Vitex littoralis(CHAPTER V. The Flavone Group.)(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.

Vitex littoralis = Vitex lucens

The Vitex littoralis (A. Cunn.) or "Puriri" is a large tree, 40-60 feet high, and 3-5 feet in diameter, which grows only in the northern portion of the North Island of New Zealand. The wood affords a very durable timber, and is chiefly used for house blocks, fencing posts, piles for bridges, railway sleepers, etc.

Vitexin, the main colouring matter, is present in the wood in the form of a glucoside which has not yet been isolated. It is prepared by digesting a purified extract of the dyestuff with boiling dilute hydrochloric acid, and by this means separates in the form of a yellow viscous mass. By extracting this crude product with boiling alcohol, a pale yellow crystalline powder remains undissolved, and this, owing to its sparing solubility, is most readily purified by acetylation, and the subsequent hydrolysis of the pure acetyl derivative (Perkin, Chem. Soc. Trans., 1898, 74, 1020).

[---]

[---] Vitexin is a somewhat feeble colouring matter, and dyes shades similar to those given by apigenin; these, employing woollen cloth mordanted with chromium, aluminium, and tin, are respectively greenish-yellow, pale bright yellow, and pale brown.

In addition to vitexin the wood of the Vitex littoralis contains (as glucoside) a small quantity of a second colouring matter, homovitexin. It was obtained as a pale yellow powder, melting-point 245-246°, and is distinguished from vitexin by its ready solubility in alcohol. Fused with alkali it gives phloroglucinol and p-hydroxybenzoic acid, and is possessed of feeble dyeing property. The analytical figures approximate to C₁₆H₁₆O₇ or C₁₈H₁₈O₈.

According to Barger (Chem. Soc. Trans., 1906, 89, 1120) the glucoside saponarin, which is present in Saponaria offirinalis (Linn.), yields on hydrolysis glucose, saponaretin, and a small quantity of vitexin. It is possible that saponaretin and homovitexin are identical.