Mercuration of nitrohydroxybenzaldehydes / by T.A. Henry and T.M. Sharp.

  • Henry, Thomas Anderson, 1873-1958
Date:
[1924.]
Catalogue details

Licence: Public Domain Mark

Credit: Mercuration of nitrohydroxybenzaldehydes / by T.A. Henry and T.M. Sharp. Source: Wellcome Collection.

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    2 : Q-diformoxydimercuriA-nitro-Z-hydroxybenzaldehyde (the formoxy- mercuri-group = — Hg*0-C0H) (Found : Hg = 61-62. C9H5OsNHg2 requires Hg — 61-13 per cent.) crystallise out. On heating, this substance darkens at 120° and explodes at 257°, but does not melt. Boiling with formic acid decomposes it with separation of metallic mercury. The compound is soluble in potassium hydroxide to a deep red solution, from which hydrochloric acid precipitates 2 : 6-dichlorodi7nercuri-4:-nitro-3-hydroxybe7izaldehyde. The latter crystallises from alcohol in bundles of minute, pale yellow needles, which darken on heating at 240°, but do not melt at 300° (Found : Hg = 61-32. C7H304NCl2Hg2,H20 requires Hg = 61-24 per cent.). The compound loses a molecule of water at 60° in a vacuum and the anhydrous substance decomposes at 282° (corr.). The solution in potassium hydroxide is decomposed by carbon dioxide with precipitation of 2 : 3-anhydro-2 : Q-dihydroxydimercuri-4:-nitro-S-hydr- oxybenzaldehyde (Found : Hg = 68-73. C7H305NHg2 requires Hg = 68-92 per cent.). The mixture of mono- and di-mercurated compounds can be separated into its components by repeated extraction with cold formic acid, in which the mono-compound is the more soluble, precipitation of the mercury compound by addition of ether, and finally crystallisation of each fraction from formic acid (Found : for the mono-compound, Hg — 49-00. C8H506NHg requires Kg = 48-74 per cent. Found : for the di-compound, Hg = 61 -63. C9H508NHg2 requires Hg = 61-13 per cent.). MonoformoxymercuriA-nitroS-hydroxybenzaldeJiyde melts at 233—- 235° (decomp.; corr.). The mixture containing only a little dimercurated compound, is best purified by steam distillation to remove 4-nitro-3-hydroxybenzaldehyde, and crystallisation of the residual mercury compound from propionic acid. Pale orange needles of propionoxymercnri-4:-nitro-3-hydroxybenzaldehyde are thus obtained (Found : Hg = 45-07. C10H9OGNHg requires Hg = 45-62 per cent.). The solution of this in potassium hydroxide gives on addition of hydrochloric acid a yellow precipitate of chloromercuri- 4-niiro-3-hydroxybenzaldehyde, which decomposes on heating at about 187° (Found : Hg = 50-23. C7H4G4NClHg requires Hg =' 49-89 per cent.). The same products are obtained (the dimercurated compound in predominating amount) when two molecular pro¬ portions of mercuric acetate are used for the preparation. On shaking the dimercurated compound with excess of a freshly prepared, cooled 5 per cent, solution of bromine in alcohol, there is formed in 80 per cent, yield a dibromo-compound, which crystallises from chloroform in colourless prisms, m. p. 152-5° (decomp.; corr.) (Found : Br = 49-25. Calc, for C7H304NBr2, Br = 49-20 per