MODES OF LINKAGE BY COVALENT BONDS 



73 



is surrounded by a hexacarboxylic acid, formed by the association of four 

 pyrrolidine rings modified by the inclusion of a conjugated system of 

 double bonds. The molecule contains six primary amide groups and one 

 secondary group joining the aminopropanol residue to the propionic acid 

 group of ring D. 



Cyanocobalamin is a phosphoric diester in which the free acid function 

 is neutralized by the positive charge on the cobalt. 



Cyanocobalamin, then, is the result of combination of adenosinemono- 

 phosphoric acid with a pyrrolidine chromogen via l-amino-2-propanol. 



CH2CONH2 



:H, H CH3 CH3 cHrCONH, 



NH.CO-CH, 

 CH3 

 CH3 



NH, CO-CH, 



CO-CH2-CH 



CH,-CH3- 

 CONH, 



CH3 CHoCHoCONH^ 



HO-CHa 



Cyanocobalamin (Formula of Todd et al.) 



