Triphenyl arsenate

Tangible evidence was found for the in situ production of perfluoro(2,3,4,5-tetrahydro-pyridines) 2, 3, and 4 during the transfer of F- from perfluoro-l-fluoropiperidine (1) to carbanionic sources.22 23 Perfluoro-l-fluoropiperidine (1) was employed to convert triphenyl-phosphane, -arsane, and -stilbane to the difluorides, triphenylphosphorus difluoride, triphenyl-arsenic difluoride, and triphenylantimony difluoride, respectively,24 and sodium phenoxide to 2- and 4-fluorophenol.25 Perfluoro-l-fluoropiperidine (1) reacts with 7V,/V-dimethylaniline, substituting the 0/7/m-hydrogen by fluorine. A similar reaction proceeds with /V,/V-diethylaniline.26... 

SFC has received attention as an alternative separation technique to liquid and gas chromatography. The coupling of SFC to plasma detectors has been studied because plasma source spectrometry meets a number of requirements for suitable detection. There have been two main approaches in designing interfaces. The first is the use of a restrictor tube in a heated cross-flow nebuliser. This was designed for packed columns. For a capillary system, a restrictor was introduced into the central channel of the ICP torch. The restrictor was heated to overcome the eluent freezing upon decompression as it left the restrictor. The interface and transfer lines were also heated to maintain supercritical conditions. Several speciation applications have been reported in which SFC-ICP-MS was used. These include alkyl tin compounds (Oudsema and Poole, 1992), chromium (Carey et al., 1994), lead and mercury (Carey et al., 1992), and arsenic (Kumar et al., 1995). Detection limits for trimethylarsine, triphenylarsine and triphenyl arsenic oxide were in the range of 0.4-5 pg. 

The product from Step 2 (1.0 mmol), diphenylphosphoryl azide (1.2 mmol), triethylamine (5 mmol), phenanthrene-9,10-dione (0.7 mmol) and triphenyl arsen oxide (0.05 mmol) were dissolved in 12 ml toluene and heated 3 hours at 60 °C. The product was purified by chromatography on silica gel using CH2Cl2/hexane, 2 1, re-crystallized in CH2Cl2/hexane, and the product isolated in 100% yield. H- and C-NMR data supplied. 

Some inhibitors are reduced on the surface to yield secondary products that are themselves the active inhibitors. In strong mineral acids, elements from Groups VI and VII tend to become protonated, a necessary prerequisite for many reduction reactions. Such is the case for triphenyl benzyl phosphonium chloride, which forms triphenyl phosphine, and triphenyl arsenic oxide, which undergoes protonation (permitting it to dissolve) and forms triphenyl arsine on the surface. Some sulfonium salts, e.g., tribenzylsulfonium hydrogen sulfate, and dibenzylsulfoxide also can be reduced by iron in HCI. 

Only the compound derived from the condensation of triphenyl-arsenic dichloride with 4,6-diamino-2-mercaptopyrimidine (poly-(AsDASP)) has been extensively studied (13). It was picked for study because of the presence of the thiol group which is both a potential modifying moiety towards the toxicity of arsenic and a typically desirable metabolite for a number of biological organisms - thus encouraging both select toxicity and metabolism. 

Arsenic Peroxides. Arsenic peroxides have not been isolated however, elemental arsenic, and a great variety of arsenic compounds, have been found to be effective catalysts ia the epoxidation of olefins by aqueous hydrogen peroxide. Transient peroxoarsenic compounds are beheved to be iavolved ia these systems. Compounds that act as effective epoxidation catalysts iaclude arsenic trioxide, arsenic pentoxide, arsenious acid, arsenic acid, arsenic trichloride, arsenic oxychloride, triphenyl arsiae, phenylarsonic acid, and the arsenates of sodium, ammonium, and bismuth (56). To avoid having to dispose of the toxic residues of these reactions, the arsenic can be immobi1i2ed on a polystyrene resia (57). 

Stibonium Ylids and Related Compounds. In contrast to phosphoms and arsenic, only a few antimony yhds have been prepared. Until quite recendy triphenyl stibonium tetraphenylcyclopentadienyUde [15081 -36-4] C H Sb, was the only antimony yUd that had been isolated and adequately characteri2ed (192). A new method, uti1i2ing an organic copper compound as a catalyst, has resulted ia the synthesis of a number of new antimony yhds (193) ... 

Sulfur atoms extraneous to the heteropentalene system in (4 X = S) can be oxidized by MCPBA to SO and SO2 groups in 64-70% yields <85JCS(P2)833>. Arsenic pentafluoride coordinates to the thiadiazole ring of (59 R = Cl) as shown in (15) (x-ray analysis) <86ZN(B)162>, whereas (rj -ethene)bis(triphenyl-phosphane)platinum(0) inserts into the thiadiazole ring to give a new six-membered metallocycle <86CB366>. 

In 1953 Wittig and Geissler (100) reported that methylene triphenyl-phosphorane reacted with benzophenone to form 1,1-diphenylethene and triphenylphosphine oxide. This experiment marked the birth of the Wittig reaction, a novel method for the conversion of carbonyl groups to olefins, and the entry of ylides into the arsenal of important synthetic tools. Since... 

Schwedt, G., RUssel, H. A. Gas chromatographic determination of arsenic as triphenyl arsane. Chromatographia 5, in press. 

During the war the Allies, in order to obtain rapid production of diphenyl chloroarsine, followed the method of Michaelis, modified by Morgan and Vining. This method consists in preparing triphenyl arsine from chlorobenzene and arsenic trichloride, in the presence of metallic sodium ... 

In order to prepare triphenyl arsine, the arsenic trichloride, the chlorobenzene and the xylene are first mixed in a separate vessel, and of this mixture a half is introduced into the reaction chamber after diluting with more xylene. 

Pope and Turner have also determined the optimum conditions for carrying out this reaction. They recommend heating the triphenyl arsine in an open vessel to 350° C. and then allowing the arsenic chloride to enter from a tap-funnel terminating in a capillary tube. 

Hydrochloric Acid. On boiling diphenyl chloroarsine with hydrochloric acid, arsenic trichloride and triphenyl arsine are formed, as follows ... 

Industrially, diphenyl bromoarsine is prepared by methods similar to those described above for the preparation of the chloro-compound. That is to say, by the action of arsenic tribromide on triphenyl arsine at 300° to 350° C. or else by the diazotisation method, using hydrobromic acid instead of hydrochloric acid. 

All the triphenyl arsoranyl radicals have similar parameters and therefore adopt a similar structure in which the unpaired electron is mainly localized in an arsenic p orbital. Moreover, for PhjAsX (X = chalcogen) the total arsenic spin density decreases with the difference of electronegativity pCchaicogen — X rsemc) which is consistent with a strong contribution of the structure since, for such a structure, the unpaired electron is located in an arsenic-axial ligand a bond. 

AsAgFsSi6, Arsenate, hexafluoro-, bis-(cycZo-octasulfur)silver(l -h), 24 74 AsBrsFgS, Arsenate, hexafluoro-, tribromo-sulfur(IV), 24 76 AsQH, Arsine, dimethyl-molybdenum complex, 25 169 AsCigHis, Arsine, triphenyl-chromium complexes, 23 38 ASC24H10, Arsonium, tetraphenyl-... 

Ester interchange can be retarded, particularly when esterification catalysts like zinc or calcium acetate are present by addition of phosphorous acid or triphenyl phosphite [415]. This improves the chances of forming block copolymers. The procedure can be applied to preparation of block copolymers of poly(ethylene terephthalate) with poly(ethylene maleate), poly(ethylene citraconate), and poly(ethylene itaconate) [416]. With ester interchange catalysts, like titanium alkoxides or their complexes, melt randomization may be inhibited by adding arsenic pentoxide that deactivates them [417]. 

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