Ammonia → 2-Amino-4-bromo-5-chlorobenzoic acid

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Reaction Steps

2.8 g (0.0196 mol) of copper(I) oxide are suspended in 120 ml (corresponding to 1.6 mol of NH3) of 25% aqueous ammonia solution under nitrogen. To this is added dropwise, at 25° C. with stirring and over the course of 40 minutes, a suspension of 63.2 g (0.2 mol) of 5-chloro-2,4-dibromobenzoic acid, 160 ml (corresponding to 2.14 mol of NH3) of 25% strength aqueous ammonia solution and 180 ml of ethyl acetate, with the exclusion of oxygen. The temperature rises to about 35° C. during the addition. Stirring is continued for 21/4 hours at30° C. Finally, 11.6 g (0.04 mol) of ethylenediaminetetraacetic acidis added to the mixture and the pH is adjusted to 3.1 by acidifying with hydrochloric acid. The ethyl acetate is distilled off at 90° C., the suspension is stirred at room temperature, and the anthranilic acid isfiltered off under suction and washed. 48.2 g of 4-bromo-5-chloroanthranilic acid is obtained as a pale-brown powder, corresponding to 96.2% of theory relative to 5-chloro-2,4-dibromobenzoic acid.

Provenance & Evidence