An lmproved synthesis of the tricyclic core of sarains by a 3-oxidopyridinium betaine cycloaddition~1

摘要

An improved synthesis of a suitably functinalized tricyclic core of sarains has been developed by adaptation of katritzky's cycloadditin using a 3-oxidopyridinium betaine.From the sponge reniera sarai,~2a,b cimino and co-workers isolated teh structurally intricate alkaloids sarains A-C (1A-C)that were reported to show antitumor,antibacterial,and insecticidal activity~2c.