The Absolute Configuration of Chrysomelidial: A Widely Distributed Defensive Component Among Oribotririid Mites (Acari: Oribatida).

The absolute configuration of the iridoid monoterpene chrysomelidial from the oribatid mite, Austrotritia dentate Aoki, was elucidated by the GC-MS and GC comparisons with four synthetic stereoisomers of this well-known natural product. This identification was made possible by asymmetric synthesis of the known alcohol, (5 S,8 S)-chrysomelidiol. The GC retention time of diol derived from the natural oribatid dial agreed with that of the synthetic (5 S,8 S)-chrysomelidiol, confirming that the absolute configurations at C5 and C8 positions of the natural chrysomelidial are both S. Chrysomelidial was detected as a single or a major component in nine oribatid mites examined; thus, this compound is considered to be commonly distributed in Oribotririidae where it serves a defensive role. [ABSTRACT FROM AUTHOR]