Online Encyclopedia


Online Encyclopedia
Originally appearing in Volume V22, Page 665 of the 1911 Encyclopedia Britannica.
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H2N CN HN•C:NH HN•C•NH2 HN•C•N Various thiopurins have been obtained by E. Fischer (Ber., 1898, 31, p. 431), principally by acting with potassium sulphydrate on chlorinated purin compounds. 2.6.8-Trithiopurin is obtained from the corresponding trichlorpurin and potassium sulphydrate. It forms a light yellow mass which carbonizes on heating. It is almost insoluble in water and alcohol; but readily dissolves in dilute solutions of the caustic alkalis and of ammonia. Much work has been done by J. Tafel (Ber., 1900, seq.) on the electrolytic reduction of the members of the purin group. The substance to be reduced is dissolved in a 50–75% solution of sulphuric acid and placed in a porous cell containing a lead cathode, the whole being then placed in a 2o–6o% solution of sulphuric acid in the anode cell. It is found that xanthine and its homologues take up four atoms of hydrogen per molecule and give rise to the so-called desoxy-compounds, which are stronger bases than the original substances. Uric acid takes up six hydrogen atoms per molecule and gives purone, C5HEN402, and it is apparently the oxygen atom attached to the carbon atom number 6 which is replaced by hydrogen, since when purone is heated with baryta, two molecules of carbon dioxide are liberated for one of purone. Consequently purone must contain two urea residues, which necessitates the presence of the> CO groups in positions 2 and 8. (F. G. P. *)
End of Article: H2N

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