Acetyl phenyl phosphate

The characteristic features of hydrolysis of diaryl phosphate monoanions (pronounced influence of leaving group on the rate of hydrolysis, k o/k = 1.6, and AS = —25 euu7y) also fail to support a metaphosphate mechanism118>. Hydrolysis of the acetyl phenyl phosphate monoanion is likewise far slower than that... 

For example, a number of studies have been made on the metal ion-catalyzed hydrolyses of acetyl phosphate and acetyl phenyl phosphate, " but the role of the metal ion in these processes remains uncertain. Investigations of catalysis by exchange labile metal ions e.g. Ca" and Mg") have yielded conflicting results and both the nature and distribution of the kinetically significant species, as well as the positions of bond cleavage, have yet to be determined unequivocally. Chelation, charge neutralization and attack by metal-bound hydroxide have variously been proposed as important factors in acyl phosphate hydrolysis. 

Buckingham, D. A., and C. R. Clark. 1981. Reactions of acyl phosphates. Base hydrolysis of [Co(NH3)jOP03COCH3] + and the metal hydroxide promoted hydrolysis of acetyl phenyl phosphate, Aust. J. Chem., 34 1769-1773. 

This conclusion agrees with other evidence for the same mechanisms (Di Sabato and Jencks, 1961). The volume of activation for the hydrolysis of acetyl phenyl phosphate mono-anion, which is —19 cm mole in water at 60°C (Di Sabato et al., 1962), is not indicative of mechanism as it can be interpreted in several ways. 

The second group of compounds studied by Jencks et al. were acyl phosphates (Table 19.2). The acetyl phosphate dianion, which is the predominant ionic species at neutral pH, has a carbonyl band at 1713 cm Acylated phosphate monoesters, such as acetyl adenylate and acetyl phenyl phosphate absorb at higher frequencies of 1737 to 1747 cm and the structurally similar acetyl phosphate monoanion absorbs... 

Tracer 0 studies have established that base hydrolysis of coordinated acetyl phosphate in the complex [(NH3)5Co-OP03COCH3] [ifcoH = 0.53 M s at 25°C and I = l.OM (NaC104)] occurs by exclusive carbon-oxygen bond fission. The hydrolysis of the acetyl phenyl phosphate monoanion is significantly catalyzed by the exchange-inert hydroxo complex [(NH3)sCoOH] ( MOH = 2.9 X 10 M s at 25 C) which operates by... 

Eckernas and Aquilonius described a simple radioenzymatic procedure for the determination of choline and acetylcholine in brain regions of rats sacrificed by microwave irradiation [215]. The methods are based on acetylation (in phosphate buffer) of free choline with [14C]-acetylcholine using purified choline acetyltransferase. After ion-pair extraction of [14C]-acetylcholine with tertiary phenyl borate contained in toluene-based scintillation cocktail, the radioactivity was measured. 

Unsaturated phosphatidylinositol has been synthesized by Molotkovskii and Bergelson (1971) using an optically active glycerol derivative but a racemic myo-inositol moiety which was added from an acetylated inositol phosphate benzyl ester. Klyash-chitski et ah (1971) prepared a completely optically active dipalmitoylphosphatidylinositol. However, because they used benzyl and phenyl protecting groups their method is not suitable for unsaturated phosphatidylinositols. 

I, 2-0-Isopropylidene-a-D-xylo- and -ribo-furanose each gave the two possible isomers of the corresponding cyclic 3,5-(phenyl phosphate) when treated with phenyl phosphorodichloridate, but only one isomer was formed on phosphorylation of the former compound with bis-(2,2,2-trichloroethyl) phosphorochlori-date. The synthesis of a new type of branched-chain sugar phosphate, trans-3-C-cyanomethylene-3-deoxy-l,2-0-isopropylidene-a-D-erythro-pentofuranose 5-[bis-(2,2,2-trichloroethyl) phosphate], was also reported. 2,3,4,6-Tetra-0-acetyl(or benzoyl)-P-D-glucopyranose reacted with tris(dimethylamino)phosphine and carbon tetrachloride to give both anomeric oxyphosphonium chlorides (see Vol. 9, p. 48), which afforded 1,2-orthoesters with alcohols or a mixture of phenyl 1-thio-D-glucopyranosides with thiophenol. Similar treatment of 2,3,4,6-tetra-... 

Shinohara K and Sakurai H (198O) 3-Naphthyl oligophosphate. Inhibitors of photophosphorylation and H+-ATPase of spinach chloroplasts. Plant Cell Physiol 21, T5 8i+ (1981) Pyridoxal 5 phosphate, phenyl phosphate and acetyl phosphate as inhibitors of photophosphorylation competitive with phosphate. Plant Cell Physiol. 22, li 7 1 5T (1982) Light-induced ATP formation from acetyl... 

A situation similar to that in acetyl phosphate is also encountered in benzoyl phosphate76 . Electron-attracting substituents on the phenyl ring accelerate the hydrolysis of the dianion (a linear relationship exists between log khydrol and the Hammett a constants with q = 1.2 and the linear log ki,j,drol./pKa relationship is the same as for the phosphoric monoaryl ester dianions65 . On the other hand, hydrolysis of the monoanion is influenced only slightly by substituents in the phenyl ring. These observations can also be rationalized in terms of the decomposition mechanism to the POf ion formulated for 116 and 117. 

The highly electrophilic character of the POf ion would suggest a very unselective phosphorylation behavior. For example, the ratio of alkyl phosphate to inorganic phosphate obtained in hydrolyses of phosphoric esters in water/alcohol mixtures should reflect the molar ratio of water and alcohol. This is indeed found in numerous cases, e.g. in the hydrolysis of phenyl and 4-nitrophenyl phosphate monoanions 97) or of 4-nitrophenyl phosphate dianions 65) at 100 °C in methanol/ water mixtures of various compositions, as also in the solvolysis of the acetyl phosphate dianion at 37 °C 97) or of phosphoenol pyruvate monoanions 82). Calculations of the free energy of the addition reactions of water and ethanol to the POf ion support the energetic similarity of the two reactions 98) (Table 4). 

Chemical synthesis of 1-phosphate esters of 2-amino-2-deoxy-n-glucose has been described.37 127 Reaction of 3,4,6-tri-0-acetyl-2-amino-2-deoxy-a-D-glucosyl bromide hydrobromide (XLII) with triethylammonium diphenyl phosphate gave the l-(diphenyl phosphate) ester, isolated as its hydrochloride (XLIII). Cleavage of the phenyl groups and subsequent deacetylation gave 2-amino-2-deoxy-D-glucosyl phosphate as the crystalline, dipolar-ionic, monopotassium salt (XLV). 

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