Structural Elucidation of Twelve Novel Esters Composed of Five Fatty Acids and Three New Branched Alcohols Together with Four Monoterpenoids from Sancassania shanghaiensis (Acari: Acaridae)

抄録

A total of 12 novel esters and four monoterpenoids (rosefuran, (2R,3R)-epoxyneral, and α- and β-acaridials) were detected by GC/MS analyses as the opisthonotal gland components of Sancassania shanghaiensis. The acidic fraction after hydrolysis was composed of five common fatty acids (palmitic, stearic, oleic, linoleic and arachidic acid), while the alcoholic fraction consisted of two major components (C₆ and C₈ alcohols with branched methyls), together with a trace amount of C₉ alcohol. The Two major alcohols were identified as new alcohols [(S)-2-methylpentanol and (2S,4S)-2,4-dimethylhexanol] by comparing the physico-chemical data of their 3,5-dinitrobenzoates with those of regio-selectively synthesized alcohols. The C₉ alcohol was suggested as (2S,4S)-2,4-dimethylheptanol, based on a structural and biogenetic analogy to the C₆ and C₈ alcohols. Five of the compounds were each identified by GC to be (S)-2-methylpentyl esters from five fatty acids, and the other five components likewise as (2S,4S)-2,4-dimethylhexyl esters. The remaining two were suggested as (2S,4S)-2,4-dimethylheptyl Stearate and linolate.