Metal Chelate Compounds of Tetracycline Derivatives. V

Structure of Aureomycin-Borate Complex

Abstract

The Aureomycin-borate complex in concentrated sulfuric acid might be composed of two components, according to the increasing concentration of sulfuric acid used, if borates are present in excess. The one somewhat stable chelate compound in 78% H₂SO₄ showed the maximum absorbance at 555mμ and the other stable one in higher concentration of sulfuric acid than 91%, showed the maximum at 530mμ. The structure and nature of these two chelate compounds were presented and the possible mechanism was discussed. The molar ratio of Aureomycin to boron was 2:1 in the former and 1:1 in the latter.