Synthesis and insecticidal activity of lipophilic amides. Part 7. Alternative aromatic groups for phenyl in 6-phenylhexa-2,4-dienamides†

Synthesis of a wide range of analogues of the lead compound, N-2-methylpropyl-6-phenylhexa-2,4-dienamide, in which phenyl was replaced by other aromatic systems is reported. In cases where rearrangement rendered the N-2-methylpropyl compound less accessible, N-2,2-dimethylpropyl substitution was used, because rearrangement was then suppressed. Several of the groups examined, for instance 2-naphthyl, enhanced insecticidal activity, and when appropriately substituted, particularly with halogen, led to the most active compounds discovered in this series.