O-Quinone-4-sulfonic acids

Hydpoxyquinone-4-imines from o-quinone-4-sulfonic acids... 

Photosynthesis of azo-dyestuffs has been reported to be effected by the irradiation of o-quinone diazides. The reaction proceeds via the contraction of the diazide CCXV to the cyclic ketene CCXVI which adds water to form the eyclopentadiene carboxylic acid CCXYII. The latter couples with unchanged CCXV (obtained from 2-amino-l-phenol-4-sulfonic acid) to form the azo-dyestuff CCXVTII.270 Similarly, V-heterocyclic azo-dyestuffs, e.g., CCXX is obtained by the photolysis of CCXIX.275... 

Action of bisulfite on a nitro compound or on a quinone or quinonemo-noxime, in which the nitro and nitroso groups are simultaneously reduced to amino groups. Examples are the preparation of l-naphthylamine-2,4-disulfonic acid from o-nitronaphthalene and bisulfite (naphthionic acid as by-product), and the manufacture of l-amino-2-naphthol-4-sulfonic acid from nitroso- -naphthol and bisulfite (page 201). 

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. (o. 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 xoo°, 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). 

The Fenton-type system, Fe(II)/Cu(n)/H202, produced phenol with a moderate selectivity [28b]. In the absence of Cu(II) or Fe(III), biphenyl was the main product. Quinones, in particular l,2-naphthoquinone-4-sulfonate, played a vital role in the Fe(III)-promoted hydroxylation of benzene with HjOj, giving moderate yields of phenol [70]. The addition of polyethyleneglycol to Fe(III)/ HjOj in aqueous acetonitrile enhanced the phenol yield and selectivity [71]. A heterophase reaction in the presence of surfactants (quaternary ammonium salts, crown ethers, and polymers) has led to a further improvement. Biphasic benzene hydroxylation in the system composed of aqueous H O, Fe SO modified with 2-pyrazinecarboxylic acid (Hpca) derivatives, and CF COOH produced phenol with a selectivity of 97% (based on benzene) at substrate conversion of 8.6% (Eq. 14.22)... 

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