3,5-Dichloro-2-aminobenzoic acid

Dichloro-2-aminobenzoic acid, 31,96 J>-Di-(chloro-ferf-butyl)-benzene, 32, 91 4,4 -Dichlorodibutyl ether, 30, 27... 

Dichloroacetic acid, 32, 47 Dichloroacetyl chloride, 32, 46 3,5-Dichloro-2-aminobenzoic acid, 31,... 

B. Diazotization of 3,5-dichloro-2-aminobenzoic acid. Fifty grams (0.24 mole) of 3,5-dichloro-2-aminobenzoic acid is dissolved in a solution of 12 g. (0.3 mole) of sodium hydroxide in 700 ml. of water. To this solution is added 20 g. (0.29 mole) of sodium nitrite, and the solution is cooled to 10° (Note 5). One hundred milliliters of concentrated hydrochloric acid (sp. gr. 1.191) and 200 ml. of water are placed in a 2-1. three-necked flask and cooled to 10°. The cold solution of sodium 3,5-dichloro-2-aminobenzoate and sodium nitrite is then added to the hydrochloric acid solution with cooling (10°) and efficient stirring at such a rate that no appreciable accumulation of undiazotized amine results (Note 6). At the conclusion of the diazotization, the resulting solution is stirred a few minutes with 2 g. of diato-maceous earth and filtered by suction (Note 7). 

Pure 3,5-dichloro-2-aminobenzoic acid 3 has a melting point of 231°. The product described here is adequate for the subsequent step. 

This solution is almost saturated with the sodium salt of 3,5-dichloro-2-aminobenzoic acid/ If crystallization occurs, additional water may be added. Obviously, temperatures below 10° should be avoided. 

Dichloro-2-aminobenzoic acid can be prepared by the chlorination of anthranilic acid in glacial acetic acid solution J and by the action of sulfuryl chloride on anthranilic acid.4-5 The above procedure is derived from a more recent detailed study of the chlorination reaction.2... 

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