Video Experimental Relacionado
Updated: May 28, 2026
11:44
Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
Síntesis y determinación estereoquímica de las complestatinas A y B (neuroprotectinas A y B)
Steven P Breazzano1, Dale L Boger
1Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
Journal of the American Chemical Society
|October 14, 2011
Resumen
Los investigadores sintetizaron la cloropeptina A y B (neuroprotectinas) a través de una nueva oxidación de la cloropeptina II (complestatina). Este trabajo establece asignaciones estereoquímicas y proporciona rutas sintéticas eficientes para estos complejos productos naturales.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Síntesis de Productos Naturales.
- Química Medicinal La Química Medicinal es un campo de estudio de la química medicinal.
Sus antecedentes:
- Las cloropeptinas son una clase de productos naturales con potenciales aplicaciones terapéuticas.
- Trabajos anteriores establecieron la síntesis total de la cloropeptina II (complestatina).
- La estereoquímica y la síntesis de la cloropeptina A (neuroprotectina A) y la cloropeptina B (neuroprotectina B) seguían siendo un reto.
Objetivo del estudio:
- Desarrollar rutas sintéticas para la cloropeptina A y la cloropeptina B.
- Establecer las asignaciones estereoquímicas para la cloropeptina A y la cloropeptina B.
- Explorar nuevas estrategias de oxidación para la cloropeptina II.
Principales métodos:
- Desarrolló dos métodos distintos de oxidación de indol en un solo paso (HCl-DMSO y NBS, THF-H2O) para la síntesis de cloropeptina A.
- Se utilizó una oxidación en dos pasos y en un solo recipiente (NCS, THF-H2O; Cs2CO3, DMF-H2O) para la síntesis de cloropeptina B.
- Se llevaron a cabo extensos estudios sobre el sistema de anillos DEF sintético de la cloropeptina II para asignar estereocímica.
Principales resultados:
- Logró la primera síntesis de cloropeptina A (neuroprotectina A) en excelentes rendimientos (93% y 82%).
- Se sintetizó con éxito la cloropeptina B (neuroprotectina B) a través de una novedosa oxidación en dos pasos y en un solo recipiente.
- Sin ambigüedad asignado la estereocímica de ambos productos naturales.
Conclusiones:
- Los métodos de oxidación desarrollados proporcionan un acceso eficiente a la cloropeptina A y B.
- Esta investigación aclara la estereoquímica de estos importantes productos naturales.
- Las estrategias sintéticas ofrecen información valiosa sobre la reactividad de la cloropeptina II.
Videos de Conceptos Relacionados
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
01:29Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
02:15SN1 Reaction: Stereochemistry
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
02:32Stereoisomers
On the basis of mirror symmetry, stereoisomers of an organic molecule can be further classified into diastereomers and enantiomers. Diastereomers are stereoisomers that are not mirror images of each other. Substituted alkenes, such as the cis and trans isomers of 2-butene, are diastereomers, as these molecules exhibit different spatial orientations of their constituent atoms, are not mirror images of each other, and do not interconvert. Here, the interconversion is suppressed due to restricted...