Phosphate monoesters oxidation

The phosphitylation procedure (step a) proceeds in the presence of EtN(i-Pr)2 (DPEA) and the subsequent oxidation by TBHP (step b). The cyclic phosphate is deprotected stepwise (steps c and d) and serves as a model for the physiological milieu . It has been possible to deliver phosphate monoesters via steps c and d in a controllable manner from cyclic phosphotri-esters at physiological pH. 

A simple Co(m) complex (32) whose structure closely resembles those of the above-mentioned enzymes (29-31) has been developed [95], lsO labeling studies showed that an oxide group that is bridging the two metal centers cleaves the bridging phosphate monoester in 32 (Figure 6.21). Kinetic isotope effect studies found that p-nitrophenyl... 

Figure 1 Active site structure of PAPs and proposed mechanisms for their catal)dic hydrolysis of a phosphate monoester, involving either a terminal (Mechanism A) or bridging (Mechanism B) hydroxide. The Fel, containing the tyrosine hgand, is in the Fe(III) oxidation state. (Reprinted with permission from Ref. 9. 2002 American Chemical Society)...

Organic phosphorus can be strongly adsorbed on ferric oxide surfaces in soils (Anderson and Arlidge, 1962) and sediments (de Groot and Golterman, 1993). Indeed, in most acidic soils and sediments the amount of iron oxide in the substrate governs the extent of adsorption of organic phosphorus (Anderson et al., 1974 Harrison, 1987 Pant et al, 1994). Phosphate monoesters such as myo-inositol hexakis-... 

Sorption of phosphate monoesters on iron and aluminum oxide surfaces and clays... 

Monoester salts of phosphoric acid derived from fatty alcohol ethylene oxide adduct or alkylphenol ethylene oxide adduct useful as surfactants are prepared by addition of R(OCH2CH2) OH, alkali fluoride and (C12P0)20 in a molar ratio of 0.9-1.5 0.05-1 1.0 at -50 to + 10°C and hydrolysis of the Cl-containing intermediates with a base. The monoester phosphates showed comparable or better washing and foaming efficiency than commercial products [12]. 

Fig. 9.10. Partial metabolic scheme of tris(2-methylphenyl) phosphate (9.44) showing hydrolysis to the diester 9.45, the monoester, and phosphate. Also shown is a reaction of oxidation to the hydroxymethyl analogue 9.46, followed by cyclization to the toxic cyclic phosphate 9.47...

A detailed study of the specific rates of solvolysis of N,N,N, N -tetra-methyldiamidophosphorochloridate (80) (TMDAPC) with analysis in terms of the extended Grunwald-Winstein equation has been reported (Scheme 19). The stereochemistry of nucleophilic attack at tetracoordinate phosphorus was also discussed." The initial reaction of bis (2,4-dinitrophenyl) phosphate (BDNPP) (81) with hydroxylamine involves release of 1 mol 2,4-dinitrophen-oxide ion and formation of a phosphorylated hydroxylamine (82), which reacts readily with further NH2OH, giving the monoester (83). The intermediate (82) also breaks down by two other independent reactions one involves intramolecular displacement of aryloxide ion (83) and the other involves migration of the 2,4-dinitrophenyl group from O to N and formation of phosphorylated 2,4-dinitrophenylhydroxylamine (84) (Scheme 20)." ... 

A new one-pot method has been developed by Kraszewski for the synthesis of aryl nucleoside phosphate (3a-p) and phosphorothioate (4a-p) diesters. This method, based on H-phosphonate chemistry, employed diphenyl phosphoroch-loridate and a series of phenols. Depending on the substituents present on the phenols, oxidation conditions were optimized to avoid competing hydrolysis. A versatile procedure that permits easy access to H-phosphonoselenoate monoesters (5) has been developed by Stawinski. These monoesters, obtained by selenisation of a phosphinate using triphenylphosphine selenide in combination with trimethylsilyl chloride, reacted with a suitable nucleoside in pyridine/acetonitrile in the presence of diphenyl phosphorochloridate to yield... 

Alkyl phenol ethoxylates can also react with P4O10 yielding alkyl phenol etherphosphates as a mixture of mono-/diesters or with maleic anhydride to yield maleic acid monoesters, which then react with NaHS03 to yield sulphosuccinate monoesters. Alkylphenolpolyglycolether sulphates, phosphates or sulphosuccinates are mainly used as primary anionic emulsifiers for the manufacturing of acrylic, styrene/acrylic or vinyl acetate co-polymer dispersions. Another type of non-ionic emulsifier is block copolymers of ethylene oxide with propylene oxide. 

Mono- and diesters are essential to life and represent some of the most important biological molecules. An example of an important monoester is glucose-6-phosphate, which represents the first intermediate compound formed when glucose is oxidized to supply energy for the body (Chapter 13) ... 

Experiments with labeled glucose, phosphate, and nicotinamide indicate that there is a rapid equilibrium between the oxidized and reduced forms of DPN (212). In a study of the incorporation of phosphate into the different pyridine nucleotide coenzymes, it was found, surprisingly, that there was a rapid turnover of the monoester phosphate grouping of TPNH. This finding contrasts with a much slower turnover of the pyrophosphate grouping of the molecule. Although there is a rapid regeneration of the monoester phosphate, there appears to be a slow equilibrium between DPN and the DPN portion of TPN. 

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