Juvenile hormone activity of optically active ethyl 4-(2-benzylalkyloxy)-benzoates inducing precocious metamorphosis

A series of ethyl 4-(2-benzylalkyloxy) benzoates possessing precocious metamorphosis-inducing activity showed juvenile hormone (JH) activity when topically applied to allatectomized 4th instar larvae of Bombyx mori. Hexyl (KF-13) and heptyl analogs, which induced precocious metamorphosis at low doses, had relatively high JH activity. In both compounds, (S)-enantiomers were more active than (R)-enantiomers. A correlation was observed between JH activity and anti-JH activity in the ethyl 4-(2-benzylalkyloxy) benzoate series. Replacement of the 4-ethoxycarbonyl group with a 4-ethyl or 3,4-methylenedioxy group in KF-13 eliminated both JH and anti-JH activity.