A mild and selective C(sp3)−H aerobic oxidation enabled by decatungstate photocatalysis has been developed. The reaction can be significantly improved in a microflow reactor enabling the safe use of ...oxygen and enhanced irradiation of the reaction mixture. Our method allows for the oxidation of both activated and unactivated C−H bonds (30 examples). The ability to selectively oxidize natural scaffolds, such as (−)‐ambroxide, pregnenolone acetate, (+)‐sclareolide, and artemisinin, exemplifies the utility of this new method.
Good clean functionalization: A mild and selective C(sp3)−H oxidation promoted by an inexpensive decatungstate photocatalyst was significantly improved by a microflow reactor, which enabled the safe use of oxygen and enhanced irradiation of the reaction mixture. Both activated and unactivated C−H bonds could be oxidized by this sustainable method, including those in natural scaffolds, such as (−)‐ambroxide and artemisinin.
The last decades have seen a tremendous expanse in the application of CH activation of many different substrate classes, including the invaluable indole scaffold. Following the exciting emergence of ...CH activation as a multi‐faceted platform for functionalization, a versatile tool box has been developed for the preparation of structurally diverse indoles. This review article discusses recent advances and strategies for transition metal‐catalyzed CH activation of indoles.
Considering the current importance of unsymmetrical mono‐ and di‐N‐functionalized ethylene side‐bridged (sb) cyclams and the need to have their C‐appended derivatives bearing an additional function ...dedicated to a conjugation to an external moiety as a targeting biomolecule, we have developed a general procedure to obtain orthogonally N‐protected sb‐cyclams with a benzyl or a Boc group. Despite the lack of symmetry of the compounds, this methodology allows the specific protection of one or the other remaining secondary amine function.
A general procedure to obtain orthogonally N‐protected side‐bridged cyclams with a benzyl or a Boc group was developed. Such methodology is especially applicable on C‐functionalized macrocycles. Despite the lack of symmetry of these compounds, this strategy allows the specific protection of one or the other remaining secondary amine function.
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•Photocatalytic alkoxy radical-mediated reactions.•Alkoxy radicals mediated CH functionalizations.•CC bond cleavage and functionalizations of alcohols.
Alkoxy radicals have been ...intensively studied as versatile synthetic intermediates with well-established reactivity and selectivity. Due to the difficulties associated with the generation of these transient and high-energy radicals, the utilization of the unique reactivity of alkoxy radicals in catalytic platforms has become a rather challenging task. Recent studies on the alkoxy radical-mediated transformations have benefited tremendously from advances in modern photoredox catalysis. In this digest, we aim to highlight reported transformations that utilize alkoxy radicals in a photocatalytic fashion, in particular, underline novel catalytic platforms which we anticipate will find broad application in the near future.
Surface functionalization of chitosan using some chelating ligands not only improves sorption capacity but also induces selectivity into the biopolymer. The current study is based on the facile ...synthesis of ethyl acetoacetate modified chitosan and surface-functionalized alginate composite beads (EAA-MCSA). Chemical modification of sodium alginate was carried out to graft amino thiocarbamate moiety (-OCSNHNH2) to entrench selectivity and specificity across the linear chains of preliminary polysaccharide. Biosorbent (EAA-MCSA) was thoroughly characterized by FT-IR and SEM analysis and employed in the form of composite hydrogel beads for competitive Cu(II) recovery. Newly grafted aminothiocarbamate (-OCSNHNH2) and 1,3-dicarbonyl moieties (-COCH2CO-) are supposed to act as potential chelating sites for enhanced Cu(II) sorption. Kinetic data could be well depicted using pseudo-second order rate law (R2 = 0.99, qexp≈qe,th = 85.25 mg/g, k2 = 0.45–1.17 ×10−2 g/mg.min−1) and sorption data was found in close agreement with Langmuir adsorption isotherm (R2 = 0.99, qm= 390.21 mg/g at 298 K and pH = 6.0, KL= 0.44–0.49 ×10−2 L/mg). The ΔG° values (−20.75, −21.10, −21.30 and −21.50 kJ/mol) and positive ΔH° (−7.63 kJ/mol) designated the sorption process as spontaneous and exothermic, respectively. Hence, EAA-MCSA could be a better sorbent for adsorptive remediation of Cu(II) from dilute effluents.
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•One pot synthesis of Ethyl acetoacetate modified chitosan via free radical grafting.•Hybrid composite hydrogel beads showed well organized 3D-porous structure.•Economical competitive recovery of Cu(II) from aqueous solution.•Maximum monolayer sorption capacity of EEA-MCSA evaluated as 390 mg/g at pH 6.0.•Adsorption process was found feasible, spontaneous and exothermic.
Functional genomics in inborn errors of immunity Hurabielle, Charlotte; LaFlam, Taylor N.; Gearing, Melissa ...
Immunological reviews,
March 2024, 2024-Mar, 2024-03-00, 20240301, Letnik:
322, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Summary
Inborn errors of immunity (IEI) comprise a diverse spectrum of 485 disorders as recognized by the International Union of Immunological Societies Committee on Inborn Error of Immunity in 2022. ...While IEI are monogenic by definition, they illuminate various pathways involved in the pathogenesis of polygenic immune dysregulation as in autoimmune or autoinflammatory syndromes, or in more common infectious diseases that may not have a significant genetic basis. Rapid improvement in genomic technologies has been the main driver of the accelerated rate of discovery of IEI and has led to the development of innovative treatment strategies. In this review, we will explore various facets of IEI, delving into the distinctions between PIDD and PIRD. We will examine how Mendelian inheritance patterns contribute to these disorders and discuss advancements in functional genomics that aid in characterizing new IEI. Additionally, we will explore how emerging genomic tools help to characterize new IEI as well as how they are paving the way for innovative treatment approaches for managing and potentially curing these complex immune conditions.
The first gold‐catalyzed photoredox C(sp2)−H difluoroalkylation and perfluoroalkylation of hydrazones with readily available RF−Br reagents is reported. The resulting gem‐difluoromethylated and ...perfluoroalkylated hydrazones are highly functionalized, versatile molecules. A mild reduction of the coupling products can efficiently produce gem‐difluoromethylated β‐amino phosphonic acids and β‐amino acid derivatives. In mechanistic studies, a difluoroalkyl radical intermediate was detected by an EPR spin‐trapping experiment, indicating that a gold‐catalyzed radical pathway is operating.
The radical C−H fluoroalkylation of hydrazones in the presence of a gold photoredox catalyst is compatible with a broad range of functional groups and provides access to E‐configured products that can be converted into useful synthetic building blocks. A radical intermediate was trapped and analyzed by EPR spectroscopy.
An unprecedented phosphine‐catalyzed remote β‐CH functionalization of amine derivatives triggered by trifluoromethylation of an alkene with Togni’s reagent was disclosed. This reaction proceeded ...through the highly selective and concomitant activation of an unactivated alkene and the β‐C sp 3H bond of an amine derivative, providing bistrifluoromethylated enamides in excellent yields with good regio‐, chemo‐, and stereoselectivity. Furthermore, the newly developed one‐pot protocol provides a facile and step‐economical access to valuable trisubstituted 5‐(trifluoromethyl)oxazoles. Mechanistic studies showed that this reaction may initiate with a novel phosphine‐catalyzed radical trifluoromethylation of unactivated alkene via a phosphorus radical cation.
The radical tandem functionalization of unactivated alkenes and the remote β‐C sp 3H bond of amine derivatives is achieved by phosphine catalysis. The one‐pot protocol provides facile access to bistrifluoromethylated enamides as well as trisubstituted 5‐(trifluoromethyl)oxazoles.
CH bonds are ubiquitous in organic compounds. It would, therefore, appear that direct functionalization of substrates by activation of CH bonds would eliminate the multiple steps and limitations ...associated with the preparation of functionalized starting materials. Regioselectivity is an important issue because organic molecules can contain a wide variety of CH bonds. The use of a directing group can largely overcome the issue of regiocontrol by allowing the catalyst to come into proximity with the targeted CH bonds. A wide variety of functional groups have been evaluated for use as directing groups in the transformation of CH bonds. In 2005, Daugulis reported the arylation of unactivated C(sp3)H bonds by using 8‐aminoquinoline and picolinamide as bidentate directing groups, with Pd(OAc)2 as the catalyst. Encouraged by these promising results, a number of transformations of CH bonds have since been developed by using systems based on bidentate directing groups. In this Review, recent advances in this area are discussed.
Caught in the act: The regiochemical functionalization of CH bonds is a reliable strategy in synthetic chemistry. The regiocontrol can be achieved by using a directing group in the substrate which brings the catalyst into proximity with the target CH bond. Bidentate directing groups in particular have proven to be extremely effective.
A tunable rhodium‐catalyzed intramolecular alkyne insertion reaction proceeding through the CC cleavage of benzocyclobutenones is described. Selective formation of either the direct or ...decarbonylative insertion product can be controlled by using different catalytic systems. A variety of fused β‐naphthol and indene scaffolds were obtained in good yields with high functional group tolerance. This work illustrates a divergent approach to synthesize fused‐ring systems by CC activation/functionalization.
Cat. in control: A tunable rhodium‐catalyzed intramolecular alkyne insertion reaction proceeding through CC cleavage of benzocyclobutenones is described. Selective formation of either the direct or decarbonylative insertion product can be controlled by using different catalytic systems. A variety of fused β‐naphthol and indene scaffolds were obtained in good yields with high functional‐group tolerance.
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