Flavones
From Wikipedia, the free encyclopedia
Flavones are a class of flavonoids based on the backbone of 2-phenylchromen-4-one (2-phenyl-1-benzopyran-4-one) shown on the right.
Natural flavones include Apigenin (4',5,7-trihydroxyflavone), Luteolin (3',4',5,7-tetrahydroxyflavone) and Tangeritin (4',5,6,7,8-pentamethoxyflavone). Synthetic flavones are Diosmin and Flavoxate
Contents |
[edit] Organic chemistry
In organic chemistry several methods exist for the synthesis of flavones:
- the Allan-Robinson reaction
- the Auwers synthesis
- the Baker-Venkataraman rearrangement
- the Algar-Flynn-Oyamada reaction
Another method is the dehydrative cyclization of certain 1,3-diaryl diketones [1]
this particular study making use of an ionic liquid solvent and microwave irradiation.
[edit] Wessely-Moser rearrangement
The Wessely-Moser rearrangement (1930) [2] has been an important tool in structure elucidation of flavonoids. It involves the conversion of 5,7,8-trimethoxyflavone into 5,6,7-trihydroxyflavone on hydrolysis of the methoxy groups to phenol groups. It also has synthetic potential for example[3]:
This rearrangement reaction takes place in several steps: A ring opening to the diketone, B bond rotation with formation of a favorable acetylacetone-like phenyl-ketone interaction and C hydrolysis of two methoxy groups and ring closure.
[edit] External links
[edit] References
- ^ A facile synthesis of flavones using recyclable ionic liquid under microwave irradiation Swapnil R. Sarda, Mohsin Y. Pathan, Vijaykumar V. Paike, Pandurang R. Pachmase, Wamanrao N. Jadhav, and Rajendra P. Pawar ARKIVOC 2006 (xvi) 43-48 Link:
- ^ Wessely, F.; Moser, G. H. Monatsh. Chem. 1930, 56, 97.
- ^ A Convenient Extension of the Wessely±Moser Rearrangement for the Synthesis of Substituted Alkylamino¯avones as Neuroprotective Agents In Vitro Ronan Larget, Brian Lockhart, Pierre Renard and Martine Largeron Bioorganic & Medicinal Chemistry Letters 10 (2000) 835±838
|
|||||||||||||||||||||||||||||
