Corresponding to the sinigrin of the black mustard, the white mustard (Sinapis alba, L; Brassica alba, Boiss.) contains the glucoside sinalbin. It was first prepared by Robiquet and Boutron-Charlard2) who boiled the seeds, deprived of their fatty oil, with alcohol. The examination of this glucoside, and more particularly the elucidation of the reaction observed in its hydrolysis, and of the products of hydrolysis produced by myrosin, were undertaken by H. Will and A. Laubenheimer3), later by J. Gadamer4).
The identity of sinalbin mustard oil with p-hydroxybenzyl isothiocyanate has been established by H. Salkowski5).
Sinalbin mustard oil, C6H4OH.Ch2ncs is but sparingly volatile with water vapor6), hence cannot be obtained from white mustard seed by distillation. It is an oily liquid with a burning taste. It draws blisters, but much more slowly than allyl mustard oil. The pungent odor becomes noticeable only when heated. In the cold the oil has but a faint odor reminding one of anise. It is soluble in dilute alkalies. Sinalbin mustard oil is prepared by hydrolysis of the glucoside, which also yields glucose and sinapin sulphate:
1) Berl. Berichte 13 (1880), 1732. 2) Journ. de Pharm. II. 17 (1831), 279. 3) Liebig's Annalen 199 (1879), 150. 4) Arch, der Pharm. 235 (1897), 83. 5) Berl. Berichte 22 (1889), 2143.
") Ground white mustard seed mixed with water has a pungent taste but is nearly odorless.
C30H42N2S2O16 + H2O = C7H7Oncs + C6H1206 +
Sinalbin Water Sinalbin mustard oil Glucose.
Acid sinapin sulphate.
Artificially it is obtained by the action of carbon disulphide on p-hydroxybenzylamine, followed by treating the reaction product with mercuric chloride.