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Bluechip
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| Joined: 12 Feb 2005 |
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627.18 Points
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Wed Apr 06, 2005 2:43 pm |
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EXAMPLE I.
1,000 grams of eugenol are mixed in a still with 1 litre of an aqueous solution containing 450 grams of caustic potash.
Water is then removed at reduced presC-Q s-at 80 -100 C and atmospheric pressure is then restored in the still.
After addition, with stirring, of 300 grams diethylene glycol and 100 grams commercial triethanolamine, the mixture is heated to about 160 -1800 C and held for three minutes when the temperature begins to fall The hot mixture is then poured into 1 litre of water and the still is washed out with 500 cc of water The liquid is acidified with sulphuric acid ( 25 % strength) and extracted with benzene or equivalent solvent After distillation of the solvent, isoeugenol is obtained Yield 90 %.
EXAMPLE II.
1,000 grams of safrole are added to 10 grams of caustic potash in 360 grams of the mono-ethyl ether of ethylene glycol and 50 grams of commercial diethanolamine The temperature is raised to -180 G After reaction, the mixture is run into water, neutralised with sulphuric acid, extracted with benzene and distilled Yield of isosafrole 95 %.
EXAMPLE III.
1,000 grams of eugenol methyl ether are added to 15 grams of potassium hydroxide and 400 grams of diethylene glycol monoethyl ether with 50 grams of monoethanolamine The temperature is raised to 160 '-180 ' C After reaction the mixture is run into water, neutralised with sulphuric acid and extracted with benzene and distilled.
Yield of isoeugenol methyl ether 95 %. |
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CherrieBaby
chouchou
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| Joined: 01 Mar 2005 |
| Posts: 67 |
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3070.02 Points
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Fri Apr 08, 2005 12:38 pm |
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| CherrieBaby wrote: |
4-ally-catechol
Indian J. Chem. 2, August 1964, pp. 323-326
...
Demethylation of eugenol - Eugenol was demethylated by the following methods:
- Pyridine hydrochloride and eugenol in equal amounts were heated to 150° for 3 hr, and the product worked up as usual. On distillation, a viscous liquid, b.p. 96-105°/1 mm., was obtained (methoxyl content: found 18.3, required for eugenol 18.9%).
----- END -----
Previously pyridine HCl has been used to cleave aryl-methyl ethers (Eugenol is an example of such). See 'Cleavage of phenol ethers with pyridine hydrochloride', CA 4809(7), (1942). which is an abstract of: Vinzenz Prey. Ber. 74B, pp. 1219-1225 (1941).
http://rapidshare.de/files/1058043/CA-dealkylations.html.html
More recently Startinout used a microwave for heating and the report we have is very promising. It is in the Rhodium archives.
https://www.synthetikal.com/Rhodiums_pdfs/chemistry/methylenation.html#pyrhcl
The beauty of this is that pyridine is an organic base and the demethylation produces is an organic acid. So we can use an A/B extraction to separate the desired allyl-catechol product.
Pyridine is a weak organic base. HCl a strong acid. This is possibly another acid catalysed demethylation. Possibly an alternative organic base would also work; perhaps with a lower yield. Triethylamine HCl has been suggested. If you try this and it doesn't work very well I suggest converting your mw oven to monomode before you completely give up on it (even if you try it with a different base). Possibly the reason why pyridine works well is because it's (a) a weak base, (b) aromatic or (c) a tertiary base. Maybe some combo of a, b and c?
Here's a summary of the pyridine HCl demethylation.
Experimental
Methyl aryl ethers and pyridine hydrochloride were prepared by standard methods.
Microwave Assisted Demethylation of Methyl Aryl Ethers. A mixture of methyl aryl ether (0.01mol) and pyridine hydrochloride (0.05mol) were placed in a stoppered round bottom Łask and subjected to microwave irradiation at 215W for various time intervals. After complete conversion the reaction mixture was decomposed using ice-water and extracted with diethyl ether. The ether extract was repeatedly washed with water, dried over anhydrous sodium sulfate and the ether removed to obtain the product.
----- END -----
see:
"pyridine.pdf" was the name of the original PDF but I've posted it for you anyway:
http://rapidshare.de/files/1145440/Pyridine_demythylation_J.Chem.Res._S_.1999.pp394-5.pdf.html
It is 'discussed' here, as well:
eugenol demethylation via MICROWAVES
http://67.15.145.24/~sciencem/talk/viewthread.php?tid=3373
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Startinout says that when microwaved "the stuff melts".
I withdraw my comment about other organic salts (eg. piperidine HCl or triethylamine HCl) working. Pyridine HCl has mp: 145-147°.
Piperidine HCl, mp 245-248°; Triethylamine HCl: mp 261° (dec); Trimethylamine HCl: mp 283-284° (dec). It seems likely to me that the organic salt should be in liquid form for this rxn to proceed and that is only going to happen with pyridine HCl under these conditions.
I think you'd need to find an organic base that forms a low mp salt and I bet there aren't that many melting as low as 145°. Seems to explain why pyridine HCl is used. Likewise the Indians, above, did their rxn at 150° (in liquid pyridine HCl).
If you need to use an alternative organic salt I think you'd need a solvent to dissolve it too. The other noticable thing about pyridine is that it's such a weak base so the salt has a strongly acidic nature. |
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CherrieBaby
chouchou
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| Joined: 01 Mar 2005 |
| Posts: 67 |
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3070.02 Points
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Mon Apr 11, 2005 9:04 am |
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ApprenticeCook sent me some comments in a PM about the PTC demethylation using AlI3,
https://www.synthetikal.com/Rhodiums_pdfs/chemistry/methylenation.html#ali3
I repeat them here because it's relevant.
| ApprenticeCook wrote: |
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TBAI is what was used however this was disputed by rhodium saying iodide salts are crap as PTC's so it was suggested TBAB was used in place
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Iodine is supposed to "poison" PTC's - makes you wonder how this reaction can work with a PTC.
You can read more about the poisoning effects of the iodine ion in "Phase Transfer Catalysis", p. 64, 323 (Starks, Liotta and Halpern, 1994, pub.: Chapman & Hall, ISBN: 0412040719). I think the poisoning is due to low cation availability (i.e. the quat. ion) with Iodide tying up the quat. The cation is the transport mechanism for transferring anions into the organic phase where the rxn takes place. Iodide ties up the quat. much more, relative to what bromide or chloride would. Iodine ion isn't so much a "poison" as just not nearly as good as other ions.
With the AlI3 demethylation we have loads of iodine. I think that even if one used a different Tertbutylammonium salt such as the bromide you'd still get a halide swap and in practice, after equilibrium had been established, have TBAI as the PTC. That seems to indicate that it wouldn't matter much which PTC you introduced because the PTC iodide salt would still predominate, no matter what.
When I- is actually the agent for the demethylation that won't matter. Look at my discussion of the mechanism in the post (Acid cleavage via SN2, pages 682-683 of McMurray's 4th edn. of "Organic Chemistry").
https://www.synthetikal.com/synthforum/viewtopic.php?t=672#2902
I- attacks the ether (Not Cl- as in the diagram). So in this case the catalyst poisoning effect is irrelevant because there's no other competing anion (replacement anions come from AlI3).
| ApprenticeCook wrote: |
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if other quat ammonium salts are used they need to be butyl or longer.
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Why? Why wouldn't methyl, ethyl, chains work?
| ApprenticeCook wrote: |
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Don't get PTC's from shampoo its a very poor source and extraction is near impossible
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I think the PTCs in shampoo and fabric conditioners usually have ethers in the alkyl chains. If so, the side chains will be cleaved first because alkyl-alkyl ether bonds are weaker than the phenyl-methyl ether bond. In practice you'd get quaternary ammonium salts terminating with alcohols which may be so polar that they don't make it much into the organic layer and no longer work as catalysts. |
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IndoleAmine
Dreamreader Deluxe
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| Joined: 09 Feb 2005 |
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18717.10 Points
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pyridine, PTCs and halides..
Mon Apr 11, 2005 9:22 am |
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Here is the known microwave Py.HCl demethylation article..
http://home.ripway.com/2005-2/264127/demethylation.pdf
And this is another pridine.hcl aryl ether deprotection, adopted to very large scale, using only conventional heating, and giving detailed kinetic data...
http://home.ripway.com/2005-2/264127/py.HCl.demethylation.pdf
And a little extraordinary method using PhS(-) with KF in n-methylpyrrolidone (we all have huge amounts of this solvent to waste in such demethylations, I know...  )
http://home.ripway.com/2005-2/264127/ether.cleavage.pdf
BTW didn't anyone talk about using other tertiary amines? Well, NMP is one...
And a few notes on the AlI3 deprotection and PTCs: firstly I think I(-) is the active reagent here, since another procedure found in the same document uses nitrobenzene and aluminium tribromide to effect same thing. No PTC involved, just a lewis acid; halide ions in excess...
The TBAI is probably used just because other PTCs would be converted through halide swap anyway, as you pointed out.
And, second thing, AFAIK the only use of PTCs is to enable reactions between normally immiscible liquids, by transferring ions from one phase into the other and thus greatly enhancing rxn rate.
They are indeed said to work only well if the alkyl side chains are longer than 4 carbons, don't know why...
(thats all I know)
cheers
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anime
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| Joined: 13 Apr 2005 |
| Posts: 131 |
| Location: Planet Earth |
3517.62 Points
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Wed Apr 13, 2005 11:33 am |
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SIBX could be used to demethylate euganol to 3,4-dihydroxyallybenzene.
I have the pdf but I'm having problems uploading it. |
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CherrieBaby
chouchou
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| Joined: 01 Mar 2005 |
| Posts: 67 |
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3070.02 Points
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CherrieBaby
chouchou
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| Joined: 01 Mar 2005 |
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3070.02 Points
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Thu Apr 14, 2005 6:13 pm |
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At some stage I think someone said that only quats. with long alkyl chains (4 or more C) make good PTCs. After having just read about 100 pages of PTC theory I wish to dispute such a claim - if ever it were made.
If, in the past, one to two other people have tried one or two other quats. in an attempted AlI3 demethylation and failed - that means nothing. Perhaps they should have used alternative solvents or reaction conditions? Perhaps the alternative quats. they used were unsuitable - that doesn't mean that every other alternative quat. is unsuitable - just because it has some alkyl chains shorter than C4.
I can't see any reason why another quaternary ammonium salt shouldn't work for PTC with the AlI3 demethylation.
You'd need to make sure that the quat. was sufficiently soluble in both organic and polar phase. Nearly all quats. should transport I-, that shouldn't be any kind of problem.
TBAB as advantages. It is a) usually soluble in organic and polar phases, b) able to transport most anions well, c) easy to recover and separate from the products, d) well known for frequently working and, so, is often used as the first choice quat. in an experiment.
In the case of this AlI3 demethylation I can see no reason why another quat., or even combination of 2 quats. should not substitute. You'd have to make sure that the solvent you were using was able to dissolve the quat. You may need to use an alternative solvent. Another problem would be separation of the catalyst after the reaction - this is easy with TBA salts but may not be nearly as easy with a different quat. I would look up all the data I could get about my alternative quat., especially data about solvent solubility and separation of the quat. after the reaction. Perhaps you should also do some tests to determine the quat. solubility in the desired solvent.
I'm still dubious about PEG working but not as dubious as I was in my posts earlier in the thead. |
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IndoleAmine
Dreamreader Deluxe
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Sat Apr 16, 2005 5:16 am |
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I once read a stement made by Rhodium where he stated that side chains shorter than 4 carbons wouldn't be good suited for quaternary ammonium PTC.
If you're sure that shorter side chains will work, I believe you.
Some more good reading on PTC chemistry (warning: file size is >5MB!):
http://home.ripway.com/2005-2/264127/AlChEJournalVol44Issue3(612-646).pdf
cheers
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nubee
Master Archiver
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| Joined: 18 Feb 2005 |
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18648.26 Points
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Mon Apr 18, 2005 7:25 am |
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hey , would someone have a look at this article over at totse.org and give some feedback ..?? ephemeral fingers crossed
http://www.totse.com/en/drugs/miscellaneous_drug_information/164160.html
MDMA from Eugenol - Outline
Eugenol is extracted from cloves or clove oil. Eugenol is refluxed with HCl to give catechol-2-chloro-propane. This is easily converted to the alcohol and then methylenated to give MD-P2Pol. The alcohol is oxidised to ketone which is then reductively aminated with MeNH2 to give MDMA. |
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IndoleAmine
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Mon Apr 18, 2005 7:33 am |
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Sounds good - provided that the demethylation and halogen addition to the allylic double bond really work one-pot, with just a PTC and HX....
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nubee
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18648.26 Points
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nubee
Master Archiver
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Mon Apr 18, 2005 12:36 pm |
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as you can see from my title , without reading this post im new to this... kinda...
but im looking at these diagrams, and myristicin looks a hell of alot similiar to safrole than eugenol does...???
so what's the in the way of getting that H3 CO thingy off and going myristicin to safrole ?
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CherrieBaby
chouchou
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| Joined: 01 Mar 2005 |
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3070.02 Points
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Mon Apr 18, 2005 2:54 pm |
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| nubee wrote: |
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so what's the in the way of getting that H3 CO thingy off and going myristicin to safrole ?
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It can't be done. The methyl-phenyl ether bond is more stable than the methylenedioxy ether bond. Any attempt to remove the H3C-O- will also result in removal of the methylenedioxy.
It's very difficult to remove a methoxy bond anyway. You would need to reduce it with a very selective reduction agent. I don't know what would work. 99% of reduction agents will reduce the alkene before acting on the methoxy. An alkene is generally easier to reduce than alkoxy attached to the aromatic ring.
It's much easier to knock off the methoxy from Eugenol leaving a phenol and then to make a new methylenedioxy.
Last edited by CherrieBaby on Mon Apr 18, 2005 3:19 pm; edited 1 time in total |
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CherrieBaby
chouchou
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Mon Apr 18, 2005 3:17 pm |
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| Quote: |
hey , would someone have a look at this article over at totse.org and give some feedback ..?? ephemeral fingers crossed
http://www.totse.com/en/drugs/miscellaneous_drug_information/164160.html
MDMA from Eugenol - Outline
Eugenol is extracted from cloves or clove oil. Eugenol is refluxed with HCl to give catechol-2-chloro-propane. This is easily converted to the alcohol and then methylenated to give MD-P2Pol. The alcohol is oxidised to ketone which is then reductively aminated with MeNH2 to give MDMA.
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It's very theoretical and old. It was first posted to USENET 8 years ago. I don't think the chemist ever did that. I think she just said "what would happen if..."
In theory it works but in practice all sorts of things could go wrong. I've read no reports of Eugenol refluxed with HCl to give catechol-2-chloro-propane (and believe-you-me I've searched). A PTC would be essential to even try it because HCl normally only cleaves phenyl ethers at 200C+ and pressure. I have read of an attempt to reflux Eugenol with HBr/PTC to give catechol-2-bromo-propane. It failed, resulting in tar.
It's also been found hard to keep the alcohol in the 2 position. It seems to want to migrate to the 1-position (benzylic) where it is more stable. So it's possible that reflux of Eugenol with HCl will actually give catechol-1-chloro-propane (unless, of course, it gives tar - which seems more likely to me).
I, personally, would try demethylation first as discussed elsewhere in this thread. Someone with excellent analytical facilities could try the totse stuff just to find out what happens but you should give it a miss. |
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nubee
Master Archiver
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Mon Apr 18, 2005 3:24 pm |
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| nuff said |
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