Cyclic and Polycyclic Quinones

Anthraquinones. The important substitution patterns in anthraquinones are those adjacent to the 9,10 carbonyl groups namely 1,4-, 1,5-, 1,8-, and 1,4,5,8- as shown in Table 2.5, with further secondary substitution in the 2-, 3- and 7- and 8-positions. The order of the bathochromic shift caused by substituents in the 1-position is OH NHj 

Other bright blues are made by further reactions of l,5-diamino-4,8-dihyroxyan-thraquinone, e.g. with bromine to give Cl Disperse Blue 56, whilst the difficult area of bright turquoises is covered by the derivatives of l,4-diamino-2,3-dicarboxylic acids, e.g. Cl Disperse Blue 60 and Blue 87 (2.16). 

Bromamine acid, l-amino-4-bromoanthraquinone-2-sulfonic acid, is a very useful intermediate for producing bine dyes. Condensation of this intermediate with aromatic amines in the presence of a copper catalyst offers a straightforward route to many commercially important acid and reactive dyes, for instance Cl Acid Blue 40 and Cl Reactive Bine 19 (Fignre 2.13). 

Benzanthrones and analogues are discussed in Chapter 3, section 3.5.1.4, because of their behaviour as fluorescent dyes. 

Other Quinone Types. Although past researchers have examined many coloured quinonoid molecules very few have achieved commercial importance. 

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Despotovic, 1., Maksic, Z.B. and Vianello, R. (2007) Design of Brpnsted neutral organic bases and superbases by computational DFT methods cyclic and polycyclic quinones and [3] carbonylradialenes. European Journal of Organic Chemistry, 3402-3413. 

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