RESUMO
The chemical modification of biopolymers like peptides and proteins is a key technology to access vaccines and pharmaceuticals. Similarly, the tunable derivatization of individual amino acids is important as they are key building blocks of biomolecules, bioactive natural products, synthetic polymers, and innovative materials. The high diversity of functional groups present in amino acid-based molecules represents a significant challenge for their selective derivatization Recently, visible light-mediated transformations have emerged as a powerful strategy for achieving chemoselective biomolecule modification. This technique offers numerous advantages over other methods, including a higher selectivity, mild reaction conditions and high functional-group tolerance. This review provides an overview of the most recent methods covering the photoinduced modification for single amino acids and site-selective functionalization in peptides and proteins under mild and even biocompatible conditions. Future challenges and perspectives are discussed beyond the diverse types of photocatalytic transformations that are currently available.
Assuntos
Aminoácidos , Proteínas , Aminoácidos/química , Proteínas/química , Peptídeos/química , PolímerosRESUMO
C-Glycosyl compounds have gained considerable attention over the last few decades due to their high chemical stability and promising applications in drug discovery. Herein we disclose an operationally simple, metal-free, photocatalytic approach for the glycosylation of azomethine imines using 4-glycosyl-1,4-dihydropyridines (DHPs) as radical precursors. The protocol features mild reaction conditions, scalability, broad substrate scope, and good functional group tolerance. Moreover, the resulting pyrazolidinone moiety can be easily deprotected, acylated or reduced into a glycosyl ß-alanine analog.
RESUMO
The preparation of amide-containing compounds is among the most interesting and challenging topics for the synthetic community. Such relevance is given by their reactive aspects explored in the context of organic synthesis and by the direct application of these compounds as pharmaceuticals and useful materials, and their key roles in biological structures. A simple and straightforward strategy for the amide moiety installation is the use of carbamoyl radicals - this nucleophilic one-electron intermediate is prone to undergo a series of transformations, providing a range of structurally relevant derivatives. In this review, we summarize the latest advances in the field from the perspective of photoinduced protocols. To this end, their synthetic applications are organized accordingly to the nature of the radical precursor (formamides through HAT, 4-substituted-1,4-dihydropyridines, oxamic acids, and N-hydroxyphthalimido esters), the mechanistic aspects also being highlighted. The discussion also includes a recent approach proceeding via photolytic C-S cleavage of dithiocarbamate-carbamoyl intermediates. By exploring fundamental concepts, this material aims to offer an understanding of the topic, which will encourage and facilitate the design of new synthetic strategies applying the carbamoyl radical.