Tautomers of Anthrahydroquinones: Enzymatic Reduction and Implications for Chrysophanol, Monodictyphenone, and Related Xanthone Biosyntheses
作者:Michael A. Schätzle、Syed Masood Husain、Sascha Ferlaino、Michael Müller
DOI:10.1021/ja307151x
日期:2012.9.12
Reduction of emodin by sodium dithionite resulted in the formation of two tautomeric forms of emodin hydroquinone. Subsequent conversion by the short-chain dehydrogenase/reductase (SDR) MdpC into the corresponding 3-hydroxy-3,4-dihydroanthracen-1(2H)-one implies that deoxygenation is the first step in monodictyphenone biosynthesis. Implications for chrysophanol formation as well as reaction sequences
Phylogenetic Studies, Gene Cluster Analysis, and Enzymatic Reaction Support Anthrahydroquinone Reduction as the Physiological Function of Fungal 17β-Hydroxysteroid Dehydrogenase
Not a common transformation: The physiological function of 17β‐hydroxysteroid dehydrogenase from the filamentous fungus Curvularialunata (teleomorph Cochliobolus lunatus) is proposed as being an NADPH‐dependent reduction of a polyhydroxyanthracene. With a substrate range from steroids to polyhydroxynaphthalenes, it might be seen as part of a diverse biosynthetic matrix.
by a biomimetic and chemoenzymatic approach using NADPH‐dependent polyhydroxyanthracence reductase (PHAR) from Cochliobolus lunatus followed by Pb(OAc)4 oxidation is reported. Subsequent dimerization through a hetero‐Diels–Alderreaction of the dihydroemodin and dihydrolunatin resulted in (−)‐flavoskyrin (68 %) and (−)‐lunaskyrin (62 %), respectively. Pyridine treatment of (−)‐flavoskyrin and (−)‐lunaskyrin
We report a first synthesis of racemic dihydroanthracenones through regioselective reduction of hydroanthraquinones using NaBH4 in water. Their use confirms the enantiopurity of chiral dihydroanthracenones synthesized chemoenzymatically and of the bisanthraquinone analogues.
Herein, we report the chemoenzymatic synthesis of a heterodimeric (-)-rugulosin B, homodimeric (-)-rugulosin C, and several rugulin analogues in three to four steps starting from anthraquinones. This work supports dimerization between variously substituted putative monomeric intermediates during the biosynthesis of naturally occurring (+)-rugulosin B and C.