Sequential Continuous-Flow Synthesis of 3-Aryl Benzofuranones

Area of Science:

• Organic Chemistry
• Chemical Engineering
• Materials Science

Background:

• 3-aryl benzofuranones are important compounds with various applications.
• Traditional synthesis methods often involve multiple steps and harsh conditions.
• Developing efficient and sustainable synthetic routes is crucial.

Purpose of the Study:

• To develop a sequential continuous-flow system for the synthesis of 3-aryl benzofuranones.
• To utilize a single heterogeneous catalyst for both cyclocondensation and Friedel-Crafts alkylation steps.
• To demonstrate the reusability and stability of the catalyst in a flow system.

Main Methods:

• A continuous-flow reactor system was designed and implemented.
• Amberlyst-15H, a heterogeneous catalyst, was employed for sequential reactions.
• 2,4-di-tert-butylphenol and glyoxylic acid monohydrate were used as starting materials.
• Various aromatic compounds were reacted under flow conditions.

Main Results:

• The developed flow system successfully produced 3-aryl benzofuranones.
• The same heterogeneous catalyst, Amberlyst-15H, effectively catalyzed both reaction steps.
• The catalyst exhibited a promising lifetime, allowing for recovery and reuse without deactivation.
• The commercial antioxidant Irganox HP-136 was synthesized in an 88% two-step yield.
• Diverse 3-aryl benzofuranone derivatives were obtained in high yields with good functional group tolerance.

Conclusions:

• A robust and efficient sequential continuous-flow system for 3-aryl benzofuranone synthesis was established.
• The use of a single, reusable heterogeneous catalyst enhances the sustainability of the process.
• The flow system provides a high-yielding and versatile method for producing valuable benzofuranone derivatives.