Novel 5β-hydroxyspirostan-6-ones ecdysteroid antagonists: Synthesis and biological testing

Eight new 5β-hydroxy-spirostan-6-ones bearing hydroxy and amino functions in the A ring, i.e., 3β-OH, 3α-OH, 2β,3β-OH, 2α,3β-OH, 3β-NH2, 2α-NH2-3β-OH, 2β-NH2-3β-OH, and 2β-OH-3β-NH2, were efficiently synthesized, and their antiecdysteroid activities were evaluated on the metamorphosis bioassay of mosquito Aedes aegypti. To our knowledge, these new steroids represent the first 5β-hydroxy-spirostanes which have been tested for antiecdysteroid activity in mosquitoes. The higher antagonistic effect was found for compounds bearing the 3β-hydroxy and 2β,3β-dihydroxy functionality, which show promise as environmental friendly insecticides.