196 Bitancourt, Nogueira, and Schwarz 



pyrrole ring, (3) oxidation and possibly opening of the benzene ring, 

 (4) polymerization. 



These possibilities have been represented in the diagram of Fig- 

 ure 1. In such a diagram the concept of pathway is all but lost. In 

 the interpretation of the facts this concept constitutes a serious 

 drawback. We suggest that the intricate network of pathways be 

 called a lattice and since it is a representation of all the possible ways 

 in which indolic compounds may be decomposed, spontaneously or 

 under the influence of pyhsical, chemical, or biochemical factors, it 

 can be called the catabolic lattice of indole derivatives. 



SUMMARY 



Solutions of 14 indole derivatives decomposed by aging, heating, 

 ultraviolet radiation, or oxidants like FeClg were studied chroma- 

 tographically and electrophoretically. Fluorescence and ultraviolet 

 absorption of spots and zones were detected under long-wave and 

 short-wave ultraviolet light respectively. Significant changes in fluo- 

 rescence and absorption were induced by exposure of the chromato- 

 grams and ionograms to ultraviolet radiation. Salko^vski, Gordon- 

 Weber, Ehrlich, and Van Eck reagents, safranin, N HCl, dinitro- 

 phenylhydrazine, dichlorophenolindophenol, and ammoniacal AgNOg 

 were applied to the chromatograms and ionograms, either to the 

 whole or to longitudinal strips cut out from them so that more than 

 one reagent could be used at a time. 



Only a small proportion of the decomposition products were in- 

 dole derivatives reacting with Salkowski and Gordon-Weber reagents. 

 A few of them were identified as the immediate product of degrada- 

 tion of the side-chain. Of those which did not react, a number of 

 spots and zones gave yellow or orange color reactions with Ehrlich's 

 reagent and are probably o-aminobenzene derivatives but not anthra- 

 nilic acid. Among them some moved to the negative side of the 

 electrophoretic strips so that the side group in the ortho position 

 must have been neutral. 



Double chromatograms produced large spots of lAA, lAAL, and 

 lA which are interpreted as made up of from 2 to 6 polymers, present 

 in the solution or formed during chromatography. 



The majority of spots were fluorescent and did not react \\ith 

 any of the reagents. It is suggested that they might be pyrrole deriva- 

 tives resulting from oxidation and cleavage of the benzene ring of the 

 indole compounds, and aliphatic compounds, the last stages of de- 

 composition of those substances. 



It is concluded that decomposition of indole derivatives may fol- 

 low four main courses or a combination of them. 



