M-Nitrophenylarsonic acid

Two normal sodium hydroxide solution is added to a suspension of 24.7 g. (0.10 mole) of m-nitrophenylarsonic acid (p. 230) until the acid is in solution. Ten grams of Raney nickel catalyst [Org. Syntheses, 21, 15 (1940)] is added, and the mixture is agitated under 30 lb. of hydrogen pressure. Thirty to sixty minutes is required for absorption of the calculated amount of hydrogen. The solution is filtered to remove catalyst and neutralized with 6 N hydrochloric acid to Congo red paper. The arsonic acid separates as a pure crystalline product and is filtered off. The yield is 95%. w-Aminophenylarsonic acid melts at 213-215° with decomposition. 

By action HN03/H2S04 on 4-chlorophenylarsonic acid is obtained 4-chloro-3-nitrophenylarsonic acid which is converted at 100°C with 33% aqueous solution of sodium hydroxide to 4-hydroxy-3-nitrophenylarsonic acid. After reduction of N02 group of 4-hydroxy-3-nitrophenylarsonic acid by the action of Na2S203 or Fe/NaOH is obtained 3-amino-4-hydroxyphenylarsonic acid. From 3-amino-4-hydroxyphenylarsonic acid and acetic anhydride is prepared N-acetyl-4-hydroxy-m-arsanilic acid. 

Nitrophenol-4-arsonic acid (4-hydroxy-3-nitrophenylarsonic acid) [121-19-7] M 263.0,... 

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