Ecdysteroids 25- deoxyecdysone

Many endogenous ecdysteroids which can be considered as the intermediates of ecdysone biosynthesis were isolated from the ovaries of L. migratoria by Hoffmann and Horn [204]. From the results of the bioconversion of labelled precursors, the following sequence in the biosynthetic pathway of ecdysteroids in vitellogenic ovaries of the insect was proposed conversion of cholesterol to 3)3-hydroxy-5)8-cholest-7-en-6-one followed by 14a-hydroxylation to 3/S,14-dihydroxy-5/6-cholest-7-en-6-one (112) hydroxylation at C-25 and C-22 (in this order) to 2-deoxyecdysone (114) hydroxylation at C-2 to ecdysone (107). 

The major ecdysteroid conjugate in newly-laid eggs of Locusta migratoria has been identified by spectroscopic methods as the 22-adenosine-5 -monophosphate ester of 2-deoxyecdysone (47). ... 

Wilson (1992) described the use of various boronic acids for the derivatiza-tion and separation of ecdysteroids by normal- and reversed-phase TLC. The derivatives were prepared from butyl-, phenyl-, and aminophenylboronic acids by over-spotting a methanolic solution of the reagent on to the applied ecdysteroids at the origin of the TLC plate. Butylboronic acid was also used as a mobile-phase additive to modify chromatographic behavior. A 20,22-diol group was an essential structural requirement for the formation of a cyclic boronate of an ecdysteroid. These procedures allowed for the selective separations of such compounds as ponasterone A and 2-deoxyecdysone. Pis and Harmatha (1992) also described the use of phenylboronic acid as a versatile derivatization agent for TLC studies of ecysteroids. 

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