Dual Strain-Promoted Alkyne–Nitrone Cycloadditions for Simultaneous Labeling of Bacterial Peptidoglycans

Abstract

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Fast Diazaborine Formation of Semicarbazide Enables Facile Labeling of Bacterial Pathogens

“…The favorable incorporation of D-AB3 into E. coli is particularly interesting given the previously reported amino acids that modify peptidoglycans largely favor gram-positive bacteria over gram-negative ones. 28,33,35 The gram-positive selectivity of these amino acids is believed to originate from their poor outer membrane permeability. Indeed, a previously reported fluorescent amino acid D-Lys-FITC in our hands stained S. aureus 50 times better than E. coli , according to our own flow cytometry analysis (Figure S22, SI).…”

“…A similar magnitude of preference for S. aureus was reported for a NBD labeled D-Lys by Pires and coworkers. 33 …”

Direct and Co‐catalytic Oxidation of Hydroxylamines to Nitrones Promoted by Rhodium Nanoparticles Supported on Carbon Nanotubes

“…Given that our system efficiently promoted the oxidation of hydroxylamines under mild conditions, we wanted to further explore the “one‐pot” 1,3‐dipolar cycloaddition of the produced nitrones with alkynes, as previously investigated by Pezacki and co‐workers . For this study, benzannulated cyclooctyne 3 was chosen as a model of a strained alkyne, whereas dimethyl acetylenedicarboxylate (DMAD, 5 ) provided a model of an electrophilic alkyne.…”

Fluorogenic diazaborine formation of semicarbazide with designed coumarin derivatives

“…The work of several groups including our own 11 has revealed a number of unnatural amino acids that can be incorporated into various bacterial species through this mechanism. 19–23 We envisioned that fluorogenic diazaborine formation of AB21/AB22 can be implemented for bacterial cell labeling via a semicarbazide-presenting D-amino acid (Figure 4a). Toward this end, we have synthesized the unnatural amino acid D-Dap-Scz, which was obtained by conjugating a semicarbazide derivative to Boc-D-Dap-OH through formation of an amide bond (Figure S4).…”