1g piperine and 10mL 10% alcoholic potassium hydroxide are refluxed for 90min.
piperidine hydrochloride, which melts at 244°C after recrystallization from ethanol.
usual alcohol is boiled mildly about 24h in a water-bath.
acid about 50 parts alcohol were required.
a 50mL round-bottomed flask. attach a condenser and heat at reflux for 90min.
attach the flask to an apparatus suitable for distillation under reduced pressure.
(in the hood) with hydrochloric acid. occasionally swirl the erlenmeyer flask.
with cold water, and recrystallize from hot ethanol (2).
note the odor of the distillate. check the distillate with litmus or pH paper (3).
(1) bumping may occur at this step.
this to be difficult and probably not worth the effort.
produce piperic acid in 85% yield, mp 126-127°C.
(mp 126-127°C looks like an error. it seems that 1 and 2 are permuted.
"piperine analogues for the treatment of skin conditions"
constitutive and inducible cytochrome P450 activities"
"piperonylic acid from black pepper"
"ANALYTICAL METHOD - Determination of the Pungent Constitueints of Piper nigrum"