Synthesis of (2-~(13)C, 4-~(13)C)-(2R,3S)-catechin and (2-~(13)C, 4-~(13)C)-(2R,3R)-epicatechin

摘要

The first synthesis of doubly labeled, [2-~(13)C, 4-~(13)C]-(2R,3S)-catechin 15 and [2-~(13)C, 4-~(13)C]-(2R,3R)-epicatechin 18 starting from labeled 2-hydroxy-4, 6-bis(benzyloxy)acetophenone 3 and labeled 3, 4-bis(benzyloxy)-benzaldehyde 7 are described. There is great interest in the role played by the polyphenolic class of compounds in health, nutrition and treatment of disease. In particular, dietary interventions using flavanol-containing foods and beverages have substantiated epidemio-logical data regarding the improvement of vasodilation and blood pressure. Moreover, numerous investigations have been conducted in vitro aimed at elucidating flavanol-mediated bioactivities. These activities include, but are not limited to inhibiting HIV-1 replication in vitro, reducing the risk of heart disease, suppressing ulcer formation, possessing antimuta-genic, neuroprotective, anti-inflammatory, antibacterial, hypertensive properties, and can inhibit the growth of cancer cells. Moreover, flavanols can affect a host of cellular functions in vitro such as signaling pathways, alter cell membrane characteristics and receptor function to imply physiological effects in vivo. It should be noted that these in vitro studies use the natural form of the flavanols as they appear in nature, whereas the biological effects elicited in vivo are the consequences of adsorption (bioavailability), their metabolism and distribution within body organs. Substantial data exists to support the in vivo biotransformation and metabolism of flavanols within the gastrointestinal tract by resident micro-flora15 as well as their hepatic metabolism.