The absolute configuration of the C27 pentahydroxy bile alcohol present in bile and feces of 2 patients with cerebrotendinous xanthomatosis (CTX) was determined by circular dichroism (CD) spectroscopy. Under anhydrous conditions CD spectra of 5.beta.-cholestane-3.alpha.,7.alpha.,12.alpha.,23,25-pentol in the presence of Eu(fod)3 [tris(1,1,1,2,2,3,3-hepta fluoro-7,7-dimethyl-octane-4,6-dionato) europium (III)] exhibited a large induced split Cotton effect at .apprx. 310 nm. The induced CD of 5.beta.-cholestane-3.alpha.,7.alpha.,12.alpha.,23,25-pentol with Eu(fod)3 suggests that the CTX bile alcohol has the 1,3 glycol structure with C 23 having the R configuration.
