Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(18), P. 4550 - 4558
Published: Jan. 1, 2023
Contrary to chemical intuition, electron-donating groups decrease the nucleophilicity of double bond in imidazolin-2-ones, switching their reactivity from “enamide” “base”. Enamide can be recovered by a careful choice catalyst and solvent.
Language: Английский
The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(8), P. 5699 - 5714
Published: April 2, 2024
Four heteroatoms dance in the cascade of four pericyclic reactions initiated by ozonolysis C═N bonds. Switching from imines to semicarbazones introduces fifth heteroatom that slows this dance, delays reaching thermodynamically favorable escape path, and allows efficient interception carbonyl oxides (Criegee intermediates, CIs) an external nucleophile. The new three-component reaction alcohols, ozone, oximes/semicarbazones greatly facilitates synthetic access monoperoxyacetals (alkoxyhydroperoxides).
Language: Английский
Citations
4
Organic Letters, Journal Year: 2025, Volume and Issue: unknown
Published: Jan. 8, 2025
The temperature-dependent switching behavior of the saccharin radical is demonstrated, enabling regiodivergent C3–H and C7–H functionalization quinoxalin-2(1H)-ones. was generated through N–Br bond cleavage in N-bromosaccharin (NBSA) observed to transition between radicophile roles. At −10 °C, it utilized as a radicophile, resulting 100% C3-amination, while at +35 acted radical, leading exclusive C7-bromination. Radical nucleophilicity controlled by temperature modulation.
Language: Английский
Citations
0
International Journal of Molecular Sciences, Journal Year: 2023, Volume and Issue: 24(16), P. 12637 - 12637
Published: Aug. 10, 2023
The utility of sterically hindered phenols (SHPs) in drug design is based on their chameleonic ability to switch from an antioxidant that can protect healthy tissues highly cytotoxic species target tumor cells. This work explores the biological activity a family 45 new hybrid molecules combine SHPs equipped with activating phosphonate moiety at benzylic position additional urea/thiourea fragments. compounds were synthesized by reaction iso(thio)cyanates C-arylphosphorylated containing pendant 2,6-diaminopyridine and 1,3-diaminobenzene moieties. SHP/urea hybrids display against number lines. Mechanistic studies confirm paradoxical nature these substances which pronounced properties radical trapping assays increased reactive oxygen generation Moreover, most inhibited process glycolysis SH-SY5Y cells caused dissipation mitochondrial membrane isolated rat liver mitochondria. Molecular docking active identified activator allosteric center pyruvate kinase M2 as one possible targets. For promising compounds, 11b 17b, this combination results induce apoptosis HuTu 80 along intrinsic pathway. Cyclic voltammetry reveal complex redox behavior be simplified addition large excess acid some oxidizable groups protonations. Interestingly, re-reduction oxidized shows considerable variations, indicating different degrees reversibility. Such reversibility (or quasi-reversibility) suggests shift phenol-quinone equilibrium toward original phenol lower pH may associated cytotoxicity.
Language: Английский
Citations
7
Chemistry of Materials, Journal Year: 2024, Volume and Issue: 36(9), P. 4275 - 4290
Published: April 25, 2024
Membranes for gas separations are limited by the trade-off relationship between permeability and selectivity. In this study, we demonstrate an in situ thermal oxidative crosslinking strategy amine-functionalized polymers using tert-butoxycarbonyl (tBOC) groups to improve separation performance. The use of labile tBOC offers two major benefits inducing crosslinks: (1) they trigger free radical chain reactions at more moderate temperatures, preventing polymer backbone degradation pathways that otherwise occur elevated (2) enable volume manipulation (FVM) conditions yield increased narrower element size distribution. This is demonstrated intrinsic microporosity (PIM-NH2). resulting crosslinked yielded up a 22-fold increase H2/CH4 selectivity while retaining 96% H2 from pristine PIM-NH2 films. By combining crosslinks FVM, effective approach overcome traditional permeability–selectivity offer greater resistance performance stability issues like plasticization physical aging, making membranes better suited industrial applications.
Language: Английский
Citations
2
Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown
Published: Dec. 27, 2024
The selective reaction of cyclic aminoperoxides with FeCl2 proceeds through a sequence O–O and C–C bond cleavages, followed by intramolecular cyclization, yielding functionalized tetrahydrofurans in 44–82% yields. Replacing the peroxyacetal group peroxide structure peroxyaminal fragment fundamentally alters pathway. Instead producing linear ketones, this modification leads to formation hard-to-access substituted tetrahydrofurans. Although aminoperoxide cores undergo multiple scissions, cascade is atom-economical. Computational analysis shows that O-ligands at Fe center have enough radical character promote fragmentation subsequent cyclization. stereoelectronic flexibility oxygen, combined iron's capacity stabilize reactive intermediates during multistep cascade, explains efficiency new atom-economic rearrangement.
Language: Английский
Citations
1
Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(18), P. 4550 - 4558
Published: Jan. 1, 2023
Contrary to chemical intuition, electron-donating groups decrease the nucleophilicity of double bond in imidazolin-2-ones, switching their reactivity from “enamide” “base”. Enamide can be recovered by a careful choice catalyst and solvent.
Language: Английский
Citations
1