167 A -169 A.] CROTONYL ISOTHIOCYANATE 



257 



disulphide [160]. On heating- the isobu- 

 tylene bromide with alcoholic ammonia 

 at 1 00, a product containing- a croton- 

 ylamine is formed (Hofmann, Ber. 

 7, 515 ; 12, 992). The latter is heated 

 with carbon disulphide in alcoholic 

 solution, and the product (the crotonyl- 

 amine salt of crotonyldithiocarbamic 

 acid) treated with an aqueous solution 

 of mercuric chloride, silver nitrate, or 

 ferric chloride, and then boiled (Ibid. 

 Ber. 1, 516; 8, 1 08; Ann. Chim. 

 Physiol. [7] 17, 262 : see also for 

 general method Rudneff, Ber. 12, 1023; 

 Hecht, Ber. 23, 282 ; Ponzio, Gazz. 



26; 323)- 



[B.] From crotonic aldehyde [1O2] 

 through crotonyl alcohol by reduction 

 (Lieben and Zeisel, Monats. 1, 825; 

 Charon, Ann. Chim. [7] 17, 223 ; Comp. 

 Rend. 128, 737). The alcohol com- 

 bines with hydrogen bromide to form 

 a-brom-/3-butylene = crotonyl bromide, 

 and this by interaction with potassium 

 or ammonium thiocyanate [174] gives 

 crotonyl iso thiocyanate (Ibid.}. 



NOTE : The generators of isobutylene re- 

 ferred to under isobutyl alcohol [18 ; B ; C, &c.] 

 thus become, with carbon disulphide, generators 

 of crotonyl mustard oil. These are isovaleric 

 acid [Vol. II] ; glycerol and acetone [48 ; 106] ; 

 acetic acid and acetone ; amyl alcohol of fusel oil 

 [22]. Tertiary butyl alcohol [19] is also a generator 

 of isobutylene (see under isobutyl alcohol 

 [18 ; A]). 



The identity of the synthetical mustard oil 

 with the natural product requires confirmation. 

 According to Sjollema (Joe. cit.~) the crotonyl 

 mustard oil from Brassica napus is not identical 

 with either Hofmann's or Charon's compounds. 



168. Aiigelyl Isothiocyaiiate 



or Thiocarbiniide ; 

 Aiigelyl Mustard Oil. 



C 5 H 9 . NCS 



NATUKAL SOURCE. 



Said to have been obtained from rape 

 seed oil-cake (Jorgensen as above under 

 167). 



SYNTHETICAL PROCESSES. 



[A.] From amyl alcohol of fusel oil 

 [22] through 'isoamylene' (see under 



acetone [106 ; E]) and carbon disul- 

 phide [160]. The amylene is converted 

 into angelylamine by heating the brom- 

 ide with alcoholic ammonia, and the 

 amine into the mustard oil by the 

 general method as described above 

 under 167 ; A (Hofmann, Ber. 8, 106 ; 

 12, 991). 



NOTE : The identity of the natural with the 

 synthetical product has not been established. 



169. Benzyl Isothiocyaiiate 



or Thiocarbiniide; 

 Benzyl Mustard Oil. 



C 6 H 5 .CH 2 .NCS 



NATURAL SOURCES. 



Occurs in the ethereal oil of the 

 Capuchin cress, Tropaolwn majus, and 

 of the garden cress, Lepid'wm sativum; 

 also as the glucoside, glucotropaeolin, 

 in seeds of the same plants (Gadamer, 

 Arch. Pharm. 237, in; 507; Ber. 

 32, 2335 ; Beyerinck, Centr. Bakter. 

 II, 6, 72). 



SYNTHETICAL PROCESSES. 



[A.] From benzole acid [Vol. II] and 

 carbon disulphide [160]. Ammonium 

 benzoate is converted into benzonitrile 

 (Fehling, Ann. 49, 91 ; Laurent and 

 Gerhardt, Jahresber. 1849,327; Wohler, 

 Ann. 192, 362 ; Anschiitz and Schultz, 

 Ann. 196, 48 ; Buckton and Hofmann, 

 Ann. 100, 155 ; Gerhardt, ' Traite, &c./ 

 IV, 762; Henke, Ann. 106,276; Henry, 

 Ber. 2, 307 : see also under benzoic 

 aldehyde [114; C]), and the latter 

 reduced to benzylamine (Mendius, Ann. 

 121, 144; Spica, Gazz. 1O, 515; Bam- 

 berger and Lodter, Ber. 20, 1709). 

 Or benzonitrile and ethyl alcohol [14] 

 and hydrogen chloride condense to the 

 hydrochloride of benzimidoethyl ether 

 (Pinner, Ber. 16, 353 : general synthe- 

 sis), and this by interaction with ammo- 

 nia gives an amidine which, on reduction 

 by sodium amalgam in acid solution, 

 yields benzylamine (Henle, Ber. 35, 



344)- 



Benzylamine and carbon disulphide 



