Arsanthrene

Hydrogen peroxide oxidizes the tellurium-bridged compound to arsanthrenic acid3. 

Reduction of this acid in concentrated hydrochloric acid solution by sulphur dioxide in the presence of potassium iodide yields arsanthrene chloride, which is oxidised by nitric acid to arsanthrenic acid or di-phenyletie-o-diarsinic add,... 

Reduction of arsanthrene chloride by fuming hydrochloric acid and zinc, or the corresponding oxide by phenylhydrazine, yields armnthrene or diphenylenediarsine, which may be represented as follows ... 

Reduction of this acid with phosphorus trichloride, or heating arsanthrene oxide in carbon dioxide under reduced pressure, forms tri-o-phenylenediarsine. This is a crystalline product, ibrniing a mercuricKlonde and yielding a tetrabromide with bromine. 

Arsanthrene or Diphenylenediarsine. —The complete synthesis of this compound (III) is shown by the following scheme ... 

Arsanthrene chloride (II).- The preceding acid is reduced by sulphur dioxide in the j)rescnec of j)otassium iodide in concentrated hydrochloric acid solution. The arsanthrene chloride obtained crystal- Kalb, AnncHen, 1921, 423, 39. 

Arsanthrene chloride in ten times its weight of warm nitric acid (density 1-38) is heated until no more nitrous fumes escape. An equal volume of water is then added and the product obtained recrystalliscd from hot dilute nitric acid (density 1 2). Large, ((olourless prisms separate (probably a dinitrate), which fall to a chalky imwdcr on washing with water. The acid does not melt at 3(i0 and is sparingly soluble in all solvents. 

Stable derivatives of (XVI) which are apparently monomers have been isolated for both P 104) and As 343) if a phenyl group is substituted for hydrogen in the 10-position. Since this report is preliminary, the assignment of the anthracene structure is only tentative. A recent X-ray structural study has shown that arsanthrene is a dimer and not the monomer 178) ... 

The trivial nomenclature for the dibenzannelated tetrahydro-l,4-oxarsinanes and the corresponding nitrogen and arsenic derivatives (14)-(16) has been maintained, too. Oxygenated i As analogues of (14) are called phenoxarsinic acids (17). Phenoxarsines, phenazarsines and arsanthrenes are all numbered regularly. 

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