Pyridoxamine disulfide was synthesized by decomposition of Bunte salt, obtained by the reaction of pyridoxamine bromide and sodium thiosulfate. Bis-4-pyridoxyldisulfide and bis-4-pyridoxylphosphate disulfide was also obtained by the reaction of pyridoxal or its 5-phosphate with NH_4SH. These compounds gave 4-pyridoxylmercaptan with diluted HCl at 25℃. The latter was easily oxidized to bis-4-pyridoxyldisulfide with iodide.
