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相关概念视频

Stability of Substituted Cyclohexanes02:30

Stability of Substituted Cyclohexanes

12.4K
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
12.4K
Conformations of Cycloalkanes02:29

Conformations of Cycloalkanes

11.5K
Adolf von Baeyer attempted to explain the instabilities of small and large cycloalkane rings using the concept of angle strain — the strain caused by the deviation of bond angles from the ideal 109.5° tetrahedral value for sp3  hybridized carbons. However, while cyclopropane and cyclobutane are strained, as expected from their highly compressed bond angles, cyclopentane is more strained than predicted, and cyclohexane is virtually strain-free. Hence, Baeyer’s theory that...
11.5K
Combustion Energy: A Measure of Stability in Alkanes and Cycloalkanes02:14

Combustion Energy: A Measure of Stability in Alkanes and Cycloalkanes

6.2K
The low reactivity in alkanes can be attributed to the non-polar nature of C–C and C–H σ bonds. Alkanes, therefore, were  initially termed as “paraffins,” derived from the Latin words: parum, meaning “too little,” and affinis, meaning “affinity.”
Alkanes undergo combustion in the presence of excess oxygen and high-temperature conditions to give carbon dioxide and water. A combustion reaction is the energy source in natural gas, liquified...
6.2K
Stability of Conjugated Dienes01:28

Stability of Conjugated Dienes

3.3K
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
3.3K
Chair Conformation of Cyclohexane02:02

Chair Conformation of Cyclohexane

14.3K
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
14.3K
Stereoisomerism of Cyclic Compounds02:33

Stereoisomerism of Cyclic Compounds

8.7K
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,...
8.7K

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Ultrasonic-Assisted Extraction of Cannabidiolic Acid from Cannabis Biomass
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卡纳比克罗 (CBC) 显示了依赖于矩阵的热配置稳定性.

Simone Manetto1, Diego Caprioglio2, Gianpaolo Grassi3

  • 1Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, p.le A. Moro 5, 00185 Rome, Italy.

Journal of natural products
|December 9, 2024
PubMed
概括

矩阵在脱碳化过程中影响了cannabichromene (CBC) 的光学纯度. 与溶液相比,固体表面显著加快了CBC的种族化,影响了报告的反体纯度.

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科学领域:

  • 大麻素的化学和分析.
  • 奇拉尔化合物的稳定性 奇拉尔化合物的稳定性
  • 植物化学 植物化学

背景情况:

  • 卡纳比克罗门 (CBC) 是一种重要的植物性大麻素,具有潜在的治疗应用.
  • 在CBC的生物活性和药理作用方面,CBC的反体纯度至关重要.
  • 目前对CBC enantiopurity的理解可能会受到提取和加工方法的影响.

研究的目的:

  • 为了研究不同矩阵在热解过程中对cannabichromene (CBC) 的光学纯度的影响.
  • 评估CBC在各种溶剂和不同表面的热激化动力学.
  • 为报告的CBC反体纯度的差异提供洞察力,并建议标准化的协议.

主要方法:

  • 在植物和提取物中以130°C的温度对大麻双酸 (CBCA) 的热解.
  • 在100°C时使用enantioselective UHPLC.使用enantiopure CBC的热激素化的动力评价.
  • 在不同溶剂 (十,异醇) 和表面 (玻璃,大麻生物质) 上进行种族化分析.

主要成果:

  • 植物中的热解导致CBC反体过量 (ee) 的降低比提取物中的更大.
  • 在异醇中,CBC的种族化显著快于在脱醇中,并且在固体表面显著加快 (t1/2~6小时).
  • 与溶液中加热相比,在固体表面加热CBC会导致较大的纯度损失.

结论:

  • 矩阵,特别是固体表面,在脱碳化过程中显著影响CBC的光学纯度.
  • 报告的CBC反体纯度的差异可能源于脱碳氧化协议,而不仅仅是生物发生.
  • 标准化脱碳化协议对于准确评估CBC的配置状态及其生物活性至关重要.