Methyl phenyl phosphate

Several papers related to the present topic have appeared in the literature after the submission of our manuscript, indicative of the great interest in this area. A peroxo-bridged dinuclear cobalt(III) complex, similar to 9, has been shown to efficiently hydrolyze the nonactivated methyl phenyl-phosphate [67]. Using 180-labeled D20 or 02, incorporation of 180 to the product was only observed from the solvent, indicating a true hydrolytic mechanism. 

Fig. 9.9. Proposed route of degradation of bis(acetoxymethyl) phenyl phosphate (9.35) and presumably other bis[(acyloxy)methyl] phenyl phosphates [92]...

Finally, the bacterial PTE mentioned above has also been exhaustively studied with regard to its enantioselectivity. Initial studies used the known crystal structure of PTE to identify the substrate-binding pocket. This was then rationally evolved for enhancement and relaxation of the stereospecificity.97 Most recently, a combinatorial library has been screened for the resolution of chiral phosphate, phosphonate, and phosphinate esters.124 This work identified two variants with markedly different preferences for 5p- and Rp-enantiomers of 4-acetylphenyl methyl phenyl phosphate. One variant preferentially catalyzed hydrolysis of the 5p-enantiomer by a factor of 3.7 x 105, while the other preferentially catalyzed hydrolysis of the A p-enantiomer by a factor of 9.7 x 102 - an enantioselective discrimination of 3.6 x 108. 

Phosphorylation. Treatment of phenyl phosphate with absolute methanol and excess cyclohexyl isocyanide in pyridine at 40° for 1 day affords methyl phenyl phosphate in 87% yield. 

Numerous investigations of phosphate esters hydrolysis continue to be reported. The nonenzymatic and alkaline phosphatase (AP) catalyzed rates of hydrolysis for a series of substituted methyl phenyl phosphate diesters have been measured. The result obtained suggest that reactions catalyzed by (AP) proceed through a synchronous transition state that is indistinguishable from that in solution, even though the AP active site is optimized for the loose transition state of the phosphate... 

Fig. 23 A plot of the observed pseudo-first-order rate constant for the methanolysis of 0.04mM HPNPP ( , left axis) catalyzed by 0.2mM35 2Zn(II) or 0.04mM methyl /j-nitro-phenyl phosphate (O, right axis) catalyzed by 0.4 mM 35 Zn(II) as a function of the [CH30-]/ [35 Zn(II)] ratio at 25 + 0.1 °C. Experiments done by pH jump method starting at a [CH30-]/ [35 Zn(II)] ratio of 1.0 (vertical dashed line, (pH = 9.5) and adding acid (left) or base (right). Reproduced with permission from ref. 95.

Methylphenol, see Phenol Methyl phenyl sulfone, see Fonofos Methyl phosphate, Trichlorfon IV-Methylphosphinic acid, see Glvphosate 2-Methylpropanal, see 2-Methylpropene, 2,2,4-... 

Reaction of both methyl phenyl sulphone and diphenyl sulphone with potasium in liquid ammonia [24] leads to the formation of a dianion, which cleaves to give CfiHs, isolated as benzene. The initial electron transfer cannot be dissociative, as was the case for diethyl phenyl phosphate (p. 163), since the phenyl c-radical is not detected. The radical-anions from these sulphones have sufficiently long lifetime in liquid annmonia to allow reaction with a further electron. 

The effectiveness is particularly dependent on the content of phosphor. Whereas pentaerythritol diphenyl diphosphate bums even at a loading of 35%, pentaerythritol bis(phenyl phosphate) reaches a V-0 rating at this loading, pentaerythritol bis(methyl phosphate) needs only a loading of 15% to reach a V-0 rating (69). 

Pentaerythritol bis(methyl phosphate) Pentaerythritol bis(phenyl phosphate)... 

Considerable ingenuity was required in both the synthesis of these chiral compounds695 697 and the stereochemical analysis of the products formed from them by enzymes.698 700 In one experiment the phospho group was transferred from chiral phenyl phosphate to a diol acceptor using E. coli alkaline phosphatase as a catalyst (Eq. 12-36). In this reaction transfer of the phospho group occurred without inversion. The chirality of the product was determined as follows. It was cyclized by a nonenzymatic in-line displacement to give equimolar ratios of three isomeric cyclic diesters. These were methylated with diazomethane to a mixture of three pairs of diastereoisomers triesters. These dia-stereoisomers were separated and the chirality was determined by a sophisticated mass spectrometric analysis.692 A simpler analysis employs 31P NMR spectroscopy and is illustrated in Fig. 12-22. Since alkaline phosphatase is relatively nonspecific, most phosphate esters produced by the action of phosphotransferases can have their phospho groups transferred without inversion to 1,2-propanediol and the chirality can be determined by this method. 

In practice it is often more convenient to measure the release of a phenol from an aryl phosphomonoester. Standard serum phosphatase methods employ phenyl phosphate (188), p-nitrophenyl phosphate (189), phenolphthalein monophosphate (140), or thymolphthalein monophosphate (141) where the phenol released can be determined spectrophoto-metrically [only the Bodansky method (13) uses a Pi determination]. A number of fluorogenic substrates have been used for phosphatase studies, e.g., jS-naphthyl phosphate (30, 148), 4-methylumbelliferyl phosphate (143), and 3-O-methylfluorescein phosphate (144) The main advantage here is the much greater sensitivity of fluorescence as compared with spectrophotometric assays as little as 1 pmole of 4-methyl-umbelliferone can be detected in continuous assay. 

The application of fluorogenic labeling to the determination of some organophosphate insecticides has been attempted [178,179]. Fenthion (0,0-dimethyl 0-[(4-metiiylthio)-m-tolyl] phosphorothioate), Ruelene (0-2-chloro-4-ferf.-butylphenyl O-methyl methyl-phosphoramidate), GC 6506 [dimethyl p-(methylthio)phenyl phosphate] and several other compounds which yield phenols on hydrolysis have been examined. The limits of detection for some of these labeled derivatives have been reported to be in the low nanogram range. The organophosphate Proban [0,0-dimethyl 0-(p-sulphamoylphenyl) phosphorothioate] has been determined directly without hydrolysis by dansylation of the free amino group of the molecule [180]. The derivative exhibited blue fluorescence, as compared to yellow for phenol and alkylamine dansyl derivatives. 

An ab initio study in the gas phase of the alcoholysis and thiolysis of methyl and phenyl phosphate, as models for phosphatase action, showed that they could react through either an associative or dissociative mechanism.91... 

Ethyl-methyl-phenyl- (hexafluoro-phosphat) Ell, 424 (S-Alkylier.)... 

Methyl phenyl thioether with hexadecane in an aqueous culture medium of diammonium hydrogen phosphate, magnesium sulphate, traces of ferrous sulphate containing yeast extract after inoculation with Corynebacterium equi, FO 3730 and incubation during 3 days at 30°C, afforded (R)-methyl phenyl sulphoxide in quantitative yield (enantiomeric excess 75%) (ref. 181). 

Related reactions in the oxygen series were first observed only recently as complications in Michaelis-Arbuzov reactions. The 2-halo-alkyl phosphate and phosphonate esters which occur as intermediates in the Michaelis-Arbuzov reaction of certain cyclic phosphites and phos-phonites (cf. Section II-A-1) undergo an internal alkyl exchange reaction (eq. 4) (176). Although reaction of 8-bromoethyl acetate with triethyl phosphite is said to furnish the expected product, diethyl fi-acetoxyethylphosphonate, in 28% yield (220), reaction of this same alkyl halide with dimethyl phenylphosphonite (129) gave the expected methyl phenyl(/9-acetoxyethyl)phosphinate in not greater than 5% yield (eq. 6). Instead, the major products were d-acetoxyethyl phenyl-(methyl)phosphinate (60%) (12) and a mixture of ethylene bi [phenyl-(methyl)phosphinate], [CH20P(0)(Me)Ph]2, (13) and an, ester of... 

P Aug FgReC 114H io6< Phosphate(l—), hexa-fluoro-, tetrahydridobis[tris(4-methyl-phenyl)phosphinc]tetrakis[(triphenyl-phosphine)gold rhenium(l +), 29 292 P,Li3, Lithium heptaphosphide, (LijP,), 27 227... 

PhP = phenyl phosphate, p-Tyr = 0-phospho-L-tyrosine, MeP = methyl phosphate, diMeP = dimethyl phosphate, ATP = adenosine 5 -triphosphate, ADP = adenosine 5 -di-phosphate, AMP = adenosine 5 -monophosphate, cAMP = adenosine 3, 5 -cyclic monophosphate. 

Ammonium, phenyltrimethyl-, hydroxide. See Tri methyl phenyl ammonium hydroxide Ammonium phosphate CAS 7722-76-1 EINECS/ELINCS 231-764-5 Synonyms Ammonium acid phosphate Ammonium biphosphate Ammonium dihydrogen orthophosphate Ammonium dihydrogen phosphate Ammonium phosphate monobasic... 

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