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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    these the 3 : 4-dihydroxybenzoic acid (protocatechuic acid) depresses the melting point of the acid under discussion to 166°. All the reactions of the latter acid are characteristic of 2 : 3-dihydroxy- benzoic acid, and the authors have no doubt they are identical, although combustions of their acid did not give good results (Found : C = 55-6, 55-9; H = 4*12, 4-12. Calc., C = 54-5; H = 3-9 per cent.) owing to the difficulty of removing the last traces of the accompanying brown resin from the small total quantity of acid obtained. This iodo-m-hydroxybenzaldehyde undergoes decom¬ position with remarkable ease, and of the reactions tried with a view to its identification only the above has given a useful product, and that in a yield less than 2 per cent, of the theoretical. In view of the production from it, as just described, of 2-nitro- 3-hydroxybenzaldehyde and 2 : 3-dihydroxybenzoic acid, the original mercury compound must be 2-acetoxymercuri-3-hvdroxy- henzaldehyde. Mercuration of NitrohydroxybenzaldeJiydes. The mercuration was effected in the same way throughout, namely, by boiling under reflux the nitrol^droxybenzaldehjffie (1 mol.) with mercuric acetate (1 mol. or 2 mols.) in 50 per cent, alcohol containing a little acetic acid, boiling being continued until the mixture dissolved completely on adding sodium hydroxide solution. The 3-nitro-4-Iiydroxybenzaldehyde used was prepared by Paal’s method (Ber., 1895, 28, 2415); the yield obtained was 70 per cent, of the 4-hydroxybenzaldehyde used and the melting point was, as recorded, 141—142°. S-HydroxymercuriS-nitroA-hydroxybenzaldeliyde, H0*Hg*C6H3(0H)(N02)-CH0. —This substance, obtained in quantitative yield by the general method, separates from the boiling solution in micro¬ scopic, orange platelets, which darken at about 285°, but do not melt at 300°. It is purified by solution in sodium hydroxide, in which it dissolves to form a deep orange-red liquid, and precipi¬ tation with carbon dioxide (Found: Hg = 52*46; 1ST = 3*76. C7H505NHg requires Hg = 52-29; N = 3-65 per cent.). Addition of dilute hydrochloric acid to such a solution causes the precipitation of 5-chloromercuri-o-nitro-4,-hydroxybenzaldehyde, which crystallises from alcohol in tufts of minute, colourless needles, m. p. 226° (decomp.; corr.) (Found : Hg = 49-77. C7H404NClHg requires Hg = 49-89 per cent.). Thehvdroxymercuri-compound is insoluble in the usual solvents except glacial acetic acid, from which there slowly separate colourless prisms of D-acetoxymercuri-3-nitroA-Jiydroxy-