Triesters, phosphoric acid

HO A phosphoric acid monoester HO A phosphoric acid diester 0 1 R" A phosphoric acid triester A carboxylic acid ester... 

The outlined scheme can also be used to calculate the amount of phosphoric acid triesters. In that case the difference must be formed of the total phosphorus content minus that of free phosphoric acid, phosphoric acid monoester, and phosphoric acid diester. The resulting value is then multiplied with the calculated molecular mass of the triester. 

The neutral surfactant is measured after fixing of the ionic substances on a combined anionic/cationic ion exchange column. Volatile substances in the eluate are determined by gas chromatography and nonvolatile substances are measured gravimetrically. In the bulk of the neutral compounds phosphoric acid triesters may be present. This part is additionally determined by atom emission spectroscopy. 

A variety of phosphoric acid triesters and their derivatives are used as pesticides. Although there are no natural phosphorotriesters, those artificial ones undergo decomposition in the soil, implying that some microorganisms exist which are capable of hydrolysing them. The first report on a stereoselective enzymatic phos-photriester hydrolysis was pubhshed in 1973, when Dudman and Zerner succeeded... 

Phosphotriesterase from P. diminuta (PTE) was found to exhibit high hydrolytic activity towards various types of tetracoordinated phosphorus acid esters. Apart from the phosphonothionate 92, phosphoric acid triesters 94 (Equation 45), °" benzenephosphonic acid diester 95 (Equation 46) ° and methyl-phenylphosphinic acid ester 96 (Equation 47) were also stereoselectively hydrolysed under kinetic resolution conditions. Of course, in the case of the latter three kinds of substrates, half of the reacting ester was irreversibly lost due to the formation of achiral phosphorus acids. 

A labeled phosphoric acid triester is formed by phosphorylation of an alcohol with a labeled phosphoric diester imidazolide [187],[188]... 

Labeled phosphoric acid triesters and diamides have been synthesized from phosphoric diimidazolide.tl92],tl93] This method was found to be superior to that involving the dichloridate (phosphoric dichlorides). 

Whereas there are relatively few phosphoric acid diesters of medicinal or toxicological interest, phosphoric acid triesters are of greater significance. Such compounds occur mainly as prodrugs, as discussed in the present section, or plasticizers and insecticides (see next section). 

The interest of glycosyl phosphoric acid triester moieties (9.43) as brain transport vectors is seemingly not limited to AZT and analogues. Indeed,... 

A variety of industrial compounds are also phosphoric acid triesters of interest in xenobiotic metabolism and molecular toxicology. First, we examine here a few triesters used for example as plasticizers, hydraulic fluids, and flame retardants. In the second part of the section, insecticides of the phosphoric acid triester class will be discussed. 

Insecticides of the phosphoric acid triester class include paraoxon (9.49) and dichlorvos (9.50). The phosphorothioate derivative parathion is a relatively non-toxic insecticide that undergoes monooxygenase-catalyzed oxidative desulfuration to paraoxon [105] (see also Chapt. 7 in [59] see Sect. 9.3.6). Paraoxon itself, like its congeners and the P-halide nerve gases, is highly toxic through its potent inactivation of acetylcholinesterase [69]. 

Ingerowski G, Friedle A, Thumulla J (2001) Chlorinated ethyl and isopropyl phosphoric acid triesters in the indoor environment - an inter-laboratory exposure study. Indoor Air Int J Indoor Air Qual Clim 11 145-149... 

Shah M, Meija J, Cabovska B, Caruso JA (2006) Determination of phosphoric acid triesters in human plasma using solid-phase microextraction and gas chromatography coupled to inductively coupled plasma mass spectrometry. J Chromatogr A 1103 329-336... 

Our aim was to synthesize phosphoric acid triesters XXV and XXVI by the reaction of chloromethyl methylnitrosamine with the corresponding silver salts. Workup allowed the isolation of crystalline substances which were shown to be triesters XXVII and XXVIII. By variation of the N-alkyl group in the nitrosamine from methyl to ethyl, the corresponding phosphoric ethyl ester were obtained. Thus it seems clear that the N-alkyl group was transferred to the oxygen of phosphorus... 

Phosphoric acid triesters in human blood plasma have been determined by GC-ICP-MS after SPME,27 after their separation from blood plasma, with detection limits of 50ngl-1 for tripropyl phosphate, 17ngl 1 for tributylphosphate and 24ngl 1 for triphenylphosphate. 

The phosphoric acid triesters (organophosphates, not to be mistaken for organophosphorous pesticides) are, like phthalates, plasticizers mixed into polymers to increase flexibility and workability. Unlike phthalates they are remarkable flame retardants as well. The total European production of phosphorous-base flame... 

Haraguchi K, Yamashita T, Shigemori N. 1985. [Sampling and analysis of phosphoric acid triesters in ambient air.] Taiki Osen Gakkaishi 20 407-415. (Japanese). 

Sasski, K., Takeda, M., Uchiyama, M. (1981) Toxicity, absorption and elimination of phosphoric acid triesters by Idllifish and gold fish. Bull. Environ. Contam. Toxicol. 27, 775-782. 

Other HTPs have been synthesized in the presence of hydrogen peroxide in combination with phosphoric acid triesters (i.e., tricresyl phosphate) or halogen-containing Ni, Pt, Pd compounds, Ag salts (e.g., AgNOs, AgjPOj at 118 °C. The yield was 60% and the functionality varied between 2.2 and 2.5 105 107)... 

In view of their extreme sensitivity to hydrogen chloride, the synthesis of aliphatic phosphorous acid triesters from phosphorus(V) oxychloride and alcohols can only be carried out in the presence of a molar mixture with inorganic or organic bases ... 

The modulation of the coordination to the transition metal has not necessarily positive implications on the reactivity. For instance, we observed [50] that the copper(II) complex (8) of tetramethyl-l,2-diaminoethane catalyzes the hydrolysis of the phosphoric acid triester PNPDPP via an electrophilic mechanism which involves the pseudointramolecular attack of deprotonated water, as illustrated in (9). The electrophilic mechanism contribution to the hydrolytic process totally disappears in micellar aggregates made of the amphiphilic complex (10). Clearly, micellization does not allow the P O group of the substrate to interact with the metal ion. This could be a result of steric constraint of the substrate when bound to the micelle and/or the formation of binuclear dihydroxy complexes, like (11), in the aggregate. So, in spite of the quite large rate accelerations observed [51] in the cleavage of PNPDPP in metallomicelles made of the amphiphilic complex (10), the second-order rate constant [allowing for the difference in pXa of the H2O molecules bound to copper(II) in micelles and monomers] is higher for (8) than for (10) (k > 250). 

The phosphoric acid triesters possess excellent anti-wear properties, see Chapters 3 and 6, and sufficient oxidative stability. Their disadvantage is their ability to hydrolyse, which depends significantly on the structure of the ester short chain alkyl esters and aryl esters hydrolyse more rapidly than the long-chain alkyl esters. The triaryl versions of phosphate esters are relatively unique among hydraulic fluids because of their self-extinguishing properties, the fluid does not create enough energy to support its own combustion in a fire [65]. 

Ingerowski G, Friedle A, Thumalla J (2001) Chlorinated Ethyl and Isopropyl Phosphoric Acid Triesters in the Indoor Environment- An Inter-Laboratory Exposure Study. Indoor Air 11, 145-149. 

CC,H4C H4CNH Reaction with phosphorous acid triesters 5,... 

Reaction with ethylene oxide 5, 3.3.5,5.2 Reaction with P(red) or P4OJ 5, 3.3.5.1 Reaction with P4OJ 5, 3.3.5.1 Reaction with P4Seio 5, 3.3.7.1 Reaction with phosphoric acid triesters 5. 

Synonyms Cocamidopropyl phosphatidyl PG-dimonium chloride Phosphoric acid, triester with N-(2,3-dihydroxypropyl)-N,N-dimethyl-3-[(1-oxococo-alkyl) amino-1-propanaminium chloride... 

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