Artamonov, Oleksiy S.;Volochnyuk, Dmitriy M.;Ryabukhin, Sergey V. [Synlett,2015,vol. 26,# 3,art. no. ST-2014-D0832-L,p. 408 - 411] Location in patent:supporting information