Flavoalkaloids-Isolation, Biological Activity, and Total Synthesis.

The flavoalkaloids possess unique molecular frameworks that contain both a flavonoid and alkaloid component. Flavoalkaloids result from the convergence of distinct biosynthetic pathways, affording natural products that display a wide range of interesting biological activities that would not be expected for flavonoids or alkaloids alone. This chapter collates all the known flavoalkaloids up until early 2016, detailing their isolation, bioactivity, and successful total syntheses.

4,4'-Bismoschamine: biomimetic synthesis and evidence to support structural equivalency to montamine.

The dimeric natural product montamine was originally reported as two N-feruloylserotonin (moschamine) units linked by a nitrogen-nitrogen bond, but our recent synthesis of this symmetrical diacyl hydrazide structure revealed this to be incorrect. We subsequently hypothesized that the moschamine subunits were linked through the indole C4 site and that montamine was structurally identical to 4,4'-bismoschamine, a known natural product present in safflower oil. However, given that authentic samples of both montamine and 4,4'-bismoschamine were unavailable and that the NMR data for the natural products were recorded in different solvents, we were unable to unequivocally prove this hypothesis.

Total syntheses of (±)-spiroindimicins B and C enabled by a late-stage Schöllkopf-Magnus-Barton-Zard (SMBZ) reaction.

The spiroindimicins are a family of structurally unprecedented alkaloids isolated from the deep-sea-derived marine actinomycete Streptomyces sp. SCSIO 03032. The total syntheses of (±)-spiroindimicins B and C are disclosed, the first of any member of this family.

Discovery of a 1,2-bis(3-indolyl)ethane that selectively inhibits the pyruvate kinase of methicillin-resistant Staphylococcus aureus over human isoforms.

Methicillin-resistant Staphylococcus aureus pyruvate kinase (MRSA PK) has recently been identified as a target for development of novel antibacterial agents. Testing a series of 1,2-bis(3-indolyl)ethanes against MRSA PK has led to the discovery of a potent inhibitor that is selective over human isoforms.

Total synthesis of putative montamine and a proposed structural reassignment.

The natural product montamine was originally assigned as a homodimer of moschamine linked by a N-N' bond at the serotonin side-chain. A total synthesis of the reported structure has shown this to be incorrect. Analysis of the spectroscopic data suggests that the dimerization site has been incorrectly assigned, and montamine is likely to be a 4,4'-bismoschamine natural product previously described in the literature.

Natural products containing a nitrogen-nitrogen bond.

As of early 2013, over 200 natural products are known to contain a nitrogen-nitrogen (N-N) bond. This report categorizes these compounds by structural class and details their isolation and biological activity.