Arsonoacetic acid

Z-Arginine hydrochloride, 12, 4 Arsanilic acid, 16, 85 Arsonoacetic acid, 10,108 Arylarsonic acid, preparation, IS, 59 y-Arylbutyric esters, 18, 25 Arylsulfur chlorides, preparation, 15, 45... 

Fig. 13. Conceivable mechanism for the decarboxylation of arsonoacetic acids. When an arsonoacetic acid is boiled in propan-l-ol, and the propanol-water azeotrope is distilled off, the acid will be esterified completely on the arsono group but not on the carboxy group. Decarboxylation is observed.

This is easily done if R is propyl, because the azeotrope of water and propan-l-ol boils at a temperature well below the boiling point of the propanol, so one can distill off this azeotrope up a fractionating column until the temperature of the vapor reaches the boiling point of propanol. When this is done with an arsonoacetic acid, decarboxylation results. It may be that that hydron is involved, as shown in Fig. 13, since the reaction does not proceed if one starts with a monoanion of the arsonoacetic acid. 

In view of the ease with which water attacks an ester of arsenate in water, we wondered if carbon nucleophiles would similarly attack a trialkyl arsenate to form a C—As bond. We (Sparkes and Dixon, unpublished work) therefore treated the sodium salt of diethyl malonate with tripropyl arsenate, and hydrolyzed during workup. Some arsonoacetic acid was formed, but we have not found conditions that give a useful yield. 

Arsonoacetic acid was obtained by Ehrlich and Bertheim 1 by treating -aminophenylarsenoacetic acid with bromine. It has been prepared by the action of three molecular equivalents of sodium chloroacetate on two of sodium arsenite, followed by isolation as the calcium salt,2 but it is found that these proportions are less satisfactory than the ones adopted.3 Arseno-acetic acid has been prepared recently by Palmer.3... 

Vigreux column, 12, 86 Arginine dinitronaphtholsulfonate, 12, 5 (/-Arginine hydrochloride, 12, 4, 6 Arsonoacetic acid, 10, 108... 

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