cosmotroniks
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Acid-catalyzed hydrolysis of 1-piperoylpiperidine
I'm posting this up as I have a question regarding what exactly went on as the result of an experimental procedure I decided to try with
1-piperoylpiperidine, otherwise known as 'piperine'..
Basically I dissolved 56 g of citric acid in 20mL of EtOH, and proceeded to slowly add 19.0 g of 1-piperoylpiperidine. This resulted in a change from
completely clear alcoholic acid solution to a grayish-white slurry, which was then slowly heated until the ethanol had come to a gentle boil. I
proceeded to reflux it for about another 45 minutes or so, and then observed an extremely rapid change in color and consistency from the grayish-white
mixture to a greenish-yellow oily liquid. I added an additional 20 mL of EtOH, followed by subsequent additional reflux for another 15 minutes, and
then allowed the remaining alcohol to boil off, with vigorous stirring. Then I allowed the resultant product to stand for awhile. Once it had reached
room temperature, it constituted itself as a bright yellow thick oily mass.
But the main question I have is related to this: I also noticed traces of a completely clear oily substance that was essentially "floating" atop the
yellow oil, which was quickly turning into more of a gum than an oil in consistency. This clear oil on the top of the mixture - I suspect that it
would be liberated piperidine freebase.
So, to end my long and rambling tangential outpouring... is it possible to achieve successful bond cleavage of the piperidine from the
5-(3,4-methylenedioxyphenyl)-2,4-pentadienonic acid [piperic acid] with a weaker acid in the hydrolysis reaction? I was always under the impression
that a strong acid, or (even more preferably for obtaining piperidine) a strong base was required.
I don't really care about the yellowish stuff so much. I've heard that it can form quite beautiful crystals if the appropriate measures are taken, but
it's the piperidine I'm after. With steam distillation I should be able to separate it, or perhaps some kind of filtration could be performed given
the miscibility of piperidine with water and the corresponding relative insolubility of piperic acid in water.
Or perhaps did something totally different occur? Obviously some sort of chemical change has taken place here, going from a powdered crystalline
substance that was off-white in color to a mixture that had clearly separated into two distinct layers, with a viscous clear oily substance on top and
a thick bright yellow mass on the bottom.
Obviously it would be much, much easier to obtain nearly pure piperidine through catalytic hydrogenation of pyridine, or by the heating of pyridine
with sodium metal in ethanol. But I just did what I did for the fun of it; just to see what would happen - that's why I love chemistry so much. My
favorite scientific discipline by far (but I still have a long ways to go and an awful lot to learn)...
Thanks in advance for any input/comments regarding this.
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Paddywhacker
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I gather that this is a new experimental procedure rather than a replication of a published one. Still, whatever relevant references you have should
have been included.
If you have successfully hydrolysed the piperine then the piperidine will be present as the water-soluble citrate salt. The piperic acid, on the
other hand, will be the thing to separate out.
How pure was your piperine? Was it an isolate from pepper?
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cosmotroniks
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The piperine was found in an oral-capsule form health food supplement that goes under various names. It can easily be found in nearly any health
food/organic-food product related retailer. The product specifies the piperine as being minimum 99.5% pure.
So piperidine citrate would actually result from this, if that is in fact what occurred (the hydrolysis)?
If so then the results are certainly very interesting. I will begin compiling bibliographic notes from/for my various sources and references and I'll
post them up when I've got everything consolidated together.
From what I understand, the piperidine would appear as a relatively clear if not totally transparently clear viscous oily substance, at least in a
freebase form. Piperidine HCl or HBr (or citrate perhaps in this case)...I'm wondering what physical appearance would that have.. white crystalline
powder, perhaps (if in extracted/washed/recrystallized form)?
And I am operating under the belief that the piperic acid is the bright yellow colored gummy mass that has partially crystallized (I've let the
mixture stand at room temperature for nearly 14 days now; probably just wash out the vessel and throw all the gunk away and start fresh, when I know I
can plan on distilling off or otherwise separating the distinct layers that result)..
My experimental synthetic procedure (well, I didn't really synthesize anything at all per se obviously) was based on information
obtained from various sources, including general research/reading up on the subject of hydrolysis in a general sense beforehand.
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