Anthrone is a tricyclic aromatic ketone. It is used for a common cellulose assay and in the colorimetric determination of carbohydrates.

Derivatives of anthrone are used in pharmacy as laxative. They stimulate the motion of the colon and reduce water reabsorption. Some anthrone derivatives can be extracted from a variety of plants, including Rhamnus frangula, Aloe ferox, Rheum officinale, and Cassia senna. Glycosides of anthrone are also found in high amounts in rhubarb leaves, and alongside concentrated amounts of oxalic acid are the reason for the leaves being inedible.

Synthesis and reactions

Anthrone can be prepared from anthraquinone by reduction with tin or copper.

An alternative synthesis involves cyclization of o-benzylbenzoic acid induced with hydrogen fluoride.

Anthrone condenses with glyoxal to give, following dehydrogenation, acedianthrone, a useful octacyclic pigment.

Anthrone is the more stable tautomer relative to the anthrol as has been established also by X-ray crystallography. The tautomeric equilibrium is estimated at 100 in aqueous solution. For the two other isomeric anthrols, the tautomeric equilibrium is reversed: they are phenolic.

Anthrone undergoes nitration using conventional conditions for aromatic nitration, implying that it is the hydroxy tautomer that is the reactant.

Applications

This is a list of some of the applications of anthrone: XE-991, DMP 543, maprotiline, 1-(9-Anthryloxy)-2-aminoethane (c.f. flunamine). In Lednicer's textbook it was said that melitracen was made from anthrone. However, since the time of publication it has now been discovered that there are other avenues to making the 10,10-dimethylanthrone [5447-86-9] precursor compound.

The Beckmann rearrangement or Schmidt reaction of anthrone would give 6-morphanthridinone [1211-06-9]. The relevance of this to drug chemistry is that it finds involvement in the synthesis of perlapine, epinastine, mianserin, prazepine & pitrazepin, for example.

References