Total synthesis of putative montamine and a proposed structural reassignment

Blair, Lachlan M.; Davie, Elizabeth A. Colby; Sperry, Jonathan

doi:10.1039/c4ob01304b

Cited by 8 publications

(8 citation statements)

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“…A total synthesis of the reported structure by Sperry and co-workers showed this assignment to be incorrect. They proposed that montamine ( 5 ) was likely to be 4,4″-bis( N -feruloyl)serotonin ( 4 ) upon analysis of the spectroscopic data . Unfortunately, they could not confirm this proposed structural reassignment of montamine ( 5 ) because the NMR data for these two natural products were reported in different solvents (CD 3 OD and DMSO- d 6 , respectively) and authentic samples of both the natural products necessary for a full spectroscopic comparison in the same NMR solvent were not available.…”

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confidence: 99%

Biomimetic Synthesis of Moschamine-Related Indole Alkaloids via Iron-Catalyzed Selectively Oxidative Radical Coupling

et al. 2016

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An iron-catalyzed oxidative radical coupling reaction was developed to selectively construct indolofuran or bisphenolic indole cores, which exist in two types of moschamine-related indole alkaloids. Both (+)-decursivine and 4,4″-bis(N-feruloyl)serotonin were biomimetically synthesized by using coupling reactions. The proposed reassignment of the structure of montamine as 4,4″-bis(N-feruloyl)serotonin was excluded.

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Biomimetic Synthesis of Moschamine-Related Indole Alkaloids via Iron-Catalyzed Selectively Oxidative Radical Coupling

et al. 2016

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“…[46] Montamine was isolated from seeds of the ornamental plant Centaurea montana and showed significant anti-colon cancer activity in vitro (IC 50 ＝43.9 μmol/L). [49] They proposed that montamine was likely to be 4,4"-bis(N-feruloyl)serotonin upon analysis of the spectroscopic data. A total synthesis of the reported structure by Sperry and co-workers showed this assignment to be incorrect.…”

Section: Total Synthesis Of 44″-bis(n-feruloyl)serotoninmentioning

confidence: 99%

Recent Advances of Transition Metal‐Mediated Oxidative Radical Reactions in Total Synthesis of Indole Alkaloids

Liang

Xia

2017

Chin. J. Chem.

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Over the past decades, transition metal-mediated oxidative radical reactions have been discovered and developed as a robust and conceptually novel approach for organic synthesis. This mini-review details the background, recent advances, and synthetic applications of transition metal-mediated oxidative radical reactions in indole alkaloids biomimetic synthesis. The organization of each section is based on the kind of indole alkaloids.

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“…3 The 1 H NMR signals for the αand β-methylene protons in montamine (2) were significantly upfield relative to those reported for moschamine (1), a shielding effect suggested to ensue from restricted rotation about the N-N′ bond placing the methylenes in close proximity to the aromatic rings. In recent reports, 4,5 we described the synthesis of the diacylhydrazide structure 2 assigned to montamine 6 and found that the 1 H and 13 C NMR data differed dramatically from that of natural product. Most notably, the 1 H NMR signals corresponding to the αand β-methylene protons in synthetic diacylhydrazide 2 were not distinctively upfield (Fig.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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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. A recent publication that claims montamine and 4,4'-bismoschamine are not the same natural product prompts us to disclose our own findings on this matter. A biomimetic synthesis of 4,4'-bismoschamine was developed that hinged on oxidative coupling of N-Boc-serotonin followed by elaboration of the resulting 4,4'-dimer to the natural product. A detailed comparison of the NMR data for synthetic 4,4'-bismoschamine with that reported for montamine revealed that while the H NMR data were in good agreement, theC NMR data displayed some discrepancies. In light of this result, the NMR data for several literature compounds was analyzed, the results of which revealed that the upfield chemical shifts of the methylene protons in the H NMR of montamine is unique to 4,4'-bistryptamines, supporting our initial statement that montamine and 4,4'-bismoschamine are structurally equivalent. Given that the main differences in theC NMR data between montamine and synthetic 4,4'-bismoschamine occur at the quaternary carbons, we propose that these peaks have been misassigned from a C NMR spectrum that was obtained from an impure sample and/or the small amount of montamine (4 mg) isolated from the natural source.

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Total synthesis of putative montamine and a proposed structural reassignment

Cited by 8 publications

References 15 publications

Biomimetic Synthesis of Moschamine-Related Indole Alkaloids via Iron-Catalyzed Selectively Oxidative Radical Coupling

Biomimetic Synthesis of Moschamine-Related Indole Alkaloids via Iron-Catalyzed Selectively Oxidative Radical Coupling

Recent Advances of Transition Metal‐Mediated Oxidative Radical Reactions in Total Synthesis of Indole Alkaloids

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

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