Synthesis 



No record of a plant physiological test of indole-3-aceto- 

 nitrile seems to have been made, but Jackson (1929) secured 

 13 gm. of the nitrile from 15-6 gm. of indole in the course of 

 preparing indole ethylamine by the method of Majima and 

 Hoshino (1925). 



The synthesis of Majima and Hoshino represents a quite 

 practical method of preparing indole-3 -acetic acid: indole 

 magnesium iodide, treated with chlor-aceto-nitrile in ethyl 

 ether or in anisole solutions, yields the nitrile. The nitrile is 

 easily hydrolyzed to the acid. 



As some of the acids, more particularly the naphthyl-acetic 

 acids, are prepared via the corresponding nitrile, Vv^e have an 

 additional reason for believing that isolation of an acid is not 

 an essential goal in the manufacture of a potent growth- 

 regulating substance. 



The Auxins 



These are true plant hormones. They have not yet been 

 synthetized. Their structure was established by the work of 

 Kogl (1935). 



The formula of auxin-a (syn., auxentriolic acid) is: 

 CH CH CH 



1^ / N I' 



CH-CH-CH-CH CH-CH-CH -CH 



^ \ / 



CH=C 



CisHa.O, " CH-CH,-CH-CH-C0OH 



mol. wt., 328 ^ ' OH OH OH 



The configuration of auxin-b (auxenolonic acid) is similar, 

 the side chain (I) being replaced by: (R=Ci3H23) 



R- 



-CH CH2 CO COOH. 



I 



OH (C18H30O4; mol. wt., 310) 



113 



