[structure: see text] Synthesis of N-acyl hemiaminal model systems related to the side chain of the antitumor natural product zampanolide is reported. Key steps involve oxidative decarboxylation of N-acyl-alpha-amino acid intermediates, followed by ytterbium triflate mediated solvolysis. Evidence for stabilization of the N-acyl hemiaminal moiety in model compounds by an intramolecular hydrogen-bonding network is described.
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http://dx.doi.org/10.1021/ol025558l | DOI Listing |
J Am Chem Soc
May 2023
Department of Chemistry, University of California, Berkeley, California 94720, United States.
Described herein are studies toward the core modification of cyclic aliphatic amines using either a riboflavin/photo-irradiation approach or Cu(I) and Ag(I) to mediate the process. Structural remodeling of cyclic amines is explored through oxidative C-N and C-C bond cleavage using peroxydisulfate (persulfate) as an oxidant. Ring-opening reactions to access linear aldehydes or carboxylic acids with flavin-derived photocatalysis or Cu salts, respectively, are demonstrated.
View Article and Find Full Text PDFRSC Chem Biol
October 2022
Department of Chemistry, Aarhus University, DK-8000 Aarhus C Denmark
Covalently acting compounds experience a strong interest within chemical biology both as molecular probes in studies of fundamental biological mechanisms and/or as novel drug candidates. In this context, the identification of new classes of reactive groups is particularly important as these can expose novel reactivity modes and, consequently, expand the ligandable proteome. Here, we investigated the electrophilic reactivity of the 3-acyl-5-hydroxy-1,5-dihydro-2-pyrrole-2-one (AHPO) scaffold, a heterocyclic motif that is present in various bioactive natural products.
View Article and Find Full Text PDFOrg Lett
November 2020
Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
We have developed a new method for the stereoselective establishment of the -acyl hemiaminal moiety in zampanolide-type structures that involves the reaction of ()-sorbamide () with BINAL-H and subsequent amide transfer from a putative aluminum carboximidoate complex to the aldehyde moiety of a dactylolide precursor, such as or . The method has enabled the efficient synthesis of 13-desmethylene-(-)-zampanolide (), which was found to be an equipotent cell growth inhibitor as the natural product (-)-zampanolide ().
View Article and Find Full Text PDFOrg Biomol Chem
April 2019
Department of Chemistry, California State University, Fresno, 2555 E. San Ramon Avenue, M/S SB70, Fresno, CA 93740, USA.
(-)-Zampanolide is a marine microtubule-stabilizing macrolide that has been shown by in vitro experiments to be a promising anticancer lead compound. Through its unique covalent-binding with β-tubulin, zampanolide exhibits cytotoxic potency towards multi-drug resistant cancer cells that is superior to paclitaxel. However, the limited availability of zampanolide impedes its further in vivo evaluation as a viable drug candidate.
View Article and Find Full Text PDFChemistry
December 2016
Department of Chemistry, University of California, 1102 Natural Sciences II, Irvine, CA, 92697-2025, USA.
A concise and stereoselective synthesis of exiguaquinol dessulfate is described. Sequential application of a Diels-Alder cycloaddition, a desymmetrizing aldol addition, and a reductive Heck cyclization established most of the architecture of exiguaquinol, and a carefully choreographed introduction of the polar substituents afforded the title compound; unfortunately, naphthoquinol sulfation could not be achieved to deliver exiguaquinol. Our hypothesis regarding the configurational preference of the N-acyl hemiaminal, which was based upon an analysis of internal hydrogen-bonding interactions with polar functional groups, was proven correct.
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