Abstract
17-Methoxy-D-homo-18-nor-5 a-androst-2, 13, 15, 17-tetraen-6-one [23] which has been derived from the product [24] resulting from the thermolysis of 1-[2-(1-cyano-4-methoxy-1, 2dihydrobenzocyclobuten - 1 - yl) - 1 - nitroethyl] -4, 4- ethylenedioxy - 2-methyl - 2- vinylcyclohexane [25] was converted into 1, 2, 3, 4, 4a α, 4 b, 5, 8, 8 aα, 9, 10, 10aβ-dodecahydro-2 α, 4 bβ-dimethyl-1β(3-pentynyl) -2β, 9β-phenanthrenediol [31], which gave 6β-hydroxy-5α-pregn-2-en-20-- one [32] on cyclization in acidic media. Jones' oxidation, followed by Prévost-Woodward re action of [31] resulted in the formation of 2β, 3β-diacetoxy-5 α-pregnane-6, 20-dione [34]. Finally, 2β, 3β, 20-triacetoxy-5α-pregnan-6-one [22] was derived from [34] by successive reduction, selective acetylation and Jones' oxidation. Since [22] has already been converted into 20-hydroxyecdysone, this work constitutes the formal total synthesis of 20-hydroxyecdysone.
