A Versatile New Monomer Family:  Functionalized 4-Vinyl-1,2,3-Triazoles via Click Chemistry

Abstract

The field of polymer science has undergone a renaissance in recent years as the ability to design, construct, and functionalize macromolecules to fit targeted applications develops. 1 While these applications are diverse, the majority of the polymer structures are based on polymerization or functionalization of vinyl monomers derived from a limited range of families. 2 Classic examples include the extensively studied and widely used styrenic, acrylate, or R-olefin-based monomer systems. The development of a new vinyl monomer family that combines the attractive features of thermal and chemical stability, yet having functional handles for compositional versatility, would represent a significant advance in the area of functionalized materials.Key considerations in the design of a novel type of vinyl monomer include the synthetic accessibility of the basic monomer unit and its ease of functionalization. Recently, the advantages of using the "click" chemistry concept and, specifically, the Cu(I)-catalyzed cycloaddition of azides and alkynes as a powerful tool in the design and synthesis of materials have been demonstrated. 3 The benign reaction conditions, functional group tolerance, quantitative yields, and broad applicability of this chemistry make it ideal for the development of unique vinylic monomers based on a triazole nucleus. In this report, we describe the first examples of an expanding library of triazole-based monomers, which are certain to have importance as polar and chemically versatile components for materials development.As shown in Figure 1, 4-vinyl-1,2,3-triazole monomers are expected to possess many of the outstanding features of traditional monomers, such as styrenics, vinyl pyridines, and acrylates. These features include an aromatic nucleus, stability to both acid and base treatment, a large dipole moment, and access to structural diversity through substitution at N-1. We now report the synthesis of a family of functionalized 4-vinyl-1,2,3-triazole monomers 4 that combine into a single structure many of the desirable features found in established monomers.Two distinct synthetic methods were examined for the preparation of 4-vinyl-1,2,3-triazoles. An initial one-pot approach was driven by the orthogonality of "click" chemistry which allows multiple chemical transformations to occur in solution without interference. 5 Coupling of a mixture of 1-trimethylsilyl-2-vinyl acetylene, 1, and an alkyl/aryl halide leads in one pot to the desired 4-vinyl-1,2,3-triazole derivatives. This is illustrated in Scheme 1 for iodobenzene, 2, which undergoes an in situ azidation by reaction with sodium azide and L-proline in the presence of Cu(I) to give azidobenzene, 3. Concurrently, 1 undergoes reaction with tetra-nbutylammonium fluoride to give the active terminal acetylene, 4.In situ coupling of 3 and 4, again by Cu(I) catalysis, then leads to 1-phenyl-4-vinyl-1,2,3-triazole, 5, in 73% overall yield (Scheme 1).The modular nature of "click" chemistry can also be exploited in an alternative two-step approach fo...

Universal Gradient Substrates for “Click” Biofunctionalization

“…[11][12][13] Thus, any appropriately engineered bioactive ligand (e.g., protein or peptide) that possesses an accessible azide group can be immobilized onto the surface-concentration gradient, which we have therefore named a "Universal Gradient Substrate for Click Biofunctionalization". The copper(I)-catalyzed Huisgen cycloaddition reaction has been highlighted recently in numerous material science applications, [12,14,15] and is proving invaluable for the facile preparation of highly functional macromolecules [15][16][17][18] and the surface immobilization of biomacromolecules. [19][20][21][22][23][24][25][26] Its versatility can be directly attributed to its high degree of conversion, complete chemical specificity, and the adaptability of the reaction to numerous aqueous and mixed solvent conditions.…”

Combining Clays and Ultrasound Irradiation for an O-Acetylation Reaction of N-Glucopyranosyl and Other Molecules

“…Normally, these alkenyl type compounds may be prepared from dehydration of tertiary alcohol linked to a 1,2,3-triazole function using POCl 3 /HCl. 19 Additionally, this mild condition was not efficient in promoting acetylation of 2-amino-1,4-naphthoquinone, which is expected for this kind of of extensive conjugated molecule, which requires harsher conditions (RCOCl/NaH).…”

Click Chemistry: Versatility and Control in the Hands of Materials Scientists

“…[67] It was quickly recognized that the use of click reactions is not limited to the synthesis and functionalization of dendrimers, but is also very useful for the synthesis of a range of functionalized polymers. The remarkable functional-group tolerance of click reactions enabled the facile introduction of reactive groups, such as hydroxyl and carboxyl groups, through conventional pre- [10,68] or post-polymerization modification. [69] The high yield and specificity of click chemistry have not only allowed the quantitative introduction of various functional groups onto polymer backbones, but also enabled both simultaneous and cascade functionalizations of a variety of macromolecules.…”