No abstract

: A new series of 5-(substituted phenoxy)pentyl 3-pyridyl ethers induced precocious metamorphosis in larvae of the silkworm, Bombyx mori. Both 2-and 4-pyridyl ethers were inactive, indicating that the 3-pyridine moiety was essential for the activity. Octyl, dodecyl and farnesyl 3-pyridyl ethers had no activity. Among the compounds tested so far, 5-(4-propylphenoxy)pentyl 3-pyridyl ether showed the highest activity. The activity fell o † with increasing or decreasing length of the carbon chain between two oxygen atoms. Introduction of a methyl group at the 6 position of the pyridine ring completely eliminated the activity. Precocious metamorphosis induced by 3-pyridyl ethers was fully reversible by a simultaneous application of a small amount of tebufenozide, an ecdysteroid agonist, or methoprene, a JH agonist.1998 SCI. ( Pestic. Sci., 52, 251È257 (1998)