Anthranols

Anthranol is isomeric with anthrone, and behaves in its reactions as a typical hydroxylic compound. The equilibrium mixture between the two compounds consists mainly of the keto form anthranol is largely converted into anthrone on heating. 

Reduction of anthraquinone with tin and concentrated hydrochloric acid in the presence of boiling glacial eicetic acid gives anthrone this substance (keto form) under certain conditions passes into the enol form, anthranol ... 

In certain cases, alkanolamines function as reduciag agents. For example, monoethanolamine reduces anthraquiaone to anthranols, acetone to 2-propanol, and azobenzene to aniline (17). The reduction reaction depends on the decomposition of the alkan olamine iato ammonia and an aldehyde. Sinulady, diethan olamine converts o-chloronitrobenzene to 2,2 -dichloroazobenzene and y -dinitrobenzene to 3,3 -diamiQoazobenzene. 

The mixture becomes yellow-brown in color and some anthranol separates, but any unreacted copper can be seen on the bottom of the flask if the stirring is stopped for a few minutes,... 

Anthranol [529-86-2] M 196.2, m 160-170°(dec). Crystd from glacial acetic acid or aqueous EtOH. 

The quinone methide can also be generated in situ, at least in aqueous NaOH, directly from the peracetate, as hydrolysis of the phenolic acetate is faster than the benzylic acetate (see an example in Section 12.5.3). This method was used to demonstrate the addition of anthrahydroquinone (AHQ) and anthranol to (actual polymeric) lignin quinone methides in studies elucidating the anthraquinone (AQ)-catalyzed 8-0-4-aryl ether cleavage mechanisms in alkaline pulping.64-66... 

Ralph, J. Ede, R. M. Robinson, N. P. Main, L. Reactions of P-aryl lignin model quinone methides with anthrahydroquinone and anthranol. J. Wood Chem. Technol. 1987, 7, 133-160. 

Landucci, L. L. Ralph, J. Adducts of anthrahydroquinone and anthranol with lignin model quinone methides. 1. Synthesis and characterization. J. Org. Chem. 1982, 47, 3486-3495. 

Anthracene is noncarcinogenic and is structurally incapable of forming a bay region diol epoxide. Anthracene 1,2-dihydrodiol is most conveniently synthesized from 2-anthranol by oxidation with phenylseleninic anhydride to anthracene 1,2-dione (55) followed by reduction with NaBH in ethanol (22) or LiAlH (55). Anthracene 1,2-dihydrodiol has also been synthesized via the Prdvost reaction route... 

If the 9,10-dihydro-9-anthranyl carbanion were to react directly with oxygen, 9,10-dihydro-9-anthranylhydroperoxide would be formed. This could decompose to give anthrone and/or anthracene. Anthrone, which would exist mainly as anthranol in a basic medium, generally is oxidized easily to anthraquinone. The following equations illustrate this reaction. 

Dianthrone derivatives Hypericin, pseudohypericin, anthranol, photohypericin, hypericodehydrodianthrone Flavanols Catechin polymers (condensed tannins), leucocyanidin, epicatechin Photodynamic, antidepressant [monoamine oxidase inhibitor (MAOI)], antiviral Astringent, anti-inflammatory, styptic, antiviral... 

Rumex patientia L. var. callosus Fr. Schm. Tu Tai Huang (root) Chrysophanol, emodin, physcion, sloeemodin, anthranol, emodin-monomethylether.33 Hemostatic, treat thrombopenia and uterus. 

Anthocyanins Anthranil acid Anthranol Anthraquinoids Anthraquinone derivative Anthraquinones... 

They were formulated by him as anthranols. Also, von Pechmann described a monooxyphenylanthranol which presumably was a mixture of7f and 9-(/ -hydroxyphenyI)anthrone (see Section IV,A,4). Now many 1,3-diarylbenzo[c]furans are known (Section IV,A,6) the preparation of the parent compound (4) and of simple derivatives has also been described (Section III,B). 

Reaction XIX. (a) Condensation of Anthranol Derivatives with Glycerol. (B., 44, 1666.)—This condensation gives rise to the benz-anthrones which are used as intermediates in the dye industry. The reaction may be assumed to go as follows —... 

Reaction XIX. (6) Condensation of Anthranol Derivatives with Formaldehyde. (A., 420,134.)—The anthranols can also give rise to other intermediates by condensation with formaldehyde. Methylene anthra-quinone is thus obtained from anthranol. 

The anthraquinones may be reduced to the corresponding anthra-quinols (hydroxyanthranols) with alkaline sodium hydrosulphite this reaction has a wide application in the dye industry. These compounds are difficult to isolate pure, for they rapidly oxidise in air. The anthranols —y-monohydroxyanthracenes—however, are stable, and may be obtained by reducing anthraquinone with acid-reducing agents—tin and hydrochloric acid, zinc and glacial acetic acid, copper or aluminium, and sulphuric acid, etc. For the complete reduction of anthraquinone, see Reaction LYIII. (a). 

The phenomenon of azo—hydrazone tautomerism is firmly established75 in the benzeneazo-phenol, -naphthol, and -anthranol series, the azo form predominating in the first of these (65), the hydrazone form in the second (66), whilst the third exists exclusively in the hydrazone form (67). The situation is less clear in the analogous o-aminodiarylazo series. Thus, whilst it is known that o-aminoazobenzene (68) exists exclusively in the azo form, it has not been established whether... 

---