7-trihydroxyxanthone, is found in the form of its methyl ether (gentisin) in gentian root; it is obtained synthetically by condensing phloroglucin with hydroquinone carboxylic acid.
Oak tannin; whilst others yield protocatechuic acid and phloroglucin, e.g.
Moringa-tannin or maclurin, C1,H1006 H20, found in Morus tinctoria, hydrolyses on fusion with caustic potash to phloroglucin and protocatechuic acid.
The bark of the horse-chestnut contains a greenish oil, resin, a yellow body, a tannin, C26 H 24012, existing likewise in the seeds and various parts of the tree, and decomposable into phloroglucin and aesciglyoxalic acid, C 7 H 6 O 3, also aesculetin hydrate, and the crystalline fluorescent compound aesculin, of the formulaC21H24013 (Rochleder and Schwarz), with which occurs a similar substance fraxin, the paviin of Sir G.
Vorlander); when fused with caustic potash, resorcin yields phloroglucin, pyrocatechin and diresorcin.
3.5) is obtained by reducing an aqueous solution of phloroglucin with sodium (W.
5 (phloroglucin) is obtained by the fusion of many resins and of resorcin with caustic alkali.