A versatile catalyst-free perfluoroaryl azide–aldehyde–amine conjugation reaction

Abstract

In a tri-component reaction, an electrophilically-activated perfluoroaryl azide, an aldehyde and an amine react readily to yield a stable amidine conjugate.

Perfluorophenyl Azides: Photo, Staudinger, and Multicomponent Postpolymerization Reactions on Homopolymers and PISA-Made Nanoparticles

“…First, the azide−aldehyde−amine multicomponent reaction was trialed using phenylacetaldehyde as an enolizable aldehyde and piperidine or morpholine as secondary amines in DCM at RT. Recently described for small molecules, 16 this reaction proceeds via cycloaddition of the electron-deficit azide onto the enamine formed in situ to give a substituted 4,5-dihydro-1,2,3-triazole, followed by cycloreversion, loss of dinitrogen, and formation of the amidine product; see Scheme 1B. 19 The complete reaction of the azide-functional groups was also confirmed by FT-IR spectroscopy, as shown in Figure 3, which showed the disappearance of the strong asymmetrical azide stretching band observed for 4 and the appearance of a characteristic CN stretching band assigned to the amidine functionality.…”

“…11,12 Para-substituted tetrafluorophenyl azides (R−C 6 F 4 −N 3 ) constitute a unique class of organic azides. With the strong electron-withdrawing effect of the fluorinated aromatic, these azides undergo a variety of reactions that are not available to the more common alkyl azides such as the formation of stable iminophosphoranes 13,14 via the Staudinger reaction with phosphines, 15 the three-component azide−aldehyde−amine reaction, 16 or the rapid formation of anilides with thioacids. 17 Compared to (nonhalogenated) phenyl azides, fluorination (at least in the ortho-positions) increases the lifetime of the singlet nitrenes formed upon UV irradiation and increases the efficiency of nitrene insertion reactions, making tetrafluorophenyl azides promising photoaffinity labels.…”

Impact of Hydrogen Bonding on the Fluorescence of N‐Amidinated Fluoroquinolones

“…[3] Recently,w er eportedanew class of N-amidinated fluoroquinolone derivatives, [4] synthesized using an ewly developed, catalyst-free perfluoroaryl azide-amine-aldehyde reaction. [5] The structures displayed pronounced aggregation-induced emission (AIE), emitting strongly in the solid state while showingw eak luminescence in solution. [6] Such AIE effects have more recently emerged as ag eneral and robusts trategy to sense molecular entities and physical factors (e.g.,f orce, temperature, acidity/basicity,p otential, viscosity),a nd monitor biological and physical processes.…”

Functionalization of pristine graphene for the synthesis of covalent graphene–polyaniline nanocomposite

“…3). [50][51][52] To facilitate material characterization, liquid-exfoliated fewlayer graphene (FLG) akes were used as the model system to demonstrate the feasibility of the conjugation chemistry. FLG akes were prepared by subjecting graphite powders to probe sonication and collecting the supernatant.…”