Piperine to Piperonal Procedure, by The Cook

Piperine is extracted from B. Pepper with an organic solvent. Duh.
Anhydrous alcohols are fine, ether is much cleaner. Solvent is evap'd to
leave yellow crystals.

Hydrolize with NaOH in Alcohol. (MeOH/EtOH both verified)

Oxidize with Potassium Permanganate, to get a flask full of chopped-up
molecules :-). Procedure:

1) 100g Black Pepper, refluxed in MeOH for 20 min. Filter, Evap. MeOH to yield
   yellow crystals. Dissolve in Acetone, filter (If needed), then recrystallize
   the Piperine, mp 131øC <- Not bad!

2) Piperine added to NaOH in MeOH. refluxed till MeOH is gone, leaving Sodium
   Piperidiene and Piperic Acid as a Brown tar, crystallizing to yellow gunk
   upon cooling. -100ml dH20 added, solution was heated to boiling. Soln.
   acidified with HCl giving a yellow suspension, and brown oil floating ontop.

3) Solution was cooled, then ugly, chunky, yellow piperic acid was filtered.
   Filter cake was dissolved in acetone, and NaCl filtered out. Recrystallize,
   Note the change of odor.

4) A 1:2:5 oxidation was dreamed, similar to the asarone oxidation. 2.18g
   (.01 Mol) Piperic Acid was suspended (Suspended, it DON'T dissolve) in 150ml
   boiling dH20, containing 4.2g (.05 Mol) Sodium Bicarbonate. To this hot
   solution, 3.16g (.02 Mol) KMnO4 [Well, some didn't dissolve] in 75ml warm
   dH20 added with an eyedropper over about 40 min. (Notes ream an addition
   funnel, or lose your mind from boredom. Keep this slightly exothermic
   reaction CONSTANTLY stirred.)

5) During the additon of the permanganate, she dreamed that the pepperish smell
   subsided almost completely, with the formation of a NEW, milder, marshmallowy
   good smell. Mmmmm. /* The Cook thinks that the oxidation could be done 'on
   the fly', using the smell as an indicator. (If you're good) But last time she
   dreamed that, she oxidized it all into piperonylic acid. OOPS! */

6) The warm brown solution was filtered to leave a slightly yellow/tan solution.
   This was chilled overnight, as per the asarone oxidation, but the crystals
   were TINY! [Actually, this 'failure' has been a reoccurring dream, the main
   cause of the frustration in this rxn]

7) The Cook cursed the slightly cloudy solution, and in a fit of rage, added
   25ml IPA. (To kill any remaining oxidizer) She dumped the solution into a
   pyrex dish, and set it on the heater for a few days.

8) The next time she slept (48h later), she dreamed the solution had evaporated
   into off-white, glassy chunks(YES!!). There was also some brown MnO2 at the
   bottom, and some tartaric acid, but that's not important. What is important
   is: that shit can be filtered/ recrystallized to give just over 1g of
   luscious translucent Piperonal rocks. MP was dreamed to be 41, so it ain't
   Lab Grade, but it ain't bad either, bees. She dreamed this substance had a
   wunnerful, indescribable odor that could be likened to marshmallow with a
   slight fruity, cherry overtone. It smelled so good, she ate it all, and died
   later that day, leaving no evidence or record other than this. So if any bees
   are feeling frisky, she'd like to know HOW BIG it can be scaled. If you dream
   the answer, point your flask towards hell, and yell real loud! ;-)


[http://www.rhodium.ws/chemistry/piperine.txt]


