Urobilins

Literature References: Bile pigments which occur in feces; and in urine. More specifically described as dipyrrylmethene compds joined at the two a-pyrrolyl positions by methylene bridges to either pyrrolenone or pyrrolidone rings. Reviews of occurrence, proposed structures, stereoisomerism, and interrelationships of i-urobilin, d-urobilin, stercobilin, urobilin IXa, and d-urobilin IXa: A. H. Jackson et al., Nature 209, 581 (1966); C. H. Gray, D. C. Nicholson, Medicine 46, 83 (1967); W. Rüdiger, Fortschr. Chem. Org. Naturst. 29, 60-139 (1971). Structure of stercobilin and d-urobilin: C. H. Gray, D. C. Nicholson, J. Chem. Soc. 1958, 3085. Revised structure of d-urobilin: S. D. Killilea, P. O'Carra, Biochem. J. 129, 1179 (1972). Stereochemistry: W. J. Cole et al., J. Chem. Soc. 1965, 4085. Spectral study: W. J. Cole et al., J. Chem. Soc. C 1966, 1321. Synthesis of optically active stercobilin: H. Plieninger, J. Ruppert, Ann. 736, 43 (1970); of optically active urobilins: H. Plieninger et al., ibid., 62. Abs config of stercobilin: H. Brockmann, Jr. et al., Proc. Natl. Acad. Sci. USA 68, 2141 (1971).