Tetramethylarsonium

Single oral dose Arsenous oxide Tetramethylarsonium iodide Dimethylarsinic acid Dimethylarsonic acid Arsenocholine Trimethylarsinoxide Arsenobetaine Sodium arsenate... 

Main metabolites in urine after 7 months of exposure to 100 mg As/L drinking water were DMA and trimethylarsin oxide (TMAO) with minute amounts of tetramethylarsonium (TMA)... 

In the presence of methanol, the ylide gave tetramethylarsonium methoxide (81). 

Plaice, oysters, mussel samples Arsenic Nine organic arsenic species HPLC with ion spray, MS-MS 0.09jug g"1 tetramethylarsonium ion by MS-MS Corr and Larsen (1996)... 

Byrne et al. (1995), in a study of arsenic-accumulating mycorrhizal and saprophytic mushrooms, identified and confirmed the presence of methylarsonic acid, arsenite, arsenate, dimethylarsinic acid and arsenobetaine. This was the first reported occurrence of arsenobetaine in terrestrial biota. In a more extensive investigation (Svlejkovec et al., 1997) in which 50 mushroom species from five countries, across three continents, were studied, arsenocholine and tetramethylarsonium ion, (CH3)4As+, were found in addition to the other arsenic species... 

A novel HPLC-AAS interface based upon thermochemical hydride generation (THG) was developed for the determination of AB, AC and tetramethylarsonium cations, which had been separated by HPLC (Blais et al., 1990 Momplaisir et al., 1991). This has been described in Section 15.7. The detection limits of the three species were 13.3 ng (AB), 14.5 ng (AC) and 7.6ng (tetramethylarsonium cations). Advantages of this interface included low purchase and operating costs, low detection limits, and good reproducibility of results. The method was applied to determinations of arsenic species in seafoods and human urine. 

Blais, J.-S., Momplaisir, G.-M. and Marshall, W.D. (1990) Determination of arsenobe-taine, arsenocholine and tetramethylarsonium cations by liquid chromatography-thermochemical hydride generation-atomic absorption spectrometry. Anal. Chem., 62, 1161-1166. 

Methylene trimethylarsorane (the term trimethylarsonium methylide is equally correct) had already been formulated in 1953 by Wittig and Torssell (104) who studied the reaction of tetramethylarsonium salts with organolithium compounds. Although this method cannot be used for the preparation of the salt-free material due to the strong complexation by the lithium cations, it is clear from reactions of the product mixture that the ylide is present in solution. The formation of arsonium salts upon addition of alkyl halides is a typical example ... 

Thick fumes are observed when the material is exposed to air and spontaneous ignition may occur. A vigorous reaction with water leads to a strongly alkaline solution of some tetramethylarsonium hydroxide, but trimethylarsenic oxide is also formed (104)- Tetramethyl methoxyarsorane can be obtained in a quantitative yield (68) with methanol under carefully... 

In his study of the reaction of tetramethylarsonium salts with dimethyl-zinc, Cahours (5) originally claimed to have obtained pentamethylarsorane. However, subsequent attempts to repeat this preparation have met with failure (16, 104). Very recent experiments have led to successful synthesis of this compound through reaction of (CH3)3AsC12 with methyllithium under very mild conditions (87). If these precautions are taken no ylide is formed in this reaction, which was first tried by Wittig and Torssell... 

At 100 °C pentamethylarsorane (/) is quantitatively decomposed to trimethyl-arsine, methane and a little ethylene, thus supporting the assumption of intermediate formation of ylide 148 ethane is only formed in traces131). With water and acids tetramethylarsonium salts are produced m) whereas with alcohols, hydroxylamines and oximes covalent pentacoordinate arsoranes 149 are obtained in which one methyl group has been replaced by the respective electronegative group Y 132,133). 

Although more than 100 years ago Cahours (35) claimed to have obtained pentamethylarsorane by the reaction of dimethylzinc with tetramethylarsonium iodide, subsequent attempts (55,195) to synthesize pentaalkylarsoranes by the reaction of tetraalkylarsonium salts with organometallic compounds were unsuccessful. However, Mitschke and Schmidbaur (137) have obtained pentamethylarsorane in 80% yield by the following reaction ... 

Geiszinger, A.E., Goessler, W., Francesconi, K.A. (2002). Biotransformation of arsenate to the tetramethylarsonium ion in the marine polychaetes Nereis diversicolor and Nereis Virens. Environ. Sci. Technol. 36 2905-10. 

Trimethylarsine, (CH3)3As.— This compound was first mentioned by Cahours and Hofmann, who stated that it was obtained by the action of potassium hydroxide on the double salt derived from arsenic trichloride and zinc dimethyl. In 1859 Cahours isolated this ansine by distilling tetramethylarsonium iodide or its double salts with potas.sium hydroxide, after having obtained only small yields by treating sodium arsenide with methyl iodide. Auger in 1904 stated that the brown polymer formed when arsenomethane is treated with a trace of hydrogen chloride yields trimethylarsine when distilled in an atmosphere of... 

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