Mercuration of some polyhydroxybenzaldehydes and their monomethyl ethers / by T.A. Henry and T.M. Sharp.

  • Henry, Thomas Anderson, 1873-1958
Date:
[1930.]
Catalogue details

Licence: Public Domain Mark

Credit: Mercuration of some polyhydroxybenzaldehydes and their monomethyl ethers / by T.A. Henry and T.M. Sharp. Source: Wellcome Collection.

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    needles from light petroleum, m. p. 46°, which agrees with the recorded melting point (Found : Br, 29-4. Calc, for C10HnO4Br : Br, 29-1%). Conversion of bromoisovanillin, m. p. 112—114°, into 6-bromo- 3 :4-dimethoxybenzoic acid. This change was effected by the methods described in the preceding paragraph. The 6-bromo- 3 : 4-dimethoxybenzaldehyde obtained crystallised from alcohol in colourless needles, m. p. 150—151° (corr.), agreeing with the figure 149—150° recorded by Pschorr (loc. cit.) (Found on substance dried at 80° in a vacuum : C, 44-4; H, 3-75; Br, 32-75. Calc, for C9H903Br : C, 44-1; H, 3-7; Br, 32-6%). The acid produced on oxidation crystallised from 50% alcohol in colourless needles, m. p. 185° (corr.), in agreement with the recorded m. p. of 6-bromo- veratric acid (Found on substance dried at 120° in a vacuum : C, 41-2; H, 3-5; Br, 30-75. Calc, for C9H904Br : C, 41-4; H, 3-5; Br, 30-6%). The methyl ester formed faintly yellow needles, m. p. 81—82° (corr.). 2-HydroxyA-methoxybenzaldehyde.—A hot filtered solution of mercuric acetate (16 g.; 1 mol.) in alcohol (100 c.c.) containing acetic acid (2-5 c.c.) was added to 2-hycfroxy-4-methoxybenz- aldehyde (7-6 g.; 1 mol.) (Ott and Nauen, Ber., 1922, 55, 925) and the solution after boiling under reflux for 5 minutes was filtered from a trace of mercurous acetate. On cooling, it deposited bundles of needle-shaped crystals (13-25 g.) consisting of almost pure 3-acet- oxymercuri-2-hydroxy-^-meihoxybenzaldehyde, and on concentration yielded a further 5-5 g. Finally there remained a sticky oil from which a little unchanged aldehyde was recovered. One recrystallis¬ ation of the first crop from alcohol containing 1% of acetic acid sufficed for purification. The remaining crops on fractional crystal¬ lisation from the same solvent furnished further quantities, leaving a residue of 1-5 g. which appeared to contain a little more highly mercurated substance. The monoacetoxymercuri-derivative melts at 159—160° (corr.) (Found on substance dried in a desiccator : Hg, 48-7; C, 29-3; H, 2-8. C10H10O5Hg requires Hg, 48-85; C, 29-2; H, 2-45%). The corresponding bromomercuri-compound on treatment with bromine in acetic acid yielded a substance which, as shown below, must be 3-bromo-2-hydroxy-4:-methoxybenzaldehyde. It crystallises from alcohol in bright colourless needles, m. p. 119—121° (corr.), and sublimes on heating at 100° in a vacuum. The melting point is depressed to 90° on admixture with 5-bromo-2-hydroxy-4-meth- oxybenzaldehyde, m. p. 120—121° (Rao, JSrikantia, and Iyengar, loc. cit.) (Found : C, 41-75; H, 3-2; Br, 34-7. C8H703Br requires C, 41-6; H, 3-1; Br, 34-6%). The phenylhydrazone forms colour-