Sixth Kober Chromogen from the Urine of Pregnant Women and its Identification

In the course of column partition-chromatographic analysis of ketonic-phenolic fractions obtained from ether extracts of enzymically hydrolysed pregnancy urine, Kober-chromogenic material slightly more 'polar' in its chromatographic behaviour than 16oc-hydroxyoestrone (17-oxooestra-1:3:5-triene-3:16oa-diol) was regularly detected. The two possibilities were at first considered that this material might have arisen by 'leakage' of the chromatographically similar 16-epioestriol (oestra-1:3:5-triene-3:16/3: 17/3-triol) into the ketonic fractions or by 'tailing' of the 16oc-hydroxyoestrone fraction on the columns. However, when a concentrate of this Kober-chromogenic material was subjected to a second Girard separation and the resulting ketonic fraction rechromatographed in the same system nearly 60% of the starting material was recovered. This finding disposed of these two possibilities and it became evident that a hitherto unknown ketonic Kober chromogen (KC-6) had been detected. Subsequently it was found that 'KC-6' was in fact a mixture of two different Kober chromogens; and in the present paper the isolation and complete characterization of one of these (KC-6A) is described. Brief preliminary accounts of the main findings reported here have been published (Loke, Watson & Marrian, 1957; Loke, Marrian, Johnson, Meyer & Cameron, 1958).