A new series of acylhydrazones derived from metribuzin with modulated herbicidal activity.

This paper reports the preparation and herbicidal evaluation of a small library of acylhydrazones based on the synthetic herbicide metribuzin. The hydrazone linkage easily obtained by reaction of metribuzin with aliphatic and aromatic aldehydes, masks efficiently the exocyclic amino group, thereby altering significantly H-bonding with the receptor and increasing the lipophilicity relative to the parent herbicide. The structures of all compounds, including key stereochemical issues on conformation and configuration around the C[bond, double bond]N bond were thoroughly elucidated by spectroscopic methods, and unambiguously corroborated by X-ray diffraction analysis.