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.

    6/16 (page 2282)
    (loc. cit.) record a melting point of 88—89°, but since the melting points of the methyl esters of 2-bromo- and 5-bromo-veratric acids are respectively 46° and 71—72° there can be no doubt that the ester formed here is the 6-bromo-derivative. Replacement of the mercury in the compound from 2-hydroxy- 4- methoxybenzaldehyde (VII) by bromine gives a bromo-deriv- ative, m. p. 119—121°, which is not identical with 5-bromo-2- hydroxy-4-methoxybenzaldehyde, m. p. 120—121°, prepared by Rao, Srikantia, and Iyengar (loc. cit.) since the melting point of a mixture of the two substances is depressed by about 30°. It is shown to be 3-bromo-2-hydroxy-4:-methoxybenzaldehyde by bromin- atio-n to the known 3 : 5-dibromo-2-hydroxy-4-methoxybenzalde- hyde (Rao, Srikantia, and Iyengar, loc. cit.), and the mercury is accordingly in position 3. The constitutions of the mercury compounds from 2-hydroxy - 5- methoxybenzaldehyde (VIII) and o-vanillin (IX) follow similarly from their conversion into the known 3-bromo-2-hydroxy-5-meth- oxybenzaldehyde (Rubenstein, J., 1925, 127, 2000) and 5-bromo- 2- hydroxy-3-methoxybenzaldehyde (Davies, J., 1923, 123, 1586, 2847; respectively. In the preparation of the mercury compounds from 2-hydroxy- 3- methoxybenzaldehyde and 2-hydroxy-5-methoxybenzaldehyde, demercuration takes place when the solutions are cooled (compare Henry and Sharp, J., 1926, 2432). The simple explanation that this is in all cases a reversible reaction, R*H + Hg(0*C0*CH3)2 ^ R-Hg-0-CO-CH3 + CH3*CO-OH, in which the reaction from left to right takes place at elevated temperatures and that in the reverse direction on cooling, appears to be rendered untenable by the fact that the mercurated product of 2-hydrox3^-3-methoxybenzaldehyde can be recrystallised from acetic acid without demercuration, although crystallisation of 5-acet- oxymercuri-4-hydroxy-3-methyl-6-^opropylbenzaldehyde from the same solvent does induce partial demercuration (loc. cit., p. 2439). The work described forms part of an investigation into the relation of chemical constitution to bactericidal action in this group of organic mercury compounds (Henry, Sharp, and Brown, Biochem. J., 1925, 19, 513). Only three of the substances now prepared are suitable for bactericidal tests; these have been kindly examined by Major H. C. Brown, C.I.E., M.B., B.Ch., of the Well¬ come Bureau of Scientific Research. They were tested as sodium salts dissolved in water, by the method already described (loc. cit.). The minimum concentration required to kill Bacillus typhosus, Rawlings, in five minutes is, for the mercury compound from