Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• designed with a PhCF2 group (Figure 1a) [8][9][10]. As a result, there is a pressing need for the development of efficient methods for incorporating both the CF2H and PhCF2 groups into diverse molecular frameworks, particularly those with bioactivity properties. The benzimidazole core is widely recognized

• as a vital pharmacophore in medicinal chemistry due to its special biological activity [11][12][13]. In particular, the tricyclic benzimidazole skeleton is ubiquitous in many bioactive compounds and therapeutic agents (Figure 1b) [14][15][16]. Recent studies have shown that fluorinated benzimidazole

• reaction of unactivated alkenes within benzimidazole molecules using CF2HSO2Na [18]. Subsequently, in 2024, Jin [19] and Yang [20] developed visible light-induced difluoromethylation strategies for unactivated alkenes within benzimidazoles using different CF2H sources (CF2HSO2Na and ([Ph3PCF2H]+Br

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• thiourea organocatalyst was prepared. Hou et al. investigated a way to prepare axially chiral compounds that contain both benzimidazole and quinoline rings 189 (Scheme 55) [83]. One route to access such compounds was possible through the reaction of 2-alkynylbenzimidazoles 187 with o-aminophenylketones 188

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• bioactivity study was proposed based on observations that indole-coumarin-thiadiazole hybrid compounds described by Kamath et al. [44], as well as indole-benzimidazole hybrids reported by Singla et al. [45] have shown potential as therapeutic agents for breast cancer treatment. Thereby, we hypothesized that

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• possibility of alkylation of the nitrogen atom in the heterocycle cannot be excluded. This alternative pathway is similar to the previously described interaction of the aforementioned catechol with 3,5-dimethylpyrazole or benzimidazole [55]. A study of the structure, electrochemical properties, anti

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• results, thiazole 2b, benzothiazole 2i and benzimidazole 2t react very well with sodium nitrite in an acidic environment (Scheme 6, red section). Among the various subclasses of compounds, pyrazole 2l exhibited a high reactivity using t-BuONO and EtONa in ethanol (Scheme 6, red section). On the other hand

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• reaction system, yielding product 3ak in good yield. Furthermore, heteroaromatic rings, such as pyridine (2l), thiophene (2m), benzoxazole (2n), and benzimidazole (2o) all afforded the desired products (3al–ao) in satisfactory yields. Subsequently, we investigated the substrate scope of amines, which is

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• lower 25% and 26% yields. Lastly, we synthesized 3f using the standard procedure for iodoliums with more sophisticated benzimidazole-containing diaryliodonium salt, but we only observed a reproducible yield of 8%. The analysis of its solid-state structure showed the desired connectivity [36]. Conclusion

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• just three decades (Figure 1) [2]. In particular, cyclic diaminocarbenes based on the imidazoline, benzimidazole, or imidazole ring system (A–C) have led to a myriad of applications in organometallic chemistry, homogeneous catalysis, and materials science, to name just a few [3][4][5]. Due to their

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• pyrazole derivatives (including indazole), benzimidazole, 1,2,3-triazole, indole, carbazole, indoline, quinazoline, and isoquinoline. Nevertheless, many heterocyclic motifs still remain beyond the attention of researchers. For example, glutarimides that incorporate tetrazole and 1,2,4-triazole substituents

• scale, and enhancing the scale of the reaction did not affect the product yield (93% vs 94%). Benzimidazole displayed relatively low reactivity, resulting in moderate yield of the desired product 6j. The introduction of a chlorine atom at the 2-position of the substrate (2-chlorobenzimidazole) actively

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• counterparts, while there has also been limited effort on examining the effects of substituents on the benzimidazole 6-membered ring in either class of reductant [16][24]. Furthermore, there has been little work on Y = 2-thienyl 1H derivatives. Here, we report two new dimers (1g2 and 1h2) and three new hydride

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• Toulouse, France University of Tunis El Manar, Laboratory of Organic Chemistry, Faculty of Sciences, Campus, 2092 Tunis, Tunisia 10.3762/bjoc.19.93 Abstract A highly α-regioselective N-nucleophilic allylic substitution of cyclic MBH alcohols and acetates with imidazole or benzimidazole, in toluene at

• reaction of the primary five-membered alcohol 4b [29] with imidazole (2a) as well as to that of alcohols 4a,b with benzimidazole (2b), leading to the SN2-type products 6b and 7b,c, respectively, in 55–80% yields (Table 1, entries 7–9). In addition, we have shown that the direct amination of the available

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• sulfides, or a separate deprotonation event can also result in similar behavior. Gimeno et al. highlighted this when they designed novel benzimidazole (BIH) donors for the photoreduction with [Cu(dipp)2]2+ photocatalysts [29][30]. They contrasted their work to a previous study by Cunningham and McMillin

• in artificial photosynthesis [3][29][48]. Glusac and co-workers published studies on the photochemical recycling of BIH analogues [49]. They used an organic photocatalyst to reduce the oxidized benzimidazole 1,3-dimethyl-2-(2,4,6-trimethoxyphenyl)-2H-benzimidazole (BIM) twice in the presence of

• system using a benzimidazole sacrificial donor. As we have discussed, examples of recycling benzimidazoles already exist which makes them excellent candidates for donor recycling. In contrast to those developed for water splitting, one of the first visible light-driven Z-scheme for carbon dioxide

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• + ions [34]. Because of the synergistic combination of Q[8], SQ2 and Hg2+ ions, it shows fluorescence quenching. Cong's group found that Q[7] can encapsulate the benzimidazole part of N-(2-benzimidazolylmethyl)-N,N-bis(2-pyridylmethyl)amine cation (BIBPA+) to construct a host–guest fluorescent probe. The

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

• -chloroperoxybenzoic acid (mCPBA) as the oxidant of choice in the presence of triflic acid (TfOH) [27][29]. Based on these promising results, the conditions were optimized using o-benzimidazole-substituted iodoarenes 4aa and 4ah (Table 1). While running the reaction in MeCN as solvent resulted in no product formation

• electron-rich salt 5al was obtained in 75% yield using modified reaction conditions B. The harsher conditions were probably required due to a sterically hindered rotation of the benzimidazole moiety in the plane of the iodophenyl, which could also be observed in two rotamers of the starting iodoarene 4al

• (see Supporting Information File 1). Next, we investigated substrates 4 having various substituents in the benzimidazole motif. Starting from 2-bromo-derivative 4am, the moisture-sensitive, brominated salt 5am was obtained in an excellent yield of 85%. Also, the C2-alkyl- and phenyl-substituted

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

• Arisu Koyanagi,
• Yuki Murata,
• Shiori Hayakawa,
• Mio Matsumura and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

• benzamidine hydrochloride G. The reaction of D with amines may require an excessive amount of D due to competition between aminophenol and the byproduct aniline. A similar mechanism is considered for the construction of benzimidazole and thiazole rings. On the other hand, the released bismuth moiety, Ph3Bi=S

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• heterocyclic scaffolds holding a broad range of biological activities [41][42][43]. For example, telmisartan, a 1,2-disubstituted benzimidazole derivative, is extensively used as an antihypertensive agent [44]. The substrate scope for the synthesis of variously substituted benzimidazoles is shown in Figure 2

• . Benzimidazoles with a variety of aryl substituents (such as bromo, nitro, chloro, and 2,4,6-trimethyl) in the 2-position of the benzimidazole (2a–d,g) were obtained in good yields. Furthermore, the synthesis of the corresponding benzimidazoles with fused aromatic systems in the 2-position such as anthracenyl (2e

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• device structure [17]. The OLED device structure applied the following configuration: –ITO/NPB [N,N’-di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine] (40 nm)/10% of 1 in CBP (20 nm)/TPBi [2,2’,2’’-(1,3,5- benzinetriyl)-tris(1-phenyl-1H-benzimidazole)] (20 nm)/BCP (bathocuproine)] (20 nm)/LiF (1

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• capacity of the nitrogen with the lone electron pair in 3b, and probably in 3a, to react with NFSI at the sulfonyl group to facilitate the formation of phenylsulfonyl fluoride (Scheme 3c). Other imidazole derivatives such as 2-methylimidazole (3c) and benzimidazole (3d) also underwent sulfonylation

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• )benzimidazole or its N-alkylated derivatives as the ancillary ligands (N^N) [43]. The prepared Ru(II) derivatives were found efficient in the synthesis of α-amino nitriles from amines via a one-pot strategy. This synthetic pathway comprises two consecutive reactions including photooxidation of the amine and the

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• activation [37][38][39][40][41]. Hou’s group presented various studies on this theme [42][43], such as a notable work recently published in which they promoted a scandium-catalyzed intramolecular cyclization on benzimidazole substrates, via a C–H activation at the C-2 position (Scheme 2B). In this process, a

• scandium(III)/Cp* catalyst containing two units of an o-N,N-(dimethylamino)benzyl ligand [Sc-1] was applied, and several examples of cyclic benzimidazole compounds were obtained in excellent yields (Scheme 2C) [37]. Benzimidazole compounds bearing substituents in their C-2 position are present in several

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• -closing metathesis (RCM), Clauson–Kaas and Ullmann-type coupling reactions as key steps. Moreover, we have also assembled some other interesting heterocyclic systems possessing oxazole, imidazole, benzimidazole, and benzoxazole in the framework of truxene. Additionally, the preliminary photophysical

• the bromination using Br2/CH2Cl2 and then subsequent alkylation followed by Ullmann-type copper-mediated cross-coupling reaction in overall good yield (Scheme 4). On the other hand, imidazole and benzimidazole containing C3-symmetric truxene-based molecules (14 and 16) have also been assembled from

• the hexaalkylated tribromotruxene 5 by means of Ullmann-type reaction in the presence of copper powder using pristine imidazole (13) and benzimidazole (15), respectively (Scheme 5). Moreover, we have successfully constructed the C3-symmetric oxazole containing truxene derivative 20 along with

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• later to form differently substituted 2-guanidinobenzimidazoles and 2-guanidinobenzothiazoles, respectively, with good to excellent yields (Scheme 11A) [30][31]. The efficiency of the reaction process usually follows the order: benzothiazole > benzimidazole > benzoxazole. The lower yields obtained with

• benzothiazole and benzimidazole-based sulfonylguanidine compounds were derived by the sulfonylation of the corresponding 2-guanidinobenzazoles and assayed as potential antimelanoma agents (Scheme 11C) [33]. Of note, a dearomatization of the benzothiazole ring was observed while grafting a sulfoguanidinyl group

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

• -ones 24 using substituted phenylenediamine 23, aldehydes 5 and cyclic 1,3-diketone such as tetronic acid 6c under microwave irradiation in aqueous conditions delivering the product in good yields (70–89%). The use of a non-polar solvent resulted in the formation of side products like benzimidazole

• first systemic synthesis of biologically interesting bisheterocycles. A three-component microwave-assisted reaction of substituted benzimidazole-linked aminopyridine 135, aldehydes 5 and isocyanide 21 using Sc(OTf)3 as the catalyst under solvent-free conditions resulted in substituted benzimidazole

• of the microwave technology was effectively explored by the authors in the synthesis of benzimidazole-linked aminopyridine, wherein every step for the construction of 135 was aided in the presence of microwave. The possible mechanistic investigation indicates the formation of imine A by condensation

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• , affording biaryl species 161. Using this strategy, several trifluoromethyl ketones 162 and alcohols 163 bearing heteroaryl substituents (i.e., benzothiazole, quinoline, isoquinoline, benzimidazole, or imidazole) prone to be protonated were elegantly converted into the corresponding alcohols 163 and biphenyl

Synthesis of purines and adenines containing the hexafluoroisopropyl group

• Viacheslav Petrov,
• Rebecca J. Dooley,
• Alexander A. Marchione,
• Elizabeth L. Diaz,
• Brittany S. Clem and
• William Marshall

Beilstein J. Org. Chem. 2020, 16, 2739–2748, doi:10.3762/bjoc.16.224

• ]. Benzimidazoles are an important class of organic materials, and many derivatives of these group are biologically active [6][7][8][9]. The benzimidazole moiety “ […] is isosteric with indole and purine nuclei, which are present in a number of fundamental cellular components and bioactive compounds. Indeed, a

• number of important drugs used in different therapeutic areas contain the benzimidazole ring […], such as proton pump inhibitors (omeprazole), antihypertensives (candesartan, telmisartan), antihistaminics (astemizole), antihelmintics (albendazole, mebendazole), as well as several other kinds of still

• for the introduction of a hexafluoroisopropyl group based on the reaction of tetrakis(trifluoromethyl)-1,3-dithietane (1) with the corresponding azoles [17]. Since this methodology is simple and works for a wide variety of imidazoles, including benzimidazole, we decided to explore the applicability of