Synthesis and Structural Revision of Glyphaeaside C

Synthetic studies toward inducamide C

Organic & Biomolecular Chemistry ◽

10.1039/d0ob01995j ◽

2021 ◽

Author(s):

Ardalan A. Nabi ◽

Lydia M. Scott ◽

Daniel P. Furkert ◽

Jonathan Sperry

Keyword(s):

Natural Product ◽

Structural Revision ◽

Synthetic Studies

The rare benzoxazepine ring in the alkaloid inducamide C is unstable and prone to rearrangement, indicating that structural revision of the natural product may be necessary.

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Structure Revision of Protoaculeine B, a Posttranslationally Modified N-Terminal Residue in the Peptide Toxin Aculeine B

10.26434/chemrxiv.13066082 ◽

2020 ◽

Author(s):

Raku Irie ◽

Kei Miyako ◽

Satoko Matsunaga ◽

Ryuichi Sakai ◽

Masato Oikawa

Keyword(s):

Mass Spectra ◽

Chemical Reactivity ◽

Model Compounds ◽

Structural Revision ◽

Structure Revision ◽

Peptide Toxin ◽

One Step ◽

Marine Peptide ◽

Synthetic Models ◽

Long Chain

<div>Here, we newly propose the structure of protoaculeine B, an N-terminal moiety of the marine peptide toxin aculeine B, as possessing the cis-disubstituted tetrahydro-beta-carboline framework. We prepared two truncated model compounds that lack long-chain polyamine by one-step Pictet-Spengler reaction of tryptophan, and compared the NMR and mass spectra and chemical reactivity with those of natural protoaculeine B. The synthetic models reproduced the profiles of the natural product well, which was conclusive for the structural revision.</div>

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Total Synthesis of (+)-Granatumine A and Related Bislactone Limonoid Alkaloids via a Pyran to Pyridine Interconversion

10.26434/chemrxiv.7865138 ◽

2019 ◽

Author(s):

Timothy Newhouse ◽

Alexander Schuppe ◽

Yizhou Zhao ◽

Yannan Liu

Keyword(s):

Total Synthesis ◽

Inhibitory Activity ◽

Knoevenagel Condensation ◽

Cost Effective ◽

Effective Procedure ◽

Direct Transformation ◽

Structural Revision ◽

Alpha Beta ◽

Ptp 1B

We report the first total synthesis of (+)-granatumine A, a limonoid alkaloid with PTP-1B inhibitory activity, in 10 steps. Over the course of this study, two key methodological advances were made: a cost effective procedure for ketone alpha,beta-dehydrogenation using allyl-Pd catalysis, and a Pd-catalyzed protocol to convert epoxyketones to 1,3-diketones. The central tetrasubstituted pyridine is formed by a convergent Knoevenagel condensation and carbonyl-selective electrocyclization cascade, which was followed by a direct transformation of a 2<i>H</i>-pyran to a pyridine. These studies have led to the structural revision of two members of this family.

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