On‐Demand Release of Secondary Amine Bases for the Activation of Catalysts and Crosslinkers

Abstract

Dynamic covalent (DCv) ureas have been used abundantly to design self‐healing materials. We demonstrate that apart from self‐healing materials, the species present in the equilibrium of DCv ureas can be employed as responsive organocatalysts. Easily controllable stimuli like heat or addition of water shift the equilibrium towards isocyanate and free base which can function as an in situ released reagent. We demonstrate this application of DCv ureas with two examples. Firstly, we use the liberated base to catalytically activate a latent organocatalyst for acylhydrazone formation. Secondly, this base can be employed in an equimolar manner to trigger the release of nitrile‐N‐oxides from chlorooximes, which react with acrylate‐terminated polymers to form an isoxazoline polymer gel.

Thermoreversible Transformations of the Cyanosubstituted 2‐Oxopyrrole Derivative by the Action of Amines for the Creation of Novel High‐Contrast Coloration/Decoloration Systems

“…On the other hand, amines are compounds whose controlled release is the desired process in many applications. For example, the on-demand release of amines from their "hidden" forms can be used to trigger polymerization, [23] autocatalytic reactions [24] and photoactivated syntheses, [25] some catalytic processes, [26] as well as in the study of drug delivery systems. [27] The most of amine-sensitive sensors and amine-releasing systems described in the literature are based on the irreversible chemical processes accompanied with registration of the corresponding optical signal.…”

Tuneable thiol exchange linkers for traceless drug release applications in prodrugs and ADCs

“…11,[14][15][16][17][18][19] A recent review gives a timely overview of the subject. 20 One covalent dynamic system of particular interest to us was the addition of thiols to electron poor alkynones resulting in thiovinylketones (TVK) (Fig. 1a).…”