BILE PIGMENTS FROM VERDOHEMOCHROME 



459 



autoxidation, such as coprohemochrome, can be transformed into 

 oxyporphyrin hem/chrome by hydrogen peroxide in the absence of 

 ascorbic acid {1732). 



OH 



verdohemochrome 



Fig. 3. Formation of verdohemochrome. 



With the modification in the structure of verdohemochrome sug- 

 gested below, the reactions leading to its formation are represented by 

 the scheme shown in Figure 3. 



2.2. Bile Pigments Formed from Verdohemochrome 



Figure 3 (c/. also Chapter IV, Fig. 7) shows that, theoretically, the 

 fission of the protoporphyrin ring can occur at any one of the four 

 methene groups, a, 0, y, or 8. 



The hiliverdin dimethyl ester, obtained from pyridine hemoclirome by 

 coupled oxidation with hydrazine hydrate, had a melting point of '208° and 

 gave no melting point depression with hiliverdin dimethyl ester (m.p. 215° C.) 

 prepared from bilirubin. The mother liquor of this ester contained hemato- 

 biliverdin ester. Two molecules of water had thus been added to the vinyl 

 groups of some of the molecules during the process. It proved difficult to 



