Toward pyridine-fused selenium-containing antioxidants

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Photochemistry

Background:

• Thiohydroximate esters are versatile synthetic intermediates.
• Selenium-containing compounds can exhibit antioxidant properties.
• Pyridine-fused heterocycles are prevalent in pharmaceuticals.

Purpose of the Study:

• To investigate the photolytic decomposition of a specific thiohydroximate ester.
• To explore the synthesis of novel pyridine-fused selenium heterocycles.
• To evaluate the potential of this methodology for creating antioxidant analogues.

Main Methods:

• Photolysis of 2-carboethoxy-2-(2-(benzylseleno)pyridin-3-yl)tridecylcarboxylic acid (20).
• Isolation and characterization of the photolysis product, 2-dodecyl-2-carboethoxy-2,3-dihydroselenolo[2,3-b]pyridine (22).
• Mechanistic investigation involving intramolecular homolytic substitution.

Main Results:

• The thiohydroximate ester (20) yielded the desired selenium heterocycle (22) in 89% yield.
• The reaction proceeded via intramolecular homolytic substitution at selenium.
• A benzyl radical was eliminated during the photolysis process.

Conclusions:

• Photolysis of thiohydroximate esters provides an efficient route to pyridine-fused selenium heterocycles.
• This methodology is a viable strategy for preparing selenium analogues of antioxidants.
• Further work is warranted to extend this synthetic approach.