Methylphosphonic dichloride

Although most of the macrocycles that contain phosphorus or arsenic which have thus far been prepared, are primarily transition metals binders, two compounds have been prepared which are essentially crown ethers containing phosphorus. Kudrya, Shtepanek and Kirsanovhave prepared two compounds which are essentially polyoxygen macrocycles but which contain one or two methylphosphonic acid esters as part of the ring. These two macrocycles are shown below as 7d and 17 and are both prepared by the reaction of 2,2 [oxybis(ethyleneoxy)] bisphenolate with methylphosphonic dichloride in a mixture of acetonitrile and benzene. The crystalline monomer 16) and dimer 17) were isolated in 17% and 11% yields respectively as indicated in Eq. (6.13). 

DF and its precursor, methylphosphonic dichloride (DC), are organophos-phonic acids. They will react with alcohols to form crude lethal nerve agents, such as crude GB. High overexposure may cause inhibition of cholinesterase activity. Although much less toxic than GB, DF and DC are toxic and corrosive materials. 

This material is a constituent in GB2, which is the binary version of Sarin (C01-A002). It is also commonly found as a decomposition product/impurity in unitary sarin. It may appear as a mixture with Methylphosphonic dichloride (C01-C046), known as Didi, that is also used as a constituent for binary G-series nerve agents. 

This material is used as a chlorinating agent for both nitrogen and sulfur based vesicants. Required in the manufacture of methylphosphonic dichloride (C01-C046). 

Conjugated olefinic systems have also been used in reaction with phosphorus-halogen species. For example, methylphosphonic dichloride adds regioselectively to acrylic acid in the presence of phosphorus trichloride (used as solvent), to produce the acid chloride 3-phosphonopropionyl chloride (Equation 4.35).158... 

Soroka, M., A simple preparation of methylphosphonous dichloride, Synthesis, 450, 1977. 

To a stirred solution of 1 mmol of thiol and 1 mmol of F.t3N in 1 mL of CDC13 is added at 0 °C a solution of 0.5 mmol of methylphosphonic dichloride in 1 mL of CDC13. Excess base should be avoided to prevent racemization. After stirring for 10 min, the reaction mixture is transferred into a NMR tube and the IP-NMR spectra are recorded. 

Methylphosphonic dichloride (98%) can be purchased from Aldrich Chemical Company, Inc., or prepared according to a reported procedure.3... 

Methylphosphonic dichloride Phosphonic dichloride, methyl- (9) (676-97-1) Butyllithium Lithium, butyl- (8,9) (109-72-8)... 

In contrast to much earlier data which has demonstrated little diastereoselectivity in reactions leading to cyclic phosphorus esters or amides, the reaction between methylphosphonic dichloride and (E)-l,1,2-triphenyl-l,2-ethanediol in pyridine led to a 9 1 diastereoisomeric control in favour of the EpBp product... 

Over a period of 3 hr a solution of 65 g (0.56 mol) of methyldichloro-phosphane (methylphosphonous dichloride) in 100 mL of dry THE is added dropwise to a stirred suspension of 10 g (1.26 mol) of lithium hydride in 200 mL of THE The reaction is started without external heating and the CH3PCI2 solution is added at such a rate, that the solvent refluxes smoothly. After additional heating at reflux for at least 3 hr, the solvent is removed in vacuo and the residue is crushed under 300 mL of dry n-pentane. The suspension is then filtered, the filter cake is washed with... 

Phosphonic and Phosphinic Adds and their Derivatives.—Oxidative chlorophos-phonylation of allyl chloride gives 60% bis(chloromethyl)methylphosphonic dichloride, which may readily be monodehydrochlorinated by triethylamine. Phosphonic bromofluorides and dibromides are both obtained, together with other products, when terminal alkenes react with phosphorus trichloride or tribromide in the presence of FCIO. ... 

The l-(trimethylsilyl)methylphosphonic dichloride is prepared in large scale, but in modest yield (31%), by reaction among (chlorometliyl)trimethylsilane, phosphorus trichloride, and aluminum trichloride followed by hydrolysis with a limited amount of water. Although this procedure gives moderate yields, the large number of phosphonic diesters subsequently prepared in fair to good yields (40-71%) by alcoholysis of l-(trimethylsilyl)methylphosphonic dichloride is compensatory (Scheme 2.3). 5 ... 

Chemistry Like tabun, sarin was first prepared (1938) by Schrader s group at LG. Farben. An early synthesis involved the use of methylphosphonic dichloride (CH3P(0)Cl2) as a starting material. An interesting route involves the reaction of a tetraalkoxysilane, (RO)4Si, as a source of the alkoxy fragment in GB (Black and Harrison, 1996a). 

Methylphosphonic Acid [CAS 993-13-5] Methylphosphonic Dichloride [CAS 676-97-1] Schedule 2 Schedule 1... 

Preparation.1 First a suspension of 0.24 mole of powdered aluminum chloride in 4 moles of methylphosphonous dichloride is stirred during the addition of 4 atoms... 

Specified examples methylphosphonic dichloride dimethyl methylphosphonate... 

Substitution of the chlorine atoms in POCI3 by biphenyl-2-ol and o-cyclo-hexylphenol and in chloromethylphosphonic dichloride, CICH2POCI2, by primary aliphatic amines has been investigated. Methylphosphonic dichloride can now be obtained in good yield by a one-step process, i.e. slow addition of MeP(0)(0Me)2 to an excess of refluxing thionyl chloride, and, while the technique can be extended to the ethyl derivative, pure BuP(0)Cl2 could not be prepared. 

Sarin can be made by more than one method, but in the usual large scale route chloromethane, phosphorus trichloride and aluminium chloride, and then water react to give methylphosphonic dichloride this, on treatment with hydrogen fluoride (or sodium fluoride), gives a mixed chlorofluoride, which, by reaction with isopropyl alcohol, pelds Sarin (Figure 3). 

With the correspondingly more reactive methylphosphonic dichloride a mixture was obtained which contained traces of phosphinic acids. More important was the observation that methylphosphonic difluoride condensed smoothly with alkyl Grignard reagents to provide unsynametrical phosphinyl halides which precipitated as insoluble complexes of magnesium salts. Decomposition of the complexes with base gave the corresponding phosphinic acids, the yields of which increased as R increased... 

Methylphosphonic dichloride (10) and methylphosphonic difluoride (11) are the most important precursors of methylphosphonofluoridates 11 is invariably synthesized from 10. 

SCHEME 3. Some methods for the preparation of methylphosphonous dichloride... 

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