Anthraquinone chloro

Anthraquinone can be sulfonated, nitrated, or halogenated. Sulfonation is of the greatest technical importance because the sulfonic acid group can be readily replaced by an amino or chloro group. Sulfonation with 20—25% oleum at a temperature of 130—135°C produces predominandy anthraquinone-2-sulfonic acid [84-48-0]. By the use of a stronger oleum, disulfonic acids are produced. The second sulfonic acid substituent never enters the same ring a mixture of 2,6- and 2,7-disulfonic acids is formed (Wayne-Armstrong rule). In order to sulfonate in the 1-, 1,5-, or 1,8-positions, mercury or one of its salts must be used as a catalyst. 

Sequential applications of these methods yield naturally occurring anthraquinones, eg, macrosporin [22225-67-8] (86) in 83% yield from 2-chloro-6-methyl-7-hydroxy-l,4-naphthoquinone [76665-67-3] (87), which is produced in 78% yield from (26) (84). 

In 1901, mercury cataly2ed a-sulfonation of anthraquinone was discovered, and this led to the development of the chemistry of a-substituted anthraquinone derivatives (a-amino, a-chloro, a-hydroxy, and a,a -dihydroxyanthraquinones). In the same year R. Bohn discovered indanthrone. Afterward flavanthrone, pyranthrone, and ben2anthrone, etc, were synthesi2ed, and anthraquinone vat dyes such as ben2oylaniinoanthraquinone, anthrimides, and anthrimidocarba2oles were also invented. These anthraquinone derivatives were widely used to dye cotton with excellent fastness, and formed the basis of the anthraquinone vat dye industry. 

Efforts have also been made to overcome compHcated processes. Methods to reduce the number of steps or to use new starting materials have been studied extensively. l-Amino-2-chloro-4-hydroxyanthraquinone (the intermediate for disperse red dyes) conventionally requires four steps from anthraquinone and four separation (filtration and drying) operations. In recent years an improved process has been proposed that involves three reactions and only two separation operations starting from chloroben2ene (Fig. 2). 

A 2-1. three-necked flask fitted with a stirrer (Notes 1 and 2), condenser, and dropping funnel (Note 3) is mounted in the hood, and in it are placed 20 g. (0.061 mole) of potassium anthra-quinone-a-sulfonate (p. 72), 500 cc. of water, and 85 cc. (1 mole) of concentrated hydrochloric acid. The solution is heated to boiling and stirred, while a solution of 20 g. (0.19 mole) of sodium chlorate (Note 4) in 100 cc. of water is added dropwise over a period of three hours (Note 5). The mixture is refluxed very slowly for an additional hour before the precipitated a-chloro-anthraquinone is collected by suction filtration and washed free from acid with hot water (about 350 cc.). After drying in vacuo at ioo°, the bright yellow product melts at 158-160° (corr.) and weighs 14.6-14.7 g. (97-98 per cent of the theoretical amount) (Notes 6 and 7). 

Fig. 1.11 Dissociation ranges of colour indicators for determination of the acidity function H0 in H2S04-H20 mixtures (1) p-nitroaniline, (2) o-nitroaniline, (3) p-chloro-o-nitroaniline, (4) p-nitrodiphenylamine, (5) 2,4-dichloro-6-nitroaniline, (6) p-nitroazobenzene, (7) 2,6-dinitro-4-methylaniline, (8) benzalacetophenone, (9) 6-bromo-2,4-dinitroaniline, (10) anthraquinone, (11) 2,4,6-trinitroaniline. (According to L. P. Hammett and A. J. Deyrup)...

The relative and absolute configurations of diepoxydicarbazoles involving the 2,6-dioxa-4,8-diazaadamantane system were determined in the course of a study on indole and indole alkaloids.242 Water-soluble azo, anthraquinone, and phthalocyanine dyes which are substituted by a 4-chloro-s-triazin-2-ylamino group can be quaternized with a l-aza-3-methyl-4,6,10-trioxa-adamantane unit in aqueous medium at 40 50"C.243 Dyes mixed with... 

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. 

Although anthraquinone is the starting point for the preparation of many derivatives, involving substitution and replacement reactions, certain compounds are obtained directly by varying the components in the above synthesis. Thus, for example, replacement of benzene with methylbenzene (toluene) leads to the formation of 2-methylanthraquinone. A particularly important variation on the phthalic anhydride route is the synthesis of 1,4-dihydroxyanthraquinone (6.6 quinizarin) using 4-chlorophenol with sulphuric acid and boric acid as catalyst (Scheme 6.3). The absence of aluminium chloride permits hydrolysis of the chloro substituent to take place. 

Pyranthrone is commonly prepared by Ullmann reaction of 1 -chloro-2-methyl-anthraquinone (100), followed by double ring closure. 

Anthraquinones. A regioselective synthesis of polyhydroxyanthraquinones is based on Dicls-Alder reactions of I with chloro-substituted naphthoquinones. An example is the synthesis of 1,6-dihydroxyanthraquinone (3) from 3-chlorojuglone (2). Analogous syntheses arc possible by use of vinylogous kctcnc acetals related to I. 

An alternative focus based on known antitumor activity of adriamycin-type systems stimulated the synthesis of the aza-anthraquinones 599 and 600 (Scheme 177) (84CC897). Thus, synergistic chloro-oxazoline directed metalation of 597 with methyllithium followed by treatment with 2,5-dimethoxybenzaldehyde and acid-promoted cyclization provided the lactone 598. Radical bromination and base-induced hydrolysis gave an intermediate keto acid which, upon Friedel-Crafts cyclization with methanesulfonic acid, led to the aza-anthraquinone 599 in modest yield. The azanaphthacene dione 600 was prepared by an analogous series of reactions starting with 597. 

Recovery experiments were conducted with the following standards, which were used as received without further purification 5-chlorouracil (Calbiochem), furfural (Aldrich), crotonaldehyde (Aldrich), caffeine (Aldrich), isophorone (Aldrich), 2,4-dichlorophenol (Aldrich), anthraquinone (Aldrich), biphenyl (Ultra Scientific), 2,4 -dichlorobiphenyl (Ultra Scientific), 2,6-bis(l,l-dimethylethyl)-4-methylphenol (Aldrich), 2,2, 5,5 -tetrachlorobiphenyl (Ultra Scientific), benzo[e]pyrene (Aldrich), bis(2-ethylhexyl) phthalate (Scientific Polymer Products), 4-methyl-2-pentanone (Aldrich), quinoline (Kodak), 1-chloro-dodecane (Eastman), stearic acid (Kodak), quinaldic acid (Aldrich), trimesic acid (Aldrich), glucose (Aldrich), glycine (Aldrich), and chloroform (Burdick and Jackson). 

Amino-3,7-disull o-9.10-anthraquinon-l-ylamino)-anilino]-5-chloro-2.4-difluoro-ElOa. 74 (Educt)... 

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. 

The heterocycle formed in the cyclocondensation reactions of 2-acetylenyl-l-chloro-9,10-anthraquinones or 5-acet-yleneyl-3-(diethylamino)-l,4-naphthaquinones with hydrazine is influenced by the presence of a heterofunctional OH group in the acetylenic substituent. This directive effect was used in the synthesis of naphtha [2,3- ]cin noline-4,7,12-triones and 4//-naphtho[ 1,8-z/7]-l, 2-dia/cpin-8-oncs <2000MC188>. 

Most of the previously identified 25 chlorinated anthraquinones are found in lichen and fungi (1). The newly discovered examples have a wider range of sources. Studies of the lichen Nephroma laevigatum from the British Columbia coast have identified the new anthraquinone, 7-chloro-l-O-methyl-co-hydroxy-emodin (2157), and the two novel hypericins, 7,7 -dichlorohypericin (2158) and 2,2, 7,7 -tetrachlorohypericin (2159) (1931), as well as 5-chloroemodin (2160), 5-c h I oro -1 - (9 - m e t h v I - o >- h yd ro x ye m od i n (2161), and 5-chloro-co-hydroxyemodin (2162) (1932). In addition to containing several known chlorinated anthraquinones, the Scandinavian fungus Dermocybe sanguinea has afforded the new 5,7-dichloroendocrocin (2163) (1933). The novel tetracyclic anthraquinones... 

Anthraquinones with electron-donating substituents, such as amino or hydroxyl groups, permit selective halogenation of one or the other nucleus by appropriate choice of reaction conditions. Only the chloro and bromo derivatives are commercial products. 

Other important anthraquinone vat dyes belong to the family known as indanthrones. Important examples of this structural type are C.I. Vat Blue 4 and Vat Blue 6. Vat Blue 4 is made by heating 1-amino or 2-aminoan-thraquinone at 220-230°C in a K0H/H20 mixture. The Vat Blue 6 synthesis is a much longer process that requires the synthesis of 2-chloro-3-aminoanthraquinone.57 The resultant amine is brominated and converted to the target dye via an Ullmann reaction. 

The synthesis of the series of 2,4,5-amino-substituted derivatives of 1-phenoxy-anthraquinone (II) was accomplished by an exchange of chlorine or bromine atoms upon heating the corresponding 1-chloro- or 1-bromoanthraquinones in a phenol-phenoxide solution as well as by alkylation of 1-aminomethyl- or dimethylanthra-quinones using methyliodide.14... 

The intramolecular condensation of o-aroylbenzoic acids in the presence of concentrated sulfuric acid gives substituted anthraquinones. The acid strength, reaction temperature, and period of heating are carefully controlled to insure optimum yields and to avoid sulfonation products. Boric acid has been added as a sulfonation inhibitor. Substitution in the para position of the aroyl group leads to 2-alkyl-, 2-chloro-, and 2-bromo-anthraquinones. ... 

Thionyl chloride converts anthraquinone-l-arsinic acid into 1-chloro-authraquinone. Antlmiquiuane-l-dickloroarsine, M.pt. 237 C., is obtained only by reduction of the acid hi the usual maiiiier. ... 

Methylaminoanthraquinone has been prepared from 1-chloro-, 1-bromo-, and 1-nitroanthraquinone by treatment with alcoholic methylamine under pressure from 1-methoxy- and 1-phenoxyanthraquinone with methylamine in pyridine solution at 150° from potassium anthraquinone-1-sulfonate with aqueous methylamine at 150-160° from 1-aminoanthraquinone by treatment with formaldehyde, or methyl alcohol in sulfuric acid or oleum and by hydrolysis of />-toluenesulfonyl-methylaminoanthraquinone with sulfuric acid. ... 

Two molecules of aluminum chloride for each molecule of the anhydride are employed in the reaction. If chlorobenzene is used in place of benzene a substituted o-benzoylbenzoic acid is formed (4 -chloro-2-benzoylbenzoic acid). The preparation of these substituted keto acids is of industrial importance, as by cyclization they form anthraquinone derivatives. 

---