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hector2000
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I now mandelamide make L-pac and this is very interesting also has easy route to produce L-pac But you should accept that 1,1 dichloroacetone method
is easier.
Unfortunately just 1,1dichloroacetone methos has low yield and long way for purification
I got red DL-PAC and it need to distil 2 or 3 time for change color
But my yield was ~30%-~40% and this reaction is lachrymatory(before you said it)
after adding 1,1dichloroacetone to benzene lot of heat involve and after reflux color of solution turn to black(i dont know why black!?!)
I did this reaction 2 time but really is simple but problem is purification.
Also maybe i test mandelamide method but i should make mandelamide first
Do you have instruction of reaction between mandelic acid and ammonia for making mandelamide?because i just find below method for making mandelamide
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv3...
[Edited on 9-5-2009 by hector2000]
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Sandmeyer
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Quote: Originally posted by Sauron  | It might help if you bothered to read the thread.
hector2000 wants to make L-PAC and is looking at non-biotech routes.
I could care less about L-PAC but was kicking some idead around.
Organotin alkyls of the tpe nBu3SnR where R is alkyl or aryl, react with oxalyl chloride to produce diketones. The sequential reaction of nBu3SnPh,
and nBu3SnMe, with oxalyl chloride gives PhCOCOMe.
The same diketone is produced by nitrosating propiophenone with MeONO and hydrolyzing w/H2SO4. This is described in Org Syn and the diketone employed
in synthesis of racemic ephedrine..
Hector has a lot to learn abour optical resolution.
But that's not my headache, |
I wanted to compare your oxalyl chloride/organotin proposal to the possibility of starting from mandelic acid since both would depend on a
intermediate having a 2 carbon atoms long alkyl chain. I haven't done any literature searches - it is possible that DL-PAC can be made more
efficiently using entirely different approach from completely OTC chemicals, but that was not my point.
Well, at least it is more OTC than using organotin reagents coupled with oxalyl chloride. 
| Quote: Originally posted by turd |
That sounds much more OTC and amateur friendly. I wonder if one would need less of an MeMgI excess if one reacted the mandelamide beforehand with Na
to obtain the Na-salt? And whether one could use other amides - mandelamide is expensive! |
Ok, I'm away from the litterature, but there are other leaving groups, for instance you can use a secondary amine to make a tertiary amide and treat
that with MeI grignard...
[Edited on 5-11-2009 by Polverone]
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Sandmeyer
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PS. Boric acid (OTC) catalysis can be used to make the amide (tertiary in this case) http://www.orgsyn.org/orgsyn/prep.asp?prep=v81p0262
[Edited on 5-11-2009 by Polverone]
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Nicodem
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You both forget that wherever there is prohibition there is also a black market for the precursors. For example, the moment most of the European
countries banned MDMA, there was immediately established a black market for 3,4-methylenedioxyphenylacetone produced semilegally in some industrial
environments specifically for costumers from Europe. I remember the criminals were able to buy it in Netherlands for an equivalent of a few thousands
dollars which was pretty cheap (IRC, the price I heard of was 10000 DM in the nineties). The main obstacle for the local criminals was to get a
chemist without any ethical concerns to synthesize the target drug.
Now, consider that in the USA the ephedrine containing pills were banned and all those poor meth cooks, who never bothered to learn chemistry, because
too busy stripping match boxes, now desperately look for more (pseudo)ephedrine. For them it does not matter that much if the precursor is racemic.
Still better than studying chemistry in order to use simpler syntheses.
Of course no chemical synthesis of L-PAC can ever be comparable to the economy of the biophermentation where the main cost is the starting materials
and the energy consumed for distillation, while most of the solvent gets recycled. I'm inclined to believe that not even racemic PAC can be made as
cheaply as L-PAC. But mind that L-PAC is immediately consumed to produce the ephedrines and it is also not available trough the chemical sellers, so I
would not be surprised that some criminal organizations desperately look for someone willing to do the custom synthesis of this stuff.
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hector2000
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| Quote: Originally posted by turd |
Yes, that would be crazy, and that's why my first guess was 4-methylaminorex. But now I'm not convinced any more and maybe hector2000 *is* crazy after
all. Seeing how he can get all kind of non-OTC chemicals, I wonder why he doesn't simply use mandelonitrile + MeMgBr or mandelic acid + MeLi or just
buys the stupid PAC. I mean really, this whole thread makes no sense.
[Edited on 9-5-2009 by turd] |
Do you know price of Meli?(very expensive)and sensitive to air.also about MeMgBr
You think this is cheap to make lpac from this method?
Who said i want to build meth?if i want to build meth i will buy ephedrine and make from that!
Please read this topic carefuly
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Sandmeyer
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| Quote: Originally posted by hector2000 |
Do you know price of Meli?(very expensive)and sensitive to air.also about MeMgBr
You think this is cheap to make lpac from this method?
Who said i want to build meth?if i want to build meth i will buy ephedrine and make from that!
Please read this topic carefuly |
If you use MeLi you don't even have to make the amide, it reacts directly with carboxylic acids to give ketones[1], hence it might potentially be a
one-step process, you can make your own MeLi from MeCl[2] (tedious, requires a real lab, but doable and cheap), or from MeI[3] (convenient) lithium
gives good atom economy ~7g/mol. Methyliodide is relatively expensive commercially, but you can recycle the expensive iodine and make your own MeI
from cheap methanol, I've done this in bathroom so it's easy. If you want to make PAC indu$trially then you should stick to the fermentation, of
course. If you're unable to do that and can't accept that a synthesis would be more costly, then find other ways to fill your pockets with money.
[1]: http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0775
[2]: http://www.orgsyn.org/orgsyn/prep.asp?prep=cv7p0346
[3]: http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0859 see note 4
[Edited on 10-5-2009 by Sandmeyer]
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Sauron
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First of all, I am only interested in the chemistry and not at all in making PAC, ephedrine or anything else in that family.
Hector2000 can and has explain his interest in making L-PAC commercially as a supplier to a pharm company in his country.
Unsubstantiated and pointless accusations serve no one.
Thanks, sandmeyer, for the ref to the Grigmard rxn with d-mandelamide. Whether hector understands it or not, or elects to do it, is beyond your
control or mine. He seems to still be focused on a low yield FC prep of racemic PAC which will do him no good at all, his client wants L-PAC.
I do not believe the scale required to produce wty he wants by S.cervisea method is viable for him, and in any case he would need some
microbio;ogists.
As usual hector is kvetching about costs.
Hector:
1. I told you upthread MAKE YOUR OWN MeI from methanol, I2 and little red P catalyst per Org Syn. This is easy and cheap.
Then use that to make your own MeMgI.
2. You need d-mandelic acid. That is dextrorotatory. If you can find it it will be costly. You have an alternative.
dl-Mandelic acid is CHEAP. Buy it and resolve it into its isomers yourself using the d- and l-isomers of ephedrine. I attach na paper describing
this, also from JACS. Same author and volume as Sandmeyer's reference.
Three crystallizations and you will have the pure d-mandelic acid.
It is easy to turn that into d-,amdelamide
And thus obtain the L-PAC you need. NOT DL-PAC.
Do you have a polarimeter? I can assure you your client does. How will you check the optical rotation of your L-PAC and thus calculate its ee?
A good Chinese polarimeter is $300, maybe double that with DHL from Shanghai. I have one. The same instrument is sold by several European companies
for $2000, but they just buy them from same factory I do. Different label same scope.
The DL-PAC route is ONLY to be condered if you have NO method for L-PAC.
Now you have such a method, so forget DL-PAC.
You did say there is lots of ephedrine in Iran so you should be able to obtain the required d-ephedrine as well as l-ephedrine.
So d-,amdelamide will be easy and cheap for you.
Folloe instructions in this paper.
[Edited on 10-5-2009 by Sauron]
Attachment: ja01381a042.pdf (76kB)
This file has been downloaded 816 times
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Sauron
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I see. Well as far as I recall hector has only asked about acetic anhydride, which many of us want, and L-PAC which has been been posted about
profusely by others, notably solo, without any objections from you.
Personally I have ebjoyed participating in this thread, and turned up a number of reactions I find interesting, even if most of them did not turn out
to be productive for hector.
So I reject your criticism, sorry.
Hector, is ephedrine's stereoisomers are unavailable or too dear you can use (+)-phenylethyllamine and (-)-phenylethylamine.
L. Smith, J. Prakt. Chem., 84, 743 (1911); A. W. Ingersoll, S. H. Babcock, and F. B. Burns, J. Am. Chem. Soc., 55, 411 (1933).
For the prep of mandelamide, see attached Org.Syn. paper and also the refs and notes below:
"Mandelamide has been prepared by treating the ethyl ester with concentrated aqueous ammonia,1,2 and a saturated ethanolic solution of ammonia has
been used to effect ammonolysis of the methyl ester.3 Esters of mandelic acid were treated with liquid ammonia at its boiling point;4 this procedure
was improved by use of ammonia at superatmospheric pressures and higher temperatures.5 The procedure described in this synthesis was first used by
Ôeda.6"
--------------------------------------------------------------------------------
References and Notes
1.
Beyer, J, prakt. Chem., (2) 31, 390 (1885).
2.
Einhorn and Feibelmann, Ann., 361, 145 (1908).
3.
McKenzie and Wren, J. Chem. Soc., 93, 311 (1908).
4.
Glattfeld and MacMillan, J. Am. Chem. Soc., 58, 898 (1936).
5.
Kleinberg and Audrieth, J. Org. Chem., 3, 312 (1938).
6.
Ôeda, Bull. Chem. Soc. Japan, 11, 385 (1936).
--------------------------------------------------------------------------------
Attachment: CV3P0536.pdf (129kB)
This file has been downloaded 1240 times
[Edited on 10-5-2009 by Sauron]
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Sauron
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L-PAC is not a controlled substance, and anyway the forum policy is to be unconcerned with law is it not?
I will admit hector is not an especially gratifying student to practice one's pdagogical skills on, but if beins a dim and sluggish student were a
crime then the univerity classrooms would be a lot emptier.
I am satisfied hector is no cook, amd so AFAUK are the mods, at least nicodem. So as long as my patience holds, and it behooves me to advise him I
will do so. I do not see how this possibly concerns you. You need not read this thread, and no one is calling upon you for assistance. You are not the
guardian of polverone's bandwidth, polverone is.
Hector
Here is the resolution of dl-mandelic acid with the two stereoisomers of a-phenylethylamine.
In Kg quantities the (R)-(+) and (S)-(-)-1-phenulethylamines are about 40 US cents a gram (BASF products sold by Acros, 99%).
DL-mandelic acid is VERY CHEAP.
So now you know how to resolve racemic mandelic acid and how to prepare (R)-(+)-mandelamide from that acid and ammonia.
All you need to do is react that with MeMgI which you can make yourself from methanol, iodine, a smmall amount of red phosphorus catalyst; mafnesium
turnings and diethyl ether.
And there is your L-PAC.
Attachment: ja01328a061.pdf (120kB)
This file has been downloaded 1342 times
[Edited on 10-5-2009 by Sauron]
[Edited on 5-11-2009 by Polverone]
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turd
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If MeI is the price determining factor then I'm not convinced this reaction is ideal. I guess quite a lot of it is lost on the alcohol group and on
the acidic amide group. Mandelic acid + 2Li + MeLi seems to be more favourable. Or mandelonitrile + Na + MeMgX, but mandelonitrile is proably harder
to make a diastereomeric derivate of.
If Nicodem is right and the "L-PAC" will sooner or later end up in American pill crusher's flask anyway, the "pharm company" might not care about
enantiomeric purity and the propiophenone process looks like a real winner.
[Edited on 5-11-2009 by Polverone]
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Sauron
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Recommending ;ithiarion to someone who ubtil a week or 10 days ago had never done a Grignard strikes me as odd. Lithiation is a technique intensive
procedure and rather unforgiving of tyros. Do I detect a whiff of disingenuosness in the suggestion?
[Edited on 5-11-2009 by Polverone]
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turd
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Feel free to detect anything you want in my suggestions, but if someone can cook Grignards, he should be able to do simple Li-organyls (we're not
talking about super reactive -78°C stuff here). Indeed, my first metal-organic reaction was with Li (admittedly with the very unreactive PhLi).
Personally I'd prefer to work with MeLi solutions over working with chloro-acetones or oxalylchloride. YMMV.
[Edited on 5-11-2009 by Polverone]
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hector2000
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I want to try mandelamide method but i have question
For making mandelamide we should use (R)-(-)-Mandelic acid(Cas#611-71-2) or (S)-(+)-Mandelic acid(Cas#17199-29-0)?Which one is d-mandelic acid?
Also i found Phenylethylamine but which one is need for my work?R-(+)-1-Phenylethylamine or S-(-)-1-Phenylethylamine?
Unfortunately i have problem with temp -10c for making mandelamide but i will try it with ice and NaCl and NH4No3
Also i can buy pseudoephedrine here(this is very cheaper than Phenylethylamine)
Pseudoephedrine is suitable for resolution mandelic acid?
[Edited on 10-5-2009 by hector2000]
[Edited on 10-5-2009 by hector2000]
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Sauron
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Hector
To make L-PAC you must use d-mandelic acid to make d-mandelamide.
This is by definition (+)-mandelic acid.
You want for resolution of dl-mandelic acid both isomers of 1-phenylethylamine.
That is (S)-(-) and (R)-(+)
Do you completely understand what all that means?
NO psuedoephedrine is NOT suitable replacement.
[Edited on 10-5-2009 by Sauron]
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turd
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| Quote: | | You want for resolution of dl-mandelic acid both isomers of 1-phenylethylamine. |
Why is that? From my limited understanding you need one enantiomer of the amine to turn your racemic acid into two diastereomeric salts, which you
then separate using conventional methods (crystallization, chromatography). Or did you mean you need either isomer?
| Quote: | | I want to try mandelamide method |
If the MeMgI is your limiting reagent you probably should try to make the salt of the alcohol and maybe try a tertiary amide? Otherwise you'll lose at
least an molar equivalent of your MeMgI. (I'm starting to sound like a broken record...)
[Edited on 5-11-2009 by Polverone]
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hector2000
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| Quote: Originally posted by turd |
I don't want to start a discussion on principles, but for me hector is the archetypical cook. Maybe he isn't cooking psychoactives, just precursors,
but AFAICT he's not interested in chemistry, only profits. |
You sure that my love is just Chemistry and learning it.
For the chemistry i lose one of the my hand and my eye(when i was youngger in lab i save life of two student and i lose my hand and eye)
Unfortunately here and in university we dont have good teacher and good equipment and really we dont learn enough about chemistry.
I wish i go to usa or germany for learn chemistry in university but this is very big wish and this is impossible
Ok back to chemistry
Sauron i underestand what you said and i want to try mandelamide method but i have problem with temp -10c.
I think for the reaction between MeMgI and mandelamide we should use N2 gas for better yield.
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DJF90
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Hector: -10C is a simple temperature to achieve. Supposedly NaCl/crushed ice in a ratio of 1:3 (w/w I believe) will get you to -20C, but this is
slightly unrealistic. However -10C should be well in its ability.
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Polverone
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I went away for the weekend and this is the mess that greets me when I return! If you think forum rules have been breached, report the specific posts
and reasons via to a mod or admin via U2U (some have already done this for posts in this thread). If you just want to speculate about someone's
motivations and character, don't do it in public here. It doesn't belong in this thread. Don't contribute to a thread if you don't like the
participants, but don't drag it off topic either.
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turd
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I wonder why you refuse to address my (IMHO valid) points: In the article Sandmeyer posted, they use a fourfold excess of MeI. Seems quite wasteful
for someone who complains about the price of MeI and there surely are better published methods around.
And why the need for *both* enantiomers of phenetylamine in optical resolution - can someone explain that?
[Edited on 5-11-2009 by Polverone]
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turd
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It would be nice if you'd someday explain that resolution thingy and if/why it wouldn't be a good idea to use tertiary amides and first make a salt of
the alcohol with cheap Na. Stirring might prove problematic, but you will end up with a Mg salt anyway.
[Edited on 5-11-2009 by Polverone]
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turd
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Well looks like MeLi on mandelic acid gives low yields.
But you may be interested in regio- and stereo(kindof)selective reduction of PhCOCOMe.
Tetrahedron Letters, 28(50), 6313-16; 1987
Journal of Catalysis, 204(2), 281-291; 2001
Tetrahedron Letters, 29(35), 4485-8; 1988
Journal of Organic Chemistry, 73(17), 6559-6569; 2008
Journal of Molecular Catalysis A: Chemical, 236(1-2), 227-238; 2005
Tetrahedron, 61(8), 2217-2231; 2005
Sorry, if these have been posted before, I can't be bothered to read this "thread".
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Sauron
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Hector
The cost of MeI is of no concern if you simply make your own.
Two methods are detailed in Org.Syn.
Methyl alcohol, Iodine and a little red P catalyst
or
KI and Me2SO4 that is (MeO)2SO2, dimethyl sulfate
Both are easy and cheap
I advise against MeLi and now the one proposing it admits it is low yield.
The proposal of regio- and stereiselective reduction of acetylbenzoyl may have merit, but the devil is in the details. See what catalysts, conditions
and yields are like.
We already know a regioselective reducing agent.
But not also stereoselective.
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DJF90
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Hector: MeI should not be a challenge for you to make so long as you have the starting materials; Sauron has listed two methods. The corresponding
grignard reagent (MeMgI) can also be made fairly easy, and as such should represent no problems. Sauron suggested making your own MeMgI wayyyyyy back
in this thread, but I guess you failed to take note. It is FAR cheaper than buying the commercial stuff!
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Sauron
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Here is the Org.Syn. prep of MeI by two methods.
Others give you citations, I give you PDFs.
Attachment: CV2P0399.pdf (185kB)
This file has been downloaded 1171 times
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Polverone
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I believe I have removed most of the bickering. Please, nobody add more for me to remove.
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