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2bob
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sorry, I must have hit the post button too early (and for some reason I cannot submit after 'editing'). The procedure that I wished to avert to is
here:
http://www.erowid.org/archive/rhodium/chemistry/electro-amph...
this is a weird, electrochemical methylation/reduction of phenylalanine to methyl phenethylamine. I am unsure if this sucker works, but I intend to
try it during the xmas break from uni.
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dr. nick
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very interesting indeed, even if i'd be more interested in simple Phenylisopropylamin - but in the end it doesn't matter, it's just for the
fascinating thing what all can be done from phenylalanine (or other amino acids).
The problem is i do not have any practical access to this kind of procedure -
can anyone provide some practical-how-to on experiments like this?
(Something like "Elektrolysis for Beginners" or even better "for Dummies"? 
Or where to find something like that?
[Edited on 18-9-2006 by dr. nick]
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solo
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Reference Information
Synthetic Organic Electrochemistry
Albert J. Fry
John Wiley & Sons, New York, 1989, 339 pp., $55.00
The reviewed book is a textbook of electrochemistry for organic synthetic chemists. It will interest beginners and please the advanced. In ten
chapters the author convinces the reader that electrochemistry has become an important and prospective tool of organic synthesis. The first three
chapters are devoted to an introduction of basic terms, electrochemical principles and techniques used in the study of electrochemical reactions
(cyclic voltam- metry, polarography, coulometry and preparative electrolysis). Of great value is the fourth chapter, dealing with methods that can
be used to influence organic electrode reactions (the effect of potential, electrode material, and surface interception of inter- mediates generated
on electrodes). Cathodic reduction of organic substrates (reductive cleavage of single bonds, reduction of multiple bonds and conjugated systems)
are the subject of Chapters 5, 6 and 7. Ox- idation processes, particularly the oxidation of carboxylic acids and aromatic compounds, are treated in
Chapter 8. Of special synthetic interest is the so-called indirect electrolysis which allows per- formance of electrochemical reactions at
potentials where the studied compound is elec- troinactive. Both the basic types of indirect electrolysis-electrocatalysis and redox re- actions
with electochemically generated reagents (mediators) are dealt with in Chapter 9. Experimental conditions for preparative electrolysis (power
sources, electrochemical cells, electrodes and their material, reference electrodes, solvents, and electrolytes ) are discussed in Chapter 10. From
an immense amount of material the author has selected many instructive, synthetically important and prospective reactions that can be performed on
electrodes. These are not only redox transformations of functional groups but also reactions of electrochemically generated intermediates leading
to new carbon skeletons. The concise, clear, and to-the-point content of the individual chapters-discussion of mechanism of electrode reactions and
comparison of their advantages over the classical ones, together with representative and recent references-make the book not only a textbook of
electroorganic synthesis, but also a useful handbook for synthetic chemists looking for applications of non-traditional procedures in organic
synthesis.
[Edited on 18-9-2006 by solo]
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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dr. nick
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thank you!
**
eek - just found out it's 199$ now ...
[Edited on 18-9-2006 by dr. nick]
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solo
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Well give some of this books a try ......solo
-----------------------------------------------------------------------
-------------------------------------------------------------------
Analytical Electrochemistry 2nd Edition
http://rapidshare.de/files/1550194/Analytical.Electrochemist...
Handbook of Solid State Electrochemistry
The Handbook of Solid State Electrochemistry is a one-stop resource treating the two main areas of solid state electrochemistry: electrochemical
properties of solids such as oxides, halides, and cation conductors; and electrochemical kinetics and mechanisms of reactions occurring on solid
electrolytes, including gas-phase electrocatalysis. The fundamentals are presented, including structural and defect chemistry, diffusion and transport
in solids, conductivity and electrochemical reaction,
http://rapidshare.de/files/14269133/HandbookofSolidStateElec...
Techniques and Mechanisms in Electrochemistry
This book reveals electrochemistry as an integral part of modern physical chemistry, in particular as a branch of surface chemistry. It is written
without excessive mathematical complexity, and with an emphasis on the mechanisms of electrochemical reactions and how they may be explored using
modern techniques. Written primarily for mid to advanced level undergraduates and postgraduates of chemistry, the book is also intended for
electrochemists working in any of the vast range of industries exploiting electrochemical technology.
http://rapidshare.de/files/14268703/TechniquesandMechanisms_...
Electrochemical Activation of Catalysis: Promotion, Electrochemical Promotion, and Metal-Support Interactions
This book describes the phenomenology, theory and potential applications of the phenomenon of electrochemical promotion, where electrochemically
induced ion spillover activates and controls heterogeneous catalysis. The origin of electrochemical promotion is discussed in light of a plethora of
surface spectroscopic and electrochemical techniques. Electrochemical and classical promotion are compared, their common rules are identified and
promotional kinetics are rigorously modeled and compared with experiment.
http://rapidshare.de/files/16998467/CGVayenas.rar.html
Password: www.AvaxHome.ru
Electrochemistry in Nonaqueous Solutions
http://rapidshare.de/files/1017981/Electrochemistry_in_Nonaq...
Electrocrystallization: Fundamentals of Nucleation and Growth
The book is an up-to-date introduction to the fundamentals of the initial stages of Electrocrystallization, which are dominated by nucleation and
growth of the first clusters of the new phase. It offers a readable exposition of the topic, in simple terms, providing a detailed theoretical
description of the phenomena involved. The most relevant aspects of the experimental studies of electrochemical nucleation and growth are considered,
as well, including some important methods for acquiring and analyzing experimental results. Having specific properties quite different from those of
bulk materials, these small, nano-clusters have always attracted considerable attention, and many sophisticated methods have been developed for
cluster studies. In spite of this, information on small clusters can still be obtained by simple experiments, and the book shows that
Electrocrystallization is unique in this respect. In this special case the phase change may be controlled experimentally by controlling the voltage
and current, two simple and easily measurable electrical quantities. Certainly, this is what makes electrochemical systems an attractive object of
study both from a scientific and from a practical point of view.
http://rapidshare.de/files/17117419/AMilchev.rar.html
Password: www.AvaxHome.ru
Modern Electrochemistry vol 02 John Bockris
http://rapidshare.de/files/3262784/electrochemistry_2.djvu.h...
Modern Electrochemistry vol 01 by John Bockris
http://rapidshare.de/files/3096358/electrochemistry_1.djvu.h...
Organic Electrochemistry
Edited by H. Lund and O. Hammerich
4th ed. 2001
1406 pp. 13.4 MB OCR’d .djvu
http://rapidshare.de/files/6171574/Organic_Electrochemistry_...
Wiley.Electroceramics..Materials_.Properties_.Applications
http://rapidshare.de/files/2580694/0471497487.Wiley.Electroc...
again from our friends at http://radioativo.wordpress.com/2006/07/08/electrochemistry-...
-
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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dr. nick
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Btw, before i forget - thank you very much for all those eBooks!
I guess i will have to get the mentioned "Synthetic Organic Electrochemistry" from somewhere - maybe anyone has it ... ?
I'm still completely confused even on the commencements of this technologie - what solvent to use, what tension, which kind of electrodes in a case
like electrolysis of Amino acids or Phenetylamines (or any other), and so on and so on - and that book sounded like it would serve my needs ...
I mean, just dissolving phenylalanine/2-phenethylamine in some water or what it needs to dissolve it, adding a batteriepole on each side of the vessel
with some stamping as electrodes ... i don't think that would work. Or ... ?
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Nicodem
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The radical formed by the phenylalanine anodic oxidation is way too unlikely to couple with anything due to the adjacent amino group. There are too
many options for the rearrangement of the radical (H abstraction from either the -NH2 or the neighboring benzylic positions, leading to much more
stable radicals and oxidation products). In short, the anodic oxidation of phenylalaninates with acetates would result in phenylalanine oxidation to
crap. However, the phthalimido protection of the amino group would actually stabilize the radical, perhaps allowing the coupling with the Me°
radicals originating from the anodic oxidation of the acetate anions. Nevertheless, the chances of success are almost negligible.
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solo
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Principles of Electrochemistry
Jiri Koryta, Jiri Dvorak, Ladislav Kavan
Book Description:
This comprehensive book describes modern electrochemistry, from fundamental principles to the methods that can be used to study electrode and
electrochemical processes, and finally, at the wide-ranging applications in sensors, industry, corrosion, and bioelectrochemistry. The breadth of
coverage ensures that this volume will be valuable not only to undergraduate and graduate students, but also to research workers
http://rapidshare.de/files/14840652/Principles_of_Electroche...
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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dr. nick
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Thanks!
That will help. i guess!
Ok, as far as i got it, Electrolysis of Phenylalanine will lead nowhere -
how about 2-PEA? I believe to remember very vaguely there was a thread
on Electrolysis of 2-PEA somewhere sometime, but can't find it anymore ...
Was it just a dream? A dream of a dream? hm ...
don't get me wrong, i don't have a special interest in the substances that may be suspected - it' just the only thing i ever heard of - i'd give
almost an arm or so for any results
btw.: thanks again, the book seems to be what i need.
[Edited on 22-9-2006 by dr. nick]
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not_important
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Nicodem, whose name I seemed to be determined to mispell, is right. You need to switch from the electron-releasing NH2 to something
elctron-withdrawing to have much luck. I may be misremembering, but I believe that plain phenylacetic acid can be coupled with itself to give 1,4
phenyl-butane and cross couplings can be done on it too.
PEA is a simple amine, don't think much interesting will happen with it.
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dr. nick
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Ah, i see.
Seems i got to get into Theory more first - hope i will find something interesting do do with it. Meanwhile i found something worthwhile (i hope) with
Pepsinolysis, but that got nothing to do with neither Phenylalanindecarbxoylation nor with Elektrolysis. If it has any results i could open a new
thread, maybe.
Thanks!
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Nicodem
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| Quote: | Originally posted by dr. nick
Ok, as far as i got it, Electrolysis of Phenylalanine will lead nowhere - |
I did not say that it is impossible to obtain the wanted product by such electrolytic means. I said that phenylalanine should be protected by the
phthalimido group first and then perhaps there would be some chance of success. (A very little chance in my opinion, but
nevertheless more than zero.)
| Quote: | how about 2-PEA? I believe to remember very vaguely there was a thread
on Electrolysis of 2-PEA somewhere sometime, but can't find it anymore ...
|
What about beta-phenylethylamine (I assume you mean this by "2-PEA")? This compound has no carboxylic groups so it can not be anodicaly oxidized to
the appropriate radical that can only form by the decarboxylation of the originally formed unstable -COO° radical:
R-COO(-) =={-e(-)}==> R-COO° =={-CO2}==> R°
2R° ==> R-R
So I don't know how beta-phenylethylamine fits into the context of this reaction?
| Quote: | Originally posted by not_important
I may be misremembering, but I believe that plain phenylacetic acid can be coupled with itself to give 1,4 phenyl-butane and cross couplings can be
done on it too. |
You probably meant 1,2-diphenylethane, since that would be the product of the anodic oxidation of the phenylacetate anions. I think such product would
form easily given that the intermediate benzylic radicals are very stabile. That is also one of the concerns on why N-phthalimido-phenylalanine salts
would not work well in the anodic oxidation. The formed radical could well rearrange to form the more stabile benzylic radical thus yielding
2,3-diphenyl-1,4-diaminobutane (with 2-phenyl-1-aminopropane in the presence of acetates) after the phthalimido deprotection. (But one could easily
answer this by checking the tables of radicals stability.)
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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dr. nick
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here probably my cluelessness will show up highly visible, but:
Did i get it right?
Elektrolysis is only of value with compounds that are able to be decarboxylated?
Or is this just the case with Phenylalanine in want of a special product?
Uff, turns out to be even more complicated than i expected it to be
ps.: yes beta-phenethylamin was meant by 2-pea, sorry if that was a completely daft idea. thought i read about it, but i probably mixed up something
...
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Nicodem
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| Quote: | Originally posted by dr. nick
Did i get it right?
Elektrolysis is only of value with compounds that are able to be decarboxylated? |
Aren't we talking about anodic coupling of the carboxylate anions? Several posts above, 2bob posted a link to a pretty unfounded idea of a mixed
couplings of the radicals formed by the anodic oxidation of acetate and phenylalaninate salts mixture.
So all my replies were done in this context and you probably misunderstood with some other topic. Perhaps with the thread title reaction, the thermal
decarboxylation of phenylalanine to beta-phenylethylamine?
Obviously, electrolytic reactions involve way more than just this single one. Besides oxidations and radical reactions like this one, there are also
many cathodic reductions that can be done. The organic electrochemistry is full of useful reactions, it is just that the field is little researched
and not really popular. Its best years were at the beginning of the 20th century. Consequently, all those books that Solo posted are useless since
they don't talk about preparative organic electrochemistry but only about the physical chemistry behind the phenomenon of electrochemistry (not really
interesting to an organic chemists unless you like mathematics).
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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dr. nick
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oh, oops ...
my fault, but nevertheless somehow enlightening to me, too!
no, the thermal decarbox of of phenetylamine is already done,
i'm just fascinated what else can be done with amino acids and
electro chemistry looked especially interesting as it might be less
complicated from viewpoint of needed equipment. But now as i read
more it also seems to be even more complicated in planing than
standard reactions ....
Thanks!
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not_important
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| Quote: | Originally posted by Nicodem
| Quote: | Originally posted by not_important
I may be misremembering, but I believe that plain phenylacetic acid can be coupled with itself to give 1,4 phenyl-butane and cross couplings can be
done on it too. |
You probably meant 1,2-diphenylethane, since that would be the product of the anodic oxidation of the phenylacetate anions |
Yes I did mean that. I plead the presence of a rather presistent distraction that resulted in elongating chains. But the basic idea was right,
alpha-amino acids generally fall down in the Kolbe reaction.
The stability of the benzylic radical isn't critical, ordinary alphatic carboxylic acids work OK in the reaction. The easy of oxidation to and
stability of the benzylic carbenium ion is important foe the amount and nature of side products. Alphatics tend to grab a H or OH, forming the monomer
hydrocarbon (vs dimer when another R. radical reacts) or alcohol, although other stuff is formed to. Phenylacetic gives noticable amounts of the
benzyl alcohol ester of phenylactetic acid and if the solvent contains an alcohol more of the mixed benzyl ether.
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Nicodem
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Well, I finally took some time to (superficially) read the abstracts provided in that old Rhodium's page. What it says useful in regard of this
particular transformation on phenylalanine is:
1.) the reaction does not work with alpha-amino acids (so it does not work on phenylalanine);
2.) the N-acyl protection on alpha-amino acids leads to the formation of N-methoxymethylamides (so a normal acyl protection on phenylalanine would not
work);
3.) the coupling of 3-phenylpropanoic acid works (so the concerns I had about the rearrangement of the intermediate radical to form a more stable
benzylic one is obsolete);
4.) if the radical is too stabile it will get oxidized further on to the carbocation before the coupling can occur (I don't know how powerful the
alpha-phthalimido group is in stabilizing the radical);
5.) there are no reports on the use of the phthalimido protected alpha-amino acids (so there still are some chances that it might work on phthalimido
protected phenylalanine).
Obviously, we already figured out about the point (1), and since I suspected about (2), I recommended the phthalimido protection instead of the
standard N-acetyl. The radical stabilization trough rearrangement is now also out of my concern due to (3). About (4) we could still check the
literature (but this won't be me since I'm not that interested). So (5) remains the only consolation to those that want to try such a reaction.
| Quote: | Originally posted by dr. nick
electro chemistry looked especially interesting as it might be less complicated from viewpoint of needed equipment. But now as i read more it also
seems to be even more complicated in planing than standard reactions .... |
I don't see what is so difficult about such a reaction. In its practical aspect it is way simpler than most organic reactions and requires only the
substrate, sodium acetate, acetic acid and methanol for the solvent. The only practical problem is in obtaining a platinum electrode.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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dr. nick
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| Quote: | | I don't see what is so difficult about such a reaction. In its practical aspect it is way simpler than most organic reactions and requires only the
substrate, sodium acetate, acetic acid and methanol for the solvent. The only practical problem is in obtaining a platinum electrode.
|
arr ... the whole discussion goes way above my head
Lost the thread somewhere and found myself lost in the wood, so to say ("Isn't it good to be lost in the wood? ..." Well, maybe, sometimes).
If it isn't too much work would you be so kind to describe the practical breadbord to me? And the Result? Either with Phenylalanine, Alanine (both L-)
or 2-PEA?
I'd even buy an Platinum Electrode, just to find out if it got at least something right.
[Edited on 23-9-2006 by dr. nick]
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