344 PRACTICAL ORGANIC AND BiO-CHEMISTRY 



Scatole or /3-Methyl Indole. 



Scatole was first isolated from faeces and re- 

 cognised as a constituent of the intestinal con- 

 tents of man and animals. Later it was obtained 

 by the fusion of proteins with alkali and isolated 

 from the products of putrefaction. It is also a 

 product of the reduction of indigo with zinc dust. 

 The preparation of scatole is given under indole. 

 Scatole crystallises in colourless platelets melting at 95 and boil- 

 ing at 265-266. It has a pungent faecal smell. It dissolves in 

 water, but less readily than indole, but is more easily volatile in steam 

 than indole. It dissolves in alcohol, ether, benzene, chloroform. 



It is a weak base and combines with acids to form salts ; the 

 hydrochloride is easily soluble in alcohol, but insoluble in water and 

 ether. 



Reactions. 



(1) It dissolves in concentrated hydrochloric acid giving a violet 

 coloured solution. A purple-red is formed on warming its solution in 

 sulphuric acid. 



(2) With nitric acid and sodium nitrite it gives a white turbidity 

 (compare indole). 



(3) With p-dimethylaminobenzaldehyde solution it gives a blue- 

 violet colour which turns blue with sodium nitrite (compare indole). 



(4) With sodium nitroprusside and soda it gives a yellow colour, 

 which turns violet on heating for a few minutes with half its volume 

 of glacial acetic acid. 



(5) The glyoxylic acid reaction is rose-red in colour. 



(6) The formaldehyde reaction is yellow or brown, but red if a 

 trace of a ferric salt be present. 



(7) The pine shaving reaction is negative, but if a pine shaving 

 dipped in an alcoholic solution of scatole be placed in cold concentrated 

 hydrochloric acid it becomes cherry-red, changing after a little while 

 to a dark violet. 



Indoxyl and Indican. 



Indoxyl occurs in various species of the in- 

 digofera and in woad, Isatis tinctoria, probably 

 in combination with glucose as the glucoside, indi- 

 can. The glucoside is hydrolysed by enzymes in 

 the plant leaves and converted into indoxyl, which 

 undergoes oxidation to indigo blue. Indoxyl occurs in human and 

 mammalin urine in combination with sulphuric acid and glycuronic 

 acid as ester. It is hydrolysed by acid and oxidised to indigo blue. 



