The chemical synthesis of ecdysone 22-long-chain fatty acyl esters in high yield.

Eight ecdysone 22-long-chain fatty-acyl esters (laurate, myristate, palmitate, stearate, oleate, linoleate, linolenate and arachidate) have been chemically synthesised in high yield. Ecdysone was first converted to the 2,3-acetonide derivative and then acylated selectively at C-22 with the appropriate acyl anhydride. The protecting acetonide group is then removed by mild acid treatment to yield the ecdysone 22-acyl ester. Reaction conditions have been optimised to maximise the overall yield (ca. 70%). The ecdysone acyl esters and their 2,3-acetonide derivatives have been characterised by 1H- and 13C-NMR and high-resolution FAB-mass-spectrometry.