Natural and Synthetic Materials With Insect Hormone Activity. 2. Juvenile Hormone Activity of Some Derivatives of Farnesenic Acid

The juvenile hormone activity of both farnesenic acid esters and their dihydrodichloro derivatives increased from the methyl to the ethyl ester, then decreased again. In some hemipteran insects enormous increases in activity were obtained after addition of two hydrogen chloride molecules to the two double bonds of farnesenic acid esters. The same change in chemical structure considerably decreased the activity on Tenebrio pupae. On Pyrrhocoris apterus, the highest activity (at the 0.1 nanogram level) was obtained with the ethyl ester of trans-3,7,11-trimethyl-7,11-dichloro-2-dodecenic acid.