Sciencemadness Discussion Board

Looking for Oxalyl Chloride (Swern ox) and 3-bromoanisole

Methyl.Magic - 22-1-2009 at 11:00

Hello

I'm lookig for these two product.

Do you know if any chemical company (who accept to deliver at home not only to companies) has these products in stock ?

I live in Switzerland.

Thanks In Advance.

Methyl.Magic

stoichiometric_steve - 22-1-2009 at 11:10

Oxalyl Chloride is T+, hence you need someone with a license to sell it to you. It's not very likely that you could easily get it.

Sauron - 22-1-2009 at 11:21

That term is meaningless outside the EU (T+)

So it depends on where Methyl Magic is.

Anyway oxalyl chloride is not hard to make.

You need TCT (cyanuric chloride) and anhydrous oxalic acid to make it.

Or PCl5, but that is hard to get.

TCT is better. Either way expect a 50% yield.

Use a fule hood, oxalyl chloride is very irritating.

You can make your own TCT from methyl thiocyanate via chlorination. I have done threads on this before, UTFSE.

Can't buy methyl thiocyanate? Make it! Start with CS2. Again UTFSE.

Can't buy anything on this post? Move to a free country. I buy oxalyl chloride from Belgium.

Methyl.Magic - 27-1-2009 at 10:09

thank you Sauron and s_steve !

Yes I have my licence and I'm authorised to have toxic chemical in my possession but the problem is that in my country chemical vendors deliver only to companies...

Sauron, you suggest to synth oxalyl chloride folowing this way :

CS2 -> methyl thiocyanate -> TCT -> oxalyl chloride

I thing that represent too much work for an available chemical... And CS2 isn't really easier to get than oxalyl chlorid itself...

You said you get it from Belgium, can you tell me your source ?

thank you !

harrydrez - 27-1-2009 at 10:24

He said that you can make your own TCT using methyl thiocynate, and you can make methyl thiocynate starting with CS2. However, TCT is what they use to chlorinate pools and spas. It comes in those tablets and it's fairly available.

You would then use the TCT to chlorinate oxalyl anhydride.

Sauron - 27-1-2009 at 10:26

Acros Organics

www.acros.com

It is not cheap! About $350 US a Kg.

The short synthesis of oxalyl chloride is with lots of PCl5. It is not very efficient, 50% yield. If you can buy red P in your country you can generate Cl2 and easily make PCl5. The reaction with anhydrous oxalic acid is a solid phase one and is a great way to make POCl3, but a medicre way to make (COCl)2. If you look at the mass balance you will see what I mean.

Or just buy cyanuric chloride (TCT) and make it with that. Yield is same as with PCl5. But this one is done in acetone with TEA as promoter, you gets lots of precipitat and extract the oxalyl chloride from that with CCl4.

There are no other methods. So you have three choices.

Buy it

Make it by one method above or the other.

Go without it.

I suppose you also have the option I mentioned upthread. Move to a free country.

[Edited on 28-1-2009 by Sauron]

Sauron - 27-1-2009 at 10:37

Quote:
Originally posted by harrydrez
He said that you can make your own TCT using methyl thiocynate, and you can make methyl thiocynate starting with CS2. However, TCT is what they use to chlorinate pools and spas. It comes in those tablets and it's fairly available.

You would then use the TCT to chlorinate oxalyl anhydride.


Where to begin? So much ignorance, so little time.

TCT is cyanuric chloride and is NOT used to chlorinate pools.

TCCA is trichloroisocyanuric acid and is what you are thinking of.

TCT is the acid chloride of cyanuric acid. The Cl replaces -OH groups linked to carbons

TCCA is a chloroamide, Cl is on N not C.

TOTALLY different compounds. Think before you post and make yourself look stupid.

TCCA cannot chlorinate anhydrous oxalic acid (there is NO SUCH THING as oxalic anhydride) Only PCl5 and cyanuric chloride (trichloro-s-triazine) can do that.

The difference between TCT and TCCA and the confusion arising from the acronyms has been discussed and clarified MANY TIMES on this forum.

Read more and post less gibberish, fella.

Sauron - 27-1-2009 at 10:55

The stoichiometry of the reaction between oxalic acid and PCl5 is

(COOH)2 + 2 PCl5 -> 2 POCl3 + (COCl)2 + 2 HCl (g)

The yield is 50% so you need 4 mols PCl5 to get one mol oxalyl chloride in practice.

Now look up the MW of PCl5.

You ought to be able to do it in your head.

One mol (COCl)2 is 126 g but requires almosy 833 g PCl5 to make it.

THIS SUCKS. To prepare a Kg you would need 7 Kg PCl5.

PCl5 is relatively cheap but the govt will be unhappy to see you buy it as it is a CW weapon precursor (nerve gases).

It is relatively simple to make from red P but the govt will be equally unhappy to see you buy that for same reason plus the meth cook application as well.

So now you can see the logic of my alternative.

[Edited on 28-1-2009 by Sauron]

biotech7 - 29-1-2009 at 06:28

3-bromoanisole is slightly easy to be synthesized starting from 3-bromophenol or 1-bromo-3-nitrobenzene.
attachment is a hint for syn. route.
enjoy! :P

[Edited on 29-1-2009 by biotech7]

1.gif - 3kB

Sauron - 29-1-2009 at 20:22

Are you in the right thread, fella?

This one is about oxalyl chloride.

sparkgap - 29-1-2009 at 20:32

Well, judging from the title, MM's asking about m-bromoanisole too, so...

sparky (~_~)

biotech7 - 29-1-2009 at 22:08

Quote:
Originally posted by Sauron
Are you in the right thread, fella?

This one is about oxalyl chloride.


oxalyl chloride is irritant and dangerous if decomposed( a release of carbonyl chloride at high temp.). besides, it is probably hard to buy it from chemical dealers or manuf. due to high transportion risk if your inquiry at small quantity

but syn. of oxalyl chloride is absolutely convienent in acceptable yields. 3-bromoanisole(also called m-bromoanisole) might be synthesized in no more than 3 steps if you find it hard to buy it.
BTW, 3-bromoanisole is reasonably cheap and easy to buy outside your country.

B.R.

[Edited on 29-1-2009 by biotech7]

Sauron - 30-1-2009 at 00:07

Methyl Magic, did you try contacting Swiss chemical companies like Fluka?

They belong to Sigma-Aldrich but they are in Switzerland so no EU bullshit to deal with.

Arrhenius - 20-2-2009 at 23:28

Swern Oxidation: You can do the swern directly with trichlorotriazine (pool chlorinator), just do a literature search for this. I have not tried it myself, but one could try to make the chloro-DMS intermediate quickly, and react any alcohol to see if you get the stinky DMS. Don't forget triethylamine in step 2.

[Edited on 20-2-2009 by Arrhenius]

Sauron - 21-2-2009 at 00:03

I am really getting tired of having to repeat myself but let's try one more time:

Trichloro-s-triazine, also called cyanuric chlorice or CC or TCT, is NOT a swimming pool cleaner.

The swimming pool cleaner is trichloroisocyanuric acid also called TCCA

These two compounds, while both derived from cyanuric acid, are structurally and chemically different.

TCT has chlorines on carbon

TCCA has chlorines on nitrogen

TCT is the acid chloride of cyanuric acid while TCCA is the chloroamide of isocyanuric acid

cyanuric and isocyanuric acid are tautomers.

I have posted drawings, and CAS numbers. You cannot use these reagents interchangeably.

Attempting to do so can be disastrous..

TCT is made industrially by combining hydrogen cyanide and chlorine to obtain cyanogen chloride which trimerizes to TCT.

In the lab it can be prepared by chlorinating CA with PCl5 or by chlorinating MeSCN with Cl2.

TCCA is made by chlorinating CA with Cl2.

CA is cyanuric acid.

PLEASE do not confuse these two different reagents again.

[Edited on 21-2-2009 by Sauron]

[Edited on 21-2-2009 by Sauron]

[Edited on 21-2-2009 by Sauron]

TCTandTCCA.jpg - 25kB

Sauron - 21-2-2009 at 01:24

Also notice that while TCCA contains three carbonyl oxygens, TCT does not. TCT contains no oxygen.

TCT is a chlorinating agent

TCCA is primarily an oxidizing agent with some utility as a chlorinating agent as well.

They derive from the two tautomers of cyanuric acid.

TCT from cyanuric acid

TCCA from isocyanuric acid.

See structures below.

Only TCCA is a pool chemical. Put TCT in your pool and no one will ever show up to swim again.

[Edited on 22-2-2009 by Sauron]

CA.jpg - 33kB

Arrhenius - 22-2-2009 at 12:28

OK, fine. Buy some cyanuric chloride and run your Swern. Maybe you should make your own website where you're God, Sauron. Then you can rant and rave all you want and not annoy people here.

Sauron - 22-2-2009 at 13:39

The attempt to correct stupid mistakes of the ignorant is neither ranting nor raving. I said nothing about Swern oxidations. I said that trichlorotriazine is NOT swimming pool cleaner, and you know what? I am right.

You want to wallow in misinformation, be my guest. Just don't dissminate it on this forum and expect others to go for it like hogs at a trough.

Polverone - 22-2-2009 at 14:01

Sauron was right and he didn't even take you personally to task until you insulted him. Be glad that you didn't learn the difference between TCT and TCCA from personal experience.

Arrhenius - 22-2-2009 at 14:20

I'm not denying your commentary, in fact I learned something. My point is, you post on these forums like a know-it-all rather than a teacher, and I find that insulting.

I tried reacting some TCCA with DMSO anyway, and yes it reacts. Do I have a dry ice bath to do attempt a Swern with it? No. Do I have any idea what's happening? No. Do you get DMS? Yes.

YOU, Sauron, suggested making oxalyl chloride from TCT. If one needs to buy TCT to get there, why not do the Swern with the TCT since this is now a known reation? (will post references if you'd like)

DJF90 - 22-2-2009 at 14:31

Sauron said nothing against using the TCT in the Swern oxidation. In fact he said nothing about the swern oxidation at all (other than mentioning he didnt comment on it!). You should read his posts more carefully.

[Edited on 22-2-2009 by DJF90]

Arrhenius - 22-2-2009 at 14:35

Zzzzzzzzzz.... no, but he suggested making oxalyl chloride from it. Would be prudent to save yourself an entire step.

Sauron - 22-2-2009 at 15:06

Read the thread title. LOOKING FOR OXALYL CHLORIDE

So don't knock me for telling the guy the slickest way to make oxalyl chloride.

"Swern Oxidation: You can do the swern directly with trichlorotriazine (pool chlorinator), just do a literature search for this. I have not tried it myself, but one could try to make the chloro-DMS intermediate quickly, and react any alcohol to see if you get the stinky DMS. Don't forget triethylamine in step 2."

[Edited on 20-2-2009 by Arrhenius]

You offered no literature to back up your assertion that TCCA can be used in the Swern, if that is in fact what you meant. If TCCA then TCT is not relevent except for making oxalyl chloride. Lacking references or citations, and with some confusion as to which reagent you mean, we are left with only your say-so, aren't we? Rather thin ice. The onus is on you to provide the lit.support.

If you really meant TCT, and it works as well as oxalyl chloride does, then yes, he could save himself a step. But that's a couple of big Ifs.

By the way, are we talking about chloromethyl methyl sulfide? Or sym. dichloromethyl sulfide? (Cl-CH2-S-CH2-Cl?

If so watch out because that is a deadly vesicant, carcinogen and homolog of mustard gas. It crosslinks DNA across the helix strands and prevents DNA replication and repair. It's not merely stinky.

[Edited on 23-2-2009 by Sauron]

Arrhenius - 22-2-2009 at 15:32

I corrected myself on TCCA v. TCT, please see above post.
Quote:

If one needs to buy TCT to get there, why not do the Swern with the TCT since this is now a known reation?


huh? no chloromethyl.... put the chlorine on the sulfur (what I called chloro-DMS). Check the reaction mechanism for Swern Oxidation. Dimethylsulfide (DMS) would be the break down product of the chloro dimethylsulfide intermediate in the Swern oxidation if you attempt to run it at 0ºC. DMS would also be what is liberated when you decompose the formed salt by addition of triethylamine.

Here is a review article mentioning TCT (not TCCA) use in Swern Oxidations:
Current Organic Chemistry, 2004, 8, 1497-1519

See Scheme 34.

Here would be the JOC article cited:
De Luca, L.; Giacomelli, G.; Porcheddu, A. J. Org. Chem. 2001,
66, 7907.

[Edited on 22-2-2009 by Arrhenius]

[Edited on 22-2-2009 by Arrhenius]

[Edited on 22-2-2009 by Arrhenius]

[Edited on 22-2-2009 by Arrhenius]

Sauron - 22-2-2009 at 15:47

Good old Lydia deLuca, grand dame of the TCT organickers.

She also did the TCT-DMF complex. Very handy.

Glad to hear "chloro-DMS} is not the chloromethyl. The proper name would be dimethylsulfenyl chloride.

(Me)2SCl

DJF90 - 22-2-2009 at 16:15

I thought the swern oxidation proceeded via the chlorosulfonium ion? i.e. (Me)2S(+)Cl (the positive charge is on the trivalent sulfur, hence the chlorine is bonded to said sulfur).

Arrhenius - 22-2-2009 at 16:51

That's correct. Sulfur is +1 throughtout the reaction until the last step, when dimethylsulfide leaves. Whatever you want to call that chlorinated species, I'm not very knowledgeable of the strictly correct terminology.

[Edited on 22-2-2009 by Arrhenius]

Sauron - 22-2-2009 at 22:35

Ionic, huh?

New one to me. The compound I am most familiar with is Cl3C-S-Cl which is covalent. Also SCl2 and S2Cl2, the sulfur chlorides, also covalent.

But always happy to learn something new.

I will have to take a closer look at the Swern.

Arrhenius - 22-2-2009 at 22:46

I don't know if I would call it ionic, judging purely from the proximity in electronegativity of oxygen, sulfur and chlorine. It's typically drawn this way, as the "ylide", in the mechanism to emphasize the "resonance form" that is highly electrophilic at the sulfur. DMSO is drawn with charge separation between the oxygen and sulfur, and the chlorine depicted as - and the sulfur + too. It's a pretty cool mechanism in total, and a challenging but robust reaction.

I guess I overlooked this... but... what are you trying to run a Swern oxidation on? There are a few oxidations that are easier, and also don't utilize chromium. Manganese dioxide comes to mind.



[Edited on 22-2-2009 by Arrhenius]

Sauron - 22-2-2009 at 23:10

I just woke up. Of course this has to have a formal charge and of course it is an ylide.

PHILOU Zrealone - 23-2-2009 at 08:44

Quote:
Originally posted by Sauron
Also notice that while TCCA contains three carbonyl oxygens, TCT does not. TCT contains no oxygen.

TCT is a chlorinating agent

TCCA is primarily an oxidizing agent with some utility as a chlorinating agent as well.

They derive from the two tautomers of cyanuric acid.

TCT from cyanuric acid

TCCA from isocyanuric acid.

See structures below.

Only TCCA is a pool chemical. Put TCT in your pool and no one will ever show up to swim again.

[Edited on 22-2-2009 by Sauron]


Just to clarify a bit 3 H atoms are missing in the structure of the isocyanuric acid, one H on each N would be better.
TCCA is related to urea,biuret and imides (-NH-CO-)3

Sauron - 23-2-2009 at 08:49

You are right. MDL Isis Draw only adds hydrogens to heteroatoms if you change the default setting. Sorry about that.

If this were not the case, Cl could not substitute on those Ns.

DJF90 - 23-2-2009 at 10:43

I've attached the mechanism for the Swern oxidation. I'm hoping its not too big.

[Edited on 23-2-2009 by DJF90]

Swern oxidation mechanism.bmp - 880kB

Arrhenius - 23-2-2009 at 13:44

Hmm... Yes... I wouldn't draw triethylamine abstracting a proton from the dimethylsulfonium ylide (last step), I would simply draw it abstracting the alpha proton, to undergo an E2 type elimitation to form the carbonyl. That would be the general theory of most oxidations to the aldehyde; adding a good "Lv" group to the alcohol so the proton can eliminate. :) But I mechanisms are just some smart guy's best guess :P

DJF90 - 23-2-2009 at 14:25

Its a good point but I think if you consider which of the hydrogens is more acidic you will find it to be the one I have shown being removed. The (+) on the sulphur helps to stabilise the resulting carbanion, whereas the oxygen has a positive mesomeric effect on the alpha position, DEstabilising the carbanion that you claim would form. Like you say mechanisms are only "best guesses" but this is the one I believe to be more accurate.

voidwalker - 5-4-2010 at 07:35

How can you make oxalyl chloride from cyanuric chlroide and oxalic acid ? I've searched the internet for refferences but can't find anything.

ziqquratu - 5-4-2010 at 21:57

To go back to the argument about activating reagents, you can use a whole range of activators for the Swern oxidation, including oxalyl chloride, thionyl chloride, trichlorotriazine (TCT), acetic anhydride, Pyridine-SO3 complex, benzoyl chloride, tosyl chloride, triflic anhydride, PCl3 and on and on... I'm fairly sure (though not 100% certain) that TCCA (pool chlorinator) is no good in this reaction, however.

In any case, as a general rule, oxalyl chloride gives the best yields under reasonable conditions (i.e. not requiring co-solvents like HMPA!) over the other reagents - hence its widespread use in the reaction (in fact, I can't remember the last time I saw a Swern using other than oxalyl chloride!).

The trick to good yields with the Swern is to control the temperature fairly well - sit by your bath and maintain it at -60*C. Since the reaction usually takes less than an hour, it's not a real hardship.

Be aware of the stench on work up, too - the formed dimethylsulfide is rather unpleasant to work with! Best done in a hood, outside if necessary (although the neighbours may not approve!). You're also going to want to remove the solvent from your product in a hood or outside.
Also, dump all your glassware in a bucket full of bleach for a while before cleaning them, and add a bit of bleach to the aqueous extracts from the work up - bleach will oxidise the DMS to non-smelly compounds.

For a comparison of the various activating reagents, see Omura and Swern, Tetrahedron 34 (1978), 1651-60

Attachment: Comparison of reagents for use in Swern oxidation.pdf (928kB)
This file has been downloaded 1335 times

DJF90 - 6-4-2010 at 09:23

For a start, you will only EVER see oxalyl chloride as the activator in a Swern oxidation; this is because by definition the reagent couple in the Swern oxidation is (COCl)2 and DMSO. Albright-Goldman oxidation uses Ac2O/DMSO, while Parikh-Doering uses the SO3-Py/DMSO. Pfitzner moffat uses DCC/DMSO/Pyridinium trifluoroacetate (or in some cases H3PO4 to advantage). Corey Kim oxidation originially used Cl2/Me2S, but a modern modification uses Me2S and NCS. I could go on for a while as there's quite a few oxidations relying on "activated DMSO"; Swern oxidation is just ONE of them.

ziqquratu - 7-4-2010 at 15:18

DJF is right, of course... I should have said a Swern-type oxidation using the other activators, with a few exceptions (the Parikh-Doering, in particular, has become somewhat more popular lately). I often forget the fact that the reactions have different names - ultimately, the mechanism is more or less the same, so mentally I lump them all together! But there are definitely differences, and they can be important depending on the material you're working with. Apologies for the slack terminology!

DJF90 - 8-4-2010 at 05:11

It's fine, you're right, they all have roughly the same mechanism; DMSO + Activator => Activated DMSO, Activated DMSO + Alcohol =base=> Aldehyde + Me2S. The exception of course is the Corey Kim, which starts from dimethylsulfide, and, in the traditional method (using Cl2), the activated species was the same as that in the swern oxidation (chlorodimethylsulfonium chloride). You are also correct when you say that the Parikh-Doering methodology has become fairly popular lately - SO3-Py is much more pleasant to handle than one would expect given it's constituents, and the reaction is actually rather clean (no chlorination as can occur with Swern conditions). Of course, the main drawback with activated DMSO type oxidations is the generation of Me2S, which must be absorbed by a scrubber.

[Edited on 8-4-2010 by DJF90]

ItalianChemist - 19-2-2011 at 12:53

I bought (COCl)2 from Sigma withouth any problem!