(1S)-1-Ethyl-2-Methylpropyl 3,13-Dimethylpentadecanoate: Major Sex Pheromone Component of Paulownia Bagworm, Clania variegata

The Paulownia bagworm, Clania variegata Snell. (Lepidoptera: Psychidae), is one of the most significant forest defoliators in China. In gas chromatographic (GC)-electroantennographic detection analyses of pheromone gland extracts of female C. variegata on three GC columns (DB-5, DB-23, DB-210), two compounds (A and B) elicited strong responses from male antennae. The more abundant component B was isolated by high-performance liquid chromatography and identified as 1-ethyl-2-methylpropyl 3,13-dimethylpentadecanoate by transesterification, GC-mass spectrometry (MS), and comparison of its spectral and GC retention characteristics with those of synthetic compounds. In field trapping experiments in China, racemic and (1S)-1-ethyl-2-methylpropyl 3,13-dimethylpentadecanoate [but not the (1R)-stereoisomer] attracted male C. variegata. The absolute configuration of B (a molecule with three chiral centers) and the structure of component A remain to be determined.