An efficient diastereoselective synthesis of carbapenem Mannich bases was developed using organocatalysis. This method also provides a route to new highly functionalized diazabicyclo[4.2.1]nonanes of proposed biological significance.
Chitosan has become an established
platform biopolymer with applications
in biomedical engineering, nanomedicine, and the development of new
materials with improved solubility, antimicrobial activity, and low
toxicity. In this study, a series of chitosan derivatives were synthesized
by conjugating various perfluorocarbon chains to chitosan via Schiff
base formation or nucleophilic substitution, followed by quaternization
with glycidyl trimethylammonium chloride to confer non-pH-dependent
permanent positive charges. Synthesized fluorinated N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride polymers
were characterized and investigated for their antibacterial efficacies
against multidrug-resistant bacteria including clinical isolates.
The polymers showed activity against both Gram-positive and Gram-negative
bacteria (MIC = 64–512 μg/mL) but with greater potency
against the former. They displayed rapid bactericidal properties,
based on the MBC/MIC ratio, which were further confirmed by the time-kill
kinetic assays. Given the properties presented here, fluorinated quaternary
chitosan derivatives can serve as great candidates to be investigated
as environmentally more benign, nontherapeutic antimicrobial agents
that could serve as alternatives to the heavy reliance on antibiotics,
which are currently in a very precarious state due to increasing occurrence
of drug resistance.
We herein report a simple and highly efficient microwave‐assisted, copper‐catalyzed and ligand‐free synthetic method for 2‐substituted 4(3H)‐quinazolinones as domino reaction. This reaction proceeds via self‐condensation of substrate (2‐bromo/iodo benzamide) in the presence of a strong base and copper catalyst. The substituted quinazolinones were obtained in one‐pot reaction by intramolecular cyclization (condensation) via Ullmann–type intermediate. Both the intermediates and quinazolinones were obtained in good yield and can be further used as building blocks for developing the potential novel drug‐like compounds.
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