Notes on scientific research. 157 



hydrazine, aminocarvacrol (melting point 134°) that forms thymoquinone on being oxidized 

 with ferric chloride. Disbenzeneazocarvacrol can be reduced to diaminocarvacrol by 

 means of phenylhydrazine, but cannot be isolated; however, oxidation with ferric chloride 

 converts it into /?-hydroxythymoquinone melting at 180°. The product of the reaction 

 of salicylic aldehyde and benzenediazoniumchloride is benzeneazosalicylic aldehyde (V) 

 (melting point 132°) which is converted into aminosalicylic aldehyde phenylhydrazone 

 on being reduced with phenylhydrazine. 



Autoxidation of a-methylindole under the influence of light. — The important part played 

 by indole in some natural and artificial flower perfumes induces us to discuss a paper 

 by 0. Baudisch and A. Hoschek 1 ) on the autoxidation of indoles when exposed to full 

 daylight. The experiments were made not only at Bologna, but also at Zurich and 

 Davos, whereby it was most undoubtedly proved that the sun's rays at considerable 

 elevations during winter, as at the Schatzalp Sanatorium (2000 m. above sea level) had 

 a much greater photo-chemical effect than those at Bologna in the height of summer. 

 The authors found that, on exposing a watery suspension of a-methylindole in an 

 atmosphere of oxygen to the rays, apparently in the first instance a red, amorphous 

 substance was formed whose chemical and physical properties indicate that a photo- 

 polymerization of this product had supervened. This red, amorphous compound gradually 

 undergoes a decomposition under the influence of photolysis and oxidation whose primary 

 result is the formation of a yellow substance which proved to be Ms-[a-methyl-/?-indoyl]-ether. 

 Further oxidation converts the latter into JV-acetylanthranilic acid besides anthranilic 

 acid. Indole itself apparently behaves in the same manner. 



Oxidation of indole when exposed to light. — That indole and its derivatives show a 

 tendency towards spontaneous oxidation is a quality of biological importance which has 

 been closely investigated by B. Oddo 2 ). He had already had occasion to observe that 

 methylketole (a-methylindole) as well as scatole are superficially transformed under the 

 influence of light into a reddish-yellow substance, insoluble in ether. The compound 



O 



NH NH 



which originates from a-methylindole forms yellow crystals, melting at 208 to 209° 

 which evidently contain oxygen. Oddo then exposed indole, scatole (/?-methylindole) 

 and methylketole to the light in alcoholic solution with the object of preparing more 

 considerable quantities of these and of analogous compounds. Hereby indole formed 

 a compound Ci 6 H 12 ON 2 , probably an indoxyl ether of the fellowing constitution. It 

 consists of a yellow powder that melts at 269° with decomp ositionand produces, when 

 boiled with hydrochloric acid, indirubin. 



Detection of indole and of scatole. — Some years ago, T. Sasaki 3 ) described a sensitive 

 reaction of scatole which is based on the violet colouring that appears when concentrated 

 sulphuric acid is stratified under a methylalcoholic scatole solution. V. E. Nelson*) detects 



*) Berl. Berichte 49 (1916), 2579. — «) Gazz. chim. ital. 46 (1916), I. 323; Chem. ZentralU. 1916, II. 577. — 

 ») Biochem. Zeitschr. 23 (1910), 402; 29 (1910), 395; Report October 1910, 203; April 1911, 192. — *) Jouni. 

 of biologic cfiem. 24 (1916), 527; Perfum. Eecord 7 (1916), 252. 



