Hydroxy anthraquinones

Amlnochrysammlc or Amlnochrysammlnlc Acid. See 2,4,5,7-Tetranitro-8-amino-1-hydroxy-anthraquinone, described under Aminohydtoxyanthraquinone and Derivatives Aminocompounds are described individually, such as amino acetic acid, aminobenzoic acid, aminocarbazole, aminotetrazole, aniline, etc... 

Note No higher nitrated derivs of amino-hydroxy anthraquinones were found in Beil of CA through 1956... 

Chrysammidic Acid. See 2,4,5,7 -Tetranitro - 8 -amino 1 - hydroxy-anthraquinone under Amino-hydroxyanthraquinones and Derivatives, Vol 1, pA217-L... 

This reaction is specially interesting since many of the above compounds readily yield the corresponding anthraquinone derivatives (see p. 82), e.g., 4-chloro-l-hydroxy-anthraquinone has been obtained from p-chloro-phenol substituted anthraquinones of this type are becoming increasingly important. 

Although tautomerism is theoretically possible in amino and hydroxy anthraquinone dyes, none has been observed. Studies by 13C NMR spectroscopy have shown convincingly that amino and hydroxy dyes of 9,10-anthraquinone exist as such. 

Blue and turquoise dyes also play an important role. The most important blue dyes come from ring- or V-substituted derivatives of the two isomers of aminodi-hydroxy-anthraquinone 8 and 9. 

The reaction of these hydroxy anthraquinones is strictly confined to the surface layer of ions. With other substances, like picric acid, the reaction resulting in the formation of HF or HC1 and picric ions proceeds further into the lattice and ultimately the whole salt layer is converted... 

Both o- and p-quinone acetals, also prepared in situ, reacted with 3-cyanophthalide affording hydroxy-anthraquinones [38],... 

Tables 7.3 and 7.4 show that unsubstituted and most of the substituted 1-phenoxy-9,10-anthraquinones exhibit photochromic properties. The majority of compounds with mono- and dialkylamino substituents shows no photochromic transformations but undergoes irreversible photochemical conversion.5,8 The photo-chromism is also absent in the case of l-phenoxy-8-hydroxy-anthraquinone. It is suggested31 that, unlike 1-naphthoxyanthraquinone,32 the structural isomer of 1-phenoxy-anthraquinone arises from the rotameric isomer.

Quite independently, and only three years after Werner s proposal, Oddo and Puxeddu proposed intramo c x x H bonded configurations for some azo derivatives of eugenol (1536). Seven years later Pfeiffer made a similar proposal of an m/ramolecular Hnner Komplexsalzbindung between the hydroxyl and carbonyl functional groups in 1-hydroxy-anthraquinone (1624),... 

I-2-Di-hydroxy Anthraquinone, Baeyer and Caro.— To test this point they prepared a di-brom anthraquinone and fused it with potassium hydroxide. The product proved to be alizarin, thus establishing it as di-hydroxy anthraquinone. 

The remarkable thing is, that while there are ten possible di-brom or di-hydroxy anthraquinones, the particular one necessary was obtained by Graebe and Liebermann. The positions of the two hydroxyl groups were determined by Baeyer and Caro. When alizarin is heated pyro-catechinol, i-2-di-hydroxy benzene, is obtained. Also when pyro-catechinol is heated with ortho- hXhaXic acid and sulphuric acid alizarin results. This last synthesis is analogous to that of anthraquinone from benzene and o //io-phthalic acid (p. 796). 

This relationship of alizarin to pyro-catechinol proves that the two hydroxyl groups must be ortho to each other, but this condition is possible if the hydroxyls are either 1-2 or 2-3. Baeyer and Caro established the positions as 1-2 as follows. When phenol is heated with ortho-phthalic acid and sulphuric acid two mono-hydroxy anthraquinones are obtained. 

As will be seen, only these two mono-hydroxy compounds are possible. Now both of these mono-hydroxy anthraquinones yield alizarin by the introduction of a second hydroxyl group. The only constitution possible for a di-hydroxy anthraquinone obtained from both of these two mono-hydroxy anthraquinones is the 1-2-di-hydroxy compound. As alizarin is thus obtained the two hydroxyl groups in it must be in the 1-2 positions and not in the 2-3 positions. 

Nitro, amino and sulphonic acid derivatives of alizarin are also dyes of various colors and are known as alizarin orange, alizarin maroon, alizarin red, etc. Also there is present in the madder root another dye compound known as puipurin which is 1-2-4-tri-hydroxy anthraqui-none. Isomeric tri-hydroxy anthraquinones are dyes also but it is interesting that in all of these poly-hydroxy anthraquinones which are dyes two of the hydroxyls are always in the 1-2 positions. 

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