Sciencemadness Discussion Board - Carboxylic acid -> Alkan

Carboxylic acid -> Alkan

nightflight - 18-3-2007 at 07:00

Hi,

I was intersted in how to perform this best, with not so expensive catalysts and good yields.

So what I cam came across to synthesize an alkane from a aninoaryl-CO2H was:

I. Reacting the carboxyclic acid with thionyl chloride to yield a
chlorocarboxylic acid.

II. Catalytic reduction of halide to yield a hydrogen, resp. aldehyde (Aluminiumamalgam?)

II. Clemmens reduction of the Aldehyde to get the alkane, by heating with Zn(Hg) in HCL.

What do you think about the Barton decarboxylation mentioned in this paper: http://www.chem.harvard.edu/groups/myers/handouts/1_Reductio...
?
Reacting an ester of N-hydroxy-2-thiopyridine with a tin-hydride catalyst -unfortunately not much is stated about the selectivity of this decarboylation.

Intresting would be Vogel´s synthsis of (S)-2-Amino-3-phenylpropan-1-ol, by reaction phenylalanine to the ethylester*hcl in EtOH and SOCL2 successive reduction in high yield by Sodiumborohydride and subsequent deoxygenation of the alcohol, by the Mitsunobu displacement, wouldn´t it?

[Edited on 18-3-2007 by nightflight]

garage chemist - 18-3-2007 at 07:17

Caboxylic acid to the alkane can be done directly in one step with red P and hydroiodic acid. Look in the old Gattermann (Sciencemadness library), theres a preparation of diphenylmethane from benzophenone in there that uses this method. It is stated there that HI/P reduces all oxygen compounds like alcohols, aldehydes and carboxylic acids, to the alkane.

[Edited on 18-3-2007 by garage chemist]

nightflight - 18-3-2007 at 07:33

Oh cool, thanks I ´ll look that up, after like spending 3 days of searching and learning the above mentioned stuff.

[Edited on 18-3-2007 by nightflight]

solo - 18-3-2007 at 08:10

Quote:

Originally posted by garage chemist
Caboxylic acid to the alkane can be done directly in one step with red P and hydroiodic acid. Look in the old Vogel (Sciencemadness library), theres a preparation of diphenylmethane from benzophenone in there that uses this method. It is stated there that HI/P reduces all oxygen compounds like alcohols, aldehydes and carboxylic acids, to the alkane.

I apologize for my question but I wasn't able to locate the preparation of diphenylmethane using the RP/HI......would it be possible to give the page #....thanks,......solo

nightflight - 18-3-2007 at 08:10

But why is it so hard to find? all I see is reductions to alcohol, using various metal catalysts or the hunsdiecker reaction using heavy metals in teh presence of Br and CCl4

garage chemist - 18-3-2007 at 08:21

Oh, I didn't remember it correctly, it was not Vogel, it was Gattermann (the 1909 version) in which the HI/P reduction of benzophenone to diphenylmethane was described.

EDIT: Page 301 in the Gattermann from 1909. Also reduction of benzoic acid to toluene, stearic acid to octadecane, glycerol to propane etc. are stated as being possible with HI/P.

[Edited on 18-3-2007 by garage chemist]

nightflight - 18-3-2007 at 08:30

.. but that´s a ketone, not a carboxylic acid. Ok, Hi is expensive, but that wouldn´t be a reason to not mentioning it as it´d be an easy and important reaction.

edit: oh-ok cool -could you provide a link? :cool:

[Edited on 18-3-2007 by nightflight]

garage chemist - 18-3-2007 at 08:33

It is clearly stated that the HI/P reaction works with all oxygen compounds, alcohols, aldehydes, carboxylic acids etc... Look it up!

Even unsaturated compounds can be converted to saturated ones by means of HI/P, like benzene ---> cyclohexane.

EDIT: OK, link: http://www.sciencemadness.org/library/books/the_practical_me...

[Edited on 18-3-2007 by garage chemist]

nightflight - 18-3-2007 at 08:57

thanks a lot!

solo - 18-3-2007 at 13:17

Quote:

Originally posted by garage chemist
It is clearly stated that the HI/P reaction works with all oxygen compounds, alcohols, aldehydes, carboxylic acids etc... Look it up!

Even unsaturated compounds can be converted to saturated ones by means of HI/P, like benzene ---> cyclohexane.

EDIT: OK, link: http://www.sciencemadness.org/library/books/the_practical_me...

[Edited on 18-3-2007 by garage chemist]

I did find the reaction on page 301 as stated, but have looked for the statement, where the author makes the statement you quoted......I'm not lazy perhaps a bit farsighted, so how about giving up the page of the 1907 publication where the information is posted.......solo

S.C. Wack - 18-3-2007 at 14:45

This all depends on what exactly you are trying to decarboxylate. I assume that the COOH is not attached to the ring, nor are groups that would cause problems. Don't count on the Hunsdieker to give good yields on aromatic cpds.

The HI/RP is in the older editions as well, but not the newer ones. The reference given is available at Gallica, and mentions some of the other reductions. What Gattermann says says nothing of the yield or conditions necessary in reduction of acids on a preparative scale - these are hot sealed glass tube methods (with pressure from gas evolution as well as vapor pressure), and acids are not likely to reduce quite as easily as benzophenone.

[Edited on 18-3-2007 by S.C. Wack]

nightflight - 19-3-2007 at 01:47

What do you all think of the steps proposed in the entry post?

And how about using Al(Hg) in the Rosemund reduction -alternatively Palladiumchloride is available -the over reduction would be a good thing in this case.

solo - 19-3-2007 at 07:00

Well since you asked, one I would react the COOH with some NaBH4 and NiCl in water at RT to get the OH then use the Hypo/I2 to reduce the OH to the CH3........solo

nightflight - 20-3-2007 at 06:39

...that came to my mind yesterday night after reading Vogels synthesis of 2-amino-3-phenylpropan-1-ol.

nightflight - 24-3-2007 at 17:37

Quote:

Originally posted by solo
Well since you asked, one I would react the COOH with some NaBH4 and NiCl in water at RT to get the OH then use the Hypo/I2 to reduce the OH to the CH3........solo

In fact it´s the PI3 that forms the alkyliodid, which then has to be reduced to yield the alkane.

So I´m now at this point, since HI redeuction needs pressure to yield 150°C and I don´t know how to perform it:

-esterification (already done with n-butanol, to provide a good leaving group and it was dry and readily available),
reduction with Al(Hg) to -hopefully- yield the alcohol,

-synthesis of the alkylhalide with 1/3P&I -> CH2I + H2PO3

-reduction with Al(Hg) getting the alkane.

Could anybody expalin how after this document: http://www.geocities.com/nepalorganic/co_acid.htm

an Alkane can be made with Grignard reagents? Is this the reaction wheere cooling to -70°C is necessary as for the gereartion of carboxyli acids by Grignard? -sorry, did´t yet find that much on it.

[Edited on 25-3-2007 by nightflight]

not_important - 24-3-2007 at 21:07

Quote:

Could anybody expalin how after this document: http://www.geocities.com/nepalorganic/co_acid.htm

an Alkane can be made with Grignard reagents? Is this the reaction wheere cooling to -70°C is necessary as for the gereartion of carboxyli acids by Grignard? -sorry, did´t yet find that much on it.

You mean the CO2 one? Works in part because the carboxylic acid salt is formed, which isn't very reactive, and in part because it is run cold.

Alkanes are made via Grignard using halides, not acids RX + R'MgX => R-R' + MgX2
acids are OK for making alcohols or sometimes ketones.

if you're starting with a carboxylic acid you need to get it to being a halide first, the route depends on where you start and what the target is.

nightflight - 25-3-2007 at 04:01

could a halide of a acid halide be swapped for an hydrogen by a grignard reagent, what is the most convenient way to do so, anyway?

I´m thinking about sealing it in a flask with a keck clamp and some wire or string and throwing it into the micro for convenient heating (mw doesn´t speed up ester cleavage so donßt I think it´ll speed up things here), to obtain 150°C, which doesn´t seem like too much pressure is needed to get to this temperature.

[Edited on 25-3-2007 by nightflight]

not_important - 25-3-2007 at 05:20

Quote:

Originally posted by nightflight
could a halide of a acid halide be swapped for an hydrogen by a grignard reagent, what is the most convenient way to do so, anyway?

Yes, sort of. It makes a ketone, which can react with the Grignard to give a tertiary alcohol. In the bad old days it was more common to make the Grignard, then convert it to the corresponding organo-cadmium compound and react that with the acid halide, as the cadmium compound is less reactive. The minor problem with this is the high toxicity of cadmium and its compounds, and the tendency of the organic cadmium compounds to ignite when exposed to air, made more interesting by the ether used as a solvent. Severe burns plus cadmium poisoning were poor incentives for recruiting new chemists.

Quote:

Almost 5 bar if using just plain water, as a baseline. You'll have to do digging to find out for the reaction mix you plan. Be interesting to see a wire wrapped flask in the microwave.

http://www.engineeringtoolbox.com/saturated-steam-properties...

Sealed tube runs use heavy walled tubing and put that inside steel pipe for tube failure containment. Sometimes water or some other liquid would be placed in the pipe was well, and it would be sealed - this to reduce the pressure differential on the glass tube. Care must be taken to correctly calculate the amount of liquid to use in order to prevent too little or too much pressure in the pipe.

nightflight - 29-3-2007 at 04:24

How convenient is a MV, when it can be heated in a secure shell in a reg. oven? ;-))

Just out of interest, could the reduction of the alcohol proced liek this:

RCH2X + 2HI + 2H3O* -> RCH3 + 2H2O + I2 ?

the I2 is then racted with the RP to regenerate the HI(aq):

3I2 + 2P + 6H2O -> 2PI3 + 6H2O -> 6HI + 2H3PO3

Theoretically it could be used less HI but with more time the rxn should go to completion, for the HI reg. is permanent, couldn´t it?

What would yo think about substituting this with the reduction in NaBH4 and F3CCO2H, price-wise ?

[Edited on 29-3-2007 by nightflight]

Barton Vs. Kolbe Decarboxylation maybye...

roamingnome - 8-6-2007 at 10:19

they join forces....

Since Barton radical decarboxylation was found threw search engine here it seems the place to ask and post

Ive been looking for interesting things to sonicate these days and radical decraboxyaltion of phenylalanine seems rather promising for interest levels…

First:
http://www.osti.gov/energycitations/product.biblio.jsp?osti_...

The methyl radical yield rises sharply at very low concentrations of methanol…..

Methyl radicals if they are needed will form in the gas bubble and be ready to react with the bulk fluid medium at collapse. Kind of a Kolbe et al. type of promise…..

Depending on the reaction methyl radicals can add to thermally decraboxylating phenylalanine, or if one had the specialized reagents barton decarboxyalation produces R groups with the addition of a hydrogen ……
http://www.organic-chemistry.org/namedreactions/barton-decar...

but im pretty sure home school techniques can deliver a ester of phenylalanine that will produce the R group with out all the fancy fine sigmaaldrich specials…

http://www.springerlink.com/content/xh07j39423831367/
Under the action of peroxides or UV radiation mercuric alkanoates undergo initiated free-radical decarboxylation with formation of alkylmercury compounds.

Um I really don’t want to create methylmercury but it shows the trend

Other refs:
Radical Reactions in Organic Synthesis By Samir Z. Zard

Provided by google books

http://www.osti.gov/em52/1999projsum/54834.pdf
The acetylene then reacts with OH•to form methyl radicals and carbon monoxide

Organikum - 8-6-2007 at 23:53

Quote:

Originally posted by S.C. Wack
This all depends on what exactly you are trying to decarboxylate. I assume that the COOH is not attached to the ring, nor are groups that would cause problems. Don't count on the Hunsdieker to give good yields on aromatic cpds.

The HI/RP is in the older editions as well, but not the newer ones. The reference given is available at Gallica, and mentions some of the other reductions. What Gattermann says says nothing of the yield or conditions necessary in reduction of acids on a preparative scale - these are hot sealed glass tube methods (with pressure from gas evolution as well as vapor pressure), and acids are not likely to reduce quite as easily as benzophenone.

[Edited on 18-3-2007 by S.C. Wack]

I translated once this german article from the 30s for the HIVE where they reduced all this acids and stuff with HI....

The procedure was like this:
95% H3PO4 + NaI or KI + a small amount of red phosphorus
The use of the highly concentrated H3PO4 allows temperatures which are sufficient to reduce almost everything without the need of a pressure vessel.
The authors explicitly suggested this method for use on an industrial scale.

The older industrial methods were indeed using HI with conc. HCl as solvent in a pressure vessel, or HI in concentrantions up to 72% IIRC under pressure - nothing for the amateur.

As a laboratory method in special to reduce alcohols the GAA/iodine/red phosphorus reduction system was used, but in these times GAA and iodine were rather expensive and chemists were poor.

The yields of the H3PO4 method were always named as >80%, H3PO4 is rather cheap and easily concentrated from the 85% of trade to the 95% asked for by simple heating, NaI and KI are also no problem, just the red phosphorus might be for some a problem in these days of the meth madness.

There was also what SAM posted at the HIVE (times before he went insane) - a scanned page from an unnamed old book - where it was stated that HI rips out oxygen from virtually EVERY organic molecule, if reaction conditions are harsh enough it goes next for the nitrogen.
This might explain that reducing phenylalanine with HI is not trivial as the conditions needed to reduce the acid will be near to the conditions reducing the nitrogen. I guess in this reaction the conditions (in special temperature) have to be very well controlled and it will take some tinkering to get them well adjusted. Then the yields should be very high as basically always with HI reductions.

/ORG

[Edited on 9-6-2007 by Organikum]

I think this maybe easy to work

tongqiancao - 9-6-2007 at 04:36

Quote:

Originally posted by nightflight
But why is it so hard to find? all I see is reductions to alcohol, using various metal catalysts or the hunsdiecker reaction using heavy metals in teh presence of Br and CCl4

Hunsdiecker reaction have been improved currently. if you have a beta-unsaturated acid as your raw material. This paper may be help:
Tetrahedron 61 (2005) 637–642.
You can get beta-arylvinyl bromides in 1-2min with high yield. Then just a reductive reagent will be needed after it.

solo - 9-6-2007 at 08:27

Reference Information

Stereoselective synthesis of (E)-b-arylvinyl bromides by microwave-induced reaction of anti-3-aryl-2,3-dibromopropanoic acids using an AgOAc–AcOH system
Chunxiang Kuang,* Hisanori Senboku and Masao Tokuda
Tetrahedron 61 (2005) 637–642.

Abstract
(E)-b-Arylvinyl bromides were stereoselectively prepared in high yields by microwave irradiation of the corresponding anti-3aryl-2,3-dibromopropanoic acids in AcOH in the presence of AgOAc for 0.5–3.0 min.

[Edited on 9-6-2007 by solo]

Attachment: Stereoselective synthesis of (E)-b-arylvinyl bromides by microwave-induced reaction of anti-3-aryl-2,3 dibromopropanoic (210kB)
This file has been downloaded 1988 times

Filemon - 9-6-2007 at 16:48

Do you know this decarboxylation? I don't know their name.

R-COONa + NaOH + CaO + Heat => R-H + NaCO3

I have read that the aldehydes alpha-halogen they are oxidized easily to carboxilic acid. That yield has the reaction:?

Acetaldehyde + NaClO + H2O => acetic acid

or

EtOH + NaClO + HCl + H2O => acetic acid

[Edited on 10-6-2007 by Filemon]

roamingnome - 10-6-2007 at 13:03

Quote:

Do you know this decarboxylation? I don't know their name.

Quote:

R-COONa + NaOH + CaO + Heat => R-H + NaCO3

well in chemistry anything can happen....
but where did the Calcium go
to a happy place?

i have been seeing that added bicarbonate facilitates decarboxylation...

So
i hold in my hand a 500 mg gelaitan capsule of L-Phenylalanine
i will separate the cellulose and Mg stearate as the only other listed ingredients.
i will add bicarbonate until a homogeneous mixture is had in water.
A catalytic amount of methanol will be added
the mixture will be sonified at 20 kHz and up to 150 Watts without temperature concerns.

i wonder the result....

Filemon - 10-6-2007 at 16:03

Quote:

Originally posted by roamingnome

Quote:

Do you know this decarboxylation? I don't know their name.

Quote:

R-COONa + NaOH + CaO + Heat => R-H + NaCO3

It appears here:

http://www.educnet.education.fr/rnchimie/chi_org/viel/acides...

roamingnome - 12-6-2007 at 08:44

That’s a good reference, Ill look into it….
I would say the CaO might be absorbing water, but in an aqueous medium that would make no sense…..

Well I began to sonicate the turbid solution of 25 mls….
But as I lusted for more power I pushed the micotip over 200 watts….
The 120 mm tip was already bent because it was used surplus of course I tried to straiten it, but somewhere after 200 watts it sheared off from the other body ending the test.
leaving me to search for a titanium rod to thread and replace the aluminum one. I also noticed the machine is not tuned anymore ahhhhh….. I should have just stuck to yeast….

Anyway…. The smell of the liquid … I simply can not describe it and remain professional in this forum….
I have not smelled phenylethylamine to compare it to….

____________________________________

CH3CH2COOH + 2 NaOH →CH3CH3 + Na2CO3 + H2O

http://en.wikibooks.org/wiki/Organic_Chemistry/Carboxylic_ac...

ok this is just forming the alkane as understood
( a 2 electron transfer?), but throwing methyl radicals in the mix is of interest...

i need a gamma radiation source probably...

[Edited on 12-6-2007 by roamingnome]

Filemon - 5-7-2007 at 02:13

Quote:

Originally posted by garage chemist
EDIT: Page 301 in the Gattermann from 1909. Also reduction of benzoic acid to toluene, stearic acid to octadecane, glycerol to propane etc. are stated as being possible with HI/P.

[Edited on 18-3-2007 by garage chemist]

Where? There not this. As much as time needs the reduction of the benzoic acid and stearic acid?

S.C. Wack - 5-7-2007 at 11:28

Actually that is on page 302, which is 314 of the .djvu.

Yet when mandelic acid was treated in a somewhat similar way to what Org was saying, the investigators obtained phenylacetic acid instead of ethylbenzene:

15 grams mandelic acid (0.1 mol) [5], 2.07g KI (6.25% of theory), and 6g Red Phosphorous is dissolved in a solution of 70ml phosphoric acid and 10 ml of water, and this solution is refluxed for six hours (bp of soln 144°C). After the reaction mixture has cooled down, a little water is added to dissolve precipitated inorganic salts. The solution is extracted with ether, and the pooled extracts washed with a little dilute NaHSO3, followed by water, and is then dried over Na2SO4. The ether is removed under diminished pressure and the residue is distilled (bp 138-139 @13mmHg). The yield is 12.5 grams (90%) of phenylacetic acid melting at 76°C. 3.2 grams of phosphorous could be recovered from the aqueous solution.

- http://www.erowid.org/archive/rhodium/chemistry/phenylacetic...

Perhaps a much larger amount of HI and phosphoric acid is necessary.

Filemon - 5-7-2007 at 16:14

Sorry but that it's an example the HI/P doesn't reduce carboxilic acid. Alone it reduces the group hydroxide.

[Edited on 6-7-2007 by Filemon]

Filemon - 5-7-2007 at 16:19

I believe that it could work. But previously it would be necessary to attack with PI3 to make iodide of acid and then to add water to complete the reduction.

[Edited on 6-7-2007 by Filemon]

chochu3 - 6-7-2007 at 04:40

I tried this reaction once and the carboxylic acid was not reduced. I did a reflux and added all reagents as a onepot synthesis, and did not record the temp. of the reaction.

The follow up rxn I will make HI first then add the Ph-alanine and run the reaction up to 150 celsius under reflux. Any suggestions on how this rxn should be ran.

According to some references PI3 forms a substitution at the alpha carbon with the halide, so that's what might have happened to my first reaction. The workup was extracted as any carboxylic acid (metal hydroxide) and then hydrolyzed with muratic acid.

[Edited on 6-7-2007 by chochu3]

solo - 6-7-2007 at 04:53

Quote:

Originally posted by chochu3
I tried this reaction once and the carboxylic acid was not reduced. I did a reflux and added all reagents as a onepot synthesis, and did not record the temp. of the reaction.

The follow up rxn I will make HI first then add the Ph-alanine and run the reaction up to 150 celsius under reflux. Any suggestions on how this rxn should be ran.

According to some references PI3 forms a substitution at the alpha carbon with the halide, so that's what might have happened to my first reaction. The workup was extracted as any carboxylic acid (metal hydroxide) and then hydrolyzed with muratic acid.

[Edited on 6-7-2007 by chochu3]

Question ....did you run you reaction in a sealed container as it was done in the Gatterman example?........solo

chochu3 - 6-7-2007 at 04:56

no it was refluxed in an open atmosphere no pressure vessels or the like.

solo - 6-7-2007 at 06:23

You might then try to at least put a ballon on top of the refluxing column to maintain a closed environment as the P&V will adjust with the ballon .....you might just do it but run it at 160 for 6 hours if you want to get any viable results....tip, after the reaction let it cool and allow the P&V come to equilibrium at RT then open the vessel under the hood or out in the open for there may be some not healthy gases post reaction.....I have planned to do the same reaction with a sealed vessel with a pressure gauge and a thermometer in the vessel to monitor the reaction , the vessel is rated at 60psi ....please report your findings as I will report mine..........solo

[Edited on 6-7-2007 by solo]

Filemon - 9-7-2007 at 04:48

Why the cinnamic acid decompose down for heat (141ºC) in styrene? For double bond in position beta?

[Edited on 9-7-2007 by Filemon]

Filemon - 24-7-2007 at 02:51

I believe that it could decrease phenylalanine with P/I if previously it has transformed to phenylalanine iodide with PI3. But which solvent you could use? The phenylalanine is alone soluble in H2O. But if phenylalanine iodide was soluble in another solvent it could also be good to make the reaction.

solo - 24-7-2007 at 02:58

In Gattermans study he doesn't mention anything about acid halogens nor esters......I would stay with water.....since it's what's needed to make HI in situ.........solo

Filemon - 24-7-2007 at 07:17

chochu3 say that it doesn't work. It's logical according to the theory, HX produces alpha halogens in the carboxilic acid.

solo - 24-7-2007 at 15:49

But did you also read he did it in an open vessel.......not sure of the temp, short in hours.....in order to prove or disprove a study one has to replicate the conditions in order to comment.

Best thing to do is for me to run my test see what the results come out to be.......solo

solo - 26-7-2007 at 17:02

Ready to go with the reaction .....will make the HI first then add the amino acid and allow it to react for 6 hours at 160 C......will post pic of final reaction.....solo

Shot with FinePix2650 at 2007-07-26

[Edited on 26-7-2007 by solo]

chochu3 - 26-7-2007 at 18:35

here is a pic (attached) of my first reaction setup. the sand bath was at a constant temp. of 145 degrees celsius.

HPIM0517.JPG - 62kB

jon - 26-7-2007 at 20:34

this is the rub, in some papers I've seen on hi reductions alcohols weren't reduced completly until 20 hrs had elapsed (by tlc anal.) so you may have to run it longer and then there is the stochiometry to consider it takes 6 mols of hi so If you only have one or two floating around it might take longer to cycle that through.

Filemon - 29-12-2007 at 10:40

I have seen an interesting reaction to reduce a carboxilic acid:

http://www.orgsyn.org/orgsyn/pdfs/CV3P0671.pdf

It should be easier to reduce a ester.

solo - 29-12-2007 at 11:13

The idea is to reduce the COOH down to CH3....as to reducing it from an ester....NaBH4 with ethanol 50%/H2O 50% will reduce the ester with 80+yield in 4.5 hours...better than messing with sodium....would like to hear anyone attempting the reduction of the COOH to the alkane.....I have had problem with my pressure gauge and I broke my thermometer so until I get a replacement my trial in the bottle will have to wait......solo

Sandmeyer - 29-12-2007 at 18:41

The issue of reducing phenylalanine to amphetamine has been brought up many times here and elsewhere, to the point of becoming boring. Wetdreams is a place to discuss repetitive, non-challenging, (meth)amphetamine-cookery topics.

[Edited on 30-12-2007 by Sandmeyer]

roamingnome - 31-12-2007 at 00:08

The use of the criticism “non-challenging” in regards to the thread title is off the mark.

Turning a carboxylate group into an alkane is front line organic transformation. Just because these experimenters are using an amino acid as a test bed is too much for you?

http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleFo...

Sono-emulsion electrosynthesis: electrode-insensitive Kolbe reactions

Save opinions for the “drug cookery vs. “bomb making” thread

Sandmeyer - 31-12-2007 at 05:13

Quote:

Originally posted by roamingnome

http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleFo...

Sono-emulsion electrosynthesis: electrode-insensitive Kolbe reactions

...and your point with that paper is?

roamingnome - 31-12-2007 at 16:02

It is merely literature that fulfills the requirements of the thread title.

Hexanoic acid a carboxylic acid dimerizes into decane an alkane.

It is also totally unrelated to drugs! Brownie points for me.

Of course if I was feeling theoretically naughty I would try to repeat this experiment with phenylalanine in an excess of acetate ions.
Happy new years to all and good reactions to people that deserve them…

maniacscientist - 3-1-2008 at 12:49

first I was intrigued by an experiment I came across in my college book, which involved Ca-salts of the aminoacid and heat, but will yield the amine with the c-chain of the other aminoacid attached to the amine group iirc.

[Edited on 3-1-2008 by maniacscientist]

[Edited on 3-1-2008 by maniacscientist]

[Edited on 9-1-2008 by maniacscientist]

Filemon - 10-1-2008 at 12:42

Quote:

Originally posted by Sandmeyer
The issue of reducing phenylalanine to amphetamine has been brought up many times here and elsewhere, to the point of becoming boring. Wetdreams is a place to discuss repetitive, non-challenging, (meth)amphetamine-cookery topics.

[Edited on 30-12-2007 by Sandmeyer]

It already knew WD. I don't speak as making amphetamine. I only say a way to reduce the COOH. I didn't know that method. It is certain that nightflight wanted it to reduce the pheylalanine. I don't believe that you can apply to the phenylalanine.

Sandmeyer - 11-1-2008 at 11:25

Quote:

Originally posted by Filemon

Quote:

It already knew WD. I don't speak as making amphetamine. I only say a way to reduce the COOH.

Ok, fair enough, but there are methods to reduce -COOH to -alkyl, it can be done and in high yield in couple of easy steps, i.e -COOH ---> ester ---> alcohol --SOCl2-> alkyl halide ---Pd/C--> alkane, or -COOH --B2H6--> alcohol --SOCl2--alkyl chloride ---Pd/C--> alkane...

solo - 11-1-2008 at 11:42

I may point out that alcohols halogenate better when they are HCl form and the reaction is not so difficult, even while using thionyl chloride, while preparing peptide linking material............solo

solo - 25-2-2008 at 07:58

The reduction with a sealed vessel was attempted with a loud boom.......all was well for 40 minutes as the pressure rose to 30psi then went down to 15 psi and the reaction was left alone for what would be 6 hours .....later away from my lab I herd the loud muffled boom.......my bottle had ruptured and all that was left was the smoldering iodine smell .....will try it again but in a metal reactor -glass lined.....that should hold back the phosphorous attempt to blow maybe I will make sure the thickness of the reactor is 1/8 " to 1/4" thickness to withstand a good amount of pressure........solo

[Edited on 25-2-2008 by solo]

jon - 15-8-2008 at 13:19

phosphine gas formation may i sugguest you prige your vessel next time it spontaously goes boom in contact with air. and it's formed at the temperatures you speak of.

ScienceSquirrel - 15-8-2008 at 14:00

There are literature procedures for the preparation of amphetamine from phenylalanine.
But reduction of the naturally occuring optical isomer of phenylalanine yields the inactive isomer of amphetamine.
So you are wasting a lot of time and money making a drug that will not get you stoned!

solo - 15-8-2008 at 14:42

Quote:

Originally posted by ScienceSquirrel
There are literature procedures for the preparation of amphetamine from phenylalanine.
But reduction of the naturally occuring optical isomer of phenylalanine yields the inactive isomer of amphetamine.
So you are wasting a lot of time and money making a drug that will not get you stoned!

..................assuming the trial was with the (-) isomer......however the issue is not if active or not, the issue is the chemical reduction of an acid to a hydrocarbon......yes, I've read the studies and know of Rhodiums first time published reduction of carboxylic acids to hydrocarbons, however this is the venue of the thread to reduce the acid via a previously documented method some time ago by both Gatterman and Vogel............solo

ScienceSquirrel - 15-8-2008 at 15:28

Fair enough.

It is good for cold cures though so you can sell it on to the snuffle inhaler people if you can make it economically

jon - 20-8-2008 at 10:20

wait a minute? so your saying d,l isomer won't yeild d,l on reduction? where did this information come from?

Arrhenius - 20-8-2008 at 10:31

Hmm.. I would think this reduction will mix up the stereochemistry, yielding probably zero ee.

[Edited on 20-8-2008 by Arrhenius]

jon - 20-8-2008 at 10:36

i.e. the chiral center remains the same unless it's"umbrellas" like in an sn2 reaction

ScienceSquirrel - 21-8-2008 at 03:02

The naturally occuring isomer of phenylalanine is L-phenylalanine and if you buy phenylalanine from a health food shop this is the one that you will get.
D- phenylalanine is available from chemical supply houses at a price.

When you reduce the carboxylic acid group to form amphetamine there is no change in the optical centre so the natural and cheap isomer gives the relatively inactive L isomer of amphetamine.

nightshade - 21-8-2008 at 09:31

So Solo you reduced the phenylalanine to what using I/RP?
Just kind of wondering someone called Krz said he did it years ago at the hive,but later someone said that he just made stuff up then krz went away just like the stories he told.Right now at wetdreams they are posts that it will but I have never heard of any sucess doing direct reduction of phenylalanine.

nightshade - 26-10-2008 at 11:18

Hello, what do you get when you reduce phenylalanine using I/RP?What I am really wondering is if can be done at all?

solo - 26-10-2008 at 12:43

Quote:

Originally posted by nightshade
So Solo you reduced the phenylalanine to what using I/RP?
sucess doing direct reduction of phenylalanine.

........can you point out to me where I made such claim?....as for the carboxylic acid being reduced to the alkane ....had you read the whole thread you would have known who made the claim.....however the alcohol of phenylalanine, phenylalaninol, has been reduced to the alkane .....that claim I've made .......next!......solo

jon - 31-10-2008 at 21:20

on the subject of the kolbe reaction it don't work here, you get dimers because the intermediates are stabilized by the lone pair on the nitrogen.
i'm retarded, but i know that much.
just so you don't waste time with that avenue.