Positions and Stereochemistry of Methyl Branches in the Novel Sex Pheromone Components Produced by a Lichen Moth, Lyclene dharma dharma

• Published in: Journal of chemical ecology Vol. 36; no. 8; pp. 814 - 823
• Main Authors: Adachi, Yasushi, Do, Nguyen Duc, Kinjo, Masakatsu, Makisako, Saori, Yamakawa, Rei, Mori, Kenji, Ando, Tetsu
• Format: Journal Article
• Language: English
• Published: New York New York : Springer-Verlag 01.08.2010; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Agriculture; Animal reproduction; Animals; Arctiidae; Biochemistry; Biological and medical sciences; Biological Microscopy; Biomedical and Life Sciences; Butterflies & moths; Chemical ecology; Chromatography, High Pressure Liquid; Control; Ecology; Entomology; Female; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Integrated pest control; Life Sciences; Male; Moths - drug effects; Moths - metabolism; Optical Phenomena; Pheromones; Phytopathology. Animal pests. Plant and forest protection; Protozoa. Invertebrates; Sex Attractants - biosynthesis; Sex Attractants - chemical synthesis; Sex Attractants - chemistry; Sex Attractants - pharmacology; Stereoisomerism; Japan, Nansei-Shoto, Okinawa, Iriomote I; Field evaluation of synthetic isomers; Methyl-branched 2-ketones; Female sex pheromone; Lepidoptera; Absolute configuration; Resolution by chiral HPLC; Positional isomers; Enantiomers; Sex pheromone; Molecular structure; Insecta; HPLC chromatography; Stereochemistry; Ketone; Field experiment; Isomer; Arthropoda; Enantiomer; Attractive trap; Female; Invertebrata; Arctiidae; Integrated pest management; Semiochemicals
• ISSN: 0098-0331; 1573-1561
• DOI: 10.1007/s10886-010-9813-3

Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produce three sex pheromone components (I-III), for which we assigned the following novel chemical structures; 6-methyl-2-octadecanone (1) for I, 14-methyl-2-octadecanone (2) for II, and 6,14-dimethyl-2-octadecanone (3) for III. In the Iriomote Islands where the insects were collected, a lure including racemic 1 and 2 attracted the male moths without mixing 3. In this study for further confirmation of the plane structures, the positional isomers with a methyl branch at the 4-, 5-, 7-, 13-, or 15-position (4-8, respectively) were synthesized. The GC-MS analyses revealed that natural components I and II were best fitted with those of 1 and 2, respectively, among the methyl-2-octadecanones examined, indicating the usefulness of this analytical instrument and authentic standards for the determination of the positions of methyl branches. In field trapping tests, 4-8 could not substitute for 1 or 2, nor did these compounds inhibit the active binary lure of 1 and 2, indicating that the males strictly recognized the 2-ketones with a methyl branch at the 6- or 14-positions. Next, the absolute configurations of I and II were determined by HPLC with a normal-phased chiral column (Chiralpak AD-H), which could separate the enantiomers of both 1 and 2. The chiral HPLC analysis of a crude pheromone extract indicated that the females exclusively produced (S)-1 and (S)-2. Furthermore, a field evaluation of each enantiomer revealed that (S)-1 and (S)-2 were bioactive but (R)-1 and (R)-2 were not.