Surface films of sterols and other substances with complex ring systems

1 The chemical literature is voluminous, but is well summarized by Rosenheim and King (Ann. Remew Biochetn. (1934), 87) and by Kon (Ann. Rep. Chetn. Soc. (1934), 206). Principal papers on sterols, c., in surface films Leathes, J. Physiol., Proc., 

3-Keto compounds. I. Cholestane-3-one. II. Copro-etane-3-one. III. A4 6-Coprostene-3-one ( cholestenone ). IV. Oxime of cholestenone. V. Cholestenone on 0 1 per cent, neutral KMn04 solution. 

In the case of coprostenone, admixture of cholesterol molecules, which stand upright, greatly decreases the area occupied by the coprostenone if cholesterol and coprostenone molecules arc present in equal numbers the area indicates that the coprostenone now stands nearly upright. 

1 For the systematic nomenclature of the oestrin group, see Nature, 132, 205 (1933). This. compound was originally described as the Clemmensen reduction product of keto-hydroxy oestrin , or oestrone (3-hydroxy 17-keto oestratriene). 

In this group of compounds the molecules are found lying flat and standing upright it is also possible, by eliminating the hydroxyls at 16 and 17, leaving only that at 3, to make the oestratriene skeleton stand upright on the other end, i.e. on the same end as the commoner sterols. 

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