Related Experiment Video
Updated: Feb 23, 2026
Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
Cnidimonins A-C, Three Types of Hybrid Dimer from Cnidium monnieri: Structural Elucidation and Semisynthesis
Fangyi Su1, Zheng Zhao1, Shuanggang Ma1
1State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing 100050, China.
Abstract:
Three pairs of racemic dimers, (±)-cnidimonins A-C (1-3), were isolated from the fruits of Cnidium monnieri. They represent novel hybrid-dimerization patterns of coumarin skeleton with structurally diverse units (flavonol, benzofuran, and chromone) via an unprecedented terminal chiral carbon of prenyl. The absolute configurations of the enantiomers were determined by electronic circular dichroism (ECD). To investigate their bioactivities in depth, (±)-cnidimonins A-C (1-3) were synthesized. The racemic mixture (±)-1 exhibited stronger antiviral activity against HSV-1 (IC50: 1.23 μM) than its corresponding optically pure enantiomers.
Related Concept Videos
01:32Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
01:10Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
01:16Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
02:33Stereoisomerism of Cyclic Compounds
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...