[Antimicrobial activity of new pyridazine derivatives].

Continuing the investigations concerning synthesis-structure-biological activity in the pyridazine series, the results of the antimicrobial and antifungal tests of some new pyridazinium compounds are presented. The test was performed using the diffusimetric method with rustles steel cylinders based on the diffusion of the tested substances on the gelose surface. The comparative analysis of the obtained data leads to the following conclusions concerning the relation between structure and activity in the pyridazine series: 1. The cis-isomers are always more active comparatively with similar trans- isomers: 2. In the pyrrolopyridazine series we remark that the saturated or partial saturated compounds have always a stronger activity as the related aromatics derivatives. We also noticed that the saturated, partial saturated and aromatic compounds have different selectivity. Thus, the saturated are more active on the Pseudomonas aeruginosa and Candida albicans, the partial saturated are more active on the Staphylococcus aureus and Bacillus subtilis while the aromatic compounds are active on the Bacillus subtilis. 3. The influence of the Y-substitutes of para position of benzoylic radical and the substitutes of pyrrolo ring is not decisive towards activity, these affecting especially the selectivity.