P-Bromophenylarsonic acid

The solvent is distilled, and the residue is recrystallized from methanol to give 23 g. (83%) of 2-bromophenoxathiin melting at 59-60°. 

A solution of 172 g. (1.0 mole) of p-bromoaniline, 300 ml. of hydrochloric acid, and 400 ml. of water is poured on to 800 g. of crushed ice. The resulting mixture is diazotized by the dropwise addition of a solution of 70 g. (1.0 mole) of sodium nitrite in 200 ml. of water, the temperature of the reaction mixture being kept below 5°. A mixture of 5 g. of copper sulfate, 50 ml. of water, and 10 ml. of concentrated aqueous ammonia solution is added to a solution of 210 g. of sodium arsenite and 250 g. of sodium carbonate in 2 1. of water, and the mixture is cooled to 15°. The solution of the diazotized amine is added to the arsenite solution with stirring over a period of 1 hour. The reaction mixture is stirred for 2 hours, allowed to stand for 12 hours, and filtered. The filtrate is acidified with concentrated hydrochloric acid to Congo red, and the precipitated p-bromophenylarsonic acid is filtered off. The yield is 193 g. 

One hundred and sixty grams (1.0 mole) of bromine is added drop-wise to a mixture of 16 g. of iodine and 160 g. (1.0 mole) of phenyl-cyclohexane. Hood.) The mixture is allowed to stand for an hour after completion of the addition and is then washed several times with 10% sodium carbonate solution followed by water. The mixture is steam-distilled with superheated steam, and the product is extracted from the distillate with ether. After drying over anhydrous sodium sulfate, the ethereal solution is distilled to give 190 g. (79%) of product boiling at 157-160°/15 mm. 

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In general, the Bosenmund reaction is carried out by heating one mole of trisodium or tripotassium arsenite with one mole of aromatic halide in boiling aqueous ethanol solution. Certain minor modifications of this procedure have been employed. If the aromatic halide contains an acidic group (e.g., o-bromophenylarsonic acid), no ethanol is necessary. Copper powder, as well as cuprous chloride, is sometimes employed as catalyst, but the value of either is uncertain. - Reactions of bromo-benzene and p-bromoacetophepone must be run in sealed tubes at temperatures of 150-200°. ... 

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