Salicylaldehyde → cis-5-(Methoxycarbonyl)piperidine-2-carboxylic Acid

Participants

Reaction Conditions

Reaction Steps

Dimethyl cis-piperidine-2,5-dicarboxylate (112 g, 0.56 mol), salicylaldehyde (3 ml, 0.056 mol) and glacial acetic acid (600 ml) were combined and the resulting mixture heated at about 100° C. for 60 hours. The mixture was cooled, than stripped in vacuo to a thick oil from which 61.7 g (59%) of title products crystallized upon stirring with 800 ml of isopropyl alcohol. Product ratio was determined by 1H-NMR (D2O, 300 MHz), a peak at 3.13 ppm (t, 1H, J=14.5 Hz) being diagnostic of trans, and a peak at 3.33 ppm (dd, 1H) being diagnostic of cis.

Provenance & Evidence