Synthesis of Enantiopure Alicyclic Ethers and Their Activity on the Chemosensory Organ of the Ectoparasite of Honey Bees, Varroa destructor
2016
Pinnelli, Govardhana R. | Singh, Nitin K. | Soroker, Victoria | Plettner, Erika
The preparation of enantiopure conformationally restricted alicyclic ethers and their inhibitory activities on the chemosensory organ of the Varroa destructor, a parasite of honey bees, are reported in this article. We tested the effect of enantiopure ethers of cis-5-(2′-hydroxyethyl)cyclopent-2-en-1-ol on the Varroa chemosensory organ by electrophysiology, for their ability to inhibit the responses to two honey bee-produced odors that are important for the mite to locate its host: nurse bee head space odor and (E)-β-ocimene, a honey bee brood pheromone. Previous work with the racemic compounds showed that they suppress the mite’s olfactory response to its bee host, which led to incorrect host choice. Based on a structure–activity relationship, we predicted that the two most active compounds cis-1-butoxy-5-(2′-methoxyethyl)cyclopent-2-ene, cy{4,1}, and (cis-1-ethoxy-5-(2′ethoxyethyl)cyclopent-2-ene, cy{2,2} could have opposite active enantiomers. Here we studied the enantiomers of both ethers, whose preparation involved enzymatic resolution of racemic diol cis-5-(2′-hydroxyethyl)cyclopent-2-en-1-ol using Lipase AK with vinyl acetate. The racemic diol was prepared from commercially available 2,5-norbornadiene. We observed that the responses of the chemosensory organ to honey bee head space volatiles were significantly decreased by both enantiomers of cy{4,1} and cy{2,2}, but that responses to (E)-β-ocimene were decreased significantly only by (+)-cy{4,1} (1R,5S) and (−)-cy{2,2} (1S,5R) and not by their respective enantiomers. The importance of this result is that the racemates could be used to inhibit olfactory detection of bee odors by mites, without a loss in activity relative to the more expensive enantiopure compounds.
显示更多 [+] 显示较少 [-]