Methylarsonate

As(ONa), -I- CH,I — [CH,As(ONa)jI] CH,AsO(ONa), — CH,AsO(OH), unstable product losing sodium iodide to form disodium methylarsonate, which on acidification liberates methylarsonic acid. Note that this synthesis is limited to alkylarsonic acids, whereas the Bart synthesis (p. 312) is limited to aiy larsonic acids. 

The process may now be continued. Methylarsonic acid, when reduced by sulphur dioxide in concentrated hydrochloric acid, gives dichloromethylarsine, CHjAsCl. If this arsine is added to aqueous sodium hydroxide, it is hydrolysed to the weakly acidic methylarsenous acid, CH3As(OH)j, which in the alkali... 

MSMA [2163-80-6] monosodium salt of methylarsonic acid CH3ASO3 -Na... 

AMA cacodyhc acid [75-60-5] ammonium methylarsonic acid dimethyl arsinic acid C2H2ASO2... 

The F nmr spectrum of this compound gives only one signal over a wide range of temperatures, a result attributed to Berry pseudorotation (144). No alkyl- or aryltetrabromoarsorane has been reported. There is, however, an early report on the preparation of tetraiodomethylarsorane from methylarsonic acid and hydriodic acid (145). 

Methyl-arsonsaure, /. methylarsonic (meth-anearsonic) acid, -ather, m. methyl ether, -blau, n. methyl blue, -chlorid, -chlordr, n. methyl chloride, chloromethane. Methylen-blsu, n. methylene blue, -gruppe, /. methylene group, -jodid, n. methylene iodide, diiodomethane. 

In 1933 Challenger et al. discovered that trimethylarsine was synthesized from inorganic arsenic compounds by molds (93). Recently, McBride and Wolfe (94), have reported the synthesis of dimethylarsine from arsenate by cell extracts of the methanogenic bacterium M. O. H. Methylcobalamin is the alkylating coenzyme for this synthesis which requires reduction of arsenate to arsenite, methylation of arsenite to methylarsonic acid, reduction and methylation of methylarsonic acid to dimethylarsinic acid, and finally a four electron reduction of dimethylarsinic acid to dimethylarsine (Fig. 13). 

Rice, Oryza sativum Disodium methylarsonate modest 75% decrease in yield at soil (silty loam) concentrations 1... 

When Schwarzenbach et al. used chloromethylphosphonic acid to phosphonomethylate amines, they noted (128, p. 1185) how slowly it reacts. The slowness is presumably due to the staggered conformation of the chloromethyl and phosphono groups, so that one of the oxygen atoms must be in the Cl—C—C plane and must hinder the approach of any nucleophile that could displace the chloride. They overcame this with long reaction times and high temperatures. In view of the lability of C—As bonds, this approach is not available with 1-haloalkylarsonic acids. Indeed, arsonochloroacetic, chloromethylarsonic, and dibromo-methylarsonic acids (129) proved inert to substitution. 

Methylarsonic acid [124-58-3] M 137.9, m 161°. Crystd from absolute EtOH,... 

Spike recovery and detection limit. Species of arsenic found in drinking water include AsO (arsenite), AsO - (arsenate), (CH3)2As02 (dimethylarsinate), and (CH3)AsO (methylarsonate). Pure water containing no arsenic was spiked with 0.40 pg arsen-ate/L. Seven replicate determinations gave 0.39, 0.40, 0.38, 0.41, 0.36, 0.35, and 0.39 pg/L.12 Find the mean percent recovery of the spike and the concentration detection limit (pg/L). 

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