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hector2000
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Thanks Sauron.
I dont access to refrence part because admin dont allow to me(yet)
You say right.ishould read more about Grignard reagents and i am donig it.
I am lucky because i found Methylmagnesiumchloride(20% solution in tetrahydrofuran) but this is very expensive.
You say true and i was wrong because PhMgCl will not produce PAC(excuse me).
Now i think everything is ready for reaction but maybe i cant provide N2 and just i will react methylmagnesiumchloride with tributyltin chloride.
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Sauron
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The forum library is not ib References and is not password protected.
Http://www.sciencemadness.org/library
You will want PRACTICAL ORGANIC CHEMISTRY by Arthur Vogel
Anything by Ludwig Gattermann
Amything by David Shirley
Anything by J.Cohen
Commercial Grignards are expensive, make your own, read the Brauer except I posted carefully
Here is a better descripttion of the prep of ethylmagnesiumbromide and from it, tetraethyltin. This from Organic Syntheses.
It states that same yields cab be had for tetra-n-propyltin and tetra-n-butyltin. Just use molar equivalents of n-butyl bromide in the Grignard step.
Ethyl bromide is C2H5Br
n-Butyl bromide is C4H9Br
Adjust accordingly
[Edited on 2-5-2009 by Sauron]
Attachment: CV4P0881.pdf (131kB)
This file has been downloaded 878 times
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hector2000
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Thanks Sauron,
I download this books and i am reading that.
also i buy Methylmagnesiumchloride(20% solution in tetrahydrofuran) and Tributyltin chloride and did reaction today.
I mix one mole Methylmagnesiumchloride and one mole Tributyltin chloride together(in dry ET2O)slowly.
i didnt use N2 gas(because i dont have it)
Now i should distil it?
Also i did reaction between oxalyl chloride and benzene in FC and i made Ph-(CO)-(CO)-Cl (GC-Ms Show yield 36%)
Now iam ready for reaction between MeSnBu3 and Ph-(CO)-(CO)-Cl (if really MeSnBu3 made successfully)
[Edited on 2-5-2009 by hector2000]
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Sauron
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I posted reaction of tributyltin chloride and a Grignsrd reagent upthread, from Org Syn.
Follow workup instrucyions in that.
MeMgCl like all Grignards is air and moisture sensitive, and should be transferred by syringe or a transfer kine, If you just opened the bottle and
poured it in you very likely lost some in the process.
I tols you study now, bench work later but you are in a hurry to throw chemicals together.
Well, good luck.
I hope you at least used a fume hood. Oxalyl chloride is very irritating, and releases carbon monoxide when it reacts. nBu3Sn Cl STINKS. Amd is toxic
like most metal alkyls. Protect yourself.
36% seems low for that Friedel Crafts, you can do better.
[Edited on 2-5-2009 by Sauron]
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DJF90
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Hector: Did you make sure you used ANHYDROUS AlCl3 for the FC reaction? Also, if you cant use an inert atmosphere for the grignard at least use dried
glassware and drying tubes to prevent ingress of moisture.
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Sauron
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On page 4 of this thread I posted a file CV90707
That is Org.Syn/ Collective Volume 9 page 707 and after.
It describes reaction of nBu3SnCl with an allyl Grignard reagent and the method of working up.
By working up we mean decomposing the complex of the two reactants to release the desired product and the byproduct (magnesium salts)
This is usually done with water first (distilled water) and then with a dile soln of HCl usually 5-10%
Two laters will form, an ether layer containing the product and an aqueous layer containing the salts
Separate the layers in a sep.funnel, dry the ether layer, strip the ether, and distill under vacuum.
For details see CV90707
USE FUME HOOD
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DJF90
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Another idea for chemical synthesis comes from along the same lines as one of Sauron's sugestions.
> React propionyl chloride with benzene in the F-C reaction (anhydrous AlCl3 as catalyst).
> The resulting compound should be oxidised to a 1,2 dicarbonyl using SeO2 (I dont think the aryl substituent on the first carbonyl alters this
reaction but I may be wrong)
>Reduce the phenyl ketone to hydroxyl with NaBH4. This ketone should be reduced in preference due to the electron withdrawing effect of the phenyl
group hence increasing the electrophilicity of this carbonyl.
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Sauron
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Product of F-C is
Ph-CO-CH2-Me
That's propiophenone, he can buy it cheap!
Target is
Ph-CHOH-CO-Me
Little or no advantage to starting with 2-chloropropionyl chloride, as far as I can see
And less advantageous that oxalyl chloride in FC followed by MeSnnBu3, or pyruvoyl chloride in the FC, or stepwise reaction of oxalyl chloride with
PhSnnBu3 and MeSnnBu3.
All of which give
Ph-CO-CO-Me
which needs only reduction at the benzylic (C1) carbonyl.
[Edited on 3-5-2009 by Sauron]
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hector2000
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I used dry glassware and dry AlCl3.
I think some Memgcl decompose in air(i used electronic Pipet but i didnt use N2)
Yes i used fume hood and mask.
But i think fc reaction has low yield
I search and didnt find Seo2.
MeMgBr will decompose i air like MeMgCl?
I used below ratio and same reaction for making Ph-(Co)-(Co)-Cl
http://www.erowid.org/archive/rhodium/chemistry/phenylaceton...
But i used more oxalyl chloride
unfortunately GC-Ms dont show MeSnBu3 and i should myself analyze result.
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DJF90
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FC acylation is fairly HIGH yielding. There is a difference between DRY and ANHYDROUS AlCl3 hector... The amount of MeMgBr to decompose through
atmospheric reaction should be fairly small unless the air has a high percentage of water vapour. Is your benzene anhydrous? I suspect that there was
some source of water somewhere that killed off your acyl chloride.
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hector2000
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Yes.all of my chemical is lab grade and without water(all of them are old merck product)
I did again FC reaction(yield was ~40).
Yield is not important problem.
seprate Ph-(Co)-(Co)-Cl from solution is problem because solution color is black and dirty and when i distil by vacum i have gummy tar in my flask.
May be water in air(moisture) make problem
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DJF90
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Sounds like you might have had some polymerisation...
For workup of FC of oxalyl chloride and benzene, first add enough 2M NaOH to hydrolyse the acid chloride and form the sodium carboxylate. Transfer the
liquid portion of the flask into a sep. funnel and you should have two layers. I assume you used benzene as the solvent in the reaction and this will
be the dark coloured layer (polymerisation products) ABOVE the aqueous layer that contains your carboxylate salt. The aqueous layer is run out of the
funnel into a beaker or conical flask where it can be acidified with 2M HCl and your product will either precipitate out, then you can filter, dry and
recrystallise
OR
You will need to add an organic solvent like ether to dissolve it from the aqueous layer, use the sep. funnel, this time keeping the TOP (ethereal)
layer, and then evapotate off the ether on a waterbath or a rotovap to leave phenylglyoxylic acid, PhC(O)COOH.
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panziandi
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Lab grade reagents are rarely anhydrous. You should always dry any reagent grades, especially older solvents in partially filled bottles.
Did you use a moisture trap? You should always use a guard tube filled with CaCl2 or NaOH pellets when doing a Grignard reaction etc if you are not
using a N2 or Ar atmosphere.
There shouldn't be any alkylations (that would be a low yielding side reaction) and multiple acylations are extremely unlikely since acylations
typically give monoacylated products. Trouble with oxalyl chloride is that the product is a acyl chloride so that could acylate another benzene.
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Sauron
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Hector, what solvent did you use in the FC acylation of benzene with (COCl)2? The solvent of choice is CS2
An excess of oxalyl chloride is required to prevent formation of Ph-CO-CO-Ph
Oxalyl chloride is a diacid chloride
Venzene can react at both ends. The excess should be 1.5-3X which makes for added cost
CS2 is a fire hazard, be careful.
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hector2000
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I didnt use solvent.
I used 85 cc Oxalyl chloride(1 mole) and 89cc Benzene(1 mol)
I did reaction like below reaction:
http://www.erowid.org/archive/rhodium/chemistry/phenylaceton...
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Sauron
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Hector, I told you to use CS2 zolvent,
That Rhodium page is about making P2P for methamphetamine cooking.
The reaction is an alkylation.
Your reaction is a acylation.
If you cannot follow instructions I cannoy help you.
Do the reaction again, use 2 mol (COCl)2 to 1 mol benzene and run this in a liter of CS2,
And you want to know why your yield was low?
No solvent
No excess oxalyl chloride
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hector2000
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Quote: Originally posted by Sauron  | Hector, I told you to use CS2 zolvent,
That Rhodium page is about making P2P for methamphetamine cooking.
The reaction is an alkylation.
Your reaction is a acylation.
If you cannot follow instructions I cannoy help you.
Do the reaction again, use 2 mol (COCl)2 to 1 mol benzene and run this in a liter of CS2,
And you want to know why your yield was low?
No solvent
No excess oxalyl chloride |
You say true that reaction is alkylation.
Tonight i will try again reaction with Cs2
This time i will use more oxalyl chloride
unfortunately MeMgCl is expensive here and i should use lot of MeMgcl(because that is 20% in THF) for 100gram PAC
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Sauron
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Make your own MeMgCl (or Br or I)
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hector2000
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I did acylation again.
I used 170 cc Oxalyl chloride(2 mole) and 89cc Benzene(1 mol) and 50cc CS2 and anhydrous AlCl3
Yield was ~69%
Remaing little red tar(not black)
Also i did final reaction (MeSnnBu3 (1 mole)+Ph-(Co)-(Co)-Cl (1 mole) in dry Et2O)
some heat produced.
Gc-Ms show Ph-(Co)-(Co)-Me Yield %10
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Sauron
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Better! You doubled your yield from the F-C acylation. Tarring is almost eliminated, and you got the organotin reaction to work.
If we can find the literature prep of phenylgkyoxalyl chloride (1-phenyl-2-oxo-acetyl chloride) it will help you optimize reaction time (or you can
follow reaction to maximum with GC).
Next you have to isolate the PhCOCOMe and reduce the stuff to DL-PAC and finally strategize the resolution to D-PAC and L-PAC.
Good work last night!.
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hector2000
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I did PhCOCOMe reaction many time(because Yield is low) and maybe tonight do final reaction.
After lot of search i found SEO2 here.
Also i want to try 2-chloropropionyl chloride method because i think that method is cheaper and maybe has better Yield.
Reaction between Ph-(CO)-CH(OH)-Me and Seo2 for making Ph(CO)-(CO)-Me has special point?(like use N2 gas,...)
I think after this reaction i can recycle Seo2(Convert SE to Seo2) by Patent number #2,616,791 then there is no need for buy seo2 again.
But i have no information and difficulty of reaction between Ph-(CO)-CH(OH)-Me and Seo2.May guide me?
[Edited on 4-5-2009 by hector2000]
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Sauron
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69% is not low yield and is not even optimized yet.
You are worried about cost of MeMg-halide? I told you - make your own!
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hector2000
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No. FC reaction for make Ph-(Co)-(Co)-Cl has good yield but reaction between MeSnnBu3 and Ph-(Co)-(Co)-Cl has bad yield(i did this reaction 5 time).
also i will do this route for making PAC but i am interesting to know about 2-chloropropionyl chloride method.
I have problem just in the Seo2 step and i dont know instruction of this reaction
i accept that i can build MeMg-hallide but i have question:
We can produce MeSnnBu3 from MeMgI and Bu3SnCl?or we should use Bu3SnI?
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DJF90
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I assume the use of methyl tributyltin is to methylate the acid chloride selectively over the ketone? Instead, might you use the methylmagnesium
iodide/bromide/chloride in the presence of cataytic Cu (I)? Or perhaps prepare the organocopper first by reaction of methylmagnesium halide with
copper (I) halide in ether, then transfer the ethereal solution to the reaction flask (or use it as is).
An alternative (with slightly more steps but still viable) is to hydolyse the acid chloride, then under acid catalysis form the ketal (and the ester)
then you can just use the methylmagnesium halide, to form 3-oxo(protected)-3-phenylpropan-2-ol. Deprotect with aqueous acid and oxidise the alcohol to
the ketone with something like acidified dichromate. The phenyl ketone can then be reduced using NaBH4.
[Edited on 4-5-2009 by DJF90]
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Sauron
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I know you can buy nBu3SnCl but it is easy to make nBu3SnI
Start with nBu-halide (which one does not matter) amd prepare nBuMg-halide in dry ether. Treat 4 mols with one mol Anhydrous SnCl4 added drop by drop.
Work up according to instructions in Org Syn paper I gace you for tetraethyltin.
Treat the tetrabutyltin with one mol I2 (again in ether), you get nBu3SnI and nBuI.
Easy.
Now you can react with MeMgI to obtain nBu3SnMe,
You can also make your own MeI for making the Grignard, It takes MeOH, I2 and a catalytic amount of red P. MUCH cheaper than buying it.
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