Perfluroaryl azides Reactivities, Unique Reactions and their Applications in the Synthesis of Theranostic Agents
Abstract: The work centersaround perfluoroaryl azides (PFAAs), and theirability to undergo certain fast and robusttransformations. The chemistry was furtherappliedfor biomedical applications.The first section focuses on the azide-aldehyde-amine cycloaddition using PFAAs. Experimental and computational investigations uncovered a fast azide-enamine cycloaddition to form triazolines, which spontaneously rearrange into stable amidine products. In addition, this transformation was explored in the formulation of pure nanodrugs. Because this reaction can introduce a phenyl and a perfluoroaryl moiety enabling supramolecular interactions near the antibiotic drug, the resulting ciprofloxacin derivatives formed nano-sized aggregates by precipitation, which displayed aggregation-induced emission for bacterial imaging as well as enhanced size-dependent antibacterial efficacy.In the second section, the high electrophilicity of PFAAs was explored to transform azides to aryl amides. The reactivity of PFAAs in the thioacid/azide reaction was studied. In addition, PFAAs were discovered to react with phenylacetaldehyde to form aryl amidesviaan azide-enol cycloaddition, similar tothe perfluoroaryl azide-aldehyde-amine reaction.This strategyof amide synthesiswas furthermoregeneralized through a combination of base-catalyzed azide-enolate cycloaddition reaction and acid-or heat-promoted rearrangement of triazolines.The last section describes a type of azide fluorogens whose fluorescence can be switched on by alight-initiated intramolecular nitrene insertion intoa C-H bond in the neighboring aromaticring. These fluorogenic structures were efficiently accessed via the direct nucleophilic aromatic substitution of PFAAs.
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