Ethanol → Ethyl (2R,4R)-4-methyl-2-piperidinecarboxylate

Participants

Reaction Steps

Thionyl chloride (128.6 g) added dropwise to a stirred suspension of (2R,4R)-4-methyl-2-piperidinecarboxylic acid (51.6 g) in absolute ethyl alcohol (690 ml) below 30° C. and stirring continued for 1 hr. at room temperature and then for 1 hr. under reflux. After evaporation of the solvent, the residue was dissolved in benzene (500 ml), washed with 5% K2CO3 solution (100 ml) and saturated NaCl solution (200 ml), and dried over anhydrous Na2SO4. Upon evaporation of benzene, the residue was distillated in vacuo to give ethyl (2R,4R)-4-methyl-2-piperidinecarboxylate (57.4 g), b.p. 83°-5° C./7 mm Hg, [α]D22 =-24.0 (C=5 in EtOH), Analysis Calcd. for C9H17NO2 (percent): C, 63.13, H, 10.00, N, 8.18 Found (percent): C, 63.20, H, 9.96, N, 8.12.

Provenance & Evidence