[Pyrazole sulfanilamides. XV. Nitroderivatives of 1-phenyl-4-sulfanilamidopyrazole]

The research on the change of antibacterial activity due to the introduction of a nitro group in the benzene nucleus linked at the heterocyclic nitrogen of N-phenylsulfanilamidopyrazoles is continued with the preparation of 1-(2'-nitrophenyl)-4-sulfanilamidopyrazole (IIa: -NO2 in 2'; R=-H), 1-(3'-nitrophenyl)-4-sulfanilamidopyrazole (IIb: -NO2 in 3'; R=-H) and 1-(4'-nitrophenyl)-4-sulfanilamidopyrazole (IIc: -NO2 in 4'; R=-H). By analogy with the results obtained for the derivatives of 4-sulfanilamidopyrazole (I) previously prepared, enhancement of the bacteriostatic activity in vitro against S. aureus and E. coli, have been observed in almost all the cases, especially with 1-(3-nitrophenyl)-4-sulfanilamidopyrazole (IIb).