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13 pages, 1414 KiB

Open AccessFeature PaperArticle

Efficient Synthesis of 2-Aminoquinazoline Derivatives via Acid-Mediated [4+2] Annulation of N-Benzyl Cyanamides

by Zhao-Yi Qin, Chen-Xi Sun, Wen-Wen Zhang, Jun-Ru Li, Yin-Xiang Gong, Wen-Ming Shu and An-Xin Wu

Catalysts 2023, 13(11), 1447; https://doi.org/10.3390/catal13111447 - 17 Nov 2023

Viewed by 761

Abstract

The synthesis of 2-aminoquinazoline derivatives is achieved by using hydrochloric acid as a mediator in the [4+2] annulation reaction between N-benzyl cyanamides and 2-amino aryl ketones. In addition, 2-amino-4-iminoquinazolines are synthesized by the reaction of 2-aminobenzonitriles, instead of 2-amino aryl ketones, with [...] Read more.

The synthesis of 2-aminoquinazoline derivatives is achieved by using hydrochloric acid as a mediator in the [4+2] annulation reaction between N-benzyl cyanamides and 2-amino aryl ketones. In addition, 2-amino-4-iminoquinazolines are synthesized by the reaction of 2-aminobenzonitriles, instead of 2-amino aryl ketones, with N-benzyl cyanamides. A wide range of substrates can be used and high yields are obtained, demonstrating the practicality of this method for the synthesis of 2-aminoquinazoline derivatives. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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16 pages, 5354 KiB

Open AccessFeature PaperArticle

Recyclable Ni-Containing Coordination Polymer as an Efficient Catalyst for the Synthesis of Oxindole and Quinoline Derivatives through the Borrowing Hydrogen Strategy

by Jiahao Li, Jiajie Tang, Likui Wang, Dawei Wang and Zheng-Chao Duan

Catalysts 2023, 13(8), 1195; https://doi.org/10.3390/catal13081195 - 09 Aug 2023

Viewed by 797

Abstract

A coordination polymer Ni-CIA has been designed, synthesized, and characterized via Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), energy-dispersive X-ray spectroscopy (EDS), and thermal gravimetric analysis (TGA). The resulting polymer reveals a slice [...] Read more.

A coordination polymer Ni-CIA has been designed, synthesized, and characterized via Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), energy-dispersive X-ray spectroscopy (EDS), and thermal gravimetric analysis (TGA). The resulting polymer reveals a slice layer stacked combination structure and good stability. Importantly, this polymer exhibited high catalytic activity for the synthesis of oxindole and quinoline derivatives via borrowing hydrogen and dehydrogenation reactions. Meanwhile, several control reactions were carried out to investigate the possible mechanisms of this transformation. Finally, the results of the recycling experiment indicate that the coordination polymer Ni-CIA could be recovered and reused at least five times. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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16 pages, 1830 KiB

Open AccessArticle

A Cascade Synthesis of Unsymmetrical Furanized Triarylmethanes via Gold Self-Relay Catalysis

by Qian Rao, Yan Zhang, Xin-Yu Gu, Yin-Ping Liu, Bo Jiang and Wen-Juan Hao

Catalysts 2023, 13(7), 1051; https://doi.org/10.3390/catal13071051 - 29 Jun 2023

Cited by 1 | Viewed by 1226

Abstract

In this paper, A new gold self-relay catalysis enabling intramolecular annulation and intermolecular Michael addition of 3-yne-1,2-diols with aurone-derived azadienes (or para-quinone methides) is reported, efficiently furnishing a range of unsymmetrical furanized triarylmethanes with substituent diversity in good yields. The overall process [...] Read more.

In this paper, A new gold self-relay catalysis enabling intramolecular annulation and intermolecular Michael addition of 3-yne-1,2-diols with aurone-derived azadienes (or para-quinone methides) is reported, efficiently furnishing a range of unsymmetrical furanized triarylmethanes with substituent diversity in good yields. The overall process was governed by the π- and σ-Lewis acid capability of gold complexes, providing a catalytic strategy for constructing triarylmethane skeletons. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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16 pages, 2323 KiB

Open AccessFeature PaperArticle

Transition Metal-Free Synthesis of 3-Acylquinolines through Formal [4+2] Annulation of Anthranils and Enaminones

by Kai-Ling Zhang, Jia-Cheng Yang, Qin Guo and Liang-Hua Zou

Catalysts 2023, 13(4), 778; https://doi.org/10.3390/catal13040778 - 20 Apr 2023

Cited by 2 | Viewed by 1502

Abstract

A transition metal-free protocol has been developed for the synthesis of 3-acyl quinolines through aza-Michael addition and intramolecular annulation of enaminones with anthranils. Both methanesulfonic acid (MSA) and NaI play an important role in the reaction. This ring-opening/reconstruction strategy features easy operation, high [...] Read more.

A transition metal-free protocol has been developed for the synthesis of 3-acyl quinolines through aza-Michael addition and intramolecular annulation of enaminones with anthranils. Both methanesulfonic acid (MSA) and NaI play an important role in the reaction. This ring-opening/reconstruction strategy features easy operation, high yields, broad substrate scope and excellent efficiency. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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13 pages, 7456 KiB

Open AccessEditor’s ChoiceArticle

One-Pot Synthesis of Benzoxazole/Benzothiazole-Substituted Esters by Michael Addition: A Selective Construction of C-N/C-S Bonds

by Zhi-Ying Gong, Cheng-Li Yang, Dan Wang, Lang Huang and Zhi-Bing Dong

Catalysts 2023, 13(4), 658; https://doi.org/10.3390/catal13040658 - 27 Mar 2023

Cited by 1 | Viewed by 1419

Abstract

An efficient and convenient synthesis of benzoxazole/benzothiazole-substituted esters in a one-pot strategy is reported. In this investigation, a selective construction of C-N and C-S bonds via simple addition is performed. Thus, using substituted 2-aminophenols/2-aminobenzenethiols, TMTD (tetramethylthiuram disulfide) and α,β-unsaturated esters [...] Read more.

An efficient and convenient synthesis of benzoxazole/benzothiazole-substituted esters in a one-pot strategy is reported. In this investigation, a selective construction of C-N and C-S bonds via simple addition is performed. Thus, using substituted 2-aminophenols/2-aminobenzenethiols, TMTD (tetramethylthiuram disulfide) and α,β-unsaturated esters as starting substrates, C-N and C-S bonds can be selectively constructed by means of the Michael addition reaction. This protocol features high selectivity, high atomic economy, mild conditions, good functional tolerance and good to excellent yields, showing the potential value for the preparation of some biologically and pharmaceutically active compounds. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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14 pages, 1700 KiB

Open AccessEditor’s ChoiceArticle

Four-Component Synthesis of 9H-Pyrimido[4,5-b]indoles Using Ammonium Iodide as the Nitrogen Source

by Yufeng Chen, Ruitong Yang, Fuhong Xiao, Tong Li, Guojiang Mao and Guo-Jun Deng

Catalysts 2023, 13(3), 623; https://doi.org/10.3390/catal13030623 - 20 Mar 2023

Cited by 2 | Viewed by 1101

Abstract

A four-component synthesis of 2-phenyl-9H-pyrimido[4,5-b]indoles was developed using indole-3-carboxaldehydes, aromatic aldehyde and ammonium iodide as the raw materials under transition-metal-free conditions. The pyrimidine ring was formed in one pot through [4 + 2] annulation reaction. Four C–N bonds were [...] Read more.

A four-component synthesis of 2-phenyl-9H-pyrimido[4,5-b]indoles was developed using indole-3-carboxaldehydes, aromatic aldehyde and ammonium iodide as the raw materials under transition-metal-free conditions. The pyrimidine ring was formed in one pot through [4 + 2] annulation reaction. Four C–N bonds were formed in one pot promoted by iodine and iodide additives. This work is highlighted by using two ammonium iodides as the sole nitrogen source. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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Review

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36 pages, 11005 KiB

Open AccessFeature PaperReview

Recent Approaches in Transition Metal-Catalyzed Chalcogenative Heteroannulation of Alkenes and Alkynes

by Elba L. Gutterres, Thiago Anjos, Felipe B. Santos, Pamela T. Bandeira, Filipe Penteado and Ricardo F. Schumacher

Catalysts 2023, 13(9), 1300; https://doi.org/10.3390/catal13091300 - 16 Sep 2023

Viewed by 881

Abstract

Organochalcogen-bearing heterocycles are important scaffolds in compounds under the spotlight of scientific interest in optoelectronic fields and for biological applications. The use of transition metals has been a versatile and reliable way to carry out the synthesis of these molecules efficiently, delivering products [...] Read more.

Organochalcogen-bearing heterocycles are important scaffolds in compounds under the spotlight of scientific interest in optoelectronic fields and for biological applications. The use of transition metals has been a versatile and reliable way to carry out the synthesis of these molecules efficiently, delivering products in high yields and with a wide functional diversity. In the last 10 years, many classes of heterocycles have been synthesized under the cyclization reaction of acyclic alkenes and alkynes with the incorporation of a chalcogen atom on its structure. Transition metal catalysts including Cu, Co, Pd, Ni, In, Ag, and Fe salts have been used in the development of new methodologies, the expansion of substrate scope, and mechanistic studies. This review provides an overview of these recent approaches with the aim of being a useful resource for interested researchers in this area. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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39 pages, 10235 KiB

Open AccessReview

Recent Advances for the Synthesis of Dihydroquinolin-2(1H)-ones via Catalytic Annulation of α,β-Unsaturated N-Arylamides

by Yan-Ning Niu, Lin-Shuang Tian, Huai-Zhong Lv and Ping-Gui Li

Catalysts 2023, 13(7), 1105; https://doi.org/10.3390/catal13071105 - 15 Jul 2023

Cited by 2 | Viewed by 1382

Abstract

Dihydroquinolin-2(1H)-ones (DHQOs) represent a class of valuable bioactive compounds with six-membered nitrogen-containing heterocyclic structures. The development of simple, mild, and efficient synthetic methods has been widely considered by synthetic chemists. In this review, we have summarized a series of different synthetic [...] Read more.

Dihydroquinolin-2(1H)-ones (DHQOs) represent a class of valuable bioactive compounds with six-membered nitrogen-containing heterocyclic structures. The development of simple, mild, and efficient synthetic methods has been widely considered by synthetic chemists. In this review, we have summarized a series of different synthetic strategies for the synthesis of DHQOs via the catalytic annulation of α,β-unsaturated N-arylamides in the past decade, including covering electrophilic cyclization, radical initiated cyclization, and photochemical cyclization reactions. Additionally, the substrate scope and mechanistic details are also discussed. This paper provides a useful reference for the development of diverse synthesis methodologies of DHQO. Full article

(This article belongs to the Special Issue Catalytic Annulation Reactions)

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