Video Experimental Relacionado
Updated: Nov 7, 2025
08:43
Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives
Published on: January 19, 2016
10.5K
Método secuencial de mediación de ir/cu para la radiofluoración meta-selectiva de C-H de las arenas hetero
Jay S Wright1, Liam S Sharninghausen2, Sean Preshlock1
1Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, United States.
Journal of the American Chemical Society
|April 29, 2021
Resumen
Este estudio presenta un nuevo método de referencia para la radiofluoración meta-selectiva de C-H de arenas mediante catálisis secuencial de iridio/cobre. El proceso produce eficientemente arenas etiquetadas con flúor-18 sin aislar intermedios, simplificando la síntesis del radiotrazador.
Área de la Ciencia:
- Química orgánica
- La radioquímica
- Catálisis
Sus antecedentes:
- El desarrollo de métodos eficientes para la introducción de fluor-18 en moléculas orgánicas es crucial para la tomografía por emisión de positrones (PET).
- Las técnicas actuales de radiofluoración a menudo requieren equipos especializados y procedimientos en varios pasos, lo que limita la accesibilidad.
- La funcionalización meta-selectiva de C-H ofrece una ruta directa a isómeros específicos, pero lograrlo con la radiofluoración sigue siendo un desafío.
Objetivo del estudio:
- Desarrollar un nuevo proceso secuencial de iridio/cobre compatible con el laboratorio para la radiofluoración meta-selectiva de C-H de (hetero) arenas.
- Para lograr altos rendimientos y pureza de las (hetero) arenas etiquetadas con flúor-18 utilizando un procedimiento simplificado de un solo recipiente.
- Demostrar la automatización de este proceso para la síntesis de agentes de imagen PET.
Principales métodos:
- La borilación secuencial Ir-catalizada C ((sp2) -H de sustratos de (hetero) areno para formar ésteres organoboronados.
- Fluoración directa mediada por cobre de los organoboronatos intermedios mediante el uso de fluoruro de tetrabutilamonio.
- Ejecución en el banco sin técnicas de Schlenk o guantera, evitando el aislamiento intermedio.
Principales resultados:
- El éxito de la meta-selectiva C-H radiofluoración de 1,3-dimetoxibenceno y un derivado de meta-tirosina.
- [18F]1-fluoro-3,5-dimetoxibenceno obtenido con un rendimiento radiocímico aislado del 37 ± 5% y una pureza radiocímica superior al 99%.
- Derivado de meta-tirosina marcado con F obtenido en un rendimiento radiocímico aislado del 25%, una pureza radiocímica del 99% y una actividad molar de 0,52 Ci/μmol.
- Proceso automatizado en un módulo TracerLab FXFN.
Conclusiones:
- El proceso secuencial desarrollado mediado por Ir/Cu proporciona un método eficiente y accesible para la radiofluoración meta-selectiva de C-H.
- La naturaleza de una sola olla de la reacción simplifica la síntesis de compuestos etiquetados con F.
- Este método es prometedor para la síntesis rutinaria de nuevos radiotrazadores para la obtención de imágenes PET.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:13Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
6.8K
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
6.8K
02:46Halogenation of Alkenes
17.2K
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
17.2K
01:30Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
4.3K
Nucleophilic substitution in aromatic compounds is feasible in substrates bearing strong electron-withdrawing substituents positioned ortho or para to the leaving group. The reaction proceeds via two steps: the addition of the nucleophile and the elimination of the leaving group.
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
4.3K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
15.2K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
15.2K
01:20Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
2.1K
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...
2.1K
02:36Regioselectivity and Stereochemistry of Hydroboration
8.7K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
8.7K