New methylcyclopentanoid terpenes from the larval defensive secretion of a chrysomelid beetle (Plagiodera versicolora).

Abstract

The defensive secretion of larvae of the chrysomelid beetle P. versicolora contains 2 unstable, volatile methylcyclopentanoid terpenes, a dialdehyde (chrysomelidial) isomeric with dolichodial and anisomorphal and a closely related enol lactone (plagiolactone). Chrysomelidial and plagiolactone are assigned structures on the basis of detailed analyses of their spectra, coupled with chemical transformations to products of known structure.