Pfeiffer WP, Dey SK, Falk H, Lightner DA. Homorubins and Homoverdins.
MONATSHEFTE FUR CHEMIE 2014;
145:963-981. [PMID:
25110360 DOI:
10.1007/s00706-014-1191-z]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The syntheses are described for centrally expanded bilirubin analogs: b -homorubins with propionic and butyric acid groups in the positions corresponding to the propionic acids of bilirubin. Their syntheses were accomplished by coupling two equivalents of a reactive monopyrrole (5-(bromomethylene)pyrrolin-2-one) to a dipyrrylethane. The corresponding b -homoverdins and dehydro- b -homoverdins were prepared by dehydrogenating the rubins or their dimethyl esters using DDQ. As supported by NMR measurements and molecular mechanics calculations, the homorubins are found to engage in conformation-determining intramolecular hydrogen bonding between the dipyrrinone and carboxylic acid moieties. Likewise, the homoverdins are believed to favor intramolecularly hydrogen-bonded conformations.
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