Phosphorus insecticide

By this procedure it is possible to derivatize all of the 10 investigated organo-phosphorus insecticides (Fig. 1). 

Phosphorus-containing pesticides la 254 Phosphorus insecticides lb 83 Phosphorus pesticides lb 32 Photochemical activation lb 13 Photochemical reactions lb 15,17 Photodiodes la 24,29 Photo effect, external la 24 -, internal la 24, 29 Photo element la 24,29 Photography, exposure times la 137 -, instmmentation la 137 Photomultiplier la 25ff -, disadvantages la 27 -, energy distribution la 26 -, head on la 27 -, maximum sensitivity la 28 -, side on la 27 -, spectral sensitivity la 28 -, window material la 28 Photocells la 25 Phloxime lb 116... 

Of the three organic phosphorus insecticides—hexaethyl tetraphosphate, tetraethyl pyrophosphate, and parathion—the first two have been shown to be mixtures (36) that contain tetraethyl pyrophosphate as the principal active ingredient. Several methods have been proposed for the determination of this compound in the commercial products (25, 35). All are based on the separation of the tetraethyl pyrophosphate from the related ethyl phosphates, followed by its hydrolysis to diethyl orthophosphoric acid and titration with standard alkali. Both hexaethyl tetraphosphate and tetraethyl pyrophosphate are soluble in water and are rapidly hydrolyzed to monoethyl and diethyl orthophosphoric acid. This rapid hydrolysis to nontoxic products greatly limits the duration of the in- secticidal effectiveness of tetraethyl pyrophosphate, but it also eliminates the danger of toxic residues on the crops treated. 

Organochlorine and organo-phosphorus insecticides Reverse osmosis [270,523]... 

The pure compound is a pale yellow, nearly odourless oil, soluble in organic solvents, but almost insoluble in water. Averell and Norris2 describe the detection of minute quantities of parathion (20 /ig.) in spray and dust, by reduction with zinc, diazotization and coupling with an amine to give an intense magenta colour. It is effective (at concentrations of 25-600 p.p.m.) against many insect species, but of course, like the majority of organo-phosphorus insecticides, it is toxic to man and to animals. 

Among phosphorus insecticides containing also nitrogen and sulphur we may mention 00 -diethyl-/S-/ -diethylaminoethyl phosphorothiolate (X). It was prepared (i) from diethyl phos-phorochloridate1 and sodium / -diethylaminoethyl mercaptide, (ii) from sodium diethyl phosphite and / -diethylaminoethyl thiocyanate, (iii) by the isomerization of OO -diethyl-O"-/ -diethylaminoethyl phosphorothionate (XI) obtained from / -diethylaminoethoxide and diethyl phosphorochloridothionate. 

Lord and Potter1 have claimed that it is important not to generalize the known anti-cholinesterase activity of organo-phosphorus insecticides in mammals to account for their action in insects. They could find no specific cholinesterase in two species of insect, but there was a general esterase inhibited by the insecticides. 

Hopf2 concludes that although insect nerve tissues produce substances that simulate acetylcholine and a cholinesterase which is inhibited by organo-phosphorus insecticides, these substances (in locusts at any rate) are not antagonized by atropine. Furthermore, tubocurarine does not poison insects, although it is active in warm-blooded animals and affects the neuromuscular junctions (see pp. 36, 37). In short, different physiological mechanisms appear to be at work in insects. In particular, it seems that acetylcholine, when injected into a variety of insects, has no marked toxic action. It seems then that, in some... 

In this connexion we will stress again that, although there is often a correspondence between toxic action of organo-phosphorus insecticides and anti-cholinesterase activity (p. 67), the relationship is not always simple. Thus parathion (p. 178), not itself an esterase inhibitor, is converted in vivo into an enzyme inhibitor.1 On the other hand, Aldridge2 has shown that the inhibitor paroxan can be hydrolysed enzymically to produce non-inhibitory substances. 

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... 

Martin, Hubert (1949). Review of Organo-phosphorus Insecticides, in Mfg Chem. 20, 158. 

Coates, H. The chemistry of phosphorus insecticides. Am. Appl. Biol, 36 156-159, 1949. 

Ronnel has not been shown to potentiate the effect of other commonly used organo-phosphorus insecticides. 

Concomitant conditions Use with caution in the following patients exposed to extreme heat or phosphorus insecticides atropine or related drugs because of additive anticholinergic effects those in a state of alcohol withdrawal those with dermatoses or other allergic reactions to phenothiazine derivatives because of the possibility of cross-sensitivity those who have exhibited idiosyncrasy to other centrally acting drugs. 

Gunther, F. A. Iwata, Y. Papadopoulou, E. Berck, B. Smith, C. A. Rapid field method for estimating organo-phosphorus insecticide residues on crop foliage. Bui1. Environm. Contam. Toxicol., 1980, 24, 903. 

Occupational Exposure during the Manufacture and Formulation of Pesticides. PHEW (NIOSH) No. 78-174 US-GP0, Washington, DC (1978), 429 pp., 343 refs., 5 appendices. Bidstrup, P., J.A. Bonnell and A. Beckett, "Paralysis following Poisoning by a New Organic Phosphorus Insecticide (Mipafox)", Brit. Med. J.(l) 1068-1072 (1953). As cited in ref. 164. 

Glutathione 5-transferases catalyze the reaction of electrophiles with glutathione to form thioether conjugates. Substrates include alkyl halides and organo-phosphorus insecticides. In the HPLC method of Brown et al. (1982), styrene oxide was used as the substrate and the activity was measured by the formation of conjugates between the styrene oxide and the reduced glutathione conjugates. 

Barnes, J.M. 1954. Organo-phosphorus insecticides. The toxic action of organo-phosphorus insecticides in mammals. Chem. and Ind. January 2, 1954, pp. 478-480. 

Sumerford, W.T., W.J. Hayes, J.M. Johnston, K. Walker and J. Spillane. 1953. Cholinesterase response and symptomatology from exposure to organic phosphorus insecticides. AMA Arch. Ind Hyg. Occup. Med. 7 383-398. 

---