A convenient synthesis of 25-deoxyecdysone, a major secretory product of crustacean Y-organs and of 2,25-dideoxyecdysone, its putative immediate precursor.

25-Deoxyecdysone, a major secretory product of Y-organs of at least several species of crustaceans and the immediate precursor of circulating ponasterone A in these animals, can easily be synthesized from ecdysone. The present four-step procedure involves the formation of a mixture of delta 24,25 and delta 25,26 intermediates which might also be used to prepare a labeled reference compound for metabolic or binding studies. Similarly, 2,25-dideoxyecdysone was prepared from 2-deoxyecdysone. These compounds have been used to identify metabolites of [3H]-2,22,25-trideoxyecdysone (= 5 beta-ketodiol) formed by Y-organs of the shore crab, Carcinus maenas.