9.10- Anthraquinone-2-carboxyhc acid

Only the reduction products involving the keto groups are of any academic or industrial importance. Complete reduction of the keto groups by ammonia and zinc (von Perger method) gives rise to anthracene in good yields and quaUty (10). This method is of importance since substituted anthracenes can be prepared from the corresponding anthraquinones. Industrially, an important dyestuff intermediate, 3-chloroanthracene-2-carboxyhc acid, (2) is prepared by this method (11) from 3-chloroanthraquinone-2-carboxyhc acid [84-32-2]... 

Acetylated cellulose Depending on acetyl content transition from normal phase to reversed phase chromatography Anthraquinones, antioxidants, polycyclic aromatics, carboxyhc acids, nitrophenols, sweeteners... 

Oxidative cleavage of ring B of anthraquinones yields benzophenone derivatives which are transformed to xanthones. Both hydroxyl groups of the symmetrically substituted benzene nucleus of the benzophenone carboxyhc acid intermediate can participate in the closure of the xanthone ring. From the xanthones dimeric products are formed probably via phenol oxidase or peroxidase-derived radicals (C 2.3.1 and C 2.4.1). 

Prenyl-naphthohydroquinone-2-carboxyhc acid is the key intermediate in the formation of anthraquinones of the alizarin type. (In contrast the A-ring-substituted anthraquinone derivatives found in fungi and certain higher plants, e.g., Rhamnaceae and Polygonaceae, are polyketides, D 3.3.5). In the biosynthesis of alizarin one C-atom of the isoprene residue is lost. In structurally related compounds, however, this C-atom may still be present in the form of a methyl, hydroxymethyl, aldehyde, or carboxy group. 

Anthraquinone pigments in madder are biosynthesised by the shikimate (chorismate) pathway, which provides only anthra-9,10-quinones. The starting compound is naphtho-l,4-quinone-2-carboxyhc acid. 

Munjistin, l,3-dihydroxyanthraquinone-2-carboxyhc acid, is an anthraquinone found as a component in roots of various Rubia, Relbunium and Morinda species it is therefore a major constituent of certain madder dyes (Schweppe and Winter, 1997). It is designated by the Colour Index as Cl 75370. 

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