Punk
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PPA->4-MAR
Can freebase phenypropanolamine oil be directly transformed into the carbamyl intermediate via sodium cyanate or does it require the hydrochloride
salt of ppa?
If not why?
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solo
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I never thought it made a difference...........but then the synthesis has not been on my table...however if you read the classic synthesis by bandil
it may clear the answer..and also the rhodium archive article............solo
https://synthetikal.com/Rhodiums_pdfs/chemistry/eleusis/amin...
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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roamingnome
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Prepartion of isocyanic acid gas
www.znaturforsch.com/ab/v57b/s57b0019.pdf
considering that this is the "active" species that forms
N-carbomylation...
hope to bubble this through a cyanate salt mixture with the ppahcl at a pH of 8.5 is best.... i think this is best way to insure the urea...
theres a another pdf worth reading about N-carbomylation of amino acids but that is not on me...
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jon
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cyanic acid isn't very stable it decomposes to ammonia and CO2 in water that's why the salt is added to the hydrochloride salt. also you have to get
stoichiometry right in the reaction not use any more than a %10 excess of cyanate that's another reason the cyanate salt is used it only generates an
equimolar amount of HOCN. using a molar excess and you get what's called a biuret reaction the cyanic acid will add to the urea thusly produced. If I
could draw it for you it would be easier to understand.
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roamingnome
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well its looks like somebody needs to read about chemical
equalibirum phenomena... it can get messy so i wouldnt expect everybody to just "get it"
cyanate breaks down itself too.. its very pH dependent
the pH of this reaction is cruicial....
you can begin getting schooled here... ironicaly of course!
http://www.dea.gov/programs/forensicsci/microgram/journal_v3...
im still looking for another pdf which i will post..
what i propose is ppahcl in 70% IPA and just bubble in the "active" species. work up would be cleaner and easier no salts to worry about in the
reaction mix...
... oh well...
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roamingnome
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http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleFo...
ok, chasing some links at the bottom you can find the .pdf
A pH-dependent cyanate reactivity model: application to preparative N-carbamoylation of amino acids.
i recomend printing them out while you can... and no i cant solve these equations with my noodle either....
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jon
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you suggest bubbling cyanic acid into the hydrochloride if you look at the reaction the lone pair on the nitrogen reacts with isocyanic acid by
donating electrons to the positively charged carbon so how are you going to have a lone pair availailable if it's protonated?
I'm sure cyanic acid will react with the base itself and yes the decomposition of cyanic acid is ph dependent it will decompose more rapidly in acidic
enviroments.
the only problem you'll have is stoichiometry look up biruret reaction you'll see what I mean. just envision cyanic acid adding to that ureide over
and over again that's a biuret reaction.
and salts are not tedious to sepreate the end product comes out as a solid when solution is basified the salts remain in solution no problem.
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roamingnome
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From what i can see quickly, biuret and polymer like compounds should be avoided in any reaction path...
www.jbc.org/cgi/reprint/242/7/1579.pdf
still digesting this material.... but acidic ph's increase this rate..
the optimium pH should be around the amino groups pka value. i thought a pH of 8 is were it is for ppa
Watch out for O terminus carbomylation from the above article..??? whats this about
Nothing could be cleaner then reacting optically pure ppa with a mass equivalent of HCNO in the proper solvent and temp.
The question that comes up is, solubilities of ppa before and after n-carbomylation?
We would want the intermediate to "stay put" in any reaction path and not polymerize or whatever...
Not trying to make the wheel more round here, but hcno is the species that is attacked by the N terminus.
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roamingnome
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jon thanks for discussing this with me....
from that one article i did learn...
The reaction of cyanate with urea to form biuret was studied
as a model system to show the possibility of linear carbamylation
of an N-carbamyl peptide to form an N-carbamocarbamyl peptide.
The rate of this reaction would be expected to increase
by a factor of 10 for each unit fall in pH.
NHzCONHR + HNCO + NHzCONHCONHR
Urea (50 mg) was dissolved in 5 ml of water, and 5 ml of 2 M
sodium cyanate were added. A portion (0.2 ml) of the reaction
mixture was added to 1 ml of 1 N hydrochloric acid and the urea
content was determined on the amino acid analyzer with a column
(150 x 0.9 cm) of IR-120 operated at 50” with 0.2 M sodium
citrate, pH 3.25, as eluent.
******
When the cyanate was destroyed by acidification, a 10% decrease in the
recovery of urea was noted. On the other hand, no carbamylation
of urea could be detected when urea was maintained at pH 6
in 1 M sodium cyanate at 30” for 1 hour. At lower pH values,
with the concentration of cyanic acid increasing lo-fold per pH
unit, the conversion of urea to biuret (or of N-carbamyl peptide
to N-carbamocarbamyl peptide) can be substantial.
basically.... when you bees or whoever acidify to cyclize your goods... this means 10% could form a polymer...
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jon
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more likely rapid decomposition would take place of the cyanic acids at a ph below 2 it will decompose almost spontaneously so your cyanic acid method
might just work so long as the ph parmeters are correct during the carbamoylation step the only by-product in this case might be urea which is no
problem.
initiation propagation termination comes to mind (polymer chem) but I have no idea what you mean with o-terminus sounds like some peptide chemistry to
me.
why reinvent the wheel?
[Edited on 5-10-2006 by jon]
[Edited on 5-10-2006 by jon]
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haribo
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Aminorex has been produced in 78% yield in 1 pot using 1 phenyl ethanolamine hydrochloride, HCl,KOCN & NaOH (or other base). Dump the 1
phenylethanolamine hydrochloride into 20x dH2O & add 1.05 molar excess of cyanate. Reflux for 2 hours. The intermediate urea forms a seperate
layer if you let it cool, but don't bother. Add 3x molar excess of HCl & reflux for another 2 hours. Let it cool, base & place into a freezer.
vaccuum filter solid product. Wash with hot water & dry. You now have almost pure product.
You need to use the hydrochloride to balance the pH because KOH is formed. In the second step, ammonia is lost and the HCl, as well as catalysing the
reaction, forms ammonium chloride.
The whole thing was much more fully written up by 64Bandil. The post isn't about, but he is. He made the para-fluoro analog which Poos article on the
series posted as the most anoretic. In fact, it's a weaker stimulant (same as pare-fluoro amphetamine). One considers this a valuable starting point
for making substituted analogs.3,4 methylenedioxy anyone? How about 2,5 dimethoxy 4 (your choice). The amino alcohol can be made from the benzaldehyde
using nitromethane. If you ensure that the conditions don't dehydrate it from a nitroalcohol to a nitrostyrene, you can reduce that nitro and voila, a
whole new series.
At this point I would point out the commercial product 'Vasoxine' aka methoxamine which is 2,5 dimethoxy phenyl propanol amine hydrochloride. Your
entry to the substituted 4-MAR series....
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Sandmeyer
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| Quote: | | Originally posted by hariboAt this point I would point out the commercial product 'Vasoxine' aka methoxamine which is 2,5 dimethoxy phenyl
propanol amine hydrochloride. Your entry to the substituted 4-MAR series.... |
Socially accepted dope dealers sell 1 mL ampouls containing 20 mg of the stuff. I meen it can be had in bulk from the same place they buy it, but in
that case make something interesting - like 2C-H... 
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haribo
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Cyanate vasoxine & add something funky to the 4 position of the phenyl ring. You now have something legal since although its structure is like
4-MAR, it's action is totally different. Just how great an even longer lasting DOB is remains to be seen. I would try for the 4 nitro. Russians made
DON in 4mg windowpanes and it sold a treat here in the UK.
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Richy
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Is there a viable means to lengthen the chain on phenylethanolamine to phenylpropanolamine, so the end product is methylaminorex? or would it be wiser
to methylate aminorex to 4mar?
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haribo
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Plain aminorex is 4 x stronger so I wouldn't bother.
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