From the seeds of Cheiranthus Cheiri, L. (Ger. Goldlack), P. Wagner2) obtained a sulphur-containing compound which he named cheirolin. Somewhat later this compound was examined by W. Schneider1) who recognized it as a mustard oil, viz., y-thiocarbimidopropyl methyl sulphone, Ch3 • So2 • CH2 • CH2 • CH2 • N: C: S.
1) Possibly substances similar to those found in the seeds. See p. 534. 2) Chem. Ztg. 32 (1908), 76.
Cheirolin also occurs in the seeds of Erysimum arkan-sanum, Nutt. (E. asperum, DC). For its preparation the seeds of the wallflower are first extracted with ether in order to remove the fat. A 5 p.c. soda solution is added to decompose the glucoside-like cheirolin compound and the solution shaken out with ether. The cheirolin thus extracted by the ether amounts to a yield of from 1,6 to 1,7 p.c. computed with reference to the seeds. The pure product crystallizes from ether in colorless and odorless prisms that melt at 47 to 48°, boil at about 200° (3 mm.) and are optically inactive. When distilled under atmospheric pressure it is decomposed. It produces a decided irritation on the mucous membrane. When saponified it decomposes quantitatively into hydrogen sulphide, carbonic acid and y-aminopropyl-methyl sulphone (m. p. 44°; of the hydrochloride 146°; m. p. of the picrate 190 to 192°), which yields a quaternary iodomethylate that melts at 150 to 152°. This is regarded as evidence of the primary character of the nitrogen in the /-aminopropylmethyl sulphone. When cheirolin is acted upon by mercuric oxide, there results, first upon the action of one-half molecule of this reagent, di-(y-methylsulphone propyl) thiourea (m. p. about 125°), and upon the renewed action of the mercuric oxide di-(y-methyl-suIphone propyl) urea (m. p. 172°).
Cheirolin is contained in the wallflower seed as glucoside which can be extracted by means of alcohol after the fat has been removed-). It is exceedingly soluble in water and possesses no characteristic melting point. Separated from the alcoholic solution, it contains from 6 to 7 p.c. of alcohol (of crystallization?) which it loses in vacuum over sodium at water-bath temperature. This glucoside has not yet been obtained in a pure condition but it is analogous to other mustard oil glucosides. It contains cheirolin, glucose, sulphuric acid and potassium. The sulphur present exists in three forms; as sulphuric acid radicle, as mustard oil sulphur and as sulphonic sulphur. Cheirolin can be isolated from the glucoside by hydrolyzing the latter with the enzyme from the white mustard. The wallflower seed itself contains an enzyme that hydrolyzes the sinigrin of black mustard with the formation of mustard oil, hence it is physiologically equivalent, if not identical, with myrosin.
1) Liebig's Annalen 375 (1910), 207.
2) W. Schneider and W. Lohmann, Berl. Berichte 45 (1912), 2954.
By treating the fatty oil of the seeds obtained by ether extraction with water-vapor, M. Matthes and W. Boltze') obtained 0,0073 p.c. (computed with reference to the seeds) of a colorless volatile oil that had an odor which reminded one of waterfennel: b. p. 120 to 125° (15 mm.); d15o0,9034; [a]D +12,73°; nD20o1,6920. Potassium permanganate and bromine are both decolorized immediately by the oil. An elementary analysis yielded 85,68 p.c. of carbon and 11,56 p.c. of hydrogen.