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Author Topic: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]  (Read 1290 times)

Naf1

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #40 on: October 06, 2009, 11:10:06 PM »
The Strecker degradation of Amino acids induced by Methyl Linoleate
http://rms1.agsearch.agropedia.affrc.go.jp/contents/JASI/pdf/academy/34-2134.pdf

I mentioned this earlier in the post, it is actually Strecker degradation. The yields and selectivity are not great especially for alanine, but methyl linoleate can be substituted with peanut oil!

Enkidu

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #41 on: October 07, 2009, 01:18:37 AM »
Quote from: Enkidu on October 06, 2009, 07:27:06 PM
Thanks for that ref. All that the decarboxylation needs is a solvent with a high boiling point (>210*C) but that is also a liquid at room temperature. Any ideas for an otc solvent that meets those requirements?

What about using naphthalene as the solvent? Just add your amino acid and naphthalene. Heat it up, and the naphthalene will melt. When the reaction finishes and cools down (probably back to a solid), just add toluene to dissolve the naphthalene. Then gas to recover your amine. Thoughts?

Sedit, I don't know if the amino acid has to be dissolved. You'd prolly have an easier time if it was. (Less chance of burning, etc.)
« Last Edit: October 07, 2009, 01:22:07 AM by Enkidu »

Sedit

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #42 on: October 07, 2009, 01:33:52 AM »
I don't know about napthalene as that has a high vapor pressure and sublimes right? If thats the line of thinking I would go with MSM instead. That would be simular to performing the decarboxylation in DMSO as they have simular solvating abilitys. I know it does NOT have to be solvated at all and heat alone will perform decarboxylations but the burning is one issue and the solvant in some decarboxyaltions is a catalyst in the reaction. Perhaps some high Bp ketones could work. I don't know of any but maybe.
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Enkidu

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #43 on: October 07, 2009, 01:34:59 AM »
^ I don't think that the naphthalene has a high enough boiling point for tyrosine. However, it might work for some other amino acids.

styphnate

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #44 on: October 07, 2009, 04:09:53 AM »
Quote from: Sedit on October 07, 2009, 01:33:52 AM
Perhaps some high Bp ketones could work. I don't know of any but maybe.

The classic method for amino acid decarboxylation uses an a,b-unsaturated ketone.  I plan on trying out decarboxylation in turpentine using carvone from spearment oil as a catalyst (as described on rhodium).  I'll post my results if I ever get around to doing it.

Happyman

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #45 on: October 07, 2009, 04:22:43 AM »
Do we know what all Grignards reagents will react with phenylacetaldehyde methylimine and hypothetically turn it to methamphetamine? Methyl iodide/Methylmagnesium iodide seems like a pain. I also see "Alkyl iodides tend to be so reactive as to undergo self-coupling reactions and therefore are generally less useful as reagents in synthetics schemes" so I wonder if another Grignard reagent would provide better yields. Not that we know the yields because they aren't posted... but still, would something like ethylmagnesium bromide/chloride do the trick? Something that would give make the next steps Very convenient. Two moles of Grignard reagent and one mole of aldimine would provide you with two moles of magnesium salt, one mole of desired product and propene? C9H11N+2C2H5MgX--->C10H15+2MgX+C3H6

Sorry about not putting this with short questions. Seemed better here.

Sedit

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #46 on: October 07, 2009, 04:27:57 AM »
Ahh yes caverone how did I forget all about that one. I would not use direct spearment oil as suggested (IIRC )though as you would more then end up with a bunch of crap from heating god knows what. Best to either synthesis it yourself from the oxidation pf Limonene which can be had from orange peels by the mass or just perform the bisulfite adduct to clean the rest of the shit out of it other then ketones.

 Dill oil also contains the other enantiomers of caverone in higher percentages then spearment oil I think. Plus the other "crap" you would be seperating it from would be dillapoil which im sure someone could find a use for here or there.
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Naf1

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #47 on: October 07, 2009, 04:40:36 AM »
"will react with phenylacetaldehyde methylimine"

Methylamine, ohh you mean after the methylamine addition. Sorry you are completely correct there.

"and hypothetically turn it to methamphetamine?"

No hypothetical about it, it is documented here;
http://www.erowid.org/archive/rhodium/chemistry/meth.phenylacetaldehyde.html
look up the references if you are still uncertain.

Also it can be turned into P2P, via a methyl grignard as documented here;
http://books.google.com.au/books?id=8JsQgRO3QcwC&lpg=PA487&ots=uQyJnqmxqM&dq=phenylacetaldehyde%20clandestine&pg=PA487#v=onepage&q=phenylacetaldehyde%20clandestine&f=false

Believe it! As phenylacetaldehyde is not restricted for no reason!

"ethylmagnesium bromide/chloride do the trick?"

It would work excellently to produce N-methyl-1-phenyl-2-aminobutane. If you wanted methamphetamine a methyl grignard would be used.
« Last Edit: October 07, 2009, 04:49:14 AM by Naf1 »

styphnate

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #48 on: October 07, 2009, 04:54:23 AM »
Sedit-

Do you have a ref for direct oxidation of limonene?  The only synthesis I've seen is via the nitrosochloride, which is more trouble than its worth IMHO.  If you know of another method I'd be very interested to hear it.

A quick search reveals that spearment oil is mostly carvone and terpenes with a little bit of menthol.  Now I think that the terpenes shouldn't interfere, afterall, that's essentially what turpentine is, so it would be just like a tad more solvent.  But I suppose if I wanted to I could purify the carvone through the bisulfite adduct.  Any reason this would be necessary?  Or any reason that it wouldn't work in with purification (I didn't find any other ketones listed in the composition)?

Thanks very much for the quick reply.

no1uno

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #49 on: October 07, 2009, 08:58:42 AM »
Here is a PDF copy of a school assessment on, what else,the extraction of Carvone from both Caraway Seeds & Spearmint Leaves:

Quote
Experimental Procedure

1) Measure 2 g of crushed caraway seeds into a 30 mL beaker and add 10 mL of ether. Ether is chosen as a solvent because the carvone is soluble in ether. Cover with aluminum foil to prevent evaporation and allow the mixture to stand for 15-30 minutes.

2) Measure 2 g of spearmint leaves into a 50 mL beaker and add 10 mL of ether. Again, cover with aluminum foil and allow the mixture to stand for 15-30 minutes. The different containers have no effect on the extraction; they simply allow you to do two extractions simultaneously without duplicating your glassware.

3) Once the seeds have soaked for the appropriate time, use a Hirsch funnel to filter the caraway seed solution (Always clamp a filter flask.). This is done by placing a piece of filter paper in the funnel, assembling the Hirsch funnel as shown in the diagram below, and starting the suction such that a vacuum builds up in the filter flask. Pre-wet the filter paper with ether, then pipette the liquid from the extraction into the funnel and collect the liquid in the receiving flask. When you have filtered the caraway seed solution, transfer the filtrate to a cleaned 30 mL beaker and wash out the receiving flask with acetone. During filtration, if you see no solvents left at the receiving flask, you can add a minimum amount of ether (~5-10 mL) to dissolve the solid substance. Ether is volatile at room temperature.

4) Repeat step 3 with the spearmint leaves extract using a clean pre-wetted piece of filter paper. Transfer this filtrate into a cleaned 50 mL flask.
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hypnos

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #50 on: October 08, 2009, 04:06:21 AM »
 hey guys most of this thread is waaaaaaaaaaaaaaaaaaaay over my head..however,, i found an interesting  source of relevant data that you may find interesting....i just hope i've posted it in the

right place!!!) its kinda bizarre what turns up from time to time-ask for one thing get another!!!

  "CRC handbook of chromatography" circa1982---its available online for about$400!!!! but here's a cheaper route-- ;D


  -http://books.google.com/books?id=e9132M-Ml2YC&pg=PA379&lpg=PA379&dq=AMINO+ACID+RESIN&source=bl&ots=7JiKuz-Iq3&sig=UbGg05KhZcPctbz2kfWU6tJJg5I&hl=en&ei=gVvNSvjtC4qqsgP9lvDEDg&sa=X&oi=book_result&ct=result&resnum=4#v=onepage&q=AMINO%20ACID%20RESIN&f=false
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no1uno

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #51 on: October 09, 2009, 09:00:24 AM »
Here is an interesting paper - it uses the schiff base of alanine t-butyl ester to alkylate to a-methylphenylalanine, but the best part is the ketone they use - l-menthone, which is not only available (although I can't find any papers on how to get menthol out of peppermint oil), but regenerable.

Presumptively, the same alkali hydroxide as a base and a less prohibitive ester could be used as with other similar procedures...
« Last Edit: October 09, 2009, 09:02:00 AM by no1uno »
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no1uno

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #52 on: October 09, 2009, 09:00:37 PM »
Here is maybe a nice route to mescaline (given the almost quantitive decarboxylation of tyrosine to tyramine above), being via the 3,5-diiodotyrosine

Of course, we'd need to protect that amine group before we could methylate the p-hydroxy, but the two m-hydroxyls should be aminated similarly to with syringol shouldn't they? Followed by decarboxylation (given the structure this is a potential prodrug too, tyrosine is decarboxylated in-vivo)
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Enkidu

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #53 on: October 10, 2009, 02:33:19 AM »
^ yeah, there's a thread about that over at SM started by stoichiometric_steve.

no1uno

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #54 on: October 10, 2009, 05:22:57 AM »
Yes, I presume you mean this...

There is nothing in the way of the source article? I mean this one:

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stoichiometric_steve
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  • posted on 1-12-2008 at 13:19    

Aromatic iodinations


Synthesis of 3,5-diiodo-4-methoxyphenethylamine. Jatzkewitz, Horst; Noeske, Hans Dietrich. Univ. Tubingen, Germany. Hoppe-Seyler's Zeitschrift fuer Physiologische Chemie (1951), 287 43-6. CODEN: HSZPAZ ISSN: 0018-4888. Journal language unavailable. CAN 49:4568 AN 1955:4568 CAPLUS

Abstract

The synthesis of 3,5-diiodo-4-methoxyphenethylamine (I) is described. I is used to study the effect of biogenic amines on the action of mescaline. To 14 g. tyramine-HCl in 23 cc. H2O and 46 cc. N NaOH, 11.8 g. iodine in alk. KI soln. (contg. 20 g. KI, 160 cc. H2O, and 46 cc. N NaOH) is added dropwise with stirring, maintaining const. alky. The soln. is filtered and acidified with excess H2SO3, giving 12 g. crude 3,5-diiodotyramine-HI (II), yellow leaves (from H2O) m. 232-4¡ (decompn.). II (12 g.) treated with the calcd. amt. of hot Na2CO3 soln. gives 6 g. free base (III), pale yellow, m. 188-90¡. III (2 g.) boiled 10 s. with 5 cc. Ac2O and dild. with H2O gives 1.75 g. N-acetyl-3,5-diiodotyramine (IV), colorless plates, m. 139-40¡. IV (6 g.) (crude) in THF is methylated with 60 cc. ethereal CH2N2 dild. with 40 cc. CHCl3, washed twice with 5% NaOH and H2O, dried and the solvent removed, giving 5.2 g. N-acetyl-3,5-diiodo-4-methoxyphenethylamine (V), needles, m. 138-40¡. V 3.8 g. is refluxed 5 h. with 19 cc. HCO2H, 14 cc. HCl, and 14 cc. H2O., evapd. in vacuo and dried with EtOH and C6H6, the residue extd. with three 15 cc.-portions of abs. C6H6 gives on evapn. of the solvent 3.4 g. crude I.HCl. The pure compd. m. 213-15¡. The salt dried in Et2O over anhyd. K2CO3, on removal of solvent and crystn. from petr. ether gives I, colorless leaflets, loses its crystal structure at 41-3¡, and m. 55-7¡.


- - - -

Now the question:

In the preparation of iodinated arylalkylamines, protection of the amine moiety is usually applied as to prevent formation of halo-amines. How come this does apparentl not happen in the above procedure?
Is anybody aware if iodine (I2 or I+) will react with arylalkylamides to produce iodoamides?
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Locked

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #55 on: October 13, 2009, 12:54:48 AM »
Sorry if this is totally off track, but...

If someone used, say, p2p to cat the decarb of glycine, might the temp drive off the water and push the imine formation to the side that some of us want anyway, eliminating the need for isolating methylamine? Is this really as easy as a vac vigreux slow distill just hot enough to drive off the water produced? Or do I have this all wrong?

Locked

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #56 on: October 13, 2009, 01:39:27 AM »
I forgot this. Check the schiff base part... I think I am getting excited.

Enkidu

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #57 on: June 24, 2011, 10:42:29 AM »
Quote from: Enkidu on October 07, 2009, 01:18:37 AM
What about using naphthalene as the solvent?

Appartently, naphthalene works as a solvent for the ketone catalyzed decarboxylation.

http://www.sciencemadness.org/talk/viewthread.php?tid=8574&page=2#pid206607

A couple posts down, Nicodem praises the solvent choice :D
« Last Edit: June 24, 2011, 08:21:23 PM by Enkidu »

Balkan Bonehead

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #58 on: June 24, 2011, 05:23:30 PM »
Mineral oil, the kind sold in the medicine aisle as a laxative, works well also. I have tried it with some alanine and mineral oil in a test tube over an open flame. The oil turns yellow, boils, and starts to stink of ethylamine.

Most of the alanine sublimed, however, and formed a crust around the top of the tube or escaped into the air. Larger MW amino acids shouldn't do this as much.

aniracetam

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Re: Tools for the Synthetic Chemist [Decarboxylation of a-Amino Acids]
« Reply #59 on: June 24, 2011, 09:19:22 PM »
I can vouch that mineral oil works, probably more effectively in the presence of inert gas to prevent oxidation.
pure tryptamine was recovered from a friedrich condenser rinsed with acetone, and compared against a standard using LC/MS. m/z was identical (160).

« Last Edit: June 24, 2011, 09:22:17 PM by aniracetam »
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