Video Experimental Relacionado
Updated: Jan 25, 2026

06:04
Source and Route of Pyrrolizidine Alkaloid Contamination in Tea Samples
Published on: September 28, 2022
2.4K
Alcalóides de tipo B de calicifilina: Síntesis total de la (-) -daflongamina H y de la (-) -isodoflongamina H
Cedric L Hugelshofer1, Vignesh Palani1, Richmond Sarpong1
1Department of Chemistry , University of California , Berkeley , California 94720 , United States.
Journal of the American Chemical Society
|May 11, 2019
Resumen
Los científicos lograron la primera síntesis total del complejo alcaloide de Daphniphyllum (-) -daphlongamine H. Este avance utilizó reacciones clave para construir la molécula
Área de la Ciencia:
- Química orgánica
- Síntesis de productos naturales
- Química medicinal
Sus antecedentes:
- Los alcaloides de Daphniphyllum son una clase compleja de productos naturales con actividades biológicas potenciales.
- La síntesis total de estas moléculas intrincadas presenta desafíos significativos en el control estereoquímico y la complejidad estructural.
Objetivo del estudio:
- Para lograr la primera síntesis total del alcaloide hexacíclico Daphniphyllum (-) -daphlongamine H.
- Desarrollar una estrategia sintética robusta aplicable a las estructuras alcaloides relacionadas.
- Proporcionar acceso a análogos para una mayor evaluación biológica.
Principales métodos:
- Se empleó una estrategia sintética convergente, con una reacción clave de Mannich que generaba complejidad.
- Se utilizaron reacciones de ciclización eficientes para construir el marco policíclico central.
- Una hidrogenación altamente diastereoselectiva estableció cuatro estereocentros contiguos.
- Reacción de Pauson-Khand para la construcción de la subestructura de hidroindeno.
- Manipulaciones redox para la formación del producto final.
Principales resultados:
- Finalización con éxito de la primera síntesis total de (-) -daphlongamine H en cantidades de multigramas.
- Conjunto de un núcleo tricíclico con cuatro estereocentros contiguos.
- Acceso a la (-) isodaflongamina H, un alcaloide relacionado.
- Revisión de la estructura reportada de la desoxisocalicifilina B.
Conclusiones:
- La vía sintética desarrollada proporciona un método eficiente y escalable para acceder a la (-) daplongamina H.
- Los estudios sintéticos validan la estructura propuesta de (-) -daphlongamine H y ofrecen información sobre la biosíntesis de alcaloides de Daphniphyllum.
- Este trabajo allana el camino para la síntesis de otros alcaloides complejos de Daphniphyllum y sus análogos.
Más Videos Relacionados
Videos de Conceptos Relacionados
Types of Hormones
83.2K
Hormones can be classified into three main types based on their chemical structures: steroids, peptides, and amines. Their actions are mediated by the specific receptors they bind to on target cells.
83.2K
Total Voids in Concrete
471
Total voids in concrete encompass gel water volume, capillary pores, and entrapped air. Gel water (retained within the cement hydration products) and physically entrapped or adsorbed water are significant for the hydration process. For complete hydration, it's estimated that the space needed for the products of a cubic centimeter of cement doubles. Capillary pores constitute the unoccupied space within the hydrated cement paste, with their size largely influenced by the water-to-cement...
471
Total Internal Reflection Fluorescence Microscopy
11.1K
Total internal reflection fluorescence microscopy or TIRF is an advanced microscopic technique used to visualize fluorophores in samples close to a solid surface with a higher refractive index, such as a glass coverslip. TIRF only allows fluorophores in proximity to the solid surface to be excited. When light from a medium with a lower refractive index (such as air) hits the glass coverslip at a critical angle, the light undergoes total internal reflection stead of passing through the glass.
11.1K
Types of RNA
72.7K
Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
72.7K
Types of Toxins
3.3K
Humans continually engage with an environment rich in potentially harmful chemicals. These are introduced to our bodies through inhalation, ingestion, or skin contact. These chemicals exist in various forms, such as air and environmental pollutants, agricultural chemicals, organic solvents, and heavy metals.
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...
3.3K
Types of Coprecipitation
6.1K
Coprecipitation is the contamination of a precipitate by otherwise soluble species and occurs via different processes. In colloidal precipitates, coprecipitation occurs via surface adsorption. For instance, barium sulfate has a primary layer of adsorbed barium ions and a secondary layer of nitrate counterions. This results in contamination of the precipitate by barium nitrate.
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
6.1K

