stoichiometric_steve
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Synthesis of Hexahydrocannabinol
Efficient one-pot synthetic approaches for cannabinoid analogues and their application to biologically interesting (-)-hexahydrocannabinol and
(+)-hexahydrocannabinol
Tetrahedron Letters 49 (2008) 3283–3287
In this publication, the author presents a synthesis of Hexahydrocannabinols from Olivetol and Citronellal catalyzed by Ethylenediamine diacetate
(EDDA) and Triethylamine (TEA) in refluxing Xylene (no volume given  ).
The problem i see here is that EDDA isn't soluble in non-polar solvents while TEA (used in HUGE amounts here, ~14 eq. wrt. Olivetol - so basically as
a solvent) doesn't help with the solubility of EDDA either.
Heating the mix of Xylene, EDDA and TEA also surely doesn't reach the bp. of Xylene with that considerable amount of TEA present.
Additionally, heating to close to 100°C will make diamides from EDDA with the elimination of water, so the "catalyst" is being consumed.
So this obviously can't work...now the question is, what information is the dude withholding or is this just another bullshit paper to boost his
position in scientific 8==D measuring contest databases?
Xylene might in theory be a good fit in terms of its high bp., but i'm thinking a similarly high boiling alcohol like 1-Hexanol might work (although
i'd assume it's already not polar enough with that long alkyl chain to be reasonably miscible with EDDA.
[Edited on 7-5-2021 by stoichiometric_steve]
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DraconicAcid
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Huh. I thought all cannibiniods came from a one-pot synthesis.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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symboom
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Interesting I've heard of Delta 8 thc and Delta 10 thc from cbd never heard of this one. It would be interesting if salvia divatorum (as a kappa
agonist) would have this many compounds.
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HeYBrO
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I definitely see your concerns, but why not give it a shot? as far as I know these reagents are pretty cheap. 2-5 ml of xylenes per 1 mmol of SM is
probably a good ball park amount of solvent. Reaction monitoring should be easy enough with TLC as long as you remove the xylenes. Experiment will
tell if this is bs or not
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stoichiometric_steve
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I've tried it different ways, there is still formation of some insoluble sludge (presumably EDDA) and the reflux temp never even gets above 100degC
for obvious reasons, even when using only a fifth the amount of TEA.
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Dr.Bob
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None of the products are going to convert into CBD or THC easily, and the starting materials are not that readily available. So not sure what
utility this would have when CBD is readily available for cheap now, both synthetically and from natural product extraction. Lots of people want to
make synthetic compounds, but given how much CBD is now available, that is the obvious SM for most cannabinoids now.
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chemist1243
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This is Neat, but I’m highly skeptical as THC of any kind is almost never made in a lab by synthesis, for a good reason too: its really difficult.
Maybe there is a pathway to the desired compound through more easy to obtain precursors, like delta 8 THC. I have no clue how you would achieve that
or what reducing agent you would need, but it’s probably easier to get than most of the stuff needed for the preperation you describe here.
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MadHatter
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Old Method
I remember this from some years ago but can't remember the source:
Citral + olivetol with boron trifluoride etherate as the catalyst.
C10H16O + C11H16O2 --> C21H30O2 + H2O
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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chemist1243
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https://www.designer-drug.com/pte/12.162.180.114/dcd/chemist...
This sort of mentions it but the yields are pathetic
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karlos³
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If you have the olivetol already, you're much better off choosing a different approach.
Pulegone and POCl3 for example.
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stoichiometric_steve
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Quote: Originally posted by karlos³  | If you have the olivetol already, you're much better off choosing a different approach.
Pulegone and POCl3 for example. |
Except
| Quote: |
The condensation between olivetol and pulegone under acid catalysis for the preparation of Δ6a,10a-THC in its racemic form was investigated in the
early 1940s |
Reference
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Pinnick
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I hope this helps, its in German but I think this reaction is somewhat similar since I also used Citronellal and EDDA. Worked fine for me. Your
required temperature could be a Problem. It says that there will be side reactions with the Methanol but thats only because the prep uses Meldrum's
Acid.
Good Luck!
Attachment: Tietze, Eicher - Reaktionen und Synthesen - 1991 P-3b.pdf (126kB)
This file has been downloaded 451 times
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stoichiometric_steve
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This type of reaction is what the dude from the paper i posted based his method on, he substituted the 1,3-dicarbonyl compound for Olivetol.
What i'm not sure about is if he even tried measuring the reflux temperature, since basically any amount of TEA mixed in with Xylene will reflux at
around 95degC.
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Opylation
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Your joke was not lost on me hahahaha
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Pinnick
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| Quote: Originally posted by stoichiometric_steve | I've tried it different ways, there is still formation of some insoluble sludge (presumably EDDA) and the reflux temp never even gets above 100degC
for obvious reasons, even when using only a fifth the amount of TEA.
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but the pkb of TEA is lower then the pkb of Ethylenediamine and it is in excess so you should get free Ethylenediamine right?(Sludge maybe is TEA
acetate?) Have you tried the hexanol yet? And have you tried the other reaction conditions with only EDDA in table 1? Maybe using EDDA:TEA 1:1 will do
the trick.
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stoichiometric_steve
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| Quote: Originally posted by Pinnick | | the pkb of TEA is lower then the pkb of Ethylenediamine and it is in excess so you should get free Ethylenediamine right |
That was my reasoning as well. I don't see how acetic acid does anything here at all if it only goes on to protonate TEA which is in drastic excess
anyways.
Maybe separately preparing the Imine of Citronellal with EDDA in a suitable solvent, then combining it with the TEA-diphenolate salt of Olivetol would
make sense.
not yet
no, and that doesn't seem like a good idea to me with the quoted product distribution. using TEA alone looke like a better idea, albeit with much
worse conversion but (probably) better selectivity.
I don't really see how, TEA is surely used to deprotonate Olivetol into the diphenolate, while ED would form an imine with Citronellal. Increasing the
amount of ED (not EDDA) might actually do something.
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Quieraña
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Interesting how the terpenes are used. I've seen pulegone and olivetol together for thc... I also wonder about Salvinorin A as thus is a diterpene.
Could be interesting. Also wonder how many more hydros we can stick onto cbn.
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Raid
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While the simple cannabinoids are all generally one-pot synthesis you can find other complex cannabinoids like MDMB-4en-PINACA(5-el-ADB-A)1 that are
most definitely not one-pot synthesis.
Honestly, I’m guessing that more then 50% of all synthesized cannabinoids are not one-pot synthesis.
[Edited on 13-12-2023 by Raid]
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