SYNTHESIS OF NONSTEROIDAL ANALOGS OF THE NATURAL INSECTICIDE VERATRIDINE

Molecular modelling analysis of veratridine, a component of insecticid al preparations from Schoenocaulon officinale (Liliaceae), indicated t hat ester derivatives of 4-[4-(N-alkyl- or arylpiperidinyl)-methyl]-be nzyl alcohols could adopt a low-energy conformation mimicking the shap e of the structurally rigid prototype steroid alkaloid. Based on this result, a series of new 4-arylmethylpiperidine and related tropane and pyridine derivatives were synthesised as putative steroid alkaloid an alogue insecticides. The key step of the preparation of the target com pounds was the Wadsworth-Emmons condensation of [4-(substituted-aryl)m ethyl]phosphonates with N-substituted 4-piperidones, tropinone or 4-py ridinecarboxaldehyde. Appropriate functional group transformations of the obtained methylidenepiperidines afforded the title products that w ere characterised by H-1-NMR spectroscopy.