Organo phosphorus compounds

The widespread use of these compounds in commerce as insecticides, oil additives, plasticisers, etc., coupled with the possibilities of studying phosphate metabolism in nucleic acids, lecithins and similar products, has stimulated a good deal of work in this field, and a number of correlations are now available. These have been summarised in correlation charts for (a) inorganic phosphorus links [22], and (b) organo phosphorus compounds [23] by Corbridge, and by Thomas and Chittenden [36]. Useful reviews of P=0 frequencies have been given by Hudson [37], and by Thomas [59]. 

A full list of the correlations which have been proposed is given in Tably 18. It should be stated at once, however, that not all of these are of equal value, and that, whilst many of them are based upon the examination of large numbers of compounds, others are only very tentative correlations based on a few compounds or on compounds of a limited type. 

The basis of each of these correlations is discussed below, and some indication is given of the degree of reliability which the correlation may be expected to show. 

Meyrick and Thompson [ 1 ] were the first to examine the infra-red and Raman spectra of a number of organo-phosphorus compounds, and as a result of studies on five phosphonates they suggested that 

This work was extended and amplified by Gore [4] and by Daasch 

R = alkyl, alkenyl, alkynyl = subs, pyrimidinyl, triazinyl bond b = satd. or unsatd. 

Q = (Un) substd. condensed hetero-aryl having a bridge head nitrogen 

Herbicides -total control over cocklebur and morning glory. 

Herbicides -useful in controlling undesirable plant growth. 

Herbicides - Gave more than 90% control of Echinochloa oryzicola,Monochoria vaginalis, Scirpus juncoides. 30 

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The reaction of cycloheptaamylose with diaryl carbonates and with diaryl methylphosphonates provides a system in which a carboxylic acid derivative can be directly compared with a structurally analogous organo-phosphorus compound (Brass and Bender, 1972). The alkaline hydrolysis of these materials proceeds in twro steps, each of which is associated with the appearance of one mole of phenol (Scheme Y). The relative rates of the two steps, however, are reversed. Whereas the alkaline hydrolysis of carbonate diesters proceeds with the release of two moles of phenol in a first-order process (kh > fca), the hydrolysis of methylphosphonate diesters proceeds with the release of only one mole of phenol to produce a relatively stable aryl methylphosphonate intermediate (fca > kb), In contrast, kinetically identical pathways are observed for the reaction of cycloheptaamylose with these different substrates—in both cases, two moles of phenol are released in a first-order process.3 Maximal catalytic rate constants for the appearance of phenol are presented in Table XI. Unlike the reaction of cycloheptaamylose with m- and with p-nitrophenyl methylphosphonate discussed earlier, the reaction of cycloheptaamylose with diaryl methylphosphonates... 

As recently as 1965, Thoma and Stewart predicted that alterations in reaction rates [in the presence of the cycloamyloses] should be anticipated whose magnitude and sign will fluctuate with the reaction type, and added that at the present juncture, it is impossible to sort out confidently. . . which factors may contribute importantly to raising or lowering the activation energy of the reaction. In the short interval between 1965 and the present, a wide variety of cycloamylose-induced rate accelerations and decelerations have, indeed, been revealed. More importantly, rate alterations imposed by the cycloamyloses can now be explained with substantially more confidence. The reactions of derivatives of carboxylic acids and organo-phosphorus compounds with the cycloamyloses, for example, proceed to form covalent intermediates. Other types of reactions appear to be influenced by the dielectric properties of the microscopic cycloamylose cavity. Still other reactions may be affected by the geometrical requirements of the inclusion process. 

The lithium salt of the stabilized anion derived from dithiane also provides displacement of halogen at phosphorus for the generation of species readily converted into additional functionalized organo-phosphorus compounds.69 The resultant materials are suitable for a wide range of applications, both as final products and as reagents for additional transformations. 

Comparison of the action of organo-phosphorus compounds on mammals and insects 183... 

Although organo-phosphorus compounds are not directly flonoemed with the peripheral endings of sympathetic fibres we may complete the picture by noting that here adrenaline or noradrenaline are liberated and that their receptor patches are blocked by priscol and dibenamine (for formulae, see p. 41). 

Just as O.M.P.A. is oxidized enzymically to a cholinesterase inhibitor of greatly enhanced activity (p. 173), so also are systox (p. 179), thimet and certain related sulphur organo-phosphorus compounds. 

Comparison of the Action of Organo-phosphorus Compounds on Mammals and Insects... 

As mentioned above, to apply to insects a conclusion drawn directly from tests on mammals may sometimes be misleading.3 For instance, American cockroaches have a remarkably high tolerance for acetylcholine,4 but, on the other hand, a substance showing some of the pharmacological properties of acetylcholine does accumulate in flies and cockroaches poisoned with D.D.T. Similarly, Hopf, working with locusts, was unable to demonstrate any increase in toxicity of eserine or T.E.P.P. resulting from the subsequent injection of acetylcholine. From this, Lord and Potter infer that acetylcholine may not be directly involved in the insecticidal action of organo-phosphorus compounds, either because the enzymes which hydrolyse acetylcholine are not inhibited to any considerable extent in vivo or because the functions performed by acetylcholine in mammals are performed by another substance in insects. 

These authors claim, therefore, that it cannot safely be assumed that the toxic action of organo-phosphorus insecticides to insects is due to the inhibition of cholinesterase, although in the case of some insect species there is considerable evidence that an enzyme capable of hydrolysing acetylcholine may be important in the toxic action of the organo-phosphorus compounds.5 Further evidence on this point6 showed that with... 

Organo-phosphorus compounds and fly control. Certain organo-phosphorus compounds have been used as fly-controlling agents, where fly populations have become resistant to chlorinated hydrocarbons such as D.D.T.2 The compounds are applied in the form of sugar baits which attract the flies and so increase the effectiveness of the poisons. 

We must stress that organo-phosphorus compounds are not specific inhibitors for the cholinesterases, but are rather inhibitors for enzymes possessing carboxylic esterase activity. All the enzymes mentioned below will hydrolyse carboxylic esters. However, not all esterases are inhibited, for example, A-esterase which hydrolyses phenyl acetate is not inhibited by organo-phosphorus compounds. 

Protection in vitro of cholinesterases against organo-phosphorus compounds... 

Further interesting observations along these lines2 are awaited especially in connexion with poisoning by organo-phosphorus compounds. 

Kosolapoef, G. M. (1950). Organo Phosphorus Compounds. Wiley and Sons. 

H. B. Kagan, Chiral Ligands for Asymmetric Catalysis, in J. D. Morrison, ed., Asymmetric Synthesis, Vol. 5, Chap. 1, Academic Press, New York, 1985 H. B. Kagan and M. Sasaki, Optically Active Phosphines Preparation, Uses and Chiroptical Properties, in F. R. Hartley, ed., The Chemistry of Organo-phosphorus Compounds, Vol. 1, Chap. 3, John Wiley Sons, New York, 1990. 

Vamek, A.A. Kuznetsov, A.N. Petrukhin, O.M. Calculation of the indexes of extract-ability of some neutral organo-phosphorus compounds within the framework of electron density functional method. Koord. Khim. (Russ.) 1991, 17, 1038-1043. 

R ac.tL jity umpoiung and 6ynthztic e.quivaJte.ntA are very fruitful concepts in modern organic synthesis, in particular for the multistep preparation of natural compounds. In this area, organo-phosphorus compounds can be useful tools, particularly for reversible umpolung by heteroatom exchange (.1.-4). 

An important aspect of this paper is the demonstrated facile formation of the P-O-P system by nucleophilic attack of phosphoryl oxygen on the four-coordinated phosphorus center. This result confirms the reaction schemes proposed earlier for a number of reactions, important from the synthetic point of view of organo-phosphorus compounds (9-13) and polymers (1 A). 

Chromatographic Separation of Acidic Organo-phosphorus Compounds... 

There are, of course, other methods for treating fibers and rayon fabrics with organo-phosphorus compounds (9-13) in order to improve their flame-retardant properties. However, the modified fibers present the changed physical and mechanical properties due to large additives utilised and often these additives are eliminated after repeated washings. 

It has been also shown that under cold plasma action some of the organo-phosphorus compounds (triphenyl phosphate or tricresyl... 

Branching of the O-alkyl ester chain of organo-phosphorus compounds may introduce an asymmetric center, which together with an asymmetric substituted phosphorus atom creates a number of stereoisomers. Diastereoisomers may even be separated on a conventional capillary GC column. This is, for instance, the case with the nerve gas soman, which usually produces two peaks in a gas chromatogram. Although this is characteristic for identifying soman, it also increases the GC/MS detection limit by a factor of two. 

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