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

• hydrogen, benzyl, or alkyl, resulted in the shut of reactivity and no formation of the corresponding N-substituted carbazoles was observed. Concerning the mechanism, the carbazole-forming reaction also required aerobic conditions in order to reoxidize the Ir-photocatalyst with molecular oxygen (Figure 12

• N-heterocyclic compounds such as phenanthridine, carbazole, and dibenzo[b,d]azepine. Simultaneously, Guo’s group published the arylation of nucleosides bearing a purine moiety. The transformation was regioselective and tolerated various substituents at the N9 position of the purine, including sugar

• good yields and the authors applied the methodology for the late-stage acylation of natural ʟ-tryptophan as well as carbazole derivatives. Cu-catalyzed transformations Sporadic examples using copper as transition metal for C–H functionalization reactions in combination with photocatalysis were also

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

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

• , bearing a quinazoline unit as the acceptor core and carbazole, dimethyldihydroacridine, or phenothiazine donor moieties, were designed and synthesized in two steps including a facile copper-catalyzed cyclization and a nucleophilic aromatic substitution reaction. The photophysical properties of the

• donor 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine. A white OLED based on these versatile exciplex systems with a relatively high maximum brightness of 3030 cd/m2 and an external quantum efficiency of 0.5% was fabricated. Keywords: carbazole; dimethyldihydroacridine; exciplex; phenothiazine

• properties [8]. A quinazoline-based emitter exhibiting thermally activated delayed fluorescence (TADF) was also reported [6] and green to yellow TADF OLEDs were fabricated with EQEs from 17.6 to 20.5%. The multicolor emission of a quinazoline–carbazole compound was employed in white OLEDs. White

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• , Turkey WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, G128QQ Glasgow, UK 10.3762/bjoc.16.93 Abstract Two novel carbazole-based compounds 7a and 7b were synthesised as potential candidates for application in organic electronics. The materials were fully characterised by NMR

• , respectively. Keywords: carbazole; electrochemistry; fluorescence; formyl group; solvatochromism; Introduction Carbazole derivatives have found many different applications in a variety of technologically important areas, such as organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), dye

• synthesised solar cells (DSSCs) and sensors [1][2]. In OLEDs, carbazole derivatives are frequently used as host materials [3][4][5]. In this respect the most frequently used host materials are 1,3-bis(N-carbazolyl)benzene (mCP) [6] and polyvinylcarbazole (PVK) [7]. Carbazole derivatives, either just by

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

• -tetraphenyl-9H-carbazole-3,6-diamine (DACT-II) were fabricated and characterized [33]. The DACT-II-based OLEDs are expected to reach an internal quantum efficiency (IQE) of 100%. The low-energy absorption bands at ≈410 nm of the film of the emitter DACT-II and the emission bands of the films of the studied

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 photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• mechanism. One year later, 2013, Collins and co-workers extended this concept to the synthesis of carbazole derivatives under continuous flow conditions (Scheme 30) [44]. Using, the [Cu(I)(dmp)(xantphos)]BF4 catalyst, the oxidative cyclization of various triarylamines was carried out in the presence of I2

• the carbazole structure, and a single isomer was formed. Then, the methodology was extended to N-alkyldiarylamines, the products were isolated in good yields, and no dealkylation was observed for N-methyldiarylamines. To explain the reaction outcome, the authors suggested a mechanism involving

• intermediate with an iodine radical, followed by aromatization, generated the desired carbazole. Later in 2015, the group of Che described the synthesis of a zwitterionic copper(I) complex having a phenanthroline ligand (bcp) and a nido-carborane-diphosphine ligand. This complex was used in a benchmark

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• oxidants [151][152][153]. To overcome these drawbacks, recently, Cho’s group synthesized carbazole derivatives using a dual photoredox-catalyzed intramolecular C−H bond amination of N-substituted 2-amidobiaryls with photoredox catalyst 14 in presence of Pd(OAc)2 as a cocatalyst under aerobic conditions

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• this in mind, we targeted donor (D)–phenylene–acceptor (A) systems that would be of potential interest to the organic semiconductor community. These compounds incorporate strong donors in the form of triphenylamine (TPA) and carbazole (Cz), as can be seen in Scheme 1. Since the corresponding

• hydroquinone dianion. LUMO energies of the four compounds are thus in the order of −4.20 eV for compounds 2 and 5 and −4.30 eV for compounds 3 and 4 (Table 1). At positive potentials, the two diphenylamine derivatives (2 and 5) showed reversible one-electron oxidation waves, while the two carbazole donor

• derivatives (3 and 4) showed irreversible oxidation waves, which is a function of the electrochemically unstable carbazole-based radical cation that can subsequently undergo dimerization [34]. The oxidation waves shifted cathodically upon increasing the donor strength from carbazole (3 and 4) to diphenylamine

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

• outstanding porous properties. Studies of the effects on porosity of HCPs are significant, but almost all investigations focused on the role of monomer length and geometry on the porosity [6][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Researchers have synthesized a series of carbazole-based

• microporous HCPs and came to the conclusion that 2D and 3D-conjugated architectures with nonplanar rigid conformation and dendritic building blocks were favorable for getting a high BET specific surface area [6][19][20][21][23][24][25]. Qiao synthesized five microporous materials using carbazole with

Palladium-catalyzed synthesis and nucleotide pyrophosphatase inhibition of benzo[4,5]furo[3,2-b]indoles

• Hoang Huy Do,
• Saif Ullah,
• Alexander Villinger,
• Joanna Lecka,
• Jean Sévigny,
• Peter Ehlers,
• Jamshed Iqbal and
• Peter Langer

Beilstein J. Org. Chem. 2019, 15, 2830–2839, doi:10.3762/bjoc.15.276

• studied double Buchwald–Hartwig reactions as the key step for the synthesis of heterocycles. For example, the cyclization of 2,2’-dibromobiaryls with amines allows for a convenient synthesis of carbazole derivatives [22][23][24][25][26][27][28][29][30]. Recently, we reported the synthesis of

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• macrocycle has been reported by Nakamura and his co-workers containing three 1,2,3-triazolium and carbazole moieties 12 (Figure 10). π–π stacking interactions and the self-association ability of the synthesized macrocycle are increased in comparison with its neutral analogue due to the decreased electron

Regioselective Pd-catalyzed direct C1- and C2-arylations of lilolidine for the access to 5,6-dihydropyrrolo[3,2,1-ij]quinoline derivatives

• Hai-Yun Huang,
• Haoran Li,
• Thierry Roisnel,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2019, 15, 2069–2075, doi:10.3762/bjoc.15.204

• an intramolecular Pd-catalyzed direct arylation was examined (Scheme 5). The reaction of compound 2 with 1,2-dibromobenzene in the presence of 2 mol % PdCl(C3H5)(dppb) catalyst and KOAc as base afforded the desired carbazole 27 in moderate yield after 16 h due to a partial conversion of 2. However

• , the use of a longer reaction time (48 h) allowed to reach an almost complete conversion of 2, and the carbazole 27 was isolated in 62% yield. A slightly lower yield in the carbazole 28 was obtained from (4-(5,6-dihydropyrrolo[3,2,1-ij]quinolin-2-yl)phenyl)(phenyl)methanone 5 and 1,2-dibromobenzene

• . This sequential C–H bond arylation strategy was also effective for the synthesis of the carbazole 29 from the pyridine α-substituted lilolidine 17. Conclusion The late stage Pd-catalyzed C–H bond functionalization allows to prepare (di)arylated lilolidine derivatives in only one or two steps. The α

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• and OUJ-2 with two (diphenylamino)carbazole thiophene units as D (electron-donating group)–π (π-conjugated bridge) moiety and a pyridine, pyrazine or triazine ring as electron-withdrawing group (electron-accepting group, A) have been designed and synthesized. The photophysical and electrochemical

• group, we have designed and synthesized the (D–π–)2A fluorescent dyes OUY-2, OUK-2 and OUJ-2 with two (diphenylamino)carbazole thiophene units as the D–π moiety and a pyridine, pyrazine or triazine ring as the A moiety (Figure 1), although we have already reported the synthesis of (D–π–)2A fluorescent

• two (diphenylamino)carbazole thiophene units as D–π moiety to a pyridine, pyrazine or triazine ring as A moiety. For OUK-2, the shoulder band was observed at around 430 nm. Thus, the ICT-based photoabsorption band of the three dyes appears at a longer wavelength region in the order of OUY-2 < OUK-2

Azologization of serotonin 5-HT₃ receptor antagonists

• Karin Rustler,
• Galyna Maleeva,
• Piotr Bregestovski and
• Burkhard König

Beilstein J. Org. Chem. 2019, 15, 780–788, doi:10.3762/bjoc.15.74

• developed [26]. Since then the development of 5-HT3R antagonists progressed. The first-generation antagonists are structurally categorized in three major classes: (I) carbazole derivatives (e.g., ondansetron), (II) indazoles (e.g., granisetron), and (III) indoles (e.g., dolasetron) [26][30]. Generally, 5

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• (TMS)3SiH), amines such as ethyl 4-(dimethylamino)benzoate (abbreviated EDB) or carbazole derivatives such as 9-vinylcarbazole (NVK) are presented. As oxidizing agent, it is possible to use a iodonium salt such as diphenyliodonium (Ph2I+). With these additives, three systems involving catalytic cycles

• organophotoredox catalysts. Here, only two examples of photoredox catalysts will be detailed: the carbazole derivatives and the TADF compounds presented as the last generation of organophotoredox catalysts. These examples are depicted in Scheme 4. 2.2.1 Carbazole derivatives: Carbazole derivatives are a good

• example of organophotoredox catalysts. A carbazole is an aromatic tricyclic organic compound with two six-membered benzene rings fused on either side of a five-membered nitrogen-containing ring. They exhibit unusual optical and electronic properties such as photoconductivity and photorefractivity [77

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• 1 h [67]. The hypercrosslinked supermicroporous polymer (HMP-1, 113) was also designed and prepared by iron(III) chloride catalyzed Friedel–Crafts alkylation of carbazole (111) with α,α′-dibromo-p-xylene (112). In the next step, HMP-1 (113) was sulfonated by Cl-SO3H to form HMP-1-SO3H material 114

• 2900 cm−1 and 3400 cm−1 were the evidence of phenylic C–H bond and N–H stretching of carbazole, respectively. Peaks at 1022 cm−1 and 1039 cm−1 corresponded to additional crosslinking during the sulfonation process. The catalyst was investigated by BET, SEM, TEM, and TGA-DTA, as well. The BET surface

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

• Mohammad A. Alnajjar,
• Jürgen Bartelmeß,
• Robert Hein,
• Pichandi Ashokkumar,
• Mohamed Nilam,
• Werner M. Nau,
• Knut Rurack and
• Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

• protonation-sensitive fluorescent dye yields a rational and modular approach towards CB–dye pairs [25]. This strategy had been previously applied to carbazole, aminonaphthalenesulfonate and aminopyrene as fluorescent dyes [25][26][27][28]. Herein, we systematically explore the utility of boron-dipyrromethenes

Anomeric modification of carbohydrates using the Mitsunobu reaction

• Julia Hain,
• Patrick Rollin,
• Werner Klaffke and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138

• ]. In spite of the fact that parent indole is too weak an acid to undergo Mitsunobu conversions, a model maleimide–indole hybrid was investigated by Ohkubo and colleagues to pave the way for the synthesis of indolo[2,3-a]pyrrolo[3,4-c]carbazole compounds with anticancer activity [90][91]. N-Glycosides

• efficiently synthesized from indolo[2,3-c]carbazole frameworks using the methodology previously developed by Voldoire et al. [93]. Further applications to 7-aza-indolic analogues of rebeccamycin [94][95][96], granulatimide and isogranulatimide [97][98][99][100] were also reported. In addition, using the same

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

• affect the final performances [60]. Alternatively, development of emissive complex incorporated in a dendritic structure allows controlling both charge transport and light emission in a single material [61]. In this regard, Yam and co-workers reported on a series of dendritic carbazole-based

• that leads to severe roll-off efficiency of OLEDs [64]. In particular, carbazole-based donor moieties and either phenylbenzimidazole (PBI) or oxadiazole (OXD) accepting units were selected as the hole-transporting and electron-transporting moiety, respectively. Two linkage fashions were explored

• , together with the use of heterocyclic moieties such as thiophene or carbazole, clearly favours the luminescence properties of these type of platinum(II) complexes [68]. As aforementioned, N-deprotonable azole units constitute a compelling alternative to C-cyclometalating ligands [16]. In this regard

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

• as a result of binding to minor groove DNA. Samanta et al. investigated a thorough structure–activity correlation between mahanine, an anticancer carbazole alkaloid, and its chemically modified analogs to test the role of various functional groups on its antiproliferative activity against 19 cancer

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

• Fabiana Pandolfi,
• Isabella Chiarotto and
• Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

• , entry 2) or 2-(bromoethynyl)naphthalene (3a, Table 1, entry 11) in high yields. Finally, to test the general applicability of the proposed electrochemical methodology, we submitted to electrolysis (under the optimized conditions reported in Table 1, entry 2), 3-(2,2-dibromovinyl)-9-ethyl-9H-carbazole

• Supporting Information File 1) and thus the electrolysis was carried out at the second wave potential. 9-Ethyl-3-ethynyl-9H-carbazole (2b) was obtained in 77% yield. Similarly, when starting from 1-(2,2-dibromovinyl)-4-methoxybenzene (1c), the corresponding terminal alkyne 2c was obtained in 62% yield

• . Electrochemical synthesis of 9-ethyl-3-ethynyl-9H-carbazole (2b). Electrochemical synthesis of 1-ethynyl-4-methoxybenzene (2c). Electrochemical synthesis of 2-ethynylnaphthalene (2a). Electrolysis conditions optimization (Scheme 5).a Supporting Information Supporting Information File 58: Detailed experimental

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• lifetime. Carbazole groups are widely used in host materials because of their high triplet energy levels and high hole mobility [15]. The Lee group [16] linked carbazolyl groups to diphenyl phosphoramines to design asymmetric (9-phenyl-9H-carbazole-2,5-diyl)bis(diphenylphosphine oxide) (PCPOs) with a

• -2-amine (DCPPy) based on carbazole group is 21.6%. The Wang group [19] designed a host material with symmetrical structure based on phenothiazine-5,5-dioxide. But the host materials with asymmetric structure based on the phenothiazine-5,5-dioxide were rarely reported. For obtaining a high triplet

• energy level and good stability, herein, with phenothiazine-5,5-dioxide as acceptor (A) and carbazole as donor (D), and introducing an alkane chain group to the host materials for better film-forming properties, two novel blue phosphorescent host materials, CEPDO and CBPDO, were synthesized. At the same

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• triarylboron moieties as acceptors. As possible donors, diarylamines have often been proposed (carbazole, triphenylamine, carbazole/triphenylamine hybrids, 9,9-dimethyl-9,10-dihydroacridine), as exemplified in Figure 2 [34][35][36]. In B1 and B2, isolation of the two parts was obtained by linking the 10H

• at 502 nm [37]. A blue shift of the emission and sky-blue OLEDs could only be obtained with this acceptor by replacing the electron-donating 9,9-dimethyl-9,10-dihydroacridinyl unit of B3 by a bis(diphenylamino)carbazole group in B4 or a diphenylaminocarbazole unit in B5. The outstanding EQE of 21.6

• dihedral angle arising from steric repulsions between hydrogen atoms in the peri-position of B6 and from the presence of methyl groups at the 3,6-positions of 1,3,6,8-tetramethylcarbazole in B7 could be obtained. In fact, the substitution at the 3,6-position of carbazole could maintain a large dihedral