Sciencemadness Discussion Board

Bicyclic Phosphates

DDTea - 17-7-2004 at 19:08

I was doing a report a while back on Chemical Warfare in WW1--but I'd gathered plenty of information about Chemical Weapons from all points in history. Of most interest, I came across this page, courtesty of ASA: http://www.asanltr.com/ASANews-98/chemistry.html . More specifically, as the this thread's title tells you, I would like to discuss Bicyclic Phosphates--*not as weapons* however, only because I think they seem neat.. Anyhow, so you won't have to go through the whole site to understand this, I'll be nice:
Quote:
Bicyclic phosphates were used as flame retardants, antioxidants, stabilizers or for spectroscopic studies. At present, they have been replaced (when possible) by other not so highly toxic compounds. When R- (see Fig. 1) is substituted by the isopropyl group, the toxicity is very near to sarin (LD50 = 0.18 mg/kg, i.m., rat). The time course of poisoning is quick, in minutes, following parenteral administration. Perturbations, muscle weakness, hyperactivity, muscle tremor, later convulsions passing to paralysis are observed. Intoxication is slightly similar to nerve agent poisoning, but with a different mechanism of action, very probably connected with GABA receptors. Specific antidotal therapy does not exist, but relatively good effects were observed following administration of benzodiazepines


The structure of bicyclic phosphates is as follows (sorry, I don't know how to insert the GIF..) :

O=P(O-C)3C-R

The synthesis of Ethyl Bicyclic Phosphate is very simple, and is often made accidentally. It can be made by heating Aluminum Phosphate and Trimethylol Propane together, or Trimethylol Propane with Sodium Acid Pyrophosphate...or any number of ways.

That's all for now...my mind really is not working right now, for some reason or other. More later, I suppose.

I've recovered my train of thought

DDTea - 19-7-2004 at 23:37

What I find neat about Bicyclic Phosphates is that they look like the most accessable toxic organophosphate compounds for amateurs. They are not nearly as volatile as say, TEPP or DFP and generally speaking, their toxicity is lower. They take the form of crystals and assuming they are not pulverized too much, they shouldn't get into the air much. Naturally, it would still be prudent to follow safety procedures like working in a fume hood and avoiding all skin contact (they are toxic via dermal exposure, too)--as they still have acute toxicity.

It was mentioned that benzodiazepines can be used to suitably treat Bicyclic Phosphate poisoning. A very common benzodiazepine which is often prescribed to treat anxiety is Xanax, if you weren't already aware... therefore, the treatment for possible poisoning is fairly accessable also.

Now, we know that Ethyl Bicyclic Phosphate can be easily made...but what about other Esters?? Synthesis of Bicyclic Phosphoric Acid or a Halogen Bicyclic Phosphate would be an interesting project, as that would allow the synthesis of other esters.

Ideas? Because I am lost as to how to begin doing this :)

[Edited on 7-20-04 by Samosa]

Sauron - 1-2-2007 at 04:23

These are GABA inhibitors, similar to the caged convulsant rat poison used in China for mass murder by rival restauranteurs. Benzodiazepines treat only the symptom (tremors) but not the GABA inhibition itself.

The only relationship between these compounds and OP military agents is that they are organophosphates. In structure they have little in common with the G and V agents. They contain neither fluorine nor nitrilo groups.

The Chinese rat poison is made from sulfamide and formaldehyde. It is now banned because of high toxicity to humans and mammals. It still turns up in rural China as a murder weapon.

It contains no P but it is a cage structure and a potent GABA antagonist and so its toxic action is very similar to the bicyclic (caged) phosphates. These are merely industrial chemicals of moderate toxicity and should not be confused with military grade OPAs.

There are many many industrial compounds that are toxic. In fact these days "toxic" is a buzzword, I mean there is toxic, there is ToXiC, there is TOXIC, and then there is REALLY FRIGGING TOXIC written in letters 3 feet high. The military agents are in the final category.

Here's the nomenclature and structural sketch.

Cage structures like this one, or quinuclidine, q.v., are quite rigid and that is likely why they have such potent in vivo activity when it so happens that they have the right docking conformation for a particular receptor site.

The precursor at right is also known as trimethylol propane. Note the similarity to pentaerythritol. In fact I bet this would be a good candidate for nitration to an energetic. Probably a better use for it than making a lame CW agent,



[Edited on 1-2-2007 by Sauron]

[Edited on 1-2-2007 by Sauron]

bicyclicphosphate.jpg - 12kB