(E)-2-(2-Hydroxyethylidene)-6-methyl-5-heptenal (α-Acariolal) and (E)-2-(2-Hydroxyethyl)-6-methyl-2,5-heptadienal (β-Acariolal), Two New Types of Isomeric Monoterpenes…

Abstract

The opisthonotal gland secretion of the acarid mite, Caloglyphus polyphyllae, contained two new monoterpenes, (E)-2-(2-hydroxyethylidene)-6-methyl-5-heptenal (1) and (E)-2-(2-hydroxyethyl)-6-methyl-2,5-heptadienal (2), to which we have given the trivial names α- and β-acariolal in relation to α- and β-acaridial (3 and 4), respectively. Elucidation of the structure of 1 was established mainly from ¹H-NMR and GC/MS spectral data after partial purification, together with the fact that 1 was recovered in the more-polar fraction from a silica gel column than α- and β-acaridial (3 and 4) present in the secretion. Compound 2 was obtained in the same fraction as a mixture with 1. Based on the facts that 2 had the same molecular weight by GC/MS and the same polarity as that of 1, compound 2 was assumed to be a structural analog of 1. The structures of compounds 1 and 2 were confirmed by their synthesis in nine and ten respective steps starting from α-bromo-γ-butyrolactone.

• Acaridae
• Caloglyphus polyphyllae
• monoterpene
• α-acariolal
• β-acariolal