Abstract
Crystal structure determination and AM1 molecular orbital calculations were performed on the flavone, 3′,5′ — dibromo — 3 — methyl — 6,4′ — dihydroxyflavone (EMD21388), crystallized as a (1:2) triphenylphosphine oxide (TPPO) co-crystal complex. This is also the first structural report of a 2∶1 TPPO co-crystal complex with a flavone. The calculated molecular structure is in good agreement with the observed crystallographic conformation which shows that the angle between the benzopyrone and phenyl rings,θ, [C(3)-C(2)-C(1′)-C(6′)] is 49.1(8)°, compared with the geometry-optimized minimum energy angle of 46.0°. The barrier to rotation in this system is about 3.5 kcal/mol. Biochemical data for EMD 21388 show it is the most potent inhibitor of the enzyme iodothyronine deiodinase and is the strongest competitor for the binding of thyroxine to its serum transport protein transthyretin. This analysis reveals that the flavone can adopt a conformation that has structural homology with the thyroid hormone.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call