Cobalt(III)-Catalyzed C-H Amidation of Dehydroalanine for the Site-Selective Structural Diversification of Thiostrepton.

Ryan J Scamp, Edward deRamon, Eric K Paulson, Scott J Miller, Jonathan A Ellman

Angewandte Chemie (International ed. in English) 2020 Jan 07

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Thiostrepton is a potent antibiotic against a broad range of Gram-positive bacteria, but its medical applications have been limited by its poor aqueous solubility. In this work, the first C(sp2 )-H amidation of dehydroalanine (Dha) residues was applied to the site selective modification of thiostrepton to prepare a variety of derivatives. Unlike all prior methods for the modification of thiostrepton, the alkene framework of the Dha residue is preserved and with complete selectivity for the Z-stereoisomer. Additionally, an aldehyde group was introduced by C-H amidation, enabling oxime ligation for the installation of an even greater range of functionality. The thiostrepton derivatives generally maintain antimicrobial activity, and importantly, eight of the derivatives displayed improved aqueous solubility (up to 28-fold), thereby addressing a key shortcoming of this antibiotic. The exceptional functional group compatibility and site selectivity of CoIII -catalyzed C(sp2 )-H Dha amidation suggests that this approach could be generalized to other natural products and biopolymers containing Dha residues. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Ryan J Scamp, Edward deRamon, Eric K Paulson, Scott J Miller, Jonathan A Ellman. Cobalt(III)-Catalyzed C-H Amidation of Dehydroalanine for the Site-Selective Structural Diversification of Thiostrepton. Angewandte Chemie (International ed. in English). 2020 Jan 07;59(2):890-895