Fungicidal and genotoxic activity of new substituted pyridazinones.

Some 2-sulfonyl- and 2-acylderivatives of the 4,5-dichloro-3(2H)-pyridazinone were prepared in order to test their fungicidal activity. Interesting results, both in vitro and in vivo, were obtained in particular from the alkylsulfonyl-derivatives. Genotoxic activity of 3(2H)-pyridazinones was evaluated in vitro by the Bacillus subtilis rec-assay and the Salmonella-microsome reversion assay.