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17 pages, 7579 KiB

Open AccessArticle

Diverse Cyclization Pathways Between Nitriles with Active α-Methylene Group and Ambiphilic 2-Pyridylselenyl Reagents Enabled by Reversible Covalent Bonding

by Alexey A. Artemjev, Alexander A. Sapronov, Alexey S. Kubasov, Alexander S. Peregudov, Alexander S. Novikov, Anton R. Egorov, Victor N. Khrustalev, Alexander V. Borisov, Zhanna V. Matsulevich, Namiq G. Shikhaliyev, Valentine G. Nenajdenko, Rosa M. Gomila, Antonio Frontera, Andreii S. Kritchenkov and Alexander G. Tskhovrebov

Int. J. Mol. Sci. 2024, 25(23), 12798; https://doi.org/10.3390/ijms252312798 - 28 Nov 2024

Cited by 3 | Viewed by 1487

Abstract

Herein, we describe a novel coupling between ambiphilic 2-pyridylselenyl reagents and nitriles featuring an active α-methylene group. Depending on the solvent employed, this reaction can yield two distinct types of cationic pyridinium-fused selenium-containing heterocycles, 1,3-selenazolium or 1,2,4-selenadiazolium salts, in high yields. This is [...] Read more.

Herein, we describe a novel coupling between ambiphilic 2-pyridylselenyl reagents and nitriles featuring an active α-methylene group. Depending on the solvent employed, this reaction can yield two distinct types of cationic pyridinium-fused selenium-containing heterocycles, 1,3-selenazolium or 1,2,4-selenadiazolium salts, in high yields. This is in contrast to what we observed before for other nitriles. Notably, the formation of selenadiazolium is reversible, gradually converting into the more thermodynamically stable selenazolium product in solution. Our findings reveal, for the first time, the reversible nature of 1,3-dipolar cyclization between the CN triple bond and 2-pyridylselenyl reagents. Nitrile substitution experiments in the adducts confirmed the dynamic nature of this cyclization, indicating potential applications in dynamic covalent chemistry. DFT calculations revealed the mechanistic pathways for new cyclizations, suggesting a concerted [3 + 2] cycloaddition for the formation of selenadiazolium rings and a stepwise mechanism involving a ketenimine intermediate for the formation of selenazolium rings. Natural bond orbital analysis confirmed the involvement of σ-hole interactions and lone pair to σ* electron donation in these processes. Additionally, theoretical investigations of σ-hole interactions were performed, focusing on the selenium-centered contacts within the new compounds. Full article

(This article belongs to the Special Issue Noncovalent Interactions and Applications in Materials and Catalysis)

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8 pages, 1063 KiB

Open AccessArticle

Copper(I)-Catalyzed Formal [4 + 2] Cyclocondensation of ortho-Hydroxybenzyl Alcohol, Aromatic Terminal Alkynes, and Sulfonyl Azides: An Alternative Approach to 2-Sulfonyliminocoumarins

by Dost Muhammad Khan, Jiaying Lv and Ruimao Hua

Molecules 2024, 29(14), 3426; https://doi.org/10.3390/molecules29143426 - 22 Jul 2024

Cited by 1 | Viewed by 1228

Abstract

In this paper, an alternative and efficient copper(I)-catalyzed synthesis of 2-sulfonyliminocoumarins is developed through a three-component reaction of ortho-hydroxybenzyl alcohol, alkynes, and p-toluenesulfonyl azide. The proposed route for access to the 2-iminocoumarin ring involves a [4 + 2] hetero-Diels-Alder reaction between [...] Read more.

In this paper, an alternative and efficient copper(I)-catalyzed synthesis of 2-sulfonyliminocoumarins is developed through a three-component reaction of ortho-hydroxybenzyl alcohol, alkynes, and p-toluenesulfonyl azide. The proposed route for access to the 2-iminocoumarin ring involves a [4 + 2] hetero-Diels-Alder reaction between ortho-quinone methide and ketenimine intermediates generated in situ. Full article

(This article belongs to the Special Issue Synthetic Studies Aimed at Heterocyclic Organic Compounds)

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13 pages, 1585 KiB

Open AccessArticle

An Oxidant-Free and Mild Strategy for Quinazolin-4(3H)-One Synthesis via CuAAC/Ring Cleavage Reaction

by Yueling He, Zhongtao Yang, Danyang Luo, Xiai Luo, Xiaodong Chen and Weiguang Yang

Molecules 2023, 28(15), 5734; https://doi.org/10.3390/molecules28155734 - 28 Jul 2023

Viewed by 1774

Abstract

An oxidant-free and highly efficient synthesis of phenolic quinazolin-4(3H)-ones was achieved by simply stirring a mixture of 2-aminobenzamides, sulfonyl azides, and terminal alkynes. The intermediate N-sulfonylketenimine underwent two nucleophilic additions and the sulfonyl group eliminated through the power of aromatization. [...] Read more.

An oxidant-free and highly efficient synthesis of phenolic quinazolin-4(3H)-ones was achieved by simply stirring a mixture of 2-aminobenzamides, sulfonyl azides, and terminal alkynes. The intermediate N-sulfonylketenimine underwent two nucleophilic additions and the sulfonyl group eliminated through the power of aromatization. The natural product 2-(4-hydroxybenzyl)quinazolin-4(3H)-one can be synthesized on a large scale under mild conditions with this method. Full article

(This article belongs to the Collection Advances in Click Chemistry)

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13 pages, 9300 KiB

Open AccessCommunication

N-(p-Toluenesulfonyl)-1-(4′-acetylphenoxy)acrylimidate: Synthesis, Crystal Structure and Theoretical Studies

by Flor María Escandón-Mancilla, Alberto Cedillo-Cruz, Raúl Eduardo Gordillo-Cruz, Diego Martínez-Otero, M. V. Basavanag Unnamatla and Erick Cuevas-Yañez

Molbank 2022, 2022(4), M1509; https://doi.org/10.3390/M1509 - 28 Nov 2022

Viewed by 1896

Abstract

The formation of N-sulfonyl-1-aryloxy acrylimidate is described, for the first time, from a consecutive process, which involves a CuAAC reaction, a ketenimine formation and subsequent rearrangement between an aryl propargyl ether and a sulfonyl azide. The structure of this newly synthesized compound was [...] Read more.

The formation of N-sulfonyl-1-aryloxy acrylimidate is described, for the first time, from a consecutive process, which involves a CuAAC reaction, a ketenimine formation and subsequent rearrangement between an aryl propargyl ether and a sulfonyl azide. The structure of this newly synthesized compound was analyzed by NMR spectra and unambiguously established by X-ray analysis. In addition, theoretical calculations, which included a Hirshfeld surface, FMO, QTAIM and NCI indices analysis, corroborated the formation of π-π stacking interactions among aromatic rings, as well as C-H···O interactions between vinyl hydrogens with ketone carbonyl oxygen. Full article

(This article belongs to the Section Organic Synthesis and Biosynthesis)

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11 pages, 5404 KiB

Open AccessArticle

Diastereoselective Synthesis of Highly Functionalized Proline Derivatives

by Anna N. Philippova, Daria V. Vorobyeva, Pavel S. Gribanov, Fedor M. Dolgushin and Sergey N. Osipov

Molecules 2022, 27(20), 6898; https://doi.org/10.3390/molecules27206898 - 14 Oct 2022

Cited by 2 | Viewed by 2562

Abstract

An efficient way to access highly functionalized proline derivatives was developed based on a Cu(I)-catalyzed reaction between CF₃-substituted allenynes and tosylazide, which involved a cascade of [3 + 2]-cycloaddition/ketenimine and a rearrangement/Alder-ene cyclization to afford the new proline framework with a [...] Read more.

An efficient way to access highly functionalized proline derivatives was developed based on a Cu(I)-catalyzed reaction between CF₃-substituted allenynes and tosylazide, which involved a cascade of [3 + 2]-cycloaddition/ketenimine and a rearrangement/Alder-ene cyclization to afford the new proline framework with a high diastereoselectivity. Full article

(This article belongs to the Special Issue Recent Advances in the Use of Azoles in Medicinal Chemistry)

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15 pages, 6645 KiB

Open AccessArticle

Phototransformations of 2,3-Diamino-2-Butenedinitrile (DAMN) Monomers Isolated in Low-Temperature Argon Matrix

by Igor Reva, Hanna Rostkowska and Leszek Lapinski

Photochem 2022, 2(2), 448-462; https://doi.org/10.3390/photochem2020031 - 16 Jun 2022

Cited by 2 | Viewed by 2315

Abstract

UV-induced transformations were studied for monomers of 2,3-diamino-2-butenedinitrile (DAMN) isolated in argon matrices. Photoinduced hydrogen-atom transfer was found to be the major process occurring upon UV (λ > 320 nm or λ > 295 nm) excitation of matrix-isolated DAMN monomers. As a result [...] Read more.

UV-induced transformations were studied for monomers of 2,3-diamino-2-butenedinitrile (DAMN) isolated in argon matrices. Photoinduced hydrogen-atom transfer was found to be the major process occurring upon UV (λ > 320 nm or λ > 295 nm) excitation of matrix-isolated DAMN monomers. As a result of the transfer of a hydrogen atom from an amino group to a nitrile fragment, a tautomer of DAMN involving a ketenimine group was generated. Identification of this photo-produced species was based on comparison of its experimental IR spectrum with the spectrum theoretically predicted for the ketenimine form. Another product photogenerated upon UV (λ > 320 nm, λ > 295 nm, or λ > 270 nm) irradiation of DAMN isolated in Ar matrices was identified as 4-amino-1H-imidazole-5-carbonitrile (AICN). The structure of this photoproduct was unambiguously assigned on the basis of an exact match of wavenumbers of the bands in the IR spectrum of this photogenerated species and the wavenumbers of IR bands of AICN trapped (in a separate experiment) from the gas phase into an Ar matrix. Full article

(This article belongs to the Special Issue Themed Issue in Honor of Prof. Maciej J. Nowak, for His Contributions to the Field of Photochemistry of Matrix-Isolated Species)

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11 pages, 1941 KiB

Open AccessArticle

Copper Catalyzed Inverse Electron Demand [4+2] Cycloaddition for the Synthesis of Oxazines

by Weiguang Yang, Zitong Zhou, Yu Zhao, Danyang Luo, Xiai Luo, Hui Luo, Liao Cui and Li Li

Catalysts 2022, 12(5), 526; https://doi.org/10.3390/catal12050526 - 7 May 2022

Cited by 3 | Viewed by 2720

Abstract

A copper catalyzed tandem CuAAC/ring cleavage/[4+2] annulation reaction of terminal ynones, sulfonyl azides, and imines has been developed to synthesize the functionalized oxazines under mild conditions. Particularly, the intermediate N-sulfonyl acylketenimines undergo cycloaddition of an inverse electron demand Diels–Alder reaction with imines [...] Read more.

A copper catalyzed tandem CuAAC/ring cleavage/[4+2] annulation reaction of terminal ynones, sulfonyl azides, and imines has been developed to synthesize the functionalized oxazines under mild conditions. Particularly, the intermediate N-sulfonyl acylketenimines undergo cycloaddition of an inverse electron demand Diels–Alder reaction with imines and a series of 1,3-oxazine derivatives were obtained successfully in good yields. Full article

(This article belongs to the Special Issue Catalysis in Green Chemistry and Organic Synthesis)

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21 pages, 7661 KiB

Open AccessReview

Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ⁵-oxaphosphetanes

by Anastasy O. Kolodiazhna and Oleg I. Kolodiazhnyi

Molecules 2016, 21(10), 1371; https://doi.org/10.3390/molecules21101371 - 17 Oct 2016

Cited by 6 | Viewed by 7344

Abstract

Results of research into four-membered 2-halo-1,2λ⁵-oxaphosphetane phosphorus(V)-heterocycles are presented. The preparation of 2-halo-1,2λ⁵-oxaphosphetanes by reaction of P-haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature [...] Read more.

Results of research into four-membered 2-halo-1,2λ⁵-oxaphosphetane phosphorus(V)-heterocycles are presented. The preparation of 2-halo-1,2λ⁵-oxaphosphetanes by reaction of P-haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature NMR investigations. 2-Halo-1,2λ⁵-oxaphosphetanes were isolated as individual compounds and their structures were confirmed by ¹Н-, ¹³C-, ¹⁹F- and ³¹Р-NMR spectra. These compounds are convenient reagents for preparing of various organic and organophosphorus compounds hardly available by other methods. Chemical and physical properties of the 2-halo-1,2λ⁵-oxaphosphetanes are reviewed. The 2-chloro-1,2λ⁵-oxaphosphetanes, rearrange with formation of 2-chloroalkyl-phosphonates or convert into trans-phosphorylated alkenes depending on the substituents at the α-carbon atom. Prospective synthetic applications of 2-halo-1,2λ⁵-oxaphosphetanes are analyzed. The 2-halo-1,2λ⁵-oxaphosphetanes may be easily converted to various alkenylphosphonates: allyl- or vinylphosphonates, phosphorus ketenes, thioketenes, ketenimines. Full article

(This article belongs to the Special Issue Recent Advances in Organophosphorus Chemistry)

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