Naphthoflavones (benzoflavones) are synthetic flavonoids commonly used in drug metabolism studies as selective activators or inhibitors of cytochrome P-450 enzymes. Nowadays they are also used as a component of food supplements for body builders. There is no data regarding naphthoflavone microbial metabolism. In the present studies sixty-three fungal strains have been screened for their ability to transform alpha-naphthoflavone (7,8-benzoflavone) or beta-naphthoflavone (5,6-benzoflavone). Five strains belonging to the genera Penicillium, Cladosporium, Aspergillus and Verticillium transformed alpha-naphthoflavone and beta-naphthoflavone to the corresponding 4'-hydroxy derivatives. These selected fungi have been used in a further study on biotransformation of naphthoflavones with a differently substituted B-ring. Only 4'-methoxy derivatives have been transformed to the related 4'-hydroxy products. Selected strains are good biocatalysts to obtain 4'-hydroxy naphthoflavones in the one step reaction. (C) 2015 Elsevier B.V. All rights reserved.
Silica-Supported Silver as a Green and Sustainable Catalyst for the [3+2]-Cycloaddition Reaction of Azomethine Ylides with 2′-Hydroxychalcone Derivatives
作者:Suchithra Madhavan、Sentaro Okamoto
DOI:10.1002/cctc.201702035
日期:2018.5.9
A reusable heterogeneous silver nanoparticle catalyst supported on silica was used for the [3+2]‐cycloadditionreaction of azomethine ylides with 2′‐hydroxychalcone derivatives. The green and sustainable catalytic protocol afforded highly functionalized pyrrolidines, indolizidines, and pyrrolizidines in good yields with high regio‐ and diastereoselectivities.