— 85 — 



place. We started from crotonic aldehyde, which is obtained by distilling 

 aldol under suitable conditions. The aldehyde was converted into the 

 oxime 1 ), m. p. 118 to 119°, and the latter by reduction with sodium 

 amalgam in almost neutral alcoholic solution into crotonylamine 2 ). 

 According to our observations the b. p. of the amine was from 85 to 88°. 

 Its conversion into mustard oil by means of carbon disulphide was carried 

 out by Hofmann's 3 ) method in alcoholic solution under the application of 

 heat, and subsequent treatment with mercuric chloride and distillation with 

 steam. The crotonyl mustard oil thus obtained had a milder odour than 

 ordinary mustard oil, and possessed the following constants: b. p. 174 to 

 176°, di 5 o 0,9785, n D15 o 1,51717. Its thio-urea formed tables of a silky lustre, 

 m. p. 65 to 66°. A mixture of this thio-urea with the derivative from 

 natural crotonyl mustard oil melted between 45 and 50°, which disposes 

 of the possibility of the two oils being identical. The crotonyl mustard 

 oils investigated by Hofmann 4 ), Charon 5 ), and Sjollema 6 ) also cannot be 

 identical with our natural oil, judging from the literary references relating 

 to them. 



The examination of the abnormal mustard oil described above has 

 therefore shown that its principal constituent (about 50°/o) is an iso- 

 meric crotonyl mustard oil of unknown constitution; and further, that 

 it contains allyl mustard oil (about 40%) and probably, as subsidiary 

 constituents, allyl cyanide and dimethyl sulphide. 



About two years ago, P. Wagner 7 ) prepared from wallflower seed a 

 sulphurous body to which he gave the name of cheirolin. W. Schneider 8 ) 

 has now examined this substance and has identified it as a mustard oil, 

 /-thiocarbimido-propyl methyl sulphone, CH 3 -S0 2 -CH 2 -CH2-CH-N : C : S. 

 Cheirolin also occurs in the seed of Erysimum arkansanum. It was prepared 

 by extracting wallflower seed with ether, thus removing the fixed oil, adding 

 5°/o aqueous sodium carbonate solution to decompose the glucoside-like 

 cheirolin-compounds, and extracting with ether. The cheirolin which is 

 present in the ethereal solution equals about 1,6 to l,7°/o of the seed. 

 The pure product crystallises from ether in colourless and odourless 

 prisms, optically inactive, m. p. 47 to 48°; b. p. about 200° (3 mm.). It 

 decomposes when distilled at atmospheric pressure. It has a powerful irrit- 

 ating effect upon the mucous membranes. When saponified it is split up 

 quantitatively into hydrogen sulphide, carbon dioxide and /-aminopropyl- 



!) Berl. Berichte 24 (1891), 400; quoted from Jahresber. d. Chem. 44* (1891), 1168. 



-) Jahresber. d. Chem. 40 a (1887), 1162. 



3 ) Berl. Berichte 3 (1870), 767; 7 (1874), 511, 516. 



*) Loc. cit. 



5 ) Annal. de Chim. et Phys. 17 (1899), 197; quoted from Chem. Zentralbl. 1899, II. 90. 



*) Recueil des trav. chim. des P. B. 20 (1901), 237; Chem. Zentralbl. 1901, II. 299. 



') Chem. Ztg. 32 (1908), 76. 



^) Liebigs Annal en 375 (1910), 207. 



