反应详情

Hydrogenation of compound 3-(1-ethoxy-ethoxymethyl)-pyridine-2-carboxylic acid isopropyl ester, following the method used for the corresponding silyl ether as in scheme 1, gave the desired product 3-(1-ethoxy-ethoxymethyl)-piperidine-2-carboxylic acid isopropyl ester. The starting pyridine compound (5.1 g, 19.1 mmol) was dissolved in 60 mL of methanol in a pressure hydrogenation vessel to which 2 g of PtO2 was added. The vessel was shaken under 60 psi of hydrogen for 5 days. The suspension was filtered through Celite and the solution was concentrated in vacuo to provide the desired compound, 3-(1-ethoxy-ethoxymethyl)-piperidine-2-carboxylic acid isopropyl ester (5.1 g, ca. 100%). Data: MS 274 (M+1); 1H NMR (300 MHz, CDCl3): δ 5.50 (br. s, 1H, NH), 5.07 (m, 1H, CH of ester), 4.60-4.64 (overlapping q's, J=7.0 Hz, 1 H), 3.41-3.73 (m, 5H), 3.10 (m, 1H), 2.69 (m, 1H), 2.30 (m, 1H), 1.80-1.95 (m, 2H), 1.41-1.63 (m, 3H), 1.19-1.30 (m, 12 H); 13C NMR (CDCl3, 75 MHz): δ 172.4, 172.3, 100.0, 99.9 68.1, 68.0, 64.4, 63.7, 61.1, 61.0, 60.4, 46.0, 45.9, 36.81, 36.76, 26.3, 26.1, 22.14, 22.07, 22.0, 21.9, 19.92, 19.85, 15.45, 15.39.