Rapid, laser-induced conversion of 20-hydroxyecdysone – A follow-up study on the products obtained

• Unique steroid derivatives were obtained from the laser photolysis of 20-hydroxyecdysone.
• A novel ring rearrangement for ecdysteroids was observed.
• Complete 1H and 13C NMR assignment of the products was achieved.
• Reaction mechanism is suggested for the formation of the three new compounds.
• In order to increase the yields of products, the set-up of a flow-system is desired.

We have recently reported the set-up of an experimental system for the laser-induced photochemical modification of bioactive substances, where two ecdysteroids, 20-hydroxyecdysone (20E) and its diacetonide derivative served as probes. As a direct continuation of our previous work, three new compounds together with five other ecdysteroid derivatives, have been identified from the novel, laser-induced photo-transformation reaction of 20E. The structures and NMR signal assignment were established by comprehensive one- and two-dimensional NMR spectroscopy supported by mass spectroscopy. Possible ways for the formation of each species is also discussed.Similar to their parental compound, the products obtained are potentially bioactive and worthy for further investigations; due to the low yields, however, a different approach for their higher scale production is suggested.

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