Pentafluorophenyl carbonate

Byeon et al. [23] described a fluorimetric method for (z>)-penicillamine using 9-fluorenylmethyl pentafluorophenyl carbonate and acetonitrile. Capsules containing penicillamine were extracted with water and then filtered. The solution was incubated at 70 °C for 40 min with borate buffer solution. After cooling, the mixture was extracted with diethyl ether and the fluorescence of the aqueous phase measured at (excitation = 260 nm, emission = 313 nm). The calibration graph was linear for 0.4-5.0 pM of penicillamine with a coefficient of variation of 0.4%. 

S. Chalais, A. Cornelis, P. Laszlo, and A. Mathy, Tetrahedron Letters, 26, 2327 (1985). 9-Fluorenylmethyl pentafluorophenyl carbonate. 

Fluorenylmethyl pentafluorophenyl carbonate, 134 Peroxides Endoperoxides Oxygen, singlet, 228 Phenols... 

C21H11F503 9-fluorenytmethyl pentafluorophenyl carbonate 88744-04-1 25.00 1.4126 2 32798 C21H2lSb tris(4-methylphenyl)stibine 5395-43-7 16.00 1.3595 1... 

In 1998, Ube Industries, Ltd. discovered that pentafluorobenzoates, such as methyl pentafluorobenzoate (62), can be used as additives in small quantities [92], Also, in 1999, Toyota Central R D Labs found that fluorinated benzoates, such as methyl 2,6-difluorobenzoate (63), can be used as additives in small quantities [93], and in 2002, Ube Industries, Ltd. found that pentafluorophenol compounds, such as pentafluorophenyl methanesulfonate (64) and methyl pentafluorophenyl carbonate (65), can be used as additives in small quantities [94]. 

Bis(pentafluorophenyl) sulfite added to a soln. of N-r rFbutyloxycarbonylglycine in DMF containing 1 eq. pyridine, and stirred for 0.1-1 h at 20° - product. Y 96% (70% from pentafluorophenol with DCCI as condensing agent). There was no racemization with a-subst. derivs. F.e.s. A.V. Hina et al., Izv. Akad. Nauk SSSR Ser. Khim. 1988, 2816-8 with methyl pentafluorophenyl carbonate cf. Izv. Akad. Nauk LatvSSR Ser. Khim. 1988, 624. 

This method has since been modified and improved further by utilizing 9-fluorenylmethyl pentafluorophenyl carbonate (eq 2). ... 

Triaryl-substituted imines are converted to the corresponding nitrones by peroxyacetic add [87] (equation 79) substitution of one pentafluorophenyl group by a phenyl group at the carbon atom reduces the yield to ca. 20% [[Pg.349]

Tnmethylpentafluorophenylsilane reacts with ketones in the presence of cyamde ion to form the silyl eiher denved from the alkoxide created by the addition of the pentafluorophenyl amon to the carbonyl carbon [89] The nucleofugal character of the pentafluorophenyl group is significantly greater than that of the added cyamde ion so that the addihon proceeds under nearly neutral condmons (equation 73)... 

The pentafluorophenylcopper tetramer is usually analytically pure as isolated and melts at 200° with decomposition. If any significant decomposition occurs during the final drying, the product can be purified by dissolution in ether, filtration to remove copper metal, and precipitation by addition of hexane. It can also be recrystallized from benzene. When kept in a sealed container under nitrogen at room temperature, pentafluorophenyl copper tetramer appears to be stable for reasonable periods. It can be stored indefinitely at -78° under an atmosphere of carbon dioxide. 

The cyclic carbene complex shown in equation 3.4 was studied by X-ray diffraction [66], it shows a linear complex (angle C—Au—C 178.6(4)°) and the gold aryl bond distance is 1.993(10) A which is in accordance with such bonds in other known pentafluorophenyl complexes. The gold carbene carbon distance is 1.961(9) A, the dihedral angle between the planes formed by the two organic ligands is 5.35° and the shortest intermolecular Au—Au distance is 3.95 A. 

Other applications that utilize different types of reversed-phase columns in both dimensions have been advocated by Carr (Stoll et al., 2006) for metabolomics work in small-molecule separations. These stationary phases include a pentafluorophenyl-propyl stationary phase in the first dimension and a carbon-coated zirconia material stationary phase in the second dimension. A common mistake in 2D method development is to mismatch the solvent system the two solvent systems must be miscible as discussed below. 

Bismuth tritelluride, 4 24 physical properties of, 4 20t Bismuth trithiocyanate, 4 25 Bismuth Vanadate Yellow, 19 405-406 pigment for plastics, 7 370t Bismuthyl carbonate hemihydrate, 4 25 Bismuthyl nitrate hemihydrate, 4 25 Bismuthyl nitrite hemihydrate, 4 25 Bis(lV-maleimidomethyl) ether (BME), hemoglobin modifier, 4 113 Bisoprolol fumarate, molecular formula and structure, 5 156t Bis(pentafluorophenyl)borane, 13 638 Bis(pentafluorophenyl)tri-4-tolylbismuth, 4 35... 

The alternative method for making activated esters is base-catalyzed transesterification. Fmoc-amino acids are esterified in excellent yields by reaction with pentafluorophenyl trifluoroacetate at 40°C in the presence of pyridine (Figure 7.13). A mixed anhydride is formed initially, and the anhydride is then attacked by the pentafluorophenoxy anion that is generated by the pyridine. Succinimido, chlorophe-nyl, and nitrophenyl esters were made by this method when it was introduced decades ago. A unique variant of this approach is the use of mixed carbonates that contain an isopropenyl group [Cf C CfyO-COjR]. These react with hydroxy compounds in the presence of triethylamine or 4-dimethylaminopyridine (see Section 4.19) to give the esters and acetone.30 35... 

Cavell and Dobbie (214-216) have suggested that halogen transfer rearrangements in trifluoromethylphosphines arise from interactions of nonbonding fluorine p orbitals with vacant d orbitals on phosphorus. Such an explanation is consistent with observations for the Groups IV and V pentafluorophenyl derivatives, exclusive of carbon and nitrogen, and similarly fits the behavior of boron with its vacant p orbital. 

Pentafluorination diminishes n electron density of phenyl, making it more suitable for participation in stacking or charge transfer with the phenyl groups of other aromatic amino acids of the active site. As an example, the inhibitory power of the carbonic anhydric hydrolase by the pentafluorophenyl analogue of methazolamide is tenfold increased (Fig. 5) [31]. 

Carbonic Anhydric Hydrolase II / =17nM Figure 3.5 C—F 0=C interactions of fluorophenyl and pentafluorophenyl group. ... 

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