Diversely Substituted Polyamides: Macromolecular Design Using the Ugi Four-Component Reaction

Abstract

A novel strategy is demonstrated to obtain polyamides with finely tunable structure using the Ugi fourcomponent reaction (Ugi-4CR). By the use of two bifunctional and two monofunctional components, six different combinations for the synthesis of polyamides via the Ugi-4CR are possible and were investigated in detail within this contribution. In contrast to conventional polyamide synthesis, this approach proceeds under very mild reaction conditions and without the use of a catalyst in a one-pot reaction. General applicability is shown by variation of the components, leading to finely tuned macromolecular structures (i.e., side groups and repeat units can be engineered). Finally, a facile introduction of clickable alkyne moieties is demonstrated, which was used for post-polymerization modification in an azide−alkyne cycloaddition, in order to demonstrate the high versatility of this approach.

Potentially biocompatible polyacrylamides derived by the Ugi four-component reaction

“…Here, it is crucial to use aldehydes with blocked a-positions since otherwise undesired aldol reactions occur [46]. This side reaction can be observed when employing heptaldehyde 3b, propylamine 2c, and tert-butyl isocyanide 4a in the Ugi-4CR, consequently resulting in a moderate isolated yield of 44% (5h).…”

Dual side chain control in the synthesis of novel sequence-defined oligomers through the Ugi four-component reaction

“…The use of multicomponent reactions in the field of organic chemistry, for instance in the synthesis of pharmaceuticals, 29 hydrogels, 30,31 peniciline 55 scaffolds 32 and peptidomimetics 33 is already well established. 32 Recently, the use of the P-3CR and the U-4CR in polymer chemistry was demonstrated by our [34][35][36][37][38][39] and other groups. [40][41][42][43] Furthermore, sequential Ugi reactions were studied by Wessjohann et al for the synthesis of peptide-peptoid 60 chimeras 31,44,45 and in the synthesis of macrocycles.…”

The Ugi reaction in polymer chemistry: syntheses, applications and perspectives

“…In the modern synthetic strategy, newly emerging efficient reactions are being introduced as polycondensation tools, such as several famous click reactions [39][40][41][42][43][44][45] (Fig. 4) 48 . All six possible monomer combinations of two bifunctional AA-type components and two monofunctional components were investigated to prepare diversely substituted polyamides.…”