Generation and Trapping of o-Thioquinones on Solid Support: Synthesis of Hydroxylated 4-Thiaflavans

Abstract

The generation and trapping of o-thioquinones was successfully applied to the synthesis of hydroxy-4-thiaflavans on solid support using commercially available carboxy and aminomethylated polystyrene resins. These valuable cycloadducts are obtained as pure compounds without any intermediate purification, in better overall yields than the solution phase procedure.

Keywords:

• Antioxidants
• phthalimidesulfenyl chloride
• solid phase synthesis
• 4-thiaflavans
• o-thioquinones

Dedicated to Professor Marian Mikołajczyk, CBMiM PAN in łódź, Poland, on the occasion of his 70th birthday.

Financial support from MIUR (Research project “Stereoselezione in Sintesi Organica. Metodologie ed Applicazioni,” contract 2005035330) is gratefully acknowledged. We also wish to thank Mrs. Brunella Innocenti for elemental analysis.