[Synthesis]
General procedure for the synthesis of tert-butyl 4-(3-ethoxy-3-oxopropanoyl)piperidine-1-carboxylate from ethanol and compound (CAS:1336874-02-2): tert-butyl 4-(3-ethoxy-3-oxopropanoyl)piperidine-1-carboxylate (3) was added to anhydrous ethanol (200 mL) and the solution was refluxed for 48 hours. Upon completion of the reaction, the solution was concentrated under vacuum and purified by fast chromatography (eluent: dichloromethane) to afford the product 3 as a slightly reddish oil (14.36 g, 85% yield). The product characterization data were as follows: 1H NMR (500 MHz, CDCl3) δ 12.09 (s, 0.14H, allyl OH), 4.89 (s, 0.14H, allyl CH), 4.13 (q, J = 7Hz, 2H), 4.10-3.96 (m, 2H), 3.42 (s, 2H), 2.81-2.67 (m, 2H), 2.62-2.52 (m, 2H). 2.62-2.52 (m, 1H), 1.85-1.71 (m, 2H), 1.55-1.43 (m, 2H), 1.39 (s, 9H), 1.21 (t, J = 7Hz, 3H); 13C NMR (125 MHz, CDCl3) δ 204.0, 180.2 (alkenols), 172.7 (enol), 167.0, 154.4, 87.52, 79.51, 61.3, 48.5, 47.1, 28.2, 27.1, 13.9; thin-layer chromatography Rf = 0.2 (dichloromethane). High-resolution mass spectrometry (HRMS) calculated value C15H26NO5(M + H)+ 300.1805, measured value 300.1808. |