The four diastereoisomers of cyclostigmastanol I and their E-22-unsatd. derivs. were prepd. Anal. of 1H and 13C NMR spectra of the synthetic model compds. and of their α-methoxy-α-(trifluoromethyl)phenylacetates provided data suitable for the assignment of configuration at C-24 and C-25 in 24-ethyl-26-hydroxysteroids. The stereochem. (24S,25S) has been assigned to 24-ethyl-5β-cholestane-3α,4α,21,26-tetrol 3,21-disulfate (II), recently isolated from the marine ophiuroid Ophiolepis supereba.
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