Identification of Thormählen-positive compound "B" in urine of patients with malignant melanoma

The identification of the entire structure of the Thormählen-positive compound B from melanotic urine is described. The compound was separated from other Thormählen-positive compounds using DEAE-cellulose column chromatography. On the basis of differential enzymic hydrolysis followed by gas chromatography-mass spectrometry analysis and comparison with synthetically prepared compounds it is possible to conclude that the Thormählen-positive compound B is a mixture of O-sulphate 5-hydroxy-6-methoxyindole and 6-hydroxy-5-methoxyindole with predominance of the latter.