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Author: Subject: Synthesis of longer chain tertiary alcohols
oldtimer
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[*] posted on 2-1-2017 at 17:27


Where I live, 1-pentanol and "octyl alcohol" are easily available. I am however not sure, if the latter is 1-octanol or some branched isomer. 1-butanol I have in the lab.
I will try to prepare some 2-methyl-2pentanol, 2-methyl-2hexanol and 3-methyl-3-heptanol.

As to quantities: If I remember blogfasts posts correctly, he used about 5 .. 6 grams of alcohol for each of his potassium runs. 25 g should therefore be a quantity that allows a few of these experiments.
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[*] posted on 17-4-2017 at 05:30


In the meantime I had two new ideas about obtaining long chain tertiary alcohols.

My first idea was to alkylate raspberry ketone and perform a Grignard afterwards. The advtantage is to deal with solid products, thus easy purification compared to high boiling and badly crystallyzing liquids.

Second, cyclization of citronellol with an acid in order to obtain either the alkene with further addition of water or dihydro terpineol directly. A problem is to obtain citronellol. An alterternative synthesis is starting from citronellal, which needs to be reduced to citronellol first. A general problem is to identfy reaction products. The advantage is to avoid reducing an alkene compared to the previously discussed synthesis of terpineol followed by precious metal reduction to dihydro terpineol.

I think I'll try the raspberry ketone based synthesis first as I expect less pitfalls and the same iodoalkane can be used for both steps. Nevertheless this may take a while...

[Edited on 17-4-2017 by Alice]
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soniccd123
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[*] posted on 11-7-2017 at 13:51


Yesterday I was reading Semimicro and Macro Organic Chemistry by Nicholas Cheronis looking for sources on alcohol oxidation to carboxylic acids and something caugh my atention: "The use of permanganate with alcohols
which contain tertiary hydrogen (branched chains), as for example,
isobutyl alcohol, (CH3)2CHCH2OH, involves the danger of oxidation
in other parts of the molecules." (page 199). I looked into more information on the internet about this and, while little was found, two papers (on the end of the message) talk about the oxidation of tertiary hydrogens to hydroxyl groups.

Wouldn't be possible to oxidate the tertiary hydrogen on Isovaleric acid to 3-metil-3-hydroxybutanoic acid and then decarboxylate this to T-butanol?

Sketch of the reaction:

[bad img]http://imgur.com/a/HJL8i[/bad img]

Papers:
http://pubs.acs.org/doi/abs/10.1021/ja00705a642?journalCode=...
http://pubs.acs.org/doi/abs/10.1021/ja01501a033?journalCode=...
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12thealchemist
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[*] posted on 17-5-2018 at 08:44


I'm aware this thread hasn't been active for nearly a year, but I had an idea that may be worth considering before discarding as too much effort.
I was reading the potassium thread out of interest (the train of thought initiated by NurdRage's recent video on making sodium via that process) and was thinking about alternative tertiary alcohols. The proportion appears to be ~5 mol%, working from woelen's numbers on http://woelen.homescience.net/science/chem/exps/synthesis_K/...

On the basis of this, I started thinking about how one could avoid any side reactions, and possibly have a "perfect" catalyst. Tertiary alcohols are used so that α-elimination products cannot occur; ethanol forming acetaldehyde, isopropanol forming acetone. These then polymerise, and form organic gunk.
However, all these thus-far proposed tertiary alcohols do have β-hydrogens, and so could undergo elimination to form alkenes, thus deactivating the catalyst. One could use tertiary alcohols that do not have β-hydrogens, but one then ends up with things like tri(t-butyl)methanol or 1,1,2,3,3-pentamethylcyclohexan-2-ol, which are difficult and complicated to synthesise (and very expensive) for obvious reasons. What if one used a bridgehead alcohol, for example bicyclo[2.2.2]octan-1-ol? Elimination products cannot form to bridgeheads due the inherently strained nature of the product. Similarly, nucleophilic substitution reactions cannot occur.

After a bit of thought, I came up with this synthesis. I figured it would be feasible for the determined amateur.

Bicyclo[2.png - 174kB

From a bit of googling, it appears that the Birch reduction cannot be carried out on phenol itself, unfortunately, hence the need to protect the OH. I wonder if it is possible to combine the hydrolysis, Diels-Alder, and decarboxylation into a one-pot reaction, thereby speeding the process up considerably. I am aware that the last step, the reduction, uses palladium on carbon, an expensive reagent, but I've seen it mentioned as being used by other SM members, hence above claim of feasibility.
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draculic acid69
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[*] posted on 19-8-2018 at 20:22


NurdRage was talking about long chain acids for use in making an ester and couldn't seem to think of an easily obtainable source.


To quote NurdRage:

In a grignard, the alcohol side of the ester is lost.

As carbon sources themselves we'd need a long-chain carboxylic acid, i don't know of any other than acetic acid.

Stearic acid is cheap and easy to get on eBay.biodiesel is a long chain ester.
Both of these could be used in a grignard to get a long chain tertiary alcohol
couldn't they?


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[*] posted on 20-8-2018 at 04:08


Quote: Originally posted by 12thealchemist  
What if one used a bridgehead alcohol, for example bicyclo[2.2.2]octan-1-ol? Elimination products cannot form to bridgeheads due the inherently strained nature of the product. Similarly, nucleophilic substitution reactions cannot occur.
That's a brilliant idea :o
Quote:
I wonder if it is possible to combine the hydrolysis, Diels-Alder, and decarboxylation into a one-pot reaction, thereby speeding the process up considerably.
I don't think that's a good idea,since the water used in the hydrolysis would undergo a michael addition to acrylic acid.
Quote:
I am aware that the last step, the reduction, uses palladium on carbon, an expensive reagent,
If you protect the phenol as a benzyl ether,then Pd/C can be used to simultaneously reduce and deprotect in the last step.That would eliminate the need for the hydrolysis step and make a one pot diels-alder/decarboxylation possible :)

But your idea has given me another idea.Why not just buy amantadine and diazotize/hydrolyse it to alcohol ? Amantadine is sold as flu/parkinson med.
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[*] posted on 20-8-2018 at 18:05


Amantadine is prescription only.at 100 mg a pillow and a month supply of 30 tablets it is in no way feasible to use it for this purpose.the whole turpineol route after19 pages yielded nothing.if I was going down this path I'd grignard some ethyl stearate made from easy to get metho and stearic acid.sounds like a great starting point.
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12thealchemist
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[*] posted on 29-8-2018 at 07:32


Since this post, I gave the idea more thought, and thought "why bother with a mono-alcohol, make the molecule symmetrical, and make it a diol?" Then, you should be able to use half the molar quantity from before, and have all the benefits outlined in the post above. Hence this proposal for bicyclo[2.2.2]octan-1,4-diol :

The first couple of steps is given in an OrgSyn procedure,
Org. Synth. 1965, 45, 25
DOI: 10.15227/orgsyn.045.0025
http://www.orgsyn.org/demo.aspx?prep=CV5P0288

And the borate ester enolate protection is based on a short lecture course at university on Main Group elements in organic synthesis.

Bicyclo[2.2.2]octane-1,4-diol.png - 205kB

[Edited on 29-8-2018 by 12thealchemist]




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[*] posted on 5-9-2018 at 04:48


Quote: Originally posted by 12thealchemist  
Since this post, I gave the idea more thought, and thought "why bother with a mono-alcohol, make the molecule symmetrical, and make it a diol?" Then, you should be able to use half the molar quantity from before, and have all the benefits outlined in the post above.
Even I suggested a diol idea in the previous page -http://www.sciencemadness.org/talk/viewthread.php?tid=15171&...
Quote:
Hence this proposal for bicyclo[2.2.2]octan-1,4-diol
isn't there a chance of polymerisation,having the OH's at two poles ?
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[*] posted on 13-9-2018 at 12:34


Quote: Originally posted by draculic acid69  


As carbon sources themselves we'd need a long-chain carboxylic acid, i don't know of any other than acetic acid.


This stuff, Windflame PureFire Lamp oil, Windflame PureFire Lamp Oil, is pretty pure methyl coconoate, which is a distribution of C10-C18, with the majority being C12 (methyl laurate). Grignard on this with your bromoalkane of choice to get your tert alcohol with a long linear tail and two symmetric "arms". Just my $0.02.

At some point in the next few months I would like to attempt making this HO(Et)subCC12 (from methyl laurate et al with bromoethane), HOMeEtCC16 (from MEK and cetyl bromide), and maybe a few more of that ilk, and try them out for sodium.

HO(iAm)3 from isoamylbromide and isoamyl acetate might be fun too.
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[*] posted on 13-9-2018 at 14:45


Walmart sells "coconut cooking oil" which advertises that it doesn't solidify. You can also buy a more pure material online called MCT Oil or Capric/Caprylic Triglyceride (from supplement supply or cosmetic supply places). The former is what happens when you partially freeze coconut oil and filter off the solids which removes much of the lauric and heavier containing triglycerides. What's left is highly enriched in hexanoic, octanoic, decanoic, and oleic acids with a healthy amount of lauric left over. This material is easy to make into biodiesel (NaOH/KOH catalyzed transesterification with a large excess of methanol) and the result is readily fractionated to give substantial amounts of methyl octanoate and methyl decanoate.

MCT Oil is what happens when you distill the free fatty acids from coconut oil or palm kernel oil and re-esterify them with glycerol. It's essentially mixed octanoic/decanoic triglyceride with a little hexanoic thrown in. The yields from processing this in the same manner as above will be even higher.

You can also just buy isopropyl myristate as a cosmetic supply.
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[*] posted on 17-9-2018 at 08:54


Triglycerides are just esters, so couldn't one just react a Grignard with the MCT oil directly? Having a hard time finding literature for this one, but this source New Trends in Lipid and Lipoprotein Analyses, is promising.

[url=https://books.google.com/books?id=-Twl5OI0VgQC&pg=PA242&lpg=PA242&dq=grignard+on+"triglyceride"+ester&source=bl&ots=4RCrkAWM6 3&sig=eLph-BIwAmaCBvoQXhTsQqgVCwA&hl=en&sa=X&ved=2ahUKEwj9tv_2u8LdAhWJTt8KHaeEC9sQ6AEwDnoECAIQAQ#v=onepage&f=false]link[/url]

edit: the board does not like this link, you will have to manually paste it I think. "Contribution of Grignard Reagents in the Analysis of Short-Chain Fatty Acids", p 242


Quote:

Application of Grignard Reagents to Oils and Fats Analysis

Two applications successfully used Grignard reagents in oils and fats analysis. One was analyzing the fatty acid regiodistribution in triglycerides. The nonselectivity regarding fatty acid chains and nonregioselectivity of Grignard reagents was used to start operations through partial deacylation. The brief, controlled degredation resulted in a mixture of diglycerides. The second involved analyzing wax constitutents, particularly jojoba. Ethylmagnesium bromide rapidly attacked the ester bonds, and in a single step completed transformed jojoba wax rapidly and completely into a mixture of tertiary alcohols that corresponded to the fatty acids and native primary alcohols. The mixture of alcohols was analyzed directly in gas chromatography with a single injection.


In theory, with enough Grignard, the triglyceride should be ripped to shreds, affording the tris-MgBr adduct of glycerol and the deprotonated tert alcohol- MgBr+, upon quench giving the tert alcohol and glycerol. I think the key phrasing is controlled degredation, which leads me to believe they tried to carefully strip off one fatty acid.

This source, Studies on the positional specificity of lipase from Mucor miehei during interesterification reactions of cod liver oil with n-3 polyunsaturated fatty acid... by Haraldsson and Almarsson, 1991, suggests that even with 6 moles of MeMgBr to 1.1 mol triglyceride, diglyceride was obtained. Again, that's not an excess of Grignard, so I think they are trying to do something to partially degrade the fats for the purpose of analysis.

[Edited on 17-9-2018 by Vinylogous]

[Edited on 17-9-2018 by Vinylogous]
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draculic acid69
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[*] posted on 15-10-2018 at 20:57


NurdRage just posted a video using 4OHterpineol from purified tea tree oil for the sodium metal rxn on YouTube with good results.seems like this is the way to go.

[Edited on 16-10-2018 by draculic acid69]
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[*] posted on 16-11-2018 at 19:46


NurdRage last video shows long chain secondary alcohol s work in the NaOH/mg rxn.they seem to have a lower yield but they work.menthol crystals on eBay or from mint flavorings for cooking or vaping are otc and ready to go.

[Edited on 17-11-2018 by draculic acid69]
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[*] posted on 16-11-2018 at 19:51


In the spirit of this post where nothing seems to work out can I just say can no-one suggest extracting the menthol from cigarettes to use in this rxn.just buy it it's otc enough.
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