4-Piperidinecarboxylic acid → 1-Acetylpiperidine-4-carboxylic acid

Participants

Reaction Steps

A mixture of 300 g (2.32 mol) of isonipecotic acid and 1,200 ml of acetic anhydride is heated under reflux for 2 hours in a 4 liter reactor equipped with a mechanical stirrer, a condenser and a thermometer, and the mixture is left to stand overnight. 1 liter of diethyl ether is added to the mixture, which is starting to crystallise, the solid is filtered off and the cake is washed with diethyl ether (4×500 ml), drained and recrystallised from a 40/60 mixture of diisopropyl ether/isopropyl alcohol. 153 g are isolated in a first crop and 141 g in a second crop. The N-acetylisonipecotic acid obtained melts at 148° C.

Provenance & Evidence