Synthesis and precocious-metamorphosis-inducing activity of 3-pyridyl ethers

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)

Synthesis and Precocious Metamorphosis-Inducing Activity of 3-(1-Alkenyl) pyridines

“…The introduction of a methyl substituent at the 2-position of ethylene (7) increased the activity in comparison with that of compound 6, while the activity drastically decreased when a phenyl substituent was introduced (8). Compounds 9-E, 9-Z and 10, which are the structural isomers of 6 and 7, respectively, had comparatively low activity, indicating that the position of a phenyl substituent bound to the double bond is significant for activity.…”