Pigments derived from tryptophan: (1) urorosein, (2) tryptochrome

Abstract
The prepn. of urorosein is described. A study of its optical and other properties indicates that its structure is indolo-(3[image] ,2[image] -2,3)-carbazole. The production of a fluorescent, red pigment, tryptochrome, is described as a delicate and selective test for free tryptophan and tryptamine. Tryptochrome and its precursor, iodoprotryptochrome, were isolated, and provisional formulae are assigned to them.