HCID 66732449, compound → HCID 131730477, compound

Participants

Reaction Steps

Methyl 2-(4-chlorobenzyl)-4-((2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)(hydroxy)-methyl)piperidine-1-carboxylate (7.00 g, 16 mmol) was dissolved in EtOH (100 mL) to give a yellow solution. The mixture was warmed up to almost reflux and stirred for 90 min. The solvent was evaporated and the residue was purified via Biotage (heptane:ethyl acetate, gradient 20%->70% ethyl acetate, 7 CV, 340 g column, two runs) to yield trans-methyl 2-(4-chlorobenzyl)-4-(3-ethoxy-3-oxopropanoyl)piperidine-1-carboxylate (780 mg, 13%) and cis-methyl 2-(4-chlorobenzyl)-4-(3-ethoxy-3-oxopropanoyl)piperidine-1-carboxylate (1.45 g, 24%) Cis-isomer: 1H NMR (400 MHz, cdcl3) δ 1.14-1.31 (m, 3H), 1.56-1.95 (m, 4H), 2.59-3.08 (m, 4H), 3.43 (d, 2H), 3.59 (d, 3H), 3.80-3.95 (m, 1H), 4.00-4.22 (m, 3H), 7.05-7.11 (m, 2H), 7.18-7.24 (m, 2H). MS m/z 382, 384 (M+H)+. Trans-isomer: 1H NMR (400 MHz, cdcl3) δ 1.26 (t, 3H), 1.39-1.99 (m, 4H), 2.46-3.06 (m, 4H), 3.35-3.72 (m, 5H), 3.95-4.32 (m, 3H), 4.40-4.72 (m, 1H), 6.99-7.37 (m, 4H). MS m/z 382, 384 (M+H)+

Provenance & Evidence