[Phytotoxicity of hydrazones of aromatic aldehydes]

A series of hydrazones of aromatic aldehydes (B) was prepared and tested for phytotoxicity. These compounds are bioisosters of 1-aryltriazenes (A) which were found to possess interesting phytotoxic properties in a previous research. The substances studied (Tables I leads to III: compounds(I leads to CLXXX)) some of which were previously unrecorded, were prepared by the usual procedures from the required aldehyde and hydrazine derivative. The phytotoxicity of all the compounds was studied using seven representative species in both pre- and post-emergence tests at a dose of 6 kg/ha. It was found that this class of compounds shows phytotoxicity by absorption through the foliage with specificity for Amaranthus retroflexus L. The only exceptions are compounds where the aryl residue is 2,6-dichlorophenyl; these compounds show wide spectrum of phytotoxicity by absorption through the leaves.