2 NOVEL POLYHYDROXYSTEROIDS WITH A 24-ETHYL-25-HYDROXY-26-SULFOXY SIDE-CHAIN FROM THE DEEP-WATER STARFISH STYRACASTER-CAROLI

The structure of two minor polyhydroxysteroids isolated from the deep water starfish Styracaster caroli were determined as (22E,24R,25R)-24- ethyl-5 alpha-cholest-22-en-3 beta,5,6 beta,8,15 alpha,25,26-heptol 26 -sulfate (1) and (24R,25R)-24-ethyl-5 alpha-cholestane-3 beta,5,6 beta ,16 beta,25,26-sulfate (2). The stereochemistry at the C-24 and C-25 p ositions was determined by enantioselective synthesis of 2-methyl-3-et hylheptane-1,2-diols as models and by comparison of the H-1-NMR data o f their (+)- and (-)-MTPA esters with those of the 26-MTPA esters of t he 22,23-dihydro derivative of the naturally occurring 1 and of 2.