Methylphosphate

CuH16N507P i ch4o Adenosine 5 -methylphosphate, methanolate ADMOPM 38 516... 

Methylcytidine (correction to previous paper), platinum complex of cytidine 3 -phosphate, l- 3-D-arabinofuranosylcytosine 5 -phosphate (2 independent analyses), 2,2 -anhydro-l-/3-D-arabinofuranosyl-5-dimethylsulphonio-6-oxocytosine chloride, 2,2 -anhydro-l-(3, 5 -di-0-acetyl-j3-D-arabinofuranosyl)-5-chloro - 6 - oxocy tosine, 2,l -anhy dro -1 - - D -arabinofuranosylcy tosine 2 5 -diphosphate, and 6,2 -anhydro-1 - 3-D-arabinofuranosyl-6-hydroxycytosine. Adenosine 5 -triphosphate disodium salt, adenosine 5 -methylphosphate, adenosine 5-methylphosphonate, 8-methyladenosine 3-phosphate, 2-aza-adenosine, 9-ce-D-arabinofuranosyladenine, 8,2 -anhydro-9- 3-D-arabino-... 

Thymidine cyclic 3, 5 -(methylphosphate), C-165 Thymidylyl-(5 - 3 )-5 -thymidylic acid, T-112... 

Aminouridine, 5-vinyl-2 -deoxyuridine, 5-ethynyl-2 -deoxyuridine, 5-nitro-l-05-D-riburonosyl)uracil, uridine 5 -methylphosphate. ... 

Enzymes are powerful catalysts. Enzyme-catalyzed reactions are typically 10 to times faster than their uncatalyzed counterparts (Table 16.1). (There is even a report of a rate acceleration of >10 for the alkaline phosphatase-catalyzed hydrolysis of methylphosphate )... 

Also, Chin s dihydroxy-bridged dicobalt(III) complex 10 provides one of the largest rate enhancements ever observed for phosphodiester hydrolysis [36]. Reaction with the activated phosphodiester methyl(p-nitrophenyl)phosphate (MNPP) yields 11. A crystal structure is available for the analogous dimethylphosphate complex in which the Co ions are 2.9 A apart. At pH 7 and 45 °C 11 releases p-nitrophenolate with k = 0.1 s 1 which corresponds to a nearly 10I2-fold rate enhancement over spontaneous hydrolysis of the substrate. The product of the reaction is a methylphosphate-bridged complex. Based on the pH rate profile and on... 

In Table 5 the values for the free standard enthalpies for the reactions of neutral donors and anion donors with vanadyl acetylacetonate are listed. It can be seen that towards the reference molecule iodide ion is a somewhat weaker ligand than propanediol carbonate, whereas the bromide ion is between tri-methylphosphate and acetone, and the chloride ion between DMF and DMSO 22>. The fluoride ion and the NCS -ion are stronger donors than all neutral donors but are somewhat weaker than the azide and the cyanide ion. 

A related methylphosphate/phosphonate oligomer has primary alcohol end groups, and can coreact with amino resins to form a water-resistant flame retardant resin finish on paper or on textile substrates. The application of this oligomer with a coreactant methylolmelamine on cotton upholstery fabric can enable furniture covered with this fabric to pass the Consumer Product Safety Commission s proposed cigarette ignition test. 

For aromatic amines (pyridines and imidazole), phosphoramidates were not detected in water. Yet the reaction appears to be essentially the same as in the former cases, because the formation of phenyl-methylphosphate, which was observed in methanol, was presumed to occur by the methanolysis of phosphoramidate. 

Figure 17. Relative gas phase energies of methylphosphate ester hydrolysis for the structures given in Figure 16.

Table 2. Calculated and experimental values for 0 equilibrium and kinetic isotope effects in methylphosphate monoanion reactions.

A theoretical study based on MP2/6-31+G(d,p) and HF/6-31G(d) ab initio quantum mechanical calculations coupled with Langevin dipoles (LD) and polarised continuum (PCM) solvation models have been carried out by Florian and Warshel [387] to achieve a first systematic study of the free energy surfaces for the hydrolysis of methylphosphate in aqueous solution. The important biological implication of this work is the fact that since the energetics of both the associative and the dissociative mechanics are not too different, the active sites of enzymes can select either mechanism depending on the particular electrostatic environment. This conclusion basically means that both mechanisms should be considered, and this fact seems to contradict some previous studies which have focused on phosphoryl transfer reactions. 

Figure I. Schematic structures of model anionic receptor sites, ammonium methylphosphate (AMP), ammonium methylsulphate (AMS), and the eight compounds studied...

In this study both the PCILO and empirical energy methods were used to characterize intermolecular interactions of typical N-substituents of rigid opiates with model anionic receptor sites. Ammonium methylphosphate (AMP) and ammonium methylsulfate (AMS) were used as model anionic receptor sites. Interaction energies of eight compounds which, as N-substituents. modulate different antagonist/agonist potencies... 

Fig. 2. Structures of glycans found in Dictyostelium discoideum. Structures of known carbohydrate components in Dictyostelium discoideum. The structures have been determined by physical/chemical methods or by the analysis of radiolabeled materials. (A) Lipid-linked oligosaccharide precursor of N-linked oligosaccharides [14] (B) truncated lipid-linked oligosaccharide precursor found in mutant strains HL24I and HL243[I4] (C) oligosaccharide with GlcNAc residues at the intersecting position and locations of the methylphosphate esters [16].

Andrus A, Beaucage SL. 2-Mercaptobenzothiazole An improved reagent for the removal of methylphosphate protecting groups from oligodeoxynucleotide phosphotriesters. Tetrahedron Lett 29 5479-5482, 1988. 

A case in which the distonic ion is considerably more stable than the conventional radical cation involves organophosphorus esters . Deuterium labelling studies combined with CA mass spectra indicate that the M of dimethyl methylphosphate undergoes the keto to enol isomerization reaction shown in equation 13 prior to dissociation". ... 

Cr(III) is not normally regarded as a good catalytic species, probably because it is substitution inert and not easily oxidized or reduced. Nevertheless, addition of Cr(III) does accelerate the Ce(IV) oxidation of allyl alcohol. There is also a report that [Cr(NH3)5(OH2)] increases the rate of 2,4-dinitrophenylethyl-methylphosphate hydrolysis in aqueous solution. ... 

The above results indicate that the adsorption site did not affect the electrostatic energy or van der Waals energy, even in cases in which the molecular sizes of the adsorbents (PAH), were quite different. Ion-dipole interactions were negligible, unlike the ion-pair formation of tetrabutyl and methylphosphate ions, with the van der Waals energy being the main contributor to adsorption. ... 

Flynn and Lamb have reported that solvolysis of meihylprednisolone-21-phosphate in dilute aqueous solution (less than 0.005 M) is qualitatively similar to that observed for the methylphosphate and other simple monoalkyl phosphates, particularly in the pH range 3-8. In more concentrated solutions (greater than 0.02 M), however, there is an acceleration of reaction velocities and marked deviation from the expected pH dependency. This change in chemical behavior is attributed to association colloid formation, and this interpretation is supported by independently determined critical micelle concentration values. 

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