Mechanism of oolongtheanin formation via three intermediates. Issue 11 (12th March 2020)

• Record Type: Journal Article
• Authors: Hirose, Sayumi; Kamatari, Yuji O.; Yanase, Emiko
• Is Part Of: Tetrahedron letters. Volume 61:Issue 11(2020)
• Publication Date: 2020-03-12
• Subjects: Oolongtheanin -- Formation mechanism -- Intermediate -- Epigallocatechin -- Oolong tea; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2020.151601
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: A novel intermediate was found in the formation of oolongtheanins from catechins. A mechanism of oolongtheanin formation was then proposed. This mechanism was confirmed by GC–MS and 1 H NMR experiments. Abstract: To clarify the mechanism of oolongtheanin formation, the oxidations of (−)-epigallocatechin and (−)-epigallocatechin gallate were investigated, and key intermediates were isolated. These intermediates were determined to be dehydrotheasinensins and pro-oolongtheanins, which we have reported previously, and one novel intermediate. Based on the chemical structures of these intermediates, a mechanism was proposed for oolongtheanin formation from catechins, and confirmed by NMR and GC–MS analysis.