- Metabolites of Microorganisms. Sulfur-Containing Ansa Compounds of the Naphthomycin Type
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From a strain of Streptomyces (Tue 2357) in addition to naphthomycin A, 4 new yellow pigments were isolated and their structures determined by spectroscopic comparison with naphthomycin A.Whereas the naphthomycins D and E are simple derivatives of naphthomycin A, having OH and H, respectively, instead of Cl, the naphthomycins F and G contain an N-acetylcysteine residue linked to the aromatic moiety by a thioether group.Degradations with O3 yielded identical products from the naphthomycins A, D, F, and G, showing coincident configurations in parts of the molecules.Naphthomycin F shows some biological activity against gram-positive bacteria and fungi, although much weaker than naphthomycin A.The naphthomycins D, E, and G are inactive against microorganisms.
- Meyer, Michael,Keller-Schierlein, Walter,Megahed, Salva,Zaehner, Hans,Segre, Annalaura
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- Chemoselective Synthesis of N-Terminal Cysteinyl Thioesters via β,γ-C,S Thiol-Michael Addition
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Dehydroalanine (ΔAla) is a highly electrophilic residue that can react efficiently with sulfur nucleophiles to furnish cysteinyl analogues. Herein, we report an efficient synthesis of N-terminal cysteinyl thioesters, suitable for S,N-acyl transfer, based on β,γ-C,S thiol-Michael addition. Both ionic and radical-based methodologies were found to be efficient for this process.
- Petracca, Rita,Bowen, Katherine A.,McSweeney, Lauren,O'Flaherty, Siobhan,Genna, Vito,Twamley, Brendan,Devocelle, Marc,Scanlan, Eoin M.
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supporting information
p. 3281 - 3285
(2019/05/10)
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