发明授权
- 专利标题: Synthesis of 4&agr;-arylepicatechins
- 专利标题(中): 4α-芳基葡聚糖的合成
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申请号: US09655360申请日: 2000-09-05
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公开(公告)号: US06476241B1公开(公告)日: 2002-11-05
- 发明人: Alan P. Kozikowski , Leo J. Romanczyk, Jr. , Werner Tückmantel
- 申请人: Alan P. Kozikowski , Leo J. Romanczyk, Jr. , Werner Tückmantel
- 主分类号: C07D31158
- IPC分类号: C07D31158
摘要:
Oligomeric procyanidins containing 4&agr;-linked epicatechin units are rare in nature and have hitherto not been accessible through stereoselective synthesis. Provided herein is the preparation of the prototypical dimer, epicatechin-4&agr;,8-epicatechin, by reaction of the protected 4-ketones with aryllithium reagents derived by halogen/metal exchange from the aryl bromides. Removal of the 4-hydroxyl group from the resulting tertiary benzylic alcohols is effected by tri-n-butyltin hydride and trifluoroacetic acid in a completely stereoselective manner, resulting in hydride delivery exclusively from the &bgr; face.
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