Ecdysone 2,3-acetonide

Scheme 3). A clone of cells from the midge Cbironomus tentans was found to be resistant to the effects of ecdysteroids because they metabolized 20-hydroxyecdysone rapidly. The initial oxidation product was 20,26-dihydroxyecdysone, but this was oxidized further to 20-hydroxy-26-oxo-ecdysone (21). This aldehyde (21) then formed a tautomeric equilibrium mixture of two cyclic hemiacetals (22) and (23), which were separable, isolated, and their structures determined (Scheme 3) with the use of acetonides (Section 4.03.3.6).32 These are the first examples of ecdysteroids with side-chain hemiacetals. Although 20,26-dihydroxyecdysterone still... 

Dinan (1987) gave Rf values of 27 different ecdysone acyl esters and their 2,3-acetonide derivatives following separation on HPTLC silica gel 60 plates (Merck, 10 X 10 cm) in chloroform—ethanol (9 1) mobile phase the Rf values of 22 of these compounds were obtained following separation on HPTLC RP-18 plates (Merck) in tbe mobile phase absolute methanol. Wilson and Lewis... 

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