Anthraquinone nitro derivatives

In an interesting study, phthalocyanine complexes containing four anthraquinone nuclei (5.34) were synthesised and evaluated as potential vat dyes and pigments [18]. Anthraquinone-1,2-dicarbonitrile or the corresponding dicarboxylic anhydride was reacted with a transition-metal salt, namely vanadium, chromium, iron, cobalt, nickel, copper, tin, platinum or lead (Scheme 5.6). Substituted analogues were also prepared from amino, chloro or nitro derivatives of anthraquinone-l,2-dicarboxylic anhydride. 

Anthraquinone-1-sulphonic acid is the traditional precursor of 1-aminoanthraquinone (6.8), the most important anthraquinone intermediate. Since it is expensive to eliminate mercury(II) ions from waste water, an alternative route via 1-nitroanthraquinone has been investigated. Nitration of anthraquinone gives, as well as the desired 1-nitro derivative, significant amounts of the 2-isomer together with 1,5- and 1,8-dinitroanthraquinones. Nevertheless, chemists at Sumitomo in Japan have optimised the nitration procedure with respect to both yield and purity of the 1-nitro compound. In particular, nitration is stopped when 80% of the anthraquinone has been substituted [5]. Nitration of anthraquinone derivatives is also of some significance. 

In this way nitro derivatives of anthraquinone are prepared on an industrial scale from corresponding derivatives of aminoanthraquinonc (Kopetsehni [212] Mosby and Berry [213]). This is rather advantageous since pure individuals are obtained instead of the mixtures of isomers which would be formed if anthraquinone were nitrated. 

A study was made of the ultraviolet spectra of benzene, alkyl-, amino-, and nitro-derivatives of benzene, diphenyl-amine, triphenylmethane, triphenylcarbinol, and anthra-quinone adsorbed on zeolites with alkali exchange cations, on Ca- and Cu-zeolites, and on decationized zeolites. The spectra of molecules adsorbed on zeolites totally cationized with alkali cations show only absorption bands caused by molecular adsorption. The spectra of aniline, pyridine, triphenylcarbinol, and anthraquinone adsorbed on decationized zeolite and Ca-zeolite are characterized by absorption of the corresponding compounds in the ionized state. The absorption bands of ionized benzene and cumene molecules appear only after uv-excitation of the adsorbed molecules. The concentration of carbonium ions produced during adsorption of triphenylcarbinol on Ca-zeolite and on the decationized zeolite depends on the degree of dehydroxyla-tion of the zeolite. 

For the sake of completeness, the so-called Bohn-Schmidt reaction should also be mentioned. This reaction is an oxidation of anthraquinone with fuming sulfuric acid or, under some circumstances, the oxidation of the nitro derivative in the presence of sulfur and boric acid. At the present time, these reactions are of little importance technically. ... 

The behavior of anthracene towards nitrating agents is determined largely by the great reactivity at positions 9 and 10. According to the reaction conditions it gives either oxidation products such as anthraquinone or nitro derivatives thereof, or else, by way of primary adducts, 9-nitro- or 9,10-dinitro-anthracene. Directions for the preparation of 9-nitroanthracene are to be found in Organic Syntheses.116... 

Anthraquinone Series. In the anthraquinone series, nitration with mixed acid containing a slight excess over one equivalent of nitric acid results in the formation of three nitro derivatives. These are the alpha-substituted 1-nitroanthraquinone and the 1,5-and 1,8-dinitroanthraqui-nones. Unless the nitric acid ratio and concentration are suflScient to ensure conaderable dinitration, some anthraquinone remains unreacted. 

Anthraquinone can be converted into nitro derivatives, halogen substitution-products, and sulphonic acids. Many derivatives of anthraquinone are known, some of which are important dyes, and will be discussed later (631). 

Anthraquinone can be brominated, chlorinated directly to the tetrachloro (I, 4, 5, 8-) stage, nitrated easily in the 1-position, but gives the 1,5-and 1,8-dinitro-derivalives on prolonged nitration the nitro groups in these compounds are easily displaced by neutral solutions of alkali sulphites yielding the corresponding sulphonic acids. Sulphonation with 20-30 % oleum gives the 2- 2,6- and 2,7-derivatives in the presence of Hg the 1- 1,5- and 1,8- derivatives are formed. 

The valence-bond approach may be used to provide a qualitative account of the /lmax values, and hence the hues, of many dyes, particularly those of the donor acceptor chromogen type. The use of this approach to rationalise differences in colour is illustrated in this section with reference to a series of dyes which may be envisaged as being derived from azobenzene, although in principle the method may be used to account for the colours of a much wider range of chemical classes of dye, including anthraquinones (see Chapter 4), polymethines and nitro dyes. 

A striking feature of disperse dye development in recent decades has been the steady growth in bathochromic azo blue dyes to replace the tinctorially weaker and more costly anthraquinone blues. One approach is represented by heavily nuclei-substituted derivatives of N,N-disubstituted 4-aminoazobenzenes, in which electron donor groups (e.g. 2-acylamino-5-alkoxy) are introduced into the aniline coupler residue and acceptor groups (acetyl, cyano or nitro) into the 2,4,6-positions of the diazo component. A PPP-MO study of the mobility of substituent configurations in such systems demonstrated that coplanarity of the two aryl rings could only be maintained if at least one of the 2,6-substituents was cyano. Thus much commercial research effort was directed towards these more bathochromic o-cyano-substituted dyes. 

Only a limited range of nitro, azo and anthraquinone disperse dyes exhibit adequate fastness to dry heat, light and weathering for application on polyester automotive fabrics. The structure of Cl Disperse Yellow 86 was modified to incorporate UV absorbers of the benzophenone, benzotriazole or oxalanilide types into the dye molecule. The derived dyes showed better fastness properties than the parent unsubstituted dye. Positioning of the photostabilising moiety within the dye molecule had little influence on the light fastness obtained, however. Built-in benzophenone residues were more effective than the other two types [177]. Nevertheless, several further monoazo and nitrodiphenylamine disperse dye... 

It will be recalled that not only halogen atoms, but also nitro and sulfo groups, can be replaced by phenyl- or arylamines. The lability of the nitro group, particularly in the anthraquinone nucleus, permits the preparation of some important intermediates which cannot be discussed here. Also, highly nitrated benzene derivatives give access to interesting condensation products. 

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. 

Sodium hydrosulfite (hyposulfite), Na2S204, in alkaline solutions has come to play an important part in the reduction of anthraquinone and in-digoid derivatives to the leuco compounds. Although it is an active reducing agent, it finds only a limited use in the reduction of nitro compounds because of its comparatively greater cost. 

Excess Acid. The helpful function of excess sulfuric acid as an inexpensive, low-viscosity solvent for most sulfonic acids is often overlooked because of the difficulty of recovering a product dissolved in it, or because of the disposal problem often encountered. Sulfonation of most of the hydroxyl, amino, nitro, and carboxylic derivatives of benzene, naphthalene, and anthraquinone is facilitated in this manner by the presence of excess acid. The same effect applies to anthraquinone itself, to petroleum lubricant fractions during sulfonation to mahogany and green acids, and to the sulfation of fatty oils. Chlorosulfonic acid, used in large excess for the conversion of aromatic compounds to sulfonyl chlorides by chlorosulfona-tion, functions in a similar manner. 

The hair dyes of Table 6-8 generally consist of neutral aromatic amine, nitro aromatic amine, or anthraquinone derivatives. They are all highly polar ingredients and can be classified as mono-, di-, or trinuclear (ring) dyes. Wong [38] has studied the kinetics of dye removal from hair for this type of hair dye and concluded that under all conditions the larger, trinuclear dyes rinse more slowly from hair than the smaller, mononuclear dyes. 

Alditols. Cyclitols and Derivatives Thereof.- 4-(D-arabino-Tetritol-l-yl)-4-imidazolin-2-ylideneammonium chloride, (4R, 5R)-4-(D-arabino-l 2.3.4-tetraacet03 butyl)-l,2-dimethyl-5-nitro-l-anthraquinone derivative (20), l-(3,5-dimethyl-3-nitro-l-pyrazolm-4-yl)-penta-Q-... 

Anthraquinone gives predominantly the 2-hydroxy derivatives on photolysis in aqueous propane-2-ol. The nitro group can be replaced by hydroxyl ion. 

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