Video Experimental Relacionado
Updated: Jul 5, 2026
07:50
Plasmid-derived DNA Strand Displacement Gates for Implementing Chemical Reaction Networks
Published on: November 25, 2015
Síntesis total de la (-) -dictyostatin también conocida como dictyostatin
Gregory W O'Neil1, Andrew J Phillips
1Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA.
Journal of the American Chemical Society
|April 20, 2006
Resumen
Este estudio detalla una nueva síntesis total convergente de dictyostatin. Los métodos clave incluyen ciclizaciones mediadas por titanio y olefinación Horner-Wadsworth-Emmons para la construcción eficiente de moléculas.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química sintética de la química sintética.
- Síntesis de Productos Naturales.
Sus antecedentes:
- Dictyostatin es un producto natural marino complejo con actividad biológica potencial.
- Las rutas sintéticas eficientes y escalables son cruciales para una mayor evaluación biológica y el desarrollo analógico.
Objetivo del estudio:
- Para describir una nueva síntesis convergente total de dictyostatin.
- Mostrar metodologías sintéticas innovadoras para la construcción de productos naturales complejos de policetida.
Principales métodos:
- Estrategia de síntesis convergente. estrategia de síntesis convergente.
- Ciclizaciones mediadas por titanio de (sililoxi) eninas para la síntesis de estereotriados.
- Acoplamiento de subunidades utilizando mettesis de olefinas.
- Macrociclado a través de la olefinación intramolecular de Horner-Wadsworth-Emmons.
Principales resultados:
- Construcción exitosa de la estructura del núcleo de la dictyostatina.
- Demostración de la utilidad de las ciclizaciones mediadas por titanio y la olefinación de Horner-Wadsworth-Emmons en la síntesis de moléculas complejas.
- Se logra un alto control estereoquímico durante toda la síntesis.
Conclusiones:
- La síntesis convergente descrita proporciona una ruta eficiente hacia la dictyostatin.
- Las estrategias sintéticas empleadas son aplicables a otros objetivos complejos de productos naturales.
- Este trabajo avanza en el campo de la síntesis total y la química de productos naturales.
Videos de Conceptos Relacionados
01:23Complexation Equilibria: Overview
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
01:09EDTA: Conditional Formation Constant
Each EDTA molecule has six binding sites: four carboxyl groups and two amino groups. The fully protonated form of EDTA is represented as H6Y2+. However, it can exist in different forms, H5Y+, H4Y, H3Y−, H2Y2−, and HY3−, depending on the pH of the solution. In very basic solutions with pH > 10.17, the fully deprotonated form, Y4−, is the predominant species that readily complexes with metal ions in a 1:1 ratio.
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...
01:26EDTA: Auxiliary Complexing Reagents
EDTA titrations are usually carried out in highly basic conditions, where the fully deprotonated form of EDTA, Y4−, actively complexes with the free metal ions in the solution. Several metal ions precipitate as hydrous oxide (hydroxides, oxides, or oxyhydroxides) under these conditions, lowering the concentration of free metal ions in the solution. For this reason, auxiliary complexing agents or ligands such as ammonia, tartrate, citrate, or triethanolamine are used in EDTA titrations to...
01:30EDTA: Direct, Back-, and Displacement Titration
The EDTA titration types for metal ion analysis include direct titration, back-titration, and replacement titration.
Direct titration involves buffering the metal ion solution to the desired pH and directly titrating with standard EDTA until the endpoint. The optimum pH ensures a large conditional formation constant of metal−EDTA and visibility of the free indicator color in the solution. In addition, auxiliary complexing reagents are used to prevent the precipitation of metal hydroxides and...
Direct titration involves buffering the metal ion solution to the desired pH and directly titrating with standard EDTA until the endpoint. The optimum pH ensures a large conditional formation constant of metal−EDTA and visibility of the free indicator color in the solution. In addition, auxiliary complexing reagents are used to prevent the precipitation of metal hydroxides and...
01:20Complexometric EDTA Titration Curves
EDTA titration curves determine the free metal ion concentration. The titration curve represents the change in concentration of free metal ions (p function) as a function of the volume of EDTA added. This curve consists of three regions: before, at, and after equivalence points. Excess free metal ions are present before the equivalence point. Equal concentrations of metal ions and EDTA are present at the equivalence point. After the equivalence point, excess EDTA exists. This means slight...