Dialkylphosphate

The first step in the degradation of phosphate and phosphorothioate esters is hydrolysis, and substantial effort has been directed to all groups. Investigations have also been directed to the use of their degradation products as a source of phosphate for the growth of bacteria, and a wide range of phosphates, dialkylphosphates, and phosphorothioates has therefore been examined as sources of phosphorus (Cook et al. 1978). 

Sometimes the choice of the solvent can exert a great influence on ion selectivity, e.g., whereas calcium dialkylphosphate in dioctylphenyl phosphonate... 

In the first class (which includes metal phosphonates, metal phosphinates, and related mono- and dialkylphosphates) both the organic and inorganic moieties belong to a structural unit repeated in an ordered 1-D, 2-D, or 3-D arrangement. 

Metal Phosphonates and Phosphinates, and Related Mono-and Dialkylphosphates... 

Lu, C., R. Bravo, L.M. Caltabiano, R.M. Irish, G. Weersekera, and D.B. Barr. 2005. The presence of dialkylphosphates in fresh fruit juices Implications for organophosphorus pesticide exposure and risk assessments. J. Toxicol. Environ. Health A 68(3) 209-227. 

Synthesis of model systems analogous to histamine led to the pharmacologically interesting aminoethylpyrazoles.32-34 Dimethyl-carbamates and dialkylphosphates of 5-hydroxypyrazoles have been used practically as choline esterase inhibitors.35-41 Such compounds as Isolan (2), Pyrolan (3), and Pyrazoxon (4), which are too toxic for pharmacology, are used as systemic insecticides. There is evidence that 3,5-dimethylpvrazole has a stimulating action on plants.42... 

Fig. 17.73. Ketone —> alkane reduction via enol phospho-noamidates (for one way to prepare A, see Figure 13.24) and enol dialkylphosphates (one way to prepare B is to use a combination of the methods depicted in Figures 13.20 and 13.25). The cleavage of the Cjjj2—0 bond of the substrates occurs in analogy to the electron transfers in the formation of methylmagnesium iodide (Figure 17.44). The alkenyl-lithium intermediates are pro-tonated in the terminating step to afford the target alkenes.

Low reactivity of ot,(B-unsaturated ketones and sterically hindered ketones as well as separation of reaction products from phosphine oxide are a few disadvantages of the classical Wittig reaction. Phosphonate anions are stronger nucleophiles than related phosphoranes thus, alkenate hindered ketones under mild conditions. The dialkylphosphate (R2PO4), the other product of the HWE reaction, can easily be removed from the reaction mixture because it is soluble in water. 

Takade DY, Reynolds JM, Nelson JH. l-(4-Nitrobenzyl)-3-(4-tolyl)triazene as a derivatizing reagent for the analysis of urinary dialkylphosphate metabolites of organophosphorus pesticides by gas chromatography. J Agric Food Chem 2005 27 746-53. 

Oglobline AN, O Donnell GE, Geyer R, Holder GM, Tattam B. Routine gas chromatographic determination of dialkylphosphate metabolites in the urine of workers occupationally exposed to organophosphorus insecticides. J Anal Toxicol 2001 25 153-7. 

H33. Hobbiger, F., Effect of nicotinhydroxamic acid methiodide on human plasma cholinesterase inhibited by organophosphates containing a dialkylphosphate group. Br. J. Pharmacol. Chemother. 10, 356-362 (1955). 

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