Tetrahydroxy-anthraquinone

Quinalizarin (0.05% in pyridine). Dissolve 0.01 g quinalizarin (1,2,5,8-tetrahydroxy-anthraquinone) in 2 ml pyridine, and dilute the solution with acetone to 20 ml. 

Lithium aluminum hydride reduced p-benzoquinone to hydroquinone (yield 70%) [576] and anthraquinone to anthrahydroquinone in 95% yield [576]. Tin reduced p-benzoquinone to hydroquinone in 88% yield [174] Procedure 35, p. 214). Stannous chloride converted tetrahydroxy-p-benzoquinone to hexa-hydroxybenzene in 70-77% yield [929], and 1,4-naphthoquinone to 1,4-di-hydroxynaphthalene in 96% yield [180]. Other reagents suitable for reduction of quinones are titanium trichloride [930], chromous chloride [187], hydrogen sulfide [248], sulfur dioxide [250] and others. Yields are usually good to excellent. Some of the reagents reduce the quinones selectively in the presence of other reducible functions. Thus hydrogen sulfide converted 2,7-dinitro-phenanthrene quinone to 9,10-dihydroxy-2,7-dinitrophenanthrene in 90% yield [248]. 

Tetrahydroxy-2-(l-oxo-2,3,4,5-tetrahydroxyhexyl)-8-methyl-anthraquinone-5-carboxylic acid (Carminic acid) ( -22 20 13 ... 

The drug contains lecithin, several anthraquinones (chrysophanol, emodin, rhein, physicon and chrysophanolanthrone), 2,3,4,5-tetrahydroxy-stilbene-2-0-P-D-glucoside, and is rich in trace elements for example Ca, Fe, Zn, Mn, Cu, Sr [84]. 

Birkinshaw, j. H., J. C. Roberts, and P. Roffey Studies in Mycological Chemistry. Part XIX. Product B (Averantin) [l,3,6,8-Tetrahydroxy-2-(l-hydroxyhexyl)-anthraquinone], a Pigment from Aspergillus versicolor (Vuillemin) Tiraboschi. J. Chem. Soc. (London) C 1966, 855. 

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