Transnitrosylation products of the dipeptide cysteinyl–cysteine: an examination by tandem mass spectrometry and density functional theory

2016 ◽  
Vol 18 (8) ◽  
pp. 6047-6052 ◽  
Author(s):  
Matias Butler ◽  
K. W. Michael Siu ◽  
Alan C. Hopkinson
Keyword(s):  
Mass Spectrometry ◽  
Density Functional Theory ◽  
Tandem Mass Spectrometry ◽  
Density Functional ◽  
Closed Shell ◽  
Tandem Mass ◽  
Functional Theory ◽  
Shell Fragment

The concomitant loss of 2 NO molecules from the protonated di-nitrosylated dipeptide leads to the formation of a closed-shell fragment.

Synthesis of urease inhibitory 2, 4-bis (4-cyanobenzyl)glycoluril using sandmeyer reaction and density functional theory investigation

2021 ◽  
Vol 18 ◽  
Author(s):  
Mirza Arfan Yawer ◽  
Shehar Bano ◽  
Muhammad Saleem ◽  
Affiefa Yawer ◽  
Riaz Hussain ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Density Functional Theory ◽  
1H Nmr ◽  
13C Nmr ◽  
Density Functional ◽  
Spectroscopic Techniques ◽  
Pure Compound ◽  
Functional Theory ◽  
Sandmeyer Reaction ◽  
Urease Enzyme

Aims: The aim of present research was to synthesize glycoluril derivative 2,4-Bis(4-cyanobenzyl)glycoluril through convergent scheme. Background: For this purpose Sandmeyer reaction procedure was employed for the synthesis of said compound. The structure of the pure compound was confirmed by using different spectroscopic techniques such as 1H-NMR, 13C-NMR and (HR-MS) Mass spectrometry. Objective: Convergent synthesis of 2,4-BIS (4-CYANOBENZYL)GLYCOLURIL USING SANDMEYER REACTION and urease inhibition study. Methods: The structure of the pure compound was confirmed by using different spectroscopic techniques such as 1H-NMR, 13C-NMR and (HR-MS) Mass spectrometry. The electronic properties of newly synthesized compound and thiourea were determined by using density functional theory. Results: Furthermore compound was evaluated against urease enzyme and was found to be potent inhibitors with IC50 value of 11.5 ± 1.50 µM when compared with standard inhibitor thiourea (IC50 = 21.0 ± 1.90 µM). Compound may serve as lead compound for the synthesis of new cyano based bambusuril in future with enhanced biological properties. Conclusion: We have synthesized a new glycoluril derivative 2,4-Bis(4-cyanobenzyl)glycoluril by the sandmeyer reaction. It has obtained in the form of light yellowish powder in good yield (96%). Glycoluril based macrocycles have been used in various fields. Starting from the 2,4-Bis(4-nitrobenzyl)glycoluril (already reported compound) which has undergone reduction (CH3OH,Pt/C) , diazotization (NaNO2/HCl), cyanation (CuCl/KCN) respectively in order to synthesize the desired new glycoluril derivative. The obtained product will be used as a building block for the synthesis of the cyano based bambusuril marcocycle in future. The yield of the obtained product has been monitored by using different amount of cyanating reagent but the best results shown by the use of 4 mmol of CuCl/KCN. KCN with CuCl assisted the conversion of diazo group into cyano group with enhanced yield when used in excess amount. It act as a catalyst. Solubility characteristic of 2,4-Bis(4-cyanobenzyl)glycoluril has determined also in different organic solvents. 1H NMR technique proved to be very helpful for the structure determination of our desired product. Benzylic protons give signals at 7.5 ppm and 7.8 ppm respectively. The downfield peaks confirm about the presence of CN group near the benzylic protons. Methine protons show signal at 5.2 ppm which ensures about the basic skeleton of glycoluril. Ureidyl protons also confirm the synthesis of the heterocyclic 2,4-Bis(4-cyanobenzyl)glycoluril compound. The negative and positive electrostatic potential sites, molecular descriptors, and charge density distribution of frontier molecular orbitals are revealing that 4a with promising sites for electrophilic and nucleophilic attacks would result to enhance the urease inhbition which is in good agreement with the experimental data.

scholarly journals Investigation of the position of the radical in z3-ions resulting from electron transfer dissociation using infrared ion spectroscopy

2019 ◽  
Vol 217 ◽  
pp. 434-452 ◽  
Author(s):  
Lisanne J. M. Kempkes ◽  
Jonathan Martens ◽  
Giel Berden ◽  
Kas J. Houthuijs ◽  
Jos Oomens
Keyword(s):  
Mass Spectrometry ◽  
Density Functional Theory ◽  
Electron Transfer ◽  
Density Functional ◽  
Electron Transfer Dissociation ◽  
Open Shell ◽  
Molecular Structures ◽  
Functional Theory ◽  
Ion Spectroscopy ◽  
Molecular Dynamics Calculations

The molecular structures of six open-shell z3-ions resulting from electron transfer dissociation mass spectrometry (ETD MS) were investigated using infrared ion spectroscopy in combination with density functional theory and molecular mechanics/molecular dynamics calculations.

Density functional theory and liquid chromatography-multistage mass spectrometry to characterize raltitrexed photo-degradation mechanisms

RSC Advances ◽  
2016 ◽  
Vol 6 (96) ◽  
pp. 93801-93814 ◽  
Author(s):  
Hassane Sadou-Yayé ◽  
Maher Karoui ◽  
Philippe-Henri Secrétan ◽  
Noureddine Ghermani ◽  
Jean-Michel Gillet ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Density Functional Theory ◽  
Liquid Chromatography ◽  
Density Functional ◽  
Degradation Mechanisms ◽  
Functional Theory ◽  
Photo Degradation

The structure of raltitrexed photoproducts was elucidated by LC-ESI-HR-MSn. Photodegradation pathways are proposed, using DFT approach to support assumptions. Ralitrexed photodegrades as per photosensitization mechanisms.

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