Efficient one-step synthesis of 3-nitroflavones via cascade nitration-cyclization

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Flavonoids are a vital class of organic compounds with diverse biological activities.
• Efficient synthesis of substituted flavonoids, such as 3-nitroflavones, is crucial for medicinal chemistry research.

Purpose of the Study:

• To develop a mild and regioselective method for synthesizing 3-nitroflavones.
• To explore the tandem nitration-cyclization of alkynyl aryl ketones.

Main Methods:

• Utilized zinc triflate (Zn(OTf)2) as a catalyst.
• Employed a tandem nitration-cyclization strategy using 68% nitric acid (HNO3).
• Conducted the reaction under mild, room-temperature conditions.

Main Results:

• Successfully synthesized a range of substituted 3-nitroflavones.
• Achieved generally good to excellent yields for the target compounds.
• Demonstrated the regioselectivity and mildness of the developed nitration-cyclization protocol.

Conclusions:

• The developed Zn(OTf)2-promoted reaction provides an efficient route to 3-nitroflavones.
• This method offers a valuable tool for accessing novel flavonoid derivatives for further study.