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Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine

Density functional calculations SMD(chloroform)//B3LYP/6-311+G(2d,p) were employed in the computational study of 1,3-dipolar cycloadditions of azides with guanidine. The formation of two regioisomeric tetrazoles and their rearrangement to cyclic aziridines and open-chain guanidine products were mode...

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Autores principales: Antol, Ivana, Glasovac, Zoran, Margetić, Davor
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10004754/
https://www.ncbi.nlm.nih.gov/pubmed/36903588
http://dx.doi.org/10.3390/molecules28052342
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author Antol, Ivana
Glasovac, Zoran
Margetić, Davor
author_facet Antol, Ivana
Glasovac, Zoran
Margetić, Davor
author_sort Antol, Ivana
collection PubMed
description Density functional calculations SMD(chloroform)//B3LYP/6-311+G(2d,p) were employed in the computational study of 1,3-dipolar cycloadditions of azides with guanidine. The formation of two regioisomeric tetrazoles and their rearrangement to cyclic aziridines and open-chain guanidine products were modeled. The results suggest the feasibility of an uncatalyzed reaction under very drastic conditions since the thermodynamically preferred reaction path (a), which involves cycloaddition by binding the carbon atom from guanidine to the terminal azide nitrogen atom, and the guanidine imino nitrogen with the inner N atom from the azide, has an energy barrier higher than 50 kcal mol(−1). The formation of the other regioisomeric tetrazole (imino nitrogen interacts with terminal N atom of azide) in direction (b) can be more favorable and proceed under milder conditions if alternative activation of the nitrogen molecule releases (e.g., photochemical activation), or deamination could be achieved because these processes have the highest barrier in the less favorable (b) branch of the mechanism. The introduction of substituents should favorably affect the cycloaddition reactivity of the azides, with the greatest effects expected for the benzyl and perfluorophenyl groups.
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spelling pubmed-100047542023-03-11 Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine Antol, Ivana Glasovac, Zoran Margetić, Davor Molecules Communication Density functional calculations SMD(chloroform)//B3LYP/6-311+G(2d,p) were employed in the computational study of 1,3-dipolar cycloadditions of azides with guanidine. The formation of two regioisomeric tetrazoles and their rearrangement to cyclic aziridines and open-chain guanidine products were modeled. The results suggest the feasibility of an uncatalyzed reaction under very drastic conditions since the thermodynamically preferred reaction path (a), which involves cycloaddition by binding the carbon atom from guanidine to the terminal azide nitrogen atom, and the guanidine imino nitrogen with the inner N atom from the azide, has an energy barrier higher than 50 kcal mol(−1). The formation of the other regioisomeric tetrazole (imino nitrogen interacts with terminal N atom of azide) in direction (b) can be more favorable and proceed under milder conditions if alternative activation of the nitrogen molecule releases (e.g., photochemical activation), or deamination could be achieved because these processes have the highest barrier in the less favorable (b) branch of the mechanism. The introduction of substituents should favorably affect the cycloaddition reactivity of the azides, with the greatest effects expected for the benzyl and perfluorophenyl groups. MDPI 2023-03-03 /pmc/articles/PMC10004754/ /pubmed/36903588 http://dx.doi.org/10.3390/molecules28052342 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Communication
Antol, Ivana
Glasovac, Zoran
Margetić, Davor
Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine
title Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine
title_full Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine
title_fullStr Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine
title_full_unstemmed Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine
title_short Mechanistic DFT Study of 1,3-Dipolar Cycloadditions of Azides with Guanidine
title_sort mechanistic dft study of 1,3-dipolar cycloadditions of azides with guanidine
topic Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10004754/
https://www.ncbi.nlm.nih.gov/pubmed/36903588
http://dx.doi.org/10.3390/molecules28052342
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