Structure-activity correlations among analogs of 4-methyl-3-heptanol,a pheromone component of the european elm bark beetle (Scolytus multistriatus)

A number of analogs of the title compound (1), with several different functional groups in place of the 3-OH and with a variety of substituents, were tested for biological acitivity by a laboratory walking-beetle assay. The electroantennogram (EAG) response was determined for many of these, as well. Field tests with baited sticky traps were carried out on compounds with activity in the walking-beetle assay and/or that gave a high EAG response. Structure-activity correlations with parameters reflecting hydrophobic, steric, electronic, and van der Waals interactions with olfactory receptors were examined primarily on the basis of the behavioral tests. Electronic substituent effects on the 3-position functional group and steric effects were found to correlate best. It is suggested that the strength of a hydrogen bond to the 3-oxygen or 3-nitrogen (as proton acceptor) is important in chemoreception by receptors that are involved in the behavioral response.