A concise synthesis of (±)-7-O-galloyltricetiflavan. Issue 26 (18th April 2018)

• Record Type: Journal Article
• Authors: Zhang, Wenxuan; Xue, Wenjie; Jia, Yuqing; Wen, Gang; Lian, Xu; Shen, Jing; Liu, Ailin; Wu, Song
• Is Part Of: RSC advances. Volume 8:Issue 26(2018)
• Page Start: 14389
• Page End: 14392
• Publication Date: 2018-04-18
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra01606b
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : We report the first total synthesis of (±)-7- O -galloyltricetiflavan (1a ) in five steps as well as an interesting discovery during the demethylation process. Abstract : (±)-7- O -galloyltricetiflavan (1a ) was synthesized successfully in five steps from the commercially available trihydroxyacetophenone (2 ) and trimethoxybenzoyl chloride (3 ). The flavone 4a was prepared in a one-pot reaction and it gave hex- O -methylflavan 6 followed by acylation and reduction. However, the demethylation of flavan 6, 5- O -acetylflavan 10 and 5- O -phenylacetylflavan 11 by BBr3 gave all the hydrolyzed fragments 7 and 8 as the major products. By contrast, in the same condition, hept- O -methylflavan 9 could provide the desired product (±)-7- O -galloyltricetiflavan (1a ) in 91% yield. The additional 5- O -B-Br2 complex may stabilize the ester bond during the demethylation process.