220612-64-6Relevant articles and documents
Carbon isotope labeling of carbamates by late-stage [11C], [13C] and [14C]carbon dioxide incorporation
Del Vecchio, Antonio,Talbot, Alex,Caillé, Fabien,Chevalier, Arnaud,Sallustrau, Antoine,Loreau, Olivier,Destro, Gianluca,Taran, Frédéric,Audisio, Davide
supporting information, p. 11677 - 11680 (2020/10/19)
A general procedure for the late-stage [11C], [13C] and [14C]carbon isotope labeling of cyclic carbamates is reported. This protocol allows the incorporation of carbon dioxide, the primary source of carbon-14 and carbon-11 radioisotopes, in a direct, cost-effective and sustainable manner. A disconnection/reconnection strategy, involving ring opening/isotopic closure, was also implemented.
Increased Degree of Unsaturation in the Lipid of Antifungal Cationic Amphiphiles Facilitates Selective Fungal Cell Disruption
Steinbuch, Kfir B.,Benhamou, Raphael I.,Levin, Lotan,Stein, Reuven,Fridman, Micha
, p. 825 - 836 (2018/05/23)
Antimicrobial cationic amphiphiles derived from aminoglycosides act through cell membrane permeabilization but have limited selectivity for microbial cell membranes. Herein, we report that an increased degree of unsaturation in the fatty acid segment of antifungal cationic amphiphiles derived from the aminoglycoside tobramycin significantly reduced toxicity to mammalian cells. A collection of tobramycin-derived cationic amphiphiles substituted with C18 lipid chains varying in degree of unsaturation and double bond configuration were synthesized. All had potent activity against a panel of important fungal pathogens including strains with resistance to a variety of antifungal drugs. The tobramycin-derived cationic amphiphile substituted with linolenic acid with three cis double bonds (compound 6) was up to an order of magnitude less toxic to mammalian cells than cationic amphiphiles composed of lipids with a lower degree of unsaturation and than the fungal membrane disrupting drug amphotericin B. Compound 6 was 12-fold more selective (red blood cell hemolysis relative to antifungal activity) than compound 1, the derivative with a fully saturated lipid chain. Notably, compound 6 disrupted the membranes of fungal cells without affecting the viability of cocultured mammalian cells. This study demonstrates that the degree of unsaturation and the configuration of the double bond in lipids of cationic amphiphiles are important parameters that, if optimized, result in compounds with broad spectrum and potent antifungal activity as well as reduced toxicity toward mammalian cells.
Selectively Guanidinylated Aminoglycosides as Antibiotics
Fair, Richard J.,Hensler, Mary E.,Thienphrapa, Wdee,Dam, Quang N.,Nizet, Victor,Tor, Yitzhak
, p. 1237 - 1244 (2012/08/29)
The emergence of virulent, drug-resistant bacterial strains coupled with a minimal output of new pharmaceutical agents to combat them makes this a critical time for antibacterial research. Aminoglycosides are a well-studied, highly potent class of naturally occurring antibiotics with scaffolds amenable to modification, and therefore, they provide an excellent starting point for the development of semisynthetic, next-generation compounds. To explore the potential of this approach, we synthesized a small library of aminoglycoside derivatives selectively and minimally modified at one or two positions with a guanidine group replacing the corresponding amine or hydroxy functionality. Most guanidino-aminoglycosides showed increased affinity for the ribosomal decoding rRNA site, the cognate biological target of the natural products, when compared with their parent antibiotics, as measured by an in vitro fluorescence resonance energy transfer (FRET) A-site binding assay. Additionally, certain analogues showed improved minimum inhibitory concentration (MIC) values against resistant bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA). An amikacin derivative holds particular promise with activity greater than or equal to the parent antibiotic in the majority of bacterial strains tested.
