NITROGEN COMPOUNDS 69 



IMIDES. Indol and skatol, products of pancreatic 

 digestion, are derivatives of secondary ammonia 

 bases. If two H atoms of NH 3 are displaced the 

 ammonia-rest or NH is designated an imido-group. 

 This displacement may occur through the influence 

 of OH ions or hydrocarbon-radicals. If the amido- 

 base NH 2 displaces one H atom from a benzene ring 

 it forms amido-benzene or Aniline. If another H 

 atom is displaced from the amido-group of aniline 

 by an ethyl-radical it forms Ethyl-aniline. This 

 may be still further attacked by OH ions, thereby 

 abstracting another H from the benzene-ring and 

 three H atoms from the ethyl-end, to form 

 water ; that which is left will form an interlocked 

 molecular ring, Indol, C 8 H 7 N ; Skatol is methyl-indol, 

 C 9 H 9 N. 



Cholin is a decomposition product of lecithin, in 

 the animal organism. It is a derivative from a 

 quaternary ammonium base, and is really hydroxy- 

 ethyl - trimethyl - ammonium - hydroxide. Now in 

 tetra - methyl - ammonium - hydroxide four methyl- 

 radicals are joined to the ammonium-hydroxide, 

 NOH, thus 4CH 3 + NOH = C 4 H 13 NO. If one of these 

 methyl-radicals is replaced by a hydroxy-ethyl 

 radical, C 2 H 5 0, we have cholin, C 5 H 15 N0 2 . If a 

 molecule of water is split off from cholin we have 

 Neurin, C 5 H 13 NO. Both these substances arise from 

 lecithin, probably as a result of hydrolysis by the 

 action of bacterial enzymes. By exposing cholin 

 to the action of oxidising agents such as OH ions, 

 it loses two atoms of H and becomes muscarine, 

 C 5 H 13 N0 2 ; the two H atoms abstracted by two OH 

 ions may form water of crystallisation, and muscarine 



