- Expanding the rubterolone family: Intrinsic reactivity and directed diversification of PKS-derived pyrans
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We characterized two key biosynthetic intermediates of the intriguing rubterolone family (tropolone alka-loids) that contain a highly reactive pyran moiety (in equilibrium with the hydrolyzed 1,5-dione form) and undergo spontaneous pyridine formation in the presence of primary amines. We exploited the intrinsic reactivity of the pyran moiety and isolated several new rubterolone derivatives, two of which contain a unique thiazolidine moiety. Three rubterolone derivatives were chemically modified with fluorescence and biotin tags using peptide coupling and click reaction. Overall, eight derivatives were fully characterized by HRMS/MS and 1D and 2D NMR spectroscopy and their antimicrobial, cytotoxic, anti-inflammatory and antiparasitic activities evaluated.
- Guo, Huijuan,Benndorf, René,K?nig, Stefanie,Leichnitz, Daniel,Weigel, Christiane,Peschel, Gundela,Berthel, Patrick,Kaiser, Marcel,Steinbeck, Christoph,Werz, Oliver,Poulsen, Michael,Beemelmanns, Christine
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- Solvatochromic characteristics of dansyl molecular probes bearing alkyl diamine chains
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A series of dansyl-based fluorescent probes bearing linear alkyl-1,n-diamine chains of different length (DA1.n, n = 2–8, 10, 12) was characterized in terms of the absorptive and emissive features in solvents of different polarity and hydrogen bond donor/hydrogen bond acceptor character. The probes show solvent-dependent absorption, a feature that is uncommon among dansyl derivatives. The dual emission of DA1.n probes is strong in non-aqueous solvents and is influenced by the chain length and interactions with the solvent. Solvent effects on the spectral parameters were rationalized on the basis of the Kamlet-Taft and Catalán solvatochromic models, in order to quantify the degree of polarity-driven and hydrogen bonding interactions. A comparative discussion of the results predicted by the two models was made. In ground state, the DA1.n probes act as hydrogen bond acceptors. In excited state, hydrogen bonding is less favoured, the solute-solvent interactions being governed by the increasing polarity of the solvent that results in a large bathochromic shift of the emission. A comparison was made with the spectral features previously reported for the corresponding series of bis-dansyl fluorescent probes (2DA1.n).
- Ionita, Gabriela,Matei, Iulia,Mocanu, Sorin
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