Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• heterocyclic compounds with CO2 resulting in higher yields than those obtained with the imidazolylidene carbene ligand, IPr (Scheme 70). 2.7 C(sp2)–H Alkenylation and allylation In 2016, Chang and co-worker [93] achieved an NHCs–Cu-catalyzed efficient C(sp2)–H allylation of polyfluoroarenes 183 and

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• rearrangement; 1,3-thiazines; thiazolidine-4-ones; Introduction Nitrogen- and sulfur-containing heterocyclic compounds are widely represented in nature and used for the synthesis of biologically active substances. Among the 1,3-thiazine derivatives, promising compounds as antimicrobial and antiviral drugs

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• ]pyridines represent an important class of heterocyclic compounds, which skeleton is the key frame of many bioactive and natural compounds. For example, tetrahydrofuro[3,2-c]pyridine A demonstrates excellent in vitro JAK2 inhibitory activity superior to tofacitinib (Figure 1) [1]. Furan B is a potent κ

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

• Xiu-Yu Chen,
• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• reactions [16][17][18][19][20][21][22][23][24][25]. Recently, much attention has been devoted to the development of new domino reactions containing reactive Huisgen 1,4-dipoles as key components for the assembly of many biologically important nitrogen-containing six-membered heterocyclic compounds [26][27

• behaved as an activated electron-rich dienophile. Inspired by these elegant synthetic methodologies and in continuation of our aim to develop well-known Huisgen 1,4-dipoles for the construction of diverse nitrogen-containing heterocyclic compounds [45][46][47][48][49][50][51][52][53][54][55][56][57][58

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• -dimethoxytetrahydrofuran; green synthesis; microwave-assisted reaction; N-substituted pyrrole; Introduction Heterocyclic compounds are the most explored molecules in organic chemistry in terms of their synthesis and various applications. Among the diverse heterocyclic compounds, N-containing heterocycles are found in

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• phosphorus-containing heterocyclic compounds [1][2] and significant agrochemicals [3], medicinal agents [4], and organic materials [5]. They are also organic synthetic intermediates and building blocks [6][7]. To date, only limited four-membered β-phostams [8][9], β-phostones and β-phostines [10] have been

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• cleavage of the Boc-group was possible in quantitative yield. Conclusion In this work, we prepared azoiodaziniums as a new class of six-membered heterocyclic iodonium salts with a wide range of substituents. Derivatizations of the reactive iodonium center allow for the formation of new heterocyclic

• compounds based on azol-based iodazinium as reactive intermediates. Most interestingly, functionalization of the heteroarene salts was achieved without an undesired attack of the delicate C–I bond at the hypervalent iodine center. Experimental General procedure for the synthesis of azoiodazinium salts

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• and pharmaceutical molecules such as N-cyclohexylethyl-ETAsV [44], carbimazole, methimazole, propylthiouracil [45], and closthioamide [46] (Figure 1). Moreover, they also find widespread applications as intermediates for the construction of five- and six-membered heterocyclic compounds [47] and active

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• Koustav Singha Imran Habib Mossaraf Hossain Synthetic Organic Research Laboratory, UGC-HRDC (Chemistry), University of North Bengal, Siliguri, Darjeeling, 734013, India 10.3762/bjoc.18.168 Abstract Nowadays heterocyclic compounds are widely used in medicinal chemistry and industry to develop life

• reaction; Introduction Imidazole is one of the best-known heterocyclic compounds. Derivatives of imidazole are powerful molecules taking part in numerous biochemical processes and exhibiting distinctive biological activities [1][2]. The imidazole motif can be seen in several natural compounds like

Cyclometalated iridium complexes-catalyzed acceptorless dehydrogenative coupling reaction: construction of quinoline derivatives and evaluation of their antimicrobial activities

• Hongling Shui,
• Yuhong Zhong,
• Renshi Luo,
• Zhanyi Zhang,
• Jiuzhong Huang,
• Ping Yang and
• Nianhua Luo

Beilstein J. Org. Chem. 2022, 18, 1507–1517, doi:10.3762/bjoc.18.159

• against Gram-positive bacteria and compound 3ck against C. albicans were better than the reference drug norfloxacin. Keywords: acceptorless dehydrogenative coupling reaction; antibacterial; cyclometalated iridium complexes; quinolines; Introduction As an important class of heterocyclic compounds

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• hydrogenation; Introduction Heterocyclic compounds with a benzothiazine moiety are attractive building blocks in medicinal chemistry. Benzo-1,4-thiazine derivatives possess a wide range of biological and pharmacological properties, such as anticancer and antitumor, antioxidant, antimicrobial, antibacterial

• literature. Syntheses and utilization of the corresponding 4H-benzo[b][1,4]thiazine-3-carboxylic acids 7 are very rare. Part of our research program is the construction of chiral heterocyclic compounds of medicinal interest [33][34]. Recently, we have been involved in the synthesis of potential SARS-CoV-2

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• ][26]. Donor–acceptor cyclopropanes constitute an easily available equivalent of all-carbon 1,3-zwitter-ions used in targeted synthesis of various alicyclic as well as carbo- or heterocyclic compounds [27][28][29][30]. The reactive synergy of the three-membered ring and the C–C bond polarization due to

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• also important substructures in a variety of non-natural compounds and their pharmacological effects against bacteria [13][14][15][16], inflammation [17][18], viruses [19], radical [20], and cancer [21][22][23][24][25][26] have been proven. It is undoubtedly true that heterocyclic compounds containing

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• ; tetrazole; triazole; Introduction Quinoxalines are amongst the most versatile N-heterocyclic compounds, combining a straightforward synthesis with a diverse set of possible functionalizations and a wide range of applications in drug development and materials sciences [1]. Different quinoxaline derivatives

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 991–998, doi:10.3762/bjoc.18.99

• directly using a mixture of phenacyl bromide and malononitrile in the reaction system [17][18][19][20][21][22]. As a consequence, the unique features of phenacylmalononitriles make them good candidates for the efficient construction of diverse carbocyclic and heterocyclic compounds [23][24][25][26][27][28

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• often employed. Médebielle et al. successfully carried out the cathodic reduction of ArCF2X and RCOCF2X with nitrobenzene as a mediator to generate the corresponding difluoromethyl radicals selectively, and they applied this electrocatalytic system to the synthesis of various heterocyclic compounds

Synthesis and HDAC inhibitory activity of pyrimidine-based hydroxamic acids

• Virginija Jakubkiene,
• Gabrielius Ernis Valiulis,
• Markus Schweipert,
• Asta Zubriene,
• Daumantas Matulis,
• Franz-Josef Meyer-Almes and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 837–844, doi:10.3762/bjoc.18.84

• interact with all HDAC isoforms of groups I, II, and IV. Thus, efforts are currently underway to synthesize inhibitors selective for certain HDAC isoforms [2]. On the other hand, pyrimidines represent an important group of heterocyclic compounds exhibiting a broad spectrum of biological activity [16][17

An isoxazole strategy for the synthesis of 4-oxo-1,4-dihydropyridine-3-carboxylates

• Timur O. Zanakhov,
• Ekaterina E. Galenko,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2022, 18, 738–745, doi:10.3762/bjoc.18.74

• derivatives of 4-oxo-1,4-dihydropyridine-3-carboxylic acid 2 via Mo(CO)6-mediated rearrangement of methyl 2-(isoxazol-5-yl)-3-oxopropanoates 1 (Scheme 1). Results and Discussion Based on our experience of using isoxazoles in the synthesis of heterocyclic compounds [14][15][16][17][18], we hypothesized that

Cholyl 1,3,4-oxadiazole hybrid compounds: design, synthesis and antimicrobial assessment

• Anas J. Rasras,
• Mohamed El-Naggar,
• Nesreen A. Safwat and
• Raed A. Al-Qawasmeh

Beilstein J. Org. Chem. 2022, 18, 631–638, doi:10.3762/bjoc.18.63

• the development of multidrug resistant bacteria due to excessive use of antibiotics [2][4]. Heterocyclic compounds are the key components for drug design and synthesis. Among them, 1,3,4-oxadiazole derivatives are attractive and have been investigated for decades. This is due to their promising

• MCF7) [13]. In 2008, Muhi-eldeen et al, synthesized a hybrid compound with 1,3,4-oxadiazole moiety and pyrrolidine connected with propargylic moiety showed antibacterial activity against Staphylococcus aureus and E. coli [14]. On the other hand, the coupling of piperazine with heterocyclic compounds

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• heterocyclic compounds, such as ring-fused pyridines (pyrido[1,2-a]pyrrolo[3,4-d]pyrimidines) and secondary aminopyridines (N-methyl-4-((pyridin-2-yl)amino)-substituted maleimides), by changing the substituents at position 5 of the 2-aminopyridine. Interestingly, among these pyridine derivatives, secondary

• -yl)amino)-substituted maleimides. Results and Discussion Maleimides are versatile reagents for the synthesis of heterocyclic compounds. Previously, we have reported functional maleimides derived from ketene dithioacetals and have prepared fluorescent compounds using this reagent [23][24]. In this

Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

• Yuki Naito,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

• with the terminal dihaloalkane to produce the corresponding heterocyclic compounds. The THF solvent is oxidized at the anode to generate protons. After electrolysis, 1 mL of the reaction solution was collected from the outlet of the reactor, diluted 5 times with THF, and analyzed using HPLC. Procedure

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

• Long Zhao,
• Mao-Lin Yang,
• Min Liu and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

• from aldehydes, a carboxylic acid, and a isonitrile as the three components [23]. The sequences of Passerini reactions, followed by post-condensation reactions, constitute useful synthetic methods in the preparation of structurally diverse heterocyclic compounds [24][25][26][27][28][29]. The aza-Wittig

Synthesis of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines and investigation of their fungistatic activity

• Anna V. Korotina,
• Svetlana G. Tolshchina,
• Rashida I. Ishmetova,
• Natalya P. Evstigneeva,
• Natalya A. Gerasimova,
• Natalya V. Zilberberg,
• Nikolay V. Kungurov,
• Gennady L. Rusinov,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2022, 18, 243–250, doi:10.3762/bjoc.18.29

• Anna V. Korotina Svetlana G. Tolshchina Rashida I. Ishmetova Natalya P. Evstigneeva Natalya A. Gerasimova Natalya V. Zilberberg Nikolay V. Kungurov Gennady L. Rusinov Oleg N. Chupakhin Valery N. Charushin Laboratory of Heterocyclic Compounds, Postovsky Institute of Organic Synthesis, Russian

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• significant development in continuous flow platforms, particularly in industry [16][17][18][19][20]. 1,3,4-Oxadiazoles are biologically relevant 5-membered heterocyclic compounds with various favourable pharmacokinetic properties and have been investigated as potential candidates for antiviral, antifungal and