Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• , etc. [14][15][16]. In addition, these compounds are important intermediates in a variety of organic reactions and key elements in many functional materials [17][18][19]. Because of their potential utility, a huge number of synthetic protocols has been developed for the preparation of benzimidazole

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• to afford the corresponding thietanes 66. The subsequent introduction of nucleobases then gave the corresponding thietanose nucleosides 68 [45] (Scheme 15). The treatment of 2-(allylthio)benzimidazole 69 with iodine in CHCl3 followed by aq. KOH gave (iodomethyl)thiazolobenzimidazole 70 which was

Anthelmintic drug discovery: target identification, screening methods and the role of open science

• Frederick A. Partridge,
• Ruth Forman,
• Carole J. R. Bataille,
• Graham M. Wynne,
• Marina Nick,
• Angela J. Russell,
• Kathryn J. Else and
• David B. Sattelle

Beilstein J. Org. Chem. 2020, 16, 1203–1224, doi:10.3762/bjoc.16.105

• benzimidazole resistance alleles have been found with increased frequency following anthelmintic treatment [34][35]. However, as the use of these anthelmintics has increased in the past decade, thanks to the donation of millions of doses of these drugs to enable mass drug administration, the selective drug

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• injecting/transporting/blocking layers hexaazatriphenylenehexacarbonitrile (HAT-CN), N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB), diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (TSPO1), 2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1H-benzimidazole) (TPBi), and fluorolithium (LiF

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• -triphenylsilylphenylphosphine oxide (TSPO1) was used as hole blocking material, while the layer of 2,2',2"-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole) (TPBi) was employed as the electron-transporting layer. Electroluminescence (EL) spectra of devices A–C and their external quantum efficiencies (EQE) are presented in

Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K₂CO₃/n-Bu₄PBr in water

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati and
• Gregor Schnakenburg

Beilstein J. Org. Chem. 2020, 16, 778–790, doi:10.3762/bjoc.16.71

• -. 5-, 6-, and 7-azaindoles, 1g–j) provided the corresponding products in the range from 91–97% yield (3u–x). We applied the developed protocol to reactions of other heterocyclic systems such as indazole (4), benzimidazole (5), carbazole (6), benzofuran (7), and benzothiophene (8) with ketone 2a

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• authors demonstrated a wide substrate scope, including an example of benzimidazole and pyrrole, although with varying chemical yields [69]. Recently Zhang et al. [70] explored various L22-containing (NHC)Cu catalysts by means of generating interesting nonracemic aminosilanes. In this case, they performed

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• , the desired triazole products were generated through the [3 + 2] cycloaddition of the azide and alkyne. The recyclability analysis of these IPSi-supported Cu(I) and Cu(II) catalysts indicated seven consecutive runs with almost equivalent performances. In 2018, silica modified with a benzimidazole

• –salen Cu(II) complex, 11, was synthesized in several steps [26]. Initially, 5‐(chloromethyl)‐2‐hydroxybenzaldehyde (6) was prepared by the reaction of 2‐hydroxybenzaldehyde (5) and paraformaldehyde in concentrated HCl at a temperature between 5 and 10 °C. At the same time, benzimidazole-substituted

• phenol 8 was generated by the reaction of 2-hydroxybenzaldehyde (5) and o‐phenylenediamine (7) at rt using a cobalt catalyst. In the next step, a benzimidazole-containing aldehyde 9 was obtained by the reaction of 6 with benzimidazole-substituted phenol 8. This ligand was immobilized on propylamine

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• ]. FDA was first used as cross-linker to knit aromatic building blocks [15]. Researchers used this method to knit triptycenes [16], triphenylphosphine [4], benzimidazole, 1,3,5-triphenylbenzene [17], carbazole [18], naphthol-based monomers [10] etc. with FDA to obtain various HCPs, which exhibited

Thermal stability of N-heterocycle-stabilized iodanes – a systematic investigation

• Andreas Boelke,
• Yulia A. Vlasenko,
• Mekhman S. Yusubov,
• Boris J. Nachtsheim and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2019, 15, 2311–2318, doi:10.3762/bjoc.15.223

• decomposition enthalpy ΔHdec. Relative reactivity is based on the negative normalized logarithm. Tpeak and ΔHdec values for a range of N- and O-substituted iodanes. Decomposition enthalpy (ΔHdec) scale for (pseudo)cyclic mesitylen(phenyl)- λ3-iodanes 18–33. TGA/DSC curves for the benzimidazole based

Synthesis of benzo[d]imidazo[2,1-b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

• Mio Matsumura,
• Yuki Kitamura,
• Arisa Yamauchi,
• Yoshitaka Kanazawa,
• Yuki Murata,
• Tadashi Hyodo,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2019, 15, 2029–2035, doi:10.3762/bjoc.15.199

• . Keywords: benzimidazole; cesium carbonate; cyclization; selenium; selenoazole; Introduction Selenium-containing heterocyclic ring systems have attracted attention not only because of their chemical properties and reactivities, but also for their wide biological activities [1][2][3][4]. For example

• conditions for the cyclization of a chalcogen with 1-(2-bromophenyl)benzimidazole (1a). Table 1 shows the results from the screening of additives, solvents, and chalcogens. Since most of these types of reactions require a transition metal catalyst such as a copper reagent [14][15][16], the reaction between

• independent molecules, and the benzimidazole and the fused benzoselenophene rings are virtually coplanar (mean deviation 0.0169 and 0.0359 Å, respectively) to each other. The molecules show head-to-tail (antiparallel) stacking with π···π interactions, with distances between the nearest neighbor atoms on

Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF₃SO₃H. NMR and DFT studies of dicationic electrophilic species

• Dmitry S. Ryabukhin,
• Alexey N. Turdakov,
• Natalia S. Soldatova,
• Mikhail O. Kompanets,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191

• common motif present in some components of human organisms, histidine, vitamin B12, purines, histamine, biotin, and in natural compounds such as lepidiline A and B [6]. Over the years of active research, benzimidazole derivatives have been involved in medicinal chemistry covering a wide range of

•  1) [1][2][3][4][5][6][7][8][9][10]. Benzimidazole fungicides (carbendazim, benomyl, thiabendazole and fuberidazole) have been widely used to fight against destructive plant pathogens (Figure 1) [7]. Interestingly, most of the above listed drugs are 2- or 1,2-disubstituted benzimidazole derivatives

• [2]. Thus, the development of further syntheses of benzimidazole derivatives and the study of their properties are important goals for chemistry, medicine and materials science. Since George Olah proposed the concept of generating superelectrophilic intermediates through the protonation by Brønsted

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• utilized as host units to construct these stimuli-responsive supramolecular self-assemblies [21][22][23][24][25][26][27]. For example, β-CD can form inclusion complexes with guests such as azobenzene [28][29], ferrocene [30][31] and benzimidazole [32][33][34] to construct light-, redox-, and pH-responsive

• been successfully conducted. Subsequently, BM-Alk was synthesized by the alkylation reaction between benzimidazole and propargyl bromide according to the literature [46]. The appearance of the alkynyl absorption peaks at 2127 cm−1 in the FTIR spectrum (Figure S1A-a, Supporting Information File 1) and

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• electrophilicity made lanthanides a catalyst of choice. Lanthanum complexes are widely used in synthetic chemistry for cycloadditions, reductions, benzimidazole syntheses, Biginelli reactions, hydrophosphinations of unsaturated substrates, double hydrophosphinylations of unactivated nitriles, Grignard additions, C

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

• Vaida Milišiūnaitė,
• Rūta Paulavičiūtė,
• Eglė Arbačiauskienė,
• Vytas Martynaitis,
• Wolfgang Holzer and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62

• ]. Recently, we used this scaffold to obtain the 2H-pyrazolo[4,3-c]pyridine [27][28], pyrazolo[4,3-f][1,2,3]triazolo[5,1-c][1,4]oxazepine [29] and pyrazolo[4’,3’:3,4]pyrido[1,2-a]benzimidazole [30] ring systems as well as to prepare building blocks for the construction of optoelectronic materials and

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• benzyl improves the in vitro antistaphylococcal activity. In contrast, the incorporation of smaller heterocycles like pyridine and imidazole as well as isosteric benzimidazole instead of the indole moieties lead to a loss of antibacterial activity. Kennedy et al. could synthesize a 2-phenyl derivative

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• biosynthesis pathway, was reported to inhibit PqsBC [31]. In a PqsBC-based biochemical assay it showed an IC50 in the micromolar range and was proven to reduce virulence in an acute mouse infection model [67]. In 2017, Maura et al. synthesized inhibitors based on a benzimidazole scaffold (Figure 13) [68

• ]. Starting from a PqsR inhibitor, changes of the electronic properties on the benzimidazole by introducing an electron-donating group led to a higher PqsBC inhibitory activity, while decreasing the affinity to PqsR (compound 28). Nevertheless, it was shown that blockage of PqsBC leads to a reduction of HHQ

• compound 37 emerged as the most potent inhibitor of this series. Compounds 37 and 39 furthermore exhibited inhibition of HHQ, PQS and HQNO production in PAO1 strains when treated with 3 × IC50, whereas in PA14 a strong decrease in activity could be observed, especially for 39. Benzamide-benzimidazole (BB

Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles

• James T. Fletcher,
• Matthew D. Hanson,
• Joseph A. Christensen and
• Eric M. Villa

Beilstein J. Org. Chem. 2018, 14, 2098–2105, doi:10.3762/bjoc.14.184

• ][14][15][16][17], quinoline [18][19], pyridazine [20][21], phthalazine [22], benzimidazole [23], phenanthroline [24], bipyridine [25] and amine [26] subunits. The utility of such chelators in constructing coordination compounds has been demonstrated for a wide range of transition metal and lanthanide

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• into an optimized planar non-doped OLED structure with architecture as follows ITO (100 nm)/1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN) (10 nm)/NPB (50 nm)/mCP (15 nm)/16 (20 nm)/2,2′,2′′-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole) (TPBi) (60 nm)/8-hydroxyquinolatolithium (Liq

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• -phenylbut-1-yne [119] tridentate tris(benzimidazole) ligands completely failed and tris(triazole) ligands gave only poor to moderate yields (16–65%) even at 100 °C, whereas all the bidentate ligands (phenanthrolines L1, L2 and diimidazo[1,2-a:2',1'-c]quinoxalines L3–L6) were found to be more efficient both

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• Shafir, Lledós, and co-workers, who investigated the intrinsic conversion of novel N-heterocyclic aryliodonium salts 1b [35]. Under the influence of base, copper catalyst and N-Me-benzimidazole as a ligand, the heterocyclic aryliodonium salt 1b was converted into the N1-aryl-5-iodoimidazole 18 as the

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

•  10. Minor groove complex formation between DNA duplex and Hoechst 33258 is shown in Figure 7b [82]. X-ray crystallographic and NMR studies confirmed that Hoechst 33258 binds to the A·T-rich sequences in minor groove with the planar benzimidazole groups are oriented parallel to the direction of the

• and antiangiogenic properties and concluded that these conjugates drastically reduced the cell viability, body weight, ascites volume and downregulated the formation of neovasculature and production of Vascular Endothelial Growth Factor (VEGF). They further reported another novel benzimidazole

• , thereby reducing strength of electrostatic interactions between the ligands with DNA phosphate backbone [120]. Wilson et al. rationally designed benzimidazole derivatives by keeping pre-organized N-methylbenzimidazole (N-MeBI)-thiophene as central fragment (conjugates 55 and 56, Figure 10) in order to

Synthesis and stability of strongly acidic benzamide derivatives

• Frederik Diness,
• Niels J. Bjerrum and
• Mikael Begtrup

Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38

• perfluorobenzene derivatives [41][42][43]. Hence, it was proposed that the 4-fluoro and the pentafluorobenzamide derivatives 9a and 9c could be functionalized through SNAr reactions. Thus, compounds 9a and 9c were reacted with benzimidazole under previously developed conditions (Scheme 2) [41][42]. The

• benzimidazole was chosen as model nucleophile for polybenzimidazole, a polymer commonly applied as a membrane in PEM fuel cells [40]. These reactions provided the 4-benzimidazolyl derivatives 13 and 14 in good yields and the N-triflylbenzamide group proved to be stable under these reaction conditions

• vial containing benzimidazole (17.7 mg, 1.5 equiv) and 4-fluoro-N-((trifluoromethyl)sulfonyl)benzamide (9a, 27.1 mg, 0.1 mmol) in dry dimethylacetamide (1.0 mL). The reaction was heated to 120 °C for 12 h. The reaction was quenched with 1.0 M HCl (aq, 100 μL) and the solvent removed in vacuo. The crude

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• with methanol. Secondly, the method was also applicable up to 10 g of 2-aminothiophenol and avoided the use of toxic metals which are common in benzimidazole synthesis [147][148]. Subsequently, the same group reported the preparation of 1,2-disubstituted benzimidazoles via mechanochemical activation