Video Experimental Relacionado
Updated: Feb 16, 2026
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
05:15
Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
7.3K
Torsión reversible de las amidas primarias a través del estado de tierra N-C(O) Desestabilización: Amidas acíclicas
Guangrong Meng1, Shicheng Shi1, Roger Lalancette1
1Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States.
Journal of the American Chemical Society
|December 15, 2017
Resumen
Los investigadores crearon las primeras amidas torcidas acíclicas, rompiendo el concepto tradicional de enlace de amida plana. Este avance permite la torsión reversible de las amidas, impactando el diseño y la síntesis químicos.
Área de la Ciencia:
- Química orgánica
- Química estructural
- La bioquímica
Sus antecedentes:
- El enlace de amida se considera tradicionalmente plano, una característica establecida por Pauling en la década de 1930.
- La planaridad de la amida influye significativamente en la reactividad y las propiedades químicas en varias disciplinas químicas.
- La restricción de la planaridad de la amida generalmente implica la incorporación de la amida en sistemas cíclicos rígidos.
Objetivo del estudio:
- Para reportar la primera clase de amidas torcidas acíclicas.
- Demostrar un nuevo método reversible para la preparación de amidas retorcidas a partir de amidas primarias.
- Explorar las implicaciones estructurales, energéticas y de reactividad de los enlaces de amida no planos.
Principales métodos:
- Di-tert-butoxicarbonización de los átomos de nitrógeno de las amidas primarias.
- Síntesis y caracterización estructural completa de diversas amidas retorcidas electrónicamente variadas.
- Estudios de reactividad y análisis computacionales para comprender la deformación y la escisión de enlaces amídicos.
Principales resultados:
- Preparación exitosa de las primeras amidas torcidas acíclicas con un giro casi perpendicular.
- Demostración de propiedades inusuales de enlace amídico, incluida la escisión selectiva en condiciones específicas.
- Evaluación estructural y energética detallada de la deformación del enlace amídico a través de estudios computacionales.
Conclusiones:
- Se ha desarrollado un nuevo método reversible para generar amidas torcidas acíclicas.
- Las amidas retorcidas exhiben una reactividad única, ofreciendo nuevas posibilidades para la síntesis química.
- Este trabajo proporciona un nuevo paradigma para manipular la no-planaridad del enlace amídico en química y bioquímica.
Videos de Conceptos Relacionados
01:07Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
3.7K
In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.
3.7K
01:19Amines to Amides: Acylation of Amines
3.5K
Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...
3.5K
01:26Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
4.1K
The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
4.1K
01:29Preparation of Amides
4.1K
Amides are synthesized by treating carboxylic acids with amines in the presence of dehydrating agents like dicyclohexylcarbodiimide (DCC).
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
4.1K
01:07Acid Halides to Amides: Aminolysis
4.4K
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
4.4K
01:28Structures of Carboxylic Acid Derivatives
3.8K
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
3.8K