INDOL AND SKATOL. 157 



(a) D = -30.33. HOPKINS and COLE give (a) D =-33 for the watery 



N N N 



solution. It is dextrorotatory in or NaOH as well as in HCL 



12 1 



Tryptophane yields indol and skatol when sufficiently heated. It 

 gives the ADAMKIEWICZ-HOPKINS x reaction and a rose-red color on the 

 addition of chlorine or bromine water (tryptophane reaction). The 

 brom-tryptophane is readily soluble in amyl alcohol or acetic ether 

 and on shaking with these solvents the reaction is more delicate. 2 If 

 a pine stick previously moistened with hydrochloric acid and washed 

 with water is introduced into a concentrated tryptophane solution, 

 it becomes purple (pyrrole reaction) on drying. The melting-points 

 of the benzoylsulphotryptophane, the |8-naphthalenesulphotryptophane 

 and the naphthylisocyanatetryptophane are according to ELLINGER 

 and FLAMAND, 3 185, 180 and 158 C. respectively. Several compounds 

 of tryptophane have been prepared by ABDERHALDEN and KEMPE. 4 

 Among these we will mention the tryptophane chloride hydrochloride, 

 because it is used as the starting material for the synthesis of trypto- 

 phane polypeptides. In the alcoholic fermentation of sugar, as found 

 by F. EHRLICH 5 the tryptophane present is transformed into tryptophol 

 (j3-indoxylethyl alcohol). 



In regard to the rather complicated method for preparing trypto- 

 phane we must refer to the original work of HOPKINS and COLE, of 

 NEUBERG, and of ABDERHALDEN and KEMPE. FASAL 6 has suggested a 

 quantitative colorimetric method for estimating tryptophane based 

 upon the ADAMKIEWICZ-HOPKINS reaction. 



As shown by HOPKINS and COLE, ? tryptophane on anaerobic putre- 

 faction yields indolpropionic acid and indolacetic acid, and indol and 

 skatol on aerobic putrefaction. Among these putrefactive products the 

 indol and skatol will be specially discussed. 



CH 



Indol, C8HyN = C6H4< y>CH, and Skatol, or ^-METHYLINDOL, 

 NH 



1 In regard to this reaction see also Dakin, Journ. of Biol. Chem. 2, and O. Rosen- 

 heim, Biochem. Journ., 1. 



2 Neuberg, Bioch. Zeitschr., 24. 

 'I.e. 



4 Zeitschr. f. physiol. Chem., 52, and Ber. d. d. chem. Gesellsch., 40. 



5 Ber. d. d. chem., Gesellsch., 45. 



8 Hopkins and Cole, Journ. of Physiol., 27 and 29; Neuberg and Popowsky, Biochem. 

 Zeitschr., 2; Abderhalden and Kempe, Zeitschr. f. physiol. Chem., 52; Fasal, Bioch. 

 Zeitschr., 44. 



7 Journ. of Physiol., 29. 



