Derivatives of p-aminobenzoic acid and their action on the growth of bacteria

Summary

Various derivatives of P.A.B. obtained by introduction of substituents in the benzene-nucleus have been examined for their action on the growth ofAerobacter aerogenes in a simple synthetic medium and ofDiplococcus pneumoniae in ascites-broth without peptone.

The following results have been obtained:

• 1. The 2-amino, 3-amino, 3-chloro, 3-bromo, 2-methyl, 3-methyl, and 2.3-dimethyl derivatives of P.A.B., and also 2-sulfanilamido-4-aminobenzoic acid have sulfonamide activity.

• 2. The 2-hydroxy, 2-fluoro, and 2-nitro derivatives have an antisulfonamide activity similar to the activity of P.A.B., although weaker.

• 3. The 3-hydroxy, 2-chloro, and 2-bromo derivatives show sulfonamide-activity in relatively high concentrations. In lower concentrations they act as anti-sulfonamides.

• 4. The 3-nitro, 2.6-dimethyl, and 3.5-dimethyl derivatives, and methyl 2-acetamino-4-amino-benzoate are completely inactive. These results have been compared with those of other investigators and the causes of some contradictions have been elucidated.