3-(4-Methyl-3-pentenyl)-2(5H )-furanone, a,a-Acariolide and 4-(4-Methyl-3-pentenyl)-2(5H )-furanone, a,b-Acariolide: New Monoterpene Lactones from the Astigmatid Mites, Schwiebea araujoae and Rhizoglyphus sp. (Astigmata: Acaridae)

A new monoterpene lactone from the acarid mite, Schwiebea araujoae, was elucidated without its isolation by GCWFT-IR and GCWMS analyses to be 3-(4-methyl-3pentenyl)-2(5H )-furanone (1) and tentatively named as a,a-acariolide. The structure of 1 was identiˆed by its synthesis from a-bromo-g-butyrolactone via 4 reaction steps. The synthesized compound gave the same GCW MS and GCWFT-IR spectra as those of the natural product. The other monoterpene lactone was likewise elucidated from the unidentiˆed Rhizoglyphus mite to be 4-(4methyl-3-pentenyl)-2(5H )-furanone (2) and named as a,b-acariolide; it was also identiˆed by its synthesis in 5 reaction steps from the same butyrolactone as the starting material. GCWMS and GCWFT-IR spectra of the preparation were identical to those of the natural product.