C13H9N

ACRIDINE  , in chemistry, a heterocyclic ring compound found in crude coal-tar anthracene . It may be separated by shaking out with dilute sulphuric acid, and then precipitating the sulphuric acid solution with potassium bichromate, the resulting acridine bichromate being decomposed by ammonia . It was first isolated in 1890 by C . Graebe and H . Caro (Ann., 1871, 158, p . 265) . Many synthetic processes are known for the production of acridine and its derivatives . A . Bernthsen (Ann., 1884, 224, p . 1) condensed diphenylamine with fatty acids, in the presence of zinc chloride . Formic acid yields acridine, and the higher homologues give derivatives substituted at the meso carbon atom, N N +H000HC6H5 /INC6H5-C6H4CI> C6H4 C6H6•NH•C6H6 CHO CH N N L +CH3000H- C6H5/I\C6H5- C6H4<I>C6H4 OCH, C(CH3) Acridine may also be obtained by passing the vapour of phenyl- ortho-toluidine through a red-hot tube (C . Graebe, Bee., 1884, 17, p .

1370); by condensing diphenylamine with

chloroform, in presence of aluminium chloride (0 . Fischer, Ber., 1884, 17, p . 102) ; by passing the vapours of orthoaminodiphenylmethane over heated litharge (O . Fischer); by heating salicylic aldehyde with aniline and zinc chloride to 26o° C . (R . Mohlau, Bee., r886, 19, p . 2452); and by distilling acridone over zinc dust (C . Graebe, Ber., 1892, 25, p . 1735) . Acridine and its homologues are very stable compounds of feebly basic character . They combine readily with the alkyl iodides to form alkyl acridinium iodides, which are readily trans-formed by the action of alkaline potassium ferricyanide to N-alkyl acridones . Acridine crystallizes in needles which melt at 11o° C .

It is characterized by its irritating action on the skin, and by the

blue fluorescence shown by solutions of its salts . On oxidation with potassium permanganate it yields acridinic acid (quinoline -a-3-dicarboxylic acid) C9H5N(000H)2 . Numerous derivatives of acridine are known and may be prepared by methods analogous to those used for the formation of the parent base . For the preparation of the naphthacridines, see F . Ullmann, German Patents 117472, 118439, 127.586, 128754, and also Ber., 1902, 35, pp . 316, 2670 . Phenyl-acridine is the parent base of chrysaniline, which is the chief constituent of the dye-stuff phosphine (a bye-product in the manufacture of rosaniline) . Chrysaniline (diamino-phenylacridine) forms red-coloured salts,which dye silk and wool a fine yellow; and the solutions of the salts are characterized by their fine yellowish-green fluorescence . It was synthesized by 0 . Fischer and G . Koerner (Ber., 1884, 17, p . 203) by condensing ortho-nitrobenzaldehyde with aniline, the resulting ortho-nitro-para-diamino-triphenylmethane being reduced to the corresponding orthoamino compound, which on oxidation yields chrysaniline .

Benzoflavin, an isomer of chrysaniline, is also a dye-stuff, and has been prepared by K .

Oehler (English Patent 9614) from meta-phenylenediamine and benzaldehyde . These substances condense to form tetra-aminotriphenylmethane, which, on heating with acids, loses ammonia and yields diaminodihydrophenylacridine, from which benzoflavin is obtained by oxidation . It is a yellow powder, soluble in hot water . The formulae of these substances are: /N/ N\I INH . H2NI \I/N I/ INH2 /Nc /\/ \/\0/ \/ /\I N H2 Chrysaniline . Benzoflavin .