Gas-Liquid Chromatographic Studies of Methyl Steroids. II. Changes in Retention Time due to the Introduction of a 6-Methyl Group into Sterols

In the previous paper of this series, the retention characteristics of 4-methyl sterols were investigated with a view for establishing a systematic relationship between the structure of sterols and their gas chromatographic characteristics. The present report deals an extended study on 6methyl sterols prepared from cholesterol. The retention data for five 6-methyl sterols and for their derivatives at C-3 were expressed in terms of relative retention times (Table-1), methylene unit values (Table-2) and retention factors due to the introduction of 6-methyl group into sterols (Table-3), on SE-30, OV-17 and DEGS phase, respectively. Main results obtained were as follows: 1) The retention times of 6-methyl sterols and their derivatives were generally or mostly found to be larger than those of the corresponding non-methylated sterols and their derivatives. However, 6-methylcholesteryl-trifluoroacetate exhibited a retention time smaller than that of cholesteryl-