134 



IV. BILE PIGMENTS 



e.g., in the Gmelin reaction. Siedel and Moller {2559) have prepared such a 

 compound ("oxorhodin") by ferric chloride oxidation of "oxourobiHn" 

 (bilene-(b)-one; Fig. 22). 



H H H Ho H 



lead tetraacetate 



biladiene-(a,b) 



HO' 



HO 



\ /\^A A^A -A^A A, 



N C^ X C^ N C N ^OH 



"oxourobiHn" 



H O H H 



H2 H 



FeCb 



"oxorhodin" 



\K\K\/^c\^ 



OH 



VAAO 



Fig. 22. Biherythrinoid oxidation product of bilatriene. 



6. BILANES, BILENES, AND RELATED SUBSTANCES 



6.1. Occurrence of Mesobilane and Tetrahydromesobilane 

 and the Corresponding Bilenes in Feces and Urine 



In 1868 Jaffe (HOS) described a pigment from bile and urine which 

 he called urobilin, and which he obtained from feces a year later. 

 It has been found to occur normally in feces, and in small amounts 

 in normal urine, while larger quantities occur in pathological urine. 

 The fecal urobilin was later named stercobilin by van Lair and Masius 

 {1633), but since it is now known that fecal urobilin is the source of 

 urinary urobilin, one of the names urobilin or stercobilin is redundant. 



Le Nobel {2057) found that urobilin occurred as a chromogen, 

 which he called urobilinogen, and which is readily oxidized to uro- 

 bilin, while Neubauer {201^2) discovered that urobilinogen was the 

 chromogen which gave the Ehrlich aldehyde reaction {652). For a 

 long time afterward it was assumed that the substance occurring in 



