Piperonyl - A Fresh look

Guest · Mon Feb 07, 2005 12:20 pm

Shulgin-Phikal

java · Consumer

Here is an interesting method to obtain some piperonal........java

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S.C. Wack
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posted on 10-3-2005 at 01:33 AM Reply With Quote Report Post to Administrator
I posted the full article before - http://www.sciencemadness.org/talk/viewthread.php?tid=1369
but no one has yet taken advantage of this opportunity to gain good karma in this life, or a seat at the right hand of God should you get another. I've heard many times that German has changed a bit more than English has since 1869. This is interesting regardless of the yield.

Die geeignetste Methode, um das Piperonal in gröfseren
Quantitäten darzustellen, ist folgende:

Man löst 1 Th. piperinsaures Kalium in 40 Th. heifsem
Wasser und fügt unter beständigem Umrühren in langsamem
Strome eine Lösung von 2 Th. krystallisirtem übermangansaurem
Kalium in 40 Th. Wasser hinzu. Der entstehende
schwarzbraune Brei läfst sich wegen des unvermeidlichen
Stofsens und Ueberschäumens weder aus Glasgefäfsen noch
aus einer kupfernen Blase destilliren. Man bringt ihn deshalb
heifs auf ein Seihtuch und wascht den Rückstand mit
dem vier- bis fünffachen Volumen siedenden Wassers aus.(1)
Die gesammte Flüssigkeit wird dann der Destillation unterworfen.
Die ersten Destillate sind sehr reich an Piperonal.
Sie gehen milchig über und scheiden häufig schon im Kühler
Krystalle ab. Man läfst das in verschiedenen Portionen aufgefangene
Destillat 24 Stunden an einem kühlen Orte stehen
und filtrirt die abgeschiedenen grofsen Kryslalle ab. Sie sind
chemisch-reines Piperonal. Die wässerigen Mutterlaugen
davon werden wiederholt mit Aether durchgeschüttelt. Die
ätherische Lösung hinterläfst bei der Destillation im Wasserbade
von 40 bis 50° noch eine ansehnliche Menge von Anfangs
flüssigem, aber sehr bald krystallinisch erstarrendem
Piperonal.

Das Piperonal krystallisirt aus Wasser in zollangen und
linienbreiten dünnen, stark glänzenden, völlig farblosen und
durchsichtigen Kryslallen. Es ist schwer löslich in kaltem
Wasser (in ungefähr 500 bis 600 Th.), leichter löslich in
heifsem Wasser und läfst sich aus letzterem umkrystallisiren.
In kaltem Alkohol ist es leicht, In heifsem und in Aether in
jedem Verhaltnifs löslich. Aus sehr concentrirter, unter
Wasser befindlicher ätherischer Lösung krystallisirt es allmälig
in derben schiefwinkeligen Tafeln. Es riecht sehr
angenehm, dem Cumarin sehr ähnlich, schmilzt genau bei 37°
und siedet bei 263° ohne Zersetzung.

(1) Es ist zu empfehlen, das Auswaschen sehr lange fortzusetzen und
die letzten verdünnteren Waschflüssigkeiten nicht mehr auf
Piperonal, sondern anf die nachher zu beschreibende Piperonylsäure
zu verarbeiten.
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posted on 10-3-2005 at 03:52 PM Reply With Quote Report Post to Administrator
The best method of making piperonal in larger quantities:

You solve 1 part "piperin acidic potassium" ("piperinsaures Kalium" -> don't know how to translate) in 40 parts hot water and slowly and stirring add a solution of 2 parts krystallic potassium permanganate in 40 parts water. The resulting black-brown mash can neither be distilled in glass vessels nor in copper ones due to the inevitable bubbles and foam.
Therefore you put it on a filter cloth and wash the residue with 4 to 5 times its volume of boiling water. (1)
All of the liquid is then distilled. The first distillates are rich on piperonal. They become milky and often already crystallises in the cooler. You let the distillate you aquired in various portions sit in a cool place for 24 hours and then filter the crystals. They consist of chamicaly pure piperonal. The aqueous mother liquors are shaken repeatedly with aether. If you distill this aether in a water quench at 40 to 50 ° Centigrade you will obtain a considerable amount of piperonal, which is liquid at first, but will soon crystallise.
The piperonal crystallises from water in uncolored, shiny, clear crystalls which are about an inch long and needle-shaped.
It is hardly soluble in cold water (in about 500 to 600 parts(?)), better soluble in hot water and can be recrystallised from this. In cold alcohol it is readyly soluble, in hot one and in aether in any proportion. From highly concentrated solution in aether under water it crystallises slowly in rough plates. It smells very good, similar to coumarin, melts exactly at 37 ° centigrade and boils at 263° without decomposing.

(1) It is advisable to continue washing quite some time and using the last, more diluted washing liquids not to make piperonal but piperoyl acid, which should be described later.

Not much for getting useful information, is it?

Kane

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S.C. Wack
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posted on 10-3-2005 at 04:46 PM Reply With Quote Report Post to Administrator
Danke!

Potassium piperate. What you get when you cleave piperine with alcoholic KOH.

That and the Berichte article that I mentioned in the other thread are the only references that I know of on the cleavage of piperic acid to piperonal with just KMnO4. Preparation of piperonal in this manner is mentioned every now and then on various international boards, yet this is the only translation/actual experimental that I've ever seen! And that's something. The most detailed translation I've ever seen before was the other article, and that was something like: "2% KMnO4 @ 3C". But then, that article itself seems to say little more.

So this is a historic event, you have much good karma from here, and yours may go down as the only surviving translation known to English-speakers of the future!

Because it really is useful, even if the copper or other methods are found to work better. There is a surprising amount of black pepper out there. I've personally been to a warehouse in St. Louis that just happened to have 90,000 pounds of Indonesian black pepper in big, white woven-plastic, neatly stacked bags on hand. Been sitting there for well over a year and making the whole place smell. Apparently it is inexpensive in bulk.

loki · guinea pig

isn't clove oil quite rich in this same starting material as black pepper? i may have this all wrong though :/