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Author: Subject: Novichoks and Related 3rd/4th Gen. OP Agents
Sauron
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[*] posted on 31-1-2007 at 21:36
Novichoks and Related 3rd/4th Gen. OP Agents


This is pretty much a summary of what I have been able to find on this, there was a thread here about this 2.5 years ago, but that seems a bit stale to reopen.

Soviet development of these very interesting and potentially highly threatening compounds apparently began in the 60s and continued through the 80s and, with ever tightening secrecy especially after 1972. It is reported that some or all of these compounds can defeat MOPP gear, that some are supertoxic (many times more toxic than GA/GB/GD/VX), that they can'be detected by western military instrumentation, all of which if true are highly alarming.

The USG appears to be trying assiduously to conceal the existance or at least delay release of much details about Novichok (despite this now being a five decade old Soviet projecy.) Acronyms appear with some regularity to replace all references to the nickname Novichok in western official documents. Two examples are NTA ("Non Traditional Agents") and FGA "Fourth Generation Agents".

Novichok simply means "newcomers" in Russian, especially in the sense of Johnny-come-lately or the VN era US military slang for replacement grunts, "FNG" (Fucking New Guys").

Some clues have emerged as to structure of at least some of the Novichok class of agents.

Author Steven Hoenig in the very recent (11/06) Springer-Verlag "Compendium of Chemical Warfare Agents", q.v., is quoted on roguescience as identifying three supertoxic Novichoks:

A-230
CAS [26102-97-6]
Cl-CH2-Ch2-O-PF(=O)-O-N=CF(Cl)

A-232
CAS [26102-98-7]
Cl-CH2-Ch(Me)-O-PF(=O)-O-N=CF(Cl)

A-234
CAS [26102-99-8]
Cl-CH(Me)-Ch(Me)-O-PF(=O)-O-N=CF(Cl)

I won't bother with Hoenig's nomenclature as it seems to be confused, but I did go draw these in ISIS/Draw 2.5

which indicates that these are all fundamentally more related to PCl3 or phosphorous acid. Note the absence of a C-P bond. P is bonded only to O and F.

The functional group on the right is a dihaloformaldoxime specifically the oxime of carbonyl chlorofluoride. The purpose of this group is to irreversibly bind to AChE and BuChE receptors and preclude reactivation by oxime therapies such as 2-PAM. The Russians have a long love affair with phosgene oximes as CW agents, going back to WWI. Carbonyl chlorofluoride is produced from Cl2, F2, and CO and reacted with hydroxylamine. However, I do not believe that the dihaloformaldoxyl group is introduced to POCl3 or a trialkyl phosphite in such a direct fashion.

The other alkoxy group is 2-chloroethyl from POCl3 and 2-chloroethanol (ethylene chlorohydrin).

The P-F moiety is probably introduced by fluorination of a P-Cl function as a final step, in a manner similar to the preparation of DFP (cf.Sanders book.)

When Ellison's "Handbook of Chemical & Biological Warfare Agents" appeared a very odd review of it showed up in amazon.com. The reviewer used the name of a recently deceased Russian general. He summarized some of the Novichok project history and that of the parallel "Dusty Agents" weaponization, named key researchers, cited journal publication prior to 1973, and gave two alleged Novichok structures. This review is now available in the MadHatter FTP site.

Later: The preparation of the dihaloformadoxime functionality attached to the P nucleus is done at low temperatures in liquid SO2 solvent by reacting POCl3, (RO)3P=O (a trialkyl phospate), (RO)3P (a trialkyl phosphite) or RP(O)Cl2 or RP(O)(OR)2 etc with chloropicrin, dichlorofluoronitromethane, dichloronitrosomethane, chlorofluoronitrosomethane, or other halogenated nitroalkanes. Possible substitutents alpha to the nitro or nitroso group are Cl, Br, F, or a stable pseudohalogen such as -CN. The entry point for these nitro/nitroso compounds is the corresponding substituted acetic acid, just as in the classical prep of nitromethane from chloroacetic acid.

So, dichlorofluoroacetic acid, as an example, is treated with sodium nitrite to obtain chlorofluoronitroacetic acid. This is then decarboxylated. The product is chlorofluoronitromethane. I do not have experimental details or physicochemical date as yet, but this ought to be in the open lit. The Novichoks are not so mysterious after all, but they constute a large and structurally varied group of agents (apparently mostly solids).


[Edited on 1-2-2007 by Sauron]

[Edited on 1-2-2007 by Sauron]

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[*] posted on 31-1-2007 at 22:37


Fellow students of OP agents will recognize the progression in the series above follows the observations of pioneers Schrader and Saunders, in that the A-232 alkoxy is secondary as opposed to the primary in A-230. We would expect therefore A-232 to be more toxic. A-234 on the other hand is more hindered and like soman (GD) may well be more persistant than the other two.

The review in amazon.com, q.v., which some have called suspect, gives a different structure for the same CAS number as A-230, and a very different structure for another Novichok.

As that review was edited by our own @samosa maybe he can shed some light on this discrepency. Was it deliberate obfuscation by the "deceased Russian general"? Or a mistake based on faulty nomenclature? The structures in amazon.com appear to be, on their face, unlikely to me.

(Later) On the E&W Forum at roguescience, Megalomania states flatly that the structures given below are incorrect and that fits in with my own view stated above.



[Edited on 1-2-2007 by Sauron]

[Edited on 1-2-2007 by Sauron]

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[*] posted on 1-2-2007 at 12:32


It appears that the only relatively exotic precursors to the Novichok class of OPAs are the dihalonitromethanes and dihalonitrosomethanes.

However, see p.164-165 of Sartori's "The War Gases"

Trichloronitrosomethane (b.p. 5 C) and trifluoronitrosomethane (b.p. -80 C) were both evaluated as CW agents a long time ago along with the rest of the chloropicrin family.

Therefore it seems very likely that the chlorofluoronitrosomethane precursor to the Novichek agents is to be found well described in the open literature.

Five minutes later after a Google: the energetics boys to the rescue. Chlorofluoronitrosomethane is an intermediate in the synthesis of an energetic plasticizer fluorodinitromethane (FDNM). From a DTIC report (Fluorochem Inc.) in 1990 (attached abstract):

"Nitration of 1,2-dichlorodifluoroethylene gave chlorofluoronitroacetic acid, which was converted to chlorofluoronitrosomethane with red fuming nitric acid and water."

[Edited on 1-2-2007 by Sauron]

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[*] posted on 1-2-2007 at 15:43


Very nasty! It looks like these, besides being lipophillic, will also penetrate most forms of rubber (latex and nitrile for sure, butyl, and maybe even, chloroprene). There appears to also be very real possibility that they can chew into the skin to adminster themselves (these would probably be very vessicating if you lived long enough to find out).

I agree that the Amazon structures look like hooey. The acetylenics would likely polymerize, and further, I see no special biologically disruptive reason for them to be there.

Interesting, I had not previously been aware of these agents.

Cheers,

O3




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[*] posted on 1-2-2007 at 21:34


Certainly if the free dihaloformaldoxime formed, there would be vessication. But if someone were exposed to enough of this stuff to have to worry about vessication they would be dead anyway. Besides, the point of that functional group is to NOT hydrolyze, not even exchange with other oximes (reactivators) so I expect it to be extremely stable both at the P-O-N bond and at the receptor site. Therefore unlikely any free oxime can form.

Yes absolutely defeat of MOPP gear was and is a design goal. This is analogous to the GF agent "cyclosarin" which defeats at least some protective gear.

On that basis I would anticipate that a Novichok in which the 2-chloroethyloxy function was replaced by a cyclohexyloxy function or a 2-chlorocyclohexyloxy function, would have enhanced capabilities against protective gear. See sketch below. I have proposed an appropriate trivial name for it.

As to the erroneous structures, I remember well once in the 1970s a house organ of the ACS (C&EN) published a VX structure with the side chain -S-CH=CHN< and we all had a good laugh about it. That pi bond of course should be a sigma. So, there's precedent for just this sort of error.

[Edited on 2-2-2007 by Sauron]

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[*] posted on 1-2-2007 at 21:43


Hence...

The F-...Same game the medicinal Chemists are playing with drug stability! Selling these compounds as the oxons as also quite nasty, but will, no doubt effect the life of the active moeity--which could be "good" because, who wants to deploy a chemical agent when they cannot enter post-haste? I think that the O-Et-Cl chain on the other end is supect as well...

Good night,

O3




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[*] posted on 1-2-2007 at 22:27


The SIPRI folks always proposed standardizing on GF because they argued that a CWA against which there was no defense would be a deterrant in the MAD sense. I think they were being overly optimistic, is not pollyannish.

Should we assume that just because the russkies engineered Novichoks to defeat western MOPP, that they did not develop their own protective and detection countermeasures against it? Not a safe assumption!

Of course there is much discussion and has been for a long time of CWAs as area denial weapons, and this is pretty consistent with the historical practice of various communist forces of not mapping their own minefields. Certainly the case in Cambodia where there are 20 million mines and the Khmer people mostly find them one at a time, the hard way, by treading on one.

PS

I am having a hell of a time finding out anything about 1,2-dichloro-1,2-difluoroethylene [27156-03-2].

Nothing in Aldrich, nothing in Merck, nothing on Acros, nothing in Ullmann. I have not even been able to locate the bp. I assume it is a gas, but with a MW of 192 maybe not. If it is a gas then I know where to look for a supplier, I am striking out with the usual suspects for reagents.

Even Fluorochem, the folks whose report DTIC has on file, do not sell it.

Is this in the unobtainium department?

[Edited on 2-2-2007 by Sauron]
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[*] posted on 2-2-2007 at 10:16


Here are the two "new" (to the public) G-agents details of which were released in Ellison's Handbook and a few more in the amazon.com review. The structures are from Ellison and probably reliable. The CAS numbers and some of the nomenclature are from the somewhat dubious Russian review and therefore may not be reliable.

[Edited on 2-2-2007 by Sauron]

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[*] posted on 2-2-2007 at 19:19


CycloSauron:D, perhaps you should change your screen-name!

With the possible exception of cycloSauron, your earlier structures looked far nastier, but still, you are considering G and V agents which are frighteningly toxic to begin with!

The big meany with the new ones is the ability to insinuate themselves though the typical polymers used to prevent intoxication.

As for Soviet MOPP gear being resistant...the only things I know that might be OK are rigid aramides, etc. which must be woven (much to rigid as solids); woven materials tend to leak. How do you think teflon would do with those fluoro-modified "business ends"? My guess is that the answer would be something like "it depends on how thick".

The G progression just looks like the old combi-chem approach, and may well be a "realistic" model to use in misdirection (they don't like to disclose the "family jewels").

Cheers,

O3




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[*] posted on 2-2-2007 at 20:28


Exactly. All the way back to Saunders, Schrader et al (rivals of course) they were screening many many structural variations and looking for toxicity spikes in the SAR. More recently we have speeded this up with QSAR and parallel synth and so on but in the 40s and 50s it was wet lab and more wet lab and I am sure they made hundreds if not thousands of variants - many of which were of low or indifferent toxicity or simply did not meet other well established military requirements. Vapor pressure, persistance, MW, phase at STP, and so on.

GP and GV look like a couple from such series, but I have not seen anything to indicate they were ever weaponized or stockpiled. GA, GB, GD yes. VX yes. These two? Dunno.

GF as far as I know was not stockpiled by anyone simply because the stuff does defeat at least some protective gear.
I didn't show that structure but I thought it was clear: GF is same as GB but with cyclohexyloxy replacing the isopropyloxy. In the G-series, secondary alcohols > primary alcohols.

2-propyl GB should be regarded as baseline
pinacolyl GD (hindered so slower hydrolysis, more persistant)
cyclohexyl GF defeats some protective gear

You can get a pretty good clue about other likely candidates for the secondary alcohol from reading the CWC schedules. All the cycloalkyl alcohols from C3 to C7 are probably similar to GF, the most practicable being cyclopentyl but who knows, maybe cyclobutyl and cyclopropyl would have special advantages?

As for the alkyl side chain linked directly to P, straight chains out to something like C10 would still be potent though likely to be solids.

But GV and GP have neither an alkyl group nor a simple alkoxy group. They have one bit from GA and one bit from a precursor of VX. I'd be curious about those structures if F were replaced with CN and/or the O in the side chain were replaced with S. But they aren't. So I smell a rat. I think those are bogus. I am not however sure enough that I'd want to get up close and personal with them.
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[*] posted on 2-2-2007 at 21:29


My guess is that the toxicity of the GV/P agents would be sufficent to make deconvolution of your data difficult. That is, with enormous dilution comes propogated error at DF 50,000 +-.0001 becomes significant. the hard nucleophile makes for a stable derivative that is less likely to be mitigated, metabolically.

I'd think that the nitrile in a P-C bonded system would be less persistant; this persistance vs. acute toxicity could be tested, I suppose, by somehow putting a nitro group onto that sucker. If this was easy, I am sure it would be a killer (and we might, could, possible have gotten wind of it--unless it was really good:).

As for a standard compound, I would be inclined to try diisopropylfluorophosphate (which is actually used as the surrogate for GB analysis--why they use a surrogate on nearly equivalent toxicity is beyond me; it makes the blanks CW toxic). It is of prototypic chemistry and toxicity for G agents *and* is well characterized.

On second thought, GP/V look like "missing links" in the evolution of G to V agents which means an increase of acute toxicity of ~2 orders of magnitude; I can only speculate on P-O agents. In a P-O agent, CN may exert a much more considerable inductive effect (the entire thing will be an electron transport chain) which can remove electron density from the active site causing it to bond much more tightly (and, probably with greater speed and specificity).

Still, I am both petrified and in awe of the hell that can be wrought with such things,

O3




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[*] posted on 2-2-2007 at 23:59


Putting on a -CN is in some ways more facile than putting on an -F.

Take GA (Tabun) as archetype.

You start with POCle. This is also the case for GP and GV and it's one of the options for Novichoks.

The proceduire is given in Saunders and also in a number of open source pubs so I am not spilling any new beans here, just emphasizing a point.

P(=O)Cl3 -> Me2NP(=O)Cl2 is usually first step and this is why dimethylamine and POCl3 are highly restricted/watched.

The second step is done at a single go. This means, really, that the product of the first step, and the reagent for second step, constitute a crude binary.

What is the reagent?

An alkali cyanide in ethanol.

How simple can you get? Oh, you probably want to have Pyr or TEA or another tertiary base for H-acceptor to drive the equilibrium to the right, in both steps.

If we take a page from GB binaries then just use NaCn an equimolar mix of ethanol and ethylamine.

GA is Me2NP9=O)(CN)OEt. By the way, decontamination with the usual mixture DC (hypochlorite) gives rise in case of GA or any other P-CN bond hydrolysis, to NCCl that is cyanogen chloride, a military agent in its own right. Combination choking agent and blood agent.

Schrader knew what he was doing.

Incidentally you don't have to be Linus Pauling to observe that the order of toxicity of the halogens goes F>Cl>Br>I

-CN is a pseudohalogen and probably fits in their right after F. Why? Toxicity parallels halogen electronegativity. Consider the consequences of those electronic effects on the P and resulting effects for the binding potency to the AChE receptor sites.

GA is nonpersistant but the military wants both persistant and nonpersistant agent options.

GA is similar to DFP in ease of prep but a lot more potent. It is a popular first agent for countries starting out in CW for those reasons. CWC can't really control the precursors for this one. It's a joke.
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[*] posted on 3-2-2007 at 03:17


GD or soman is also impossible to treat with oximes. It ages within minutes and binds irreversibly, while most agents take several hours (V agents) to days (Sarin). When the ester hydrolyses, then it's aged. Don't know why pinacolyl would age so much faster than any of the others.

It certainly is a fascinating subject, and a completely misunderstood one in terms of the toxic effects. A simple proof is that there are a certain breed of rats with acetylcholinesterase, which nerve agents inhibit. They are pretty fragile but with car they can live hundreds of days. Despite not having any AcCholinesterase to inhibit, nerve agents still kill them, although at roughly half the potency. Nerve agents also have different effects as sub-toxic levels and exhibit many weird things which are not explained except by a vast array of complex interactions with the nervous system.
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[*] posted on 3-2-2007 at 12:24


OK I worked out four different feedstocks and routes to a variety of the immediate precursors to the Novichok dihaloformaldoxime side chain (which is the only real novelty about these agents). I deleted all the previous nattering which was just me thinking out loud. Instead I now present the Isis/Draw sketch of this set of schemes which I believe is pretty close to what the Russians are up to.

[Edited on 4-2-2007 by Sauron]

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[*] posted on 4-2-2007 at 09:26


http://www.patentgenius.com/patent/H1223.html

The patent for FDNE with chlorofluoronitrosomethane as intermediate (see above.)

The patent describes how the starting material 1,2-dichlorodifluoroethylene can be prepared from commercially available 1,2difluorotetrachloroethylene, citing Locke et at, JACS 56, 1726 (1934) for details. It also states that the 1,2-dichlorodifluoroethylene is available commercially.

Chlorofluoronitrosomethane is described as an intensely blue liquid, stable at r.t. for a few days, but usually used directly in subsequent steps. I would expect this dihalogenated nitrosomethane to be a highly irritating substance, based on the known irritant properties of trichloronitrosomethane and tricfluoronitrosomethane (see Sartori, "The War Gases" in the forum library, pp.164-65.)

Apart from that, the two stage nitration/oxidation does not appear to be any more hazardous (or any less so!) than many of the nitrations proposed on this forum.

[Edited on 4-2-2007 by Sauron]
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[*] posted on 4-2-2007 at 09:40


If you think this stuff is too much toxic then why don't you write their synthesis processes?

By synthesis processes, more people came to know how this stuff was made.

Besides Novichok, Dimethylmercury was also good and toxic stuff, if possible provide synthesis processes of this also.
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[*] posted on 4-2-2007 at 10:24


All my source material is in the open literature. Anyone could read them. Anyone with the skills could draw the same conclusions. This is a chemistry forum, and as far as I am concerned I am talking about interesting chemistry. I am not advocating making this stuff, and certainly not advocating using it.

Are you advocating censorship? If so you are facing a hostile audience.

Dimethylmercury is not a military agent, it is a byproduct of the pulp and paper industry. Do you happen to reside near a pulp mill?
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[*] posted on 4-2-2007 at 10:54


@Sauron:

A recently came across an article in "Archives of Toxicology" wherein it was proved that the F- does not dissociate from GB when AChE binding takes place. What do you suppose is the fate of the F- when bonded as N-P(F)-O-C? Seems to me that the F binding constant whoudl be smaller with these molecules.

@ hbx53

There are other threads that are more appropriate for the discussion of Me2Hg such as:

http://www.sciencemadness.org/talk/viewthread.php?tid=7231#p...

Detritus then too, hmm?

Cheers,

O3

[Edited on 4-2-2007 by Ozone]




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[*] posted on 4-2-2007 at 11:09


Maybe there are more OTC-methods:

If Freon 11 (CCl3F) or even Freon 21 (HCCl2F) is available, it would be possible to oxidise them with oelum or chromsulfonic acid to carbonyl chlorofluoride.
I expect because the C-F bond is stronger than the C-Cl bond, that the Cl-Atoms will oxidise first. So the reaction should work like with carbon tetrachloride or thrichlormethane:

SO3 + CCl3F =heat==> SO2Cl2 + O=CFCl
or
CHCl2F + (O2 from air but slow) or chromsulfonic acid ==> O=CClF + H2O +Cl2

The produced carbonyl chlorofluoride could then condensed with hydroxylamine, but there I don't know whether in the second part of the reaction the Cl or the OH group will be eliminated.

O=CFCl + H2N-O-H ==> HO-C(FCl)-NH-OH ==> FClC=N-OH + H2O
or in bad case:
O=CFCl + H2N-O-H ==> HO-C(FCl)-NH-OH ==> HO-C(F)=N-OH + HCl

Probably you'll get a mix of both, but the OH Group might be rechlorinated by thionyl chloride. The whole condensation must carried out in a non nucleophilic solvent, as the esters of carbonyl chlorofluoride are easily produced. A good solvent might be dimethyl sulfoxide.
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[*] posted on 4-2-2007 at 11:23


mmm. DMSO can explode when mixed with acyl chlorides (which is what carbonyl chlorofluoride is). This particular acyl chloride might be weird, though, since the F- will be strongly inductive leading to a positive C-Cl polarization. Still, I think it will react leading to, at the very least a loss of product (and maybe the synthesis of some unwanted and very nasty side products). Nevermind the immediate reduction of the DMSO to DMS (which stinks like hell) that would ultimately result when your primary oxidant is exhausted (you would have to watch it like a hawk).

The acidity usually required for operations like these take place in anhydrous HF:SbF5, for example. I would be very surprised if it (the oxidation) took place in oleum. Do you have any reference material for your proposed transformation?

Cheers,

O3

[Edited on 4-2-2007 by Ozone]




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[*] posted on 4-2-2007 at 11:33


The oxime of carbonyl chlorofluoride was my very first supposition but, in the absence of experimental results reported I see no reason to assume that such an oxime =N-OH will bond with P-Cl, or replace P-OR.

The Russians are definitely using dihalogenatednitromethanes and nitrosomethanes which do react with both types of P bond.

The Russians were the first to weaponize phosgene oxime and use it in warfare, and they have more experience with its manufacture than anyone else AFAIK. So if they could use carbonyl chlorofluoride they could. But they don't.

BTW you don't need to oxidize one-carbon Freons to get that stuff, all you need is carbon monoxide, clorine and fluorine or, ClF interhalogen.

Anyway is starting with one CFC refrigerant any more OTC than starting with another? No more no less.

The purpose of this whole exercise from my point of view was to explicate what the Russians were doing and not especially to come up with alternative (and unproven) routes. I interjected the Fluorochem prep of the precursor because it is proven and because at the time I had not yet worked out the likely Russian processes.

Trichloroacetic acid, acetonitrile and chlorinated acetonitriles, and chloropicrin (cheap agro fumigant) are all very OTC as well.

But thanks for the comment.

[Edited on 4-2-2007 by Sauron]
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[*] posted on 4-2-2007 at 11:50


@O3
The oxidation with oelum should work with trichlorofluormethane as well as with carbon tetrachloride for phosgene, since the fluorine group is not changed, the reference for this is "the war gasses " p61. But instead of heating CCl4 I would preheat the oelum and bubble gaseous CClF3 through it and trap unreacted Cl3CF in a cold trap with dry ice/acetone.

For the second reaction I've no reference, the courageous home chemist would have to try it, but your're right, the condensation of hydroxylamie with formaldehyde has less side reactions, there is only one OH group and no more halogens that might eliminate, the best solvent has also to be searched. A bit tricky as it has to dissolve both carbonyl chlorofluoride and hydroxylamie and be non ncleophilic, too.

@Sauron
I wish a lot of fun to the chemist that has to work with fluorine, chlorine and carbon monoxide at the same time, futhermore I don't think the chlorine in trichloracetic acid is that simple replaced by flourine or even by NO2-, it's far too much steric hindered

[Edited on 4-2-2007 by hinz]
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[*] posted on 4-2-2007 at 12:33


No more so than in trichloronitromethane (chloropicrin) yet that is precisely what the Russians are starting with, there's over 1000 Russian publications on this topic (mostly pretending to be about pesticides of course) and the evidence is all there.

To get from trichloronitromethane to chlorofluoronitromethane they must be knockig off one Cl, which solves your steric hindrance problem, then exchanging one Cl for F, and there's the reagent.

We are told that they are also using acetonitrile, and that some of their formaldoximes contain a -CN instead of one of the halogens. I say it is reasonable to assume that these two facts are not unrelated, and therefore they are making a halocyanonitrosomethane or -nitromethane, and if so, they are dichlorinating acetonitrile, or dechlorinating trichloroacetonitrile to the dichloro form. Again, no steric hindrance issue. (Zinc dechlorinates hexachloroethane just fine, which is how smoke grenades work.) After that the same two steps apply.

It would be trivial to painstakingly repeat the explanation of the procedures for the reported Br containing variants. I believe the F/Cl and F/CN pairs on the dihaloformaldoxime chains are probably the major ones.

As to carbonyl chlorofluoride, have a peek at Brauer's book. Personally I would not care to work with carbonyl chlorofluoride under any circumstances, any more than phosgene. But these do in fact get used in labs and industrially (well, at least phosgene is). My objection is that they are insidious. You can get a lethal exposure long before symptoms appear.

The nitrosomethane is probably intensely irritating rather than insidious. I's guess it is a likely carcinogen, after all nitromethane is now a suspect so nitrosomethane ought to be more so. And at least it's a liquid, and therefore more manageable.

Bottom line: show me a publication that says that P-Cl and HO-N=CX2 condense to P-O-N=CX2 and I'll agree that this route is practicable. Or demonstrate it experimentally, say with PCl3 and acetone oxime, harmless enough. Until then it is conjecture. Maybe reasonable conjecture but conjecture the same. What I am describing is not conjecture. I have filled in a few blanks but the starting materials were stated and the immediate precursors reported. I just played connect the dots.
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[*] posted on 4-2-2007 at 22:29


Here's a 1989 US patent on conversion of Freon-112 (1,1,2,2,-tetrachloro-1,2-difluoroethane) to 1,2-dichloro-1,2-difluoroethylene by catalytic hydrogenation at elevated temperatures in gas phase.

And also the older JACS article on doing same with zinc in absolute methanol. Not as selective but simpler.

Enjoy!

[Edited on 5-2-2007 by Sauron]

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[*] posted on 5-2-2007 at 06:18


Something I ignored till now mostly because I needed to look up the unfamiliar nomenclature.

The "suspicious" amazon.com review, which now is not looking suspicious at all but 24K gold, prominently referenced an article in the proceedings of a 1969 conference. The title referred to 1,3,2-dixaphospholanes and iminophosphites.

I was unable to obtain the article but I did learn that the phospholanes are 5-membered cyclic phosphorus heterocycles and therefore [1,3,2[-dioxaphospolanes look like this:

[Edited on 5-2-2007 by Sauron]

The review actually talks about substitutes 1,3,2 phospholanes as precursors to the Novichoks with the final step being the ring opening by heating.

Well, I suspect that the ring opening may be by HCl hydrolysis. Remember, the examples of final product we have been shown all had a 2-chloroethyloxy side chain. The phospholanes shown are essentially cyclic esters of PClx and ethylene glycol. Open that heterocyclopentyl ring up with HCl and what do you get?

In examples we have been shown, R=H or Me, R2=H or Me, R3=F. After ring opening there's an available P-OH or P-Cl to react with the dihalonitrosomethane to form the dihaloformaldoxime side chain.

In short, the Russians may not be using PCl3 or POCl3 at all if they can buy this phospholane.

Interesting?

[Edited on 5-2-2007 by Sauron]

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