Ecdysones biological activity

The stereocontroUed syntheses of steroid side chains for ecdysone, cmstecdysone, brassinoHde, withanoHde, and vitamin D have been reviewed (185). Also, other manuscripts, including reviews on the partial synthesis of steroids (186), steroid dmgs (187—189), biologically active steroids (190), heterocychc steroids (191), vitamin D (192), novel oxidations of steroids (193), and template-directed functionali2ation of steroids (194), have been pubhshed. 

The term ecdysteroid was originally defined as "all compounds structurally related to ecdysone" [4], However, Lafont and Horn [5] differentiated between true ecdysteroids and ecdysteroid-related compounds. True ecdysteroids possess a steroid nucleus with an A/B-cis-ring junction and a 14a-hydroxy-7-en-6-one chromophore, irrespective of their biological activity, while ecdysteroid-related compounds do not fulfil all these criteria. 

Because compounds (345)—(348) show the same biological activity it was argued185 that compound (349) (2,25-dideoxy-a-ecdysone) should also exhibit maximum... 

After processing a larger group of 7-dey-old pupae the more polar ecdysteroid was isolated and identified as 20,26-dihydro iyecdysone (3). This ecdysteroid was only 1/10 to 1/15 as biologically active as ecdysone or 20-hydroxyecdysone in the house fly assey. The structures and biological activity of the ecdysteroids indicated the sequence of conversion shown in [1]... 

This chapter reviews the structures and biology (physiological, biochemical and molecular basis of mode of action, insect activity spectrum, and eco-toxicological safety) of the commercialized BAH non-steroidal ecdysone agonist insecticides (refer to former reviews on this topic [4—6, 12]). 

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