p-Toluenesulfonic acid → Pipecolic Acid

Participants

Reaction Steps

(R)-N-acetylpipecolic acid was placed in 10 volumes of toluene and heated, with stirring, to reflux. On attaining reflux, a catalytic amount of 4-toluenesulphonic acid was added to the solution which was then left to reflux for two hours with stirring. After this time had elapsed, the toluene was removed by rotary evaporation. To the residual solid was added 10 volumes of distilled water; this was then extracted with methyl ethyl ketone (MEK) (3×10 vols) to leave the sulphonic acid in the aqueous layer with any pipecolic acid formed. The MEK extracts were then concentrated down to a solid on the rotary evaporator to give racemic-N-acetylpipecolic acid, with 97% recovery.

Provenance & Evidence