Punk
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Why does ppa require hcl boil before a reaction?
This has been tested on pure lab grade phenypropanolamine hydrochloride AND ppa extracted from the animal prescription PROIN.
The isomers of these salts are not known.
When these ppa sources are used directly in the HI/RP reduction to amph AND the cyanate rought to 4mar only the amide is formed meaning the proper
smells and sights are there but nothing will precipitate in the end BUT when either of these ppa sources are boiled in 32% hydrochloric acid for
4-8hours, washed with acetone then used in one of the above reactions 30-40% yeild of the desired compound is obtained WHY?
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enhzflep
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It may simply be a matter of the reaction needs quite a push to proceed in the direction required. The other alternative that I can think of is that
the boiling supplies the required activation energy..
Never had anything to do with reactions of that nature, so as will be obvious to many - I'm only speculating...
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pelnicki
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I've never heard of anything like this before.
I'd swear that from the experiences of others I've read about, no such boil was neccessary, and would probably result in partial coversion of PPA
-> P2P (as per Rhodium's ephedrines and phenylpropanolamines -> P2P reaction involving boiling in sulfuric acid. HCl isn't strong enough to
cause much of this conversion, but I have read that even the HI reflux during an HI/RP reaction causes a partial breakdown of the PPA into P2P, which
reacts into further byproducts and being responsible for the "veritable zoo of byproducts from sidereactions" that HI/RP is known for.
However, what you write of disturbs me, as it sounds like you know what you're doing and would have been unlikely to make some schoolboy error.
I wish someone else had replied to this thread. Please keep us updated if you figure out what's going on for your particular experiment conditions.
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Organikum
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Boiling in conc. HCl forms a mixture of norephedrine and norpseudoephedrine. This shouldn´t affect yields in a reduction by means of HI and should
reduce yields of the oxazilone to the named 30% from the expected 60%+.
How do you know for sure you got the amide?
I want to add that here on this board we don´t like the use of these bad reputed shortcuts like "amph" and RP for we don´t want to become a place
for "cooks". Kindly word your questions a little bit more chemical if you expect an answer in future or if you don´t like this, go to WD
(wetdreams.ws).
/ORG
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pelnicki
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Thanks, Org! Good call and what an exceptional resource you always seem to be for such details!
Formation of an amide doesn't sound likely to me.
Re: racemizing as an explanation: the formation of norpseudo- and nor- isomers means the hydroxyl group changes position about the beta carbon (the
one adj. to the phenyl group).
Is it just the hydroxyl group that shifts (whose position doesn't matter as far as activity of the compound is concerned) , or has the entire alkyl
chain been effectively "twisted" about its axis (eg. the -NH2 switches with -CH3 group around the alpha carbon)?
If the racemization results in a mixture of active and inactive (pharmacologically speaking) isomers this would exlain the ~0% to ~50% change in
expected yield.
For this to explain anything, Professor Punk would've had to've begun with the inactive isomers only (ie. only d-norephedrine &
l-norpseudoephedrine).
How likely is this? He says he doesn't know about isomerism of the laboratory grade amine. Let's assume (for argument's sake) that this is inactive.
But what about the PROIN? I always assumed that to be effective at bladder control it would need to be the active isomer. Is this right?
So, anyway, what I was sort of saying is that:
Perhaps: Professor Punk purchased PPA pills for the pooch, from his preferred pet-care professionals, called www.Pretend Pets Prescribed
Precursors.com, a popular chain of veterinarians, or something along these lines.
Either: Canine bladder-control muscles respond well to inactive isomers of PPA, and these are now provided in PROIN prescriptions.
Or: 'Pierre' (Punk's pretend pedigree poodle with prostate problems) positively plagues Punk's parents, producing pissy patches and puddles in
unpredictable places.
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Organikum
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A HCl boil only changes the orientation of the OH group, not the amine. To change the orientation on the alpha position one would have to use heavier
guns aka, sodium metal or high pressure Ni catalyst AFAIK.
That the reduction of the substrate by HI shall have resulted in nada is completely unexplainable to me. The problems with the formation of the
oxazilone by means of cyanates might be explained by stereochemical aspects.
On a second note: The traditional way of oxazilone formation was by urea/acetic acid before the cyanate route was employed. I don´t know if this
method is sensitive to stereochemistry as the cyanate route is. If not, well then....
(Information from the webpage of a supplier of cyanates and it was also mentioned by a very knowledgable bee named Peyote at the HIVE)
/ORG
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pelnicki
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(Slightly offtopic) What's the mechanism/reason behind an HCl boil altering the position of the -OH group?
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Organikum
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It was proposed this is a kinda partial halogenation of the functional group followed by rearrangement. But to tell the truth, I personally believe
that practically all "reaction mechanisms" as written in all these papers are just products of phantasy - a lot of blaba to diguise the fact that
nobody knows whats actually going on in a chemical reaction.
IMHO chemistry is still a empirical science without conclusive theory.
Also AFAIK analysis of reactions with femto-second lasers seems to show that reactions, even the simplest ones proceed through all theoretical
possible variations. Uh! Not so rewarding for mechanism seekers.
IMHO the result of a chemical reaction is statistical not mechanistic.
IMHO this correspondends well with quantum physics.
IMHO the world as we know it is not so stable as we think. I believe that our perception of the world and we ourselves are not so really factive as
we want to believe. It´s more like looking so often at Schrödingers cat that it becomes a movie.
Probably I will get flamed for this.
/ORG
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Punk
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wd=waste of web space
This was a simple question and nobody that replied to it new the answer.
It took about 3 weeks but rhodium replied to my email stating that the starting material is most likely to be +/-norpseudoephedrine hydrochloride and
that only the amine will form.
Boiling in hcl at the optimum time/temp will yeild 50/50 mix of +/-norpseudoephedrine hydrochloride and +/-norephedrine hydrochloride.
Highest yeild so far was 4 grams of amphetamine monophosphate synthesized from 15 grams of +/-norpseudoephedrine boiled in hcl.
Anyone know the proper way to turn freebase 4-mar into a salt? The freebase degrades rather quickly and the usual A/B rout does not seem to be
compatable here.
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Organikum
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| Quote: |
Anyone know the proper way to turn freebase 4-mar into a salt? The freebase degrades rather quickly and the usual A/B rout does not seem to be
compatable here.
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Sure I know it. Actually there are two ways to do this. Search a little bit on the net and might find
them. Or ask Rhodium.
Have a nice and successful day.
/ORG
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Punk
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go away
Already asked rhod and im sure ill get an answer 3 weeks from now and I garentee you will not find a single blog about the 4mar hydrochloride
formation that one would be looking for here or at google or the arcHIVEs.
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Vitus_Verdegast
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You are acting like a moron.
Using one single google search I can find the answer.
Sic transit gloria mundi
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Punk
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you go away to
As the first post in this thread says the (cyanate) method being administered and not the cyanogen bromide rout like your single google search shows
a lot of.
After bandils cyanate rout you end up with 4mar hcl but the only prob is you have to seporate it from the rxn nasties which means adding sodium bicarb
to nutralize the ph and the 4mar freebase crashes out.
These freebase crystals do not disolve in benzene or toluene or xylene.
Ohh wouldnt you know it rhod just emailed suggesting one could add the freebase crystals to a 15% hcl solution and crash out with cold dry acetone.
Ive should have known.
[Edited on 28-7-2006 by Punk]
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Nicodem
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I think this tread should migrate to Detritus!
Posting incomprehensible text, misinformation, emailing with an imaginary friend, seeing problems where there are none, aking questions that were
already answered...
Either it is the usual stimulants induced psychosis or this Punk is just trying to step on everybody's nerves. In both cases it is good enough only
for Detritus.
…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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Organikum
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I second that notion.
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Punk
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Nicodem please explain in detail this "misinformation" you speak of.
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Nicodem
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All claims without providing proof, like claiming the identity of a product without analysis, is considered misinformation by me personally. But that
is the least problematic part of your attitude, that actually by itself would not bother me at all.
…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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Punk
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bandil
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| Quote: | Originally posted by Punk
Ohh wouldnt you know it rhod just emailed suggesting one could add the freebase crystals to a 15% hcl solution and crash out with cold dry acetone.
Ive should have known.
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I doubt Rhodium has stated that the salt of 4-methylaminorex will precipitate that easily, because it will definately not.
The only practical way of forming any salts of 4-methylaminorex, is by dissolving the freebase in 10-20X the volume of toluene or xylene. Then add
equimolar amounts of aq. HCl while stirring. Distill of most of the volatiles, while stirring heavily. This will remove any water present. Adding dry
acetone (its often nessecary to dry commercial acetone to get this to work) and cooling the mixture will yield the desired precipitate.
Kind regards
Bandil
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jon
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the deal with the cyantate route is that the isomer has to be erythro and not threo which means +,- or vise versa supposedly the carbonyl function
causes walden inversion of the hydroxy group in the case of the erthyro isomer in the case of the threo isomer the NH2 group is oriented towards the
OH group so when you react it with HCL you get elimination of NH3 and oxazolidinones in the other case the NH2 group is oriented away and the carbonyl
is closest to the OH and water splits off giving the oxazolidine.
treatment with HCl of the norephedrine will chlorinate the OH group and then hydrolysis will occur in equilibrium this is what gives inversion of the
alpha hydroxy I noticed in the case of ephedrines I got aziridines I don't know about norephedrines though the primary amine isn't as good a
nucleophile.
[Edited on 4-10-2006 by jon]
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transformer
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So is (1r,2r)-(-)-1-phenyl-2-amino-1-propanol (d-norpseudoephedrine) converted to the racemate when it is boiled in hcl ? or would this also
chlorinate the oh group?
Edit, got my answer apparently boiling norephedrine in HCl will produce mixture of norephedrine and norpseudoephedrine.
[Edited on 1-21-2011 by Polverone]
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