Oenin.(CHAPTER VIII. Pyran Group. Delphinidin (and its derivates))(Osa artikkelista)

The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918

Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.

Oenin - a monoglucoside of oenidin - is the colouring matter of the black grape (North Italian or hothouse) and of red wine. It has received more attention than any other member of this series of colouring matters, but satisfactory chemical data concerning it only became available as the result of the work of Willstatter and Zollinger. In the grape skins this colouring matter appears to be accompanied by a small proportion of oenidin, and of a diglucoside (as yet unexamined) of this latter. Most of the early workers made use of red wine in their attempts to isolate the pigment, but on account of the small percentage present, the use of grape skins is much more convenient for this purpose.

* Maumene gave the name "oenocyanin" to the product obtained by Mulder.In his book "Chemie des Weines" (Leipzig, 1856) Mulder described a method of isolating this pigment by precipitating the lead salt and decomposing this with sulphuretted hydrogen, but his product contained lead. The first attempt to use the lead salt for the isolation of an anthocyan pigment was described by Berzelius (Annalen, 1837, 21, 262).* The work of Mulder was followed by that of Glénard (Comptes rend., 1858, 47, 268; Ann. Chim. Phys., 1858, (3), 54, 366), who used ethereal hydrochloric acid for the decomposition of the lead salt, and he thus obtained an amorphous product to which he gave the name "oenolin," and assigned the formula C₂₀H₂₀O₁₀ - the percentage composition of which does not differ greatly from that of C₂₃H₂₄O₁₂ now proved to be correct for the acid-free base. The method of Glénard was also employed by Gautier, who isolated a variety of compounds from related plants of the vine species, and was of the opinion that a whole series of these pigments occurred therein (Comptes rend., 1878, 86, 1507; 87, 64; 1892, 114, 623; 1911, 153, 531; cf. Willstatter and Zollinger, Annalen, 1916, 412, p. 198). Andree (Archiv f. Pharm., 1879, 13, 90) also attempted to isolate the pigment of the grape by the use of Mulder's method, whilst Heise (Arbeit, a. d. K. Gesundheitsamte, 1889, v., 618) described the preparation of two amorphous and impure products from red wine, using again the method of Glénard.

[---]