Synthesis of Electron‐Deficient Corona[5]arenes and Their Selective Complexation with Dihydrogen Phosphate: Cooperative Effects of Anion–π Interactions

2020 ◽  
Vol 59 (21) ◽  
pp. 8078-8083 ◽  
Author(s):  
Shen‐Yi Guo ◽  
Qing‐Hui Guo ◽  
Shuo Tong ◽  
Mei‐Xiang Wang
Keyword(s):  
Dihydrogen Phosphate ◽  
Cooperative Effects ◽  
Π Interactions ◽  
Selective Complexation

MP2 study of cooperative effects between cation–π, anion–π and π–π interactions

2007 ◽  
Vol 31 (4) ◽  
pp. 556-560 ◽  
Author(s):  
Antonio Frontera ◽  
David Quiñonero ◽  
Antoni Costa ◽  
Pablo Ballester ◽  
Pere M. Deyà
Keyword(s):  
Cooperative Effects ◽  
Π Interactions

Cooperative and substitution effects in enhancing the strength of fluorine bonds by anion−π interactions

2015 ◽  
Vol 93 (11) ◽  
pp. 1169-1175 ◽  
Author(s):  
Mehdi D. Esrafili ◽  
Fariba Mohammadian-Sabet ◽  
Mohammad Mehdi Baneshi
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electrostatic Potential ◽  
Molecular Electrostatic Potential ◽  
Atoms In Molecules ◽  
Substitution Effects ◽  
Cooperative Effects ◽  
Π Interactions ◽  
Binding Distance

In this work, the cooperative effects between anion−π and fluorine bond interactions are studied by ab initio calculations at the MP2/6-311++G** level. Cooperative effects are observed in complexes in which anion−π and fluorine bond interactions coexist. For each complex, the shortening of the binding distance in the fluorine bond is more prominent than that in the anion−π bond. Favorable cooperativity energies are found with values that range between –0.51 and –0.76 kcal/mol. The atoms in molecules and molecular electrostatic potential analyses are carried out for these complexes to understand the nature of anion−π and fluorine bond interactions and the origin of the cooperativity.

Determination of Impurities in Perampanel Bulk Drugs by High-Performance Liquid Chromatography and Gas Chromatography

2020 ◽  
Vol 16 ◽  
Author(s):  
Yun-Yan Xia ◽  
Qiao-Gen Zou ◽  
Yu-Fei Yang ◽  
Qian Sun ◽  
Cheng-Qun Han
Keyword(s):  
Gas Chromatography ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Quantitative Detection ◽  
Dihydrogen Phosphate ◽  
Phosphate Solution ◽  
Related Impurities ◽  
Bulk Drug

Background: High-performance liquid chromatography (HPLC) method has been used to detect related impurities of perampanel. However, the detection of impurities is incomplete, and the limits of quantification and detection are high. A sensitive, reliable method is in badly to be developed and applied for impurity detection of perampanel bulk drug. Objective: Methodologies utilising HPLC and gas chromatography (GC) were established and validated for quantitative determination of perampanel and its related impurities (a total of 10 impurities including 2 genotoxic impurities). Methods: The separation was achieved on a Dikma Diamonsil C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of 0.01 mol/L potassium dihydrogen phosphate solution (A) and acetonitrile (B) in gradient elution mode. The compound 2-bromopropane was determined on an Agilent DB-624 column (0.32 mm × 30 m, 1.8 μm) by electron capture detector (μ-ECD) with split injection ratio of 1:5 and proper gradient temperature program. Result: Both HPLC and GC methods were established and validated to be sensitive, accurate and robust according to International Council for Harmonization (ICH) guidelines. The methods developed were linear in the selected concentration range (R 2≥0.9944). The average recovery of all impurities was between 92.6% and 103.3%. The possible production mechanism of impurities during the synthesis and degradation processes of perampanel bulk drug was also discussed. Five impurities were analyzed by liquid chromatography–mass spectrometry (LC-MS). Moreover, two of them were simultaneously characterized by LC-MS, IR and NMR. Conclusion: The HPLC and GC methods were developed and optimized, which could be applied for quantitative detection of the impurities, and further stability study of perampanel.

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