One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• ]quinazolines (Scheme 2D) [40]. There are numbers of Ugi and subsequential Heck (or reductive Heck) reactions that have been developed for the synthesis of poly-heterocyclic compounds [43][44][45][46][47][48][49][50][51]. Reported in this paper is a one-pot Ugi-azide reaction followed by an intramolecular Heck

• used as the isocyanide source, the Ugi-azide reaction gives rise to ring-fused tetrazolo[1,5-a]pyrazin-6(5H)-one adducts 5. The subsequent Pd-catalyzed intramolecular Heck reaction of compounds 5 or 7 then affords 1,2,3,4-tetrohydroisoquinolines 6 and 8, respectively. Results and Discussion Following

• effort was then focused on the optimization of the intramolecular Heck reaction of 5a for making 1,2,3,4-tetrahydroisoquinoline 6a. A systematic evaluation of different catalysts and ligands, solvents, bases, as well as reaction temperatures and times was conducted (Table 1). The Heck reaction of 5a was

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• preparation of hitherto inaccessible types of densely functionalized vinylazoles with tetrasubstituted olefinic moiety. Results and Discussion Our group has demonstrated benziodoxole triflate (BXT) [26] and related compounds as a versatile iodine(III) electrophile for the inter- and intramolecular

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• ) [32]. The synthesis of the corresponding 2-aza-1,5-BCHs 13 was achieved by an intramolecular photochemical [2 + 2] cycloaddition. They were able to employ this synthetic route to synthesise a variety of 1,2-BCPs (±)-14 bearing a protected amine in the bridge position. In early 2023, MacMillan and co

• catalytic system of B2cat2 and 4-phenylpyridine to form pyridine-boryl radicals which initiated ring expansion. The method was shown to be similarly tolerable of functional groups as Procter’s synthesis. Intramolecular crossed [2 + 2] cycloadditions offer an alternative approach to 1,2-disubstituted BCHs

• intramolecular crossed [2 + 2] cycloaddition strategy (Scheme 4C) [36]. They were able to avoid purification by column chromatography by transformation of BCH ester (±)-53 into BCH acid (±)-54, allowing isolation of pure 1,2-BCH (±)-54 by crystallisation. Through their synthesis they were able to access both

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• have been employed in benzocyclization and arylocyclization reactions, enabling intramolecular cyclization by forming aromatic or heterocyclic rings as a part of cyclic structures [8]. In these reactions, the dual activation of a C–I bond and vicinal C–H bonds/functional groups features a distinct

• -trifluoroborate-substituted diaryliodonium salts furnished iodonium zwitterions as bifunctional reagents [22][23][24][25]. Additionally, ortho-trifluoromethanesulfonate, N-sulfonyl, or tosylmethylene-substituted diaryliodonium salts can undergo intramolecular aryl migrations [26][27][28]. More recently, we

• diaryliodonium salt 2a. Naphthol 1a forms intermediate B with A after participation with the Cu(II) catalyst. Intermediate B generates C by radical substitution. A final intramolecular transesterification yields the benzocoumarin product 3aa. Conclusion In summary, we have employed ortho-ester-substituted

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• polyketides or peptides, and form an ester bond. Then, they catalyze either intramolecular macrocyclization to give macrolactones or macrolactams with attacking of internal nucleophiles (alcohols or amine), or hydrolysis to release linear acids or peptides (Scheme 1b). Although TE domains may display

• increase the ratio of intramolecular nucleophilic attack, resulting in macrocyclic products via preorganization of substrate and enzyme in an active conformation [17][18]. Chemoenzymatic strategies, which merge practical enzymatic transformations with modern organic synthetic methods to increase the

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• can be found in bioactive molecules and have been tested in structure–activity relationship studies (Scheme 1A) [8][9][10]. Moreover, transformations have been developed to exploit the two functional groups simultaneously, for example through their intramolecular cyclization to form pyrroles in the

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• ], intramolecular cyclisation [36] or a mixture of both [8][37][38][39]. The new ligand system proved to deliver competent catalysis. Conversion was seen in all cases at 1 mol % catalyst loading (Scheme 3). Use of 13 resulted in a slight increase of the anti-Markovnikov hydration product 17 over 18 when compared to

• IPrAuCl [35]. In arylative cyclisations incomplete reaction was seen with enyne 19 [8][37] but ynone 22 [39] afforded high yield of 24. A quantitative conversion was seen in the intramolecular arylative cyclisation of 25 where 13 outperformed IPrAuCl [36]. Conclusion An L-shaped NHC ligand motif, AImOx

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• alcohols, followed by base-promoted cyclization to afford the target spirocyclic compounds in good to high yields. Keywords: diazoarylidene succinimides; intramolecular cyclization; rhodium(II) carbene O–H insertion; spirocycles; Introduction Spirocyclic motifs have emerged as auspicious frameworks for

• synthesis of spiro-annulated pyrrolidine-2,5-diones by catalyzed spirocyclizations involving aldehydes [11], tetrahydrofuran [12][13], and in the O–H insertion/Claisen rearrangement/intramolecular oxa-Michael addition cascade [14] (Scheme 1). Herein, we report our findings obtained, while investigating the

• reaction products using diazo reagent 1b as an example, but we failed to observe the formation of spirocyclic cyclization products as a result of intramolecular substitution of the bromine atom (Scheme 7). For example, during the attempted cyclization of compound 18, obtained from 2-(bromomethyl)benzoic

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• mainly driven by intramolecular hydrogen bonds. The methoxyphenyl-pyridine-methoxyphenyl moiety, developed by Petitjean et al. [19], demonstrates conformational switching upon the addition of acid in aqueous media (Figure 2). The neutral tweezers adopt a "U"-shaped conformation with both arms pointing in

• quenched when the tweezers are closed by the addition of a Zn2+ cation because of intramolecular π–π stacking interactions between the chromophores. The system can be reopened and its luminescence properties restored by introducing tris(2-aminoethyl)amine (TREN), which has a better affinity for Zn2+ and

• tweezers with tert-butyl groups positioned farther from the salphen via alkyne spacers were synthesized [42]. While, like in the parent tweezers 12, no intercalation of aromatic guests was observed in the closed form, strong intramolecular and intermolecular Pt–Pt bonds were achieved in the solid state

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• Ruichen Lan Brock Yager Yoonsun Jee Cynthia S. Day Amanda C. Jones Chemistry, Wake Forest University, 1834 Gulley Rd., Winston-Salem, NC, 27109, USA 10.3762/bjoc.20.43 Abstract Kinetic studies on the intramolecular hydroamination of protected variants of 2,2-diphenylpent-4-en-1-amine were carried

• of alkenes remains challenging. Advances in asymmetric catalysis [2][3][4][5][6][7][8][9][10], C–N [11][12][13][14][15][16][17] and C–C functionalization [18][19] reveal opportunities, but harsh conditions and limited substrate scope present problems. Intramolecular reactions almost invariably

• ) protodeauration (Scheme 1), the depth of experimental mechanistic validation achieved for allenes and alkynes have not been reproduced with alkenes. In an important foundational study by Toste, the expected alkylgold intermediate from intramolecular alkene hydroamination was isolated, however, turnover

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• palladium-catalyzed direct intermolecular arylation, followed by a direct intramolecular arylation step. As the C–H bond activation of several benzene derivatives remains very challenging, the preparation of fluoranthenes from 1,8-dibromonaphthalene via Suzuki coupling followed by intramolecular C–H

• contrast, only a few examples of fluoranthene backbone preparation by Pd-catalyzed C–H arylation have been reported. Some examples of the preparation of this skeleton by Suzuki coupling followed by intramolecular C–H coupling have been described [18][19][20][21][22][23][24]. In 2017, Metin, Türkmen and co

• %) using again a large excess of DBU base (7 equiv) also allowed to prepare unsubstituted fluoranthene in 87% yield (Scheme 1c) [22]. The reaction of naphthol with aryl bromides followed by nonaflation and intramolecular C–H activation for the access to fluoranthenes has also been reported [23]. Most of

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• oxidation of 35 to 36, the photocatalyst is regenerated and product 37 is formed through intramolecular nucleophilic cyclization facilitated by the phosphate base. Importantly, the activation of NHPI esters through PCET may also play a role in transformations mediated by the cyanoarene-based donor–acceptor

• ) for π-stacking between the furan and phthalimide rings, before EnT from *IrIII leads to the formation of an excited charge-transfer complex 47. This species would undergo intramolecular electron transfer (IET) giving rise to intermediate 48, which upon fragmentation would form radical 49

• . Intramolecular radical addition into the radical cation of the furan ring would then form cation 50 before nucleophilic capture by H2O leads to product 45. In 2020, the Wang group reported the functionalization of enamides employing radicals derived from NHPI esters in combination with indole nucleophiles [57

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• recognized as valuable synthetic tools in organic chemistry [54], with the most famous S-extrusion process to generate new C–C bonds probably being the Ramberg–Bäcklund reaction [55]. In the case of heteropines, chalcogen extrusion leads to a six-membered ring via the intramolecular formation of a C–C bond

• [4,5]thieno[3,2-c][1,2]dithiin (39) was prepared by intramolecular oxidative coupling of a dithiolate generated in situ from dithioacetate 38, and subsequent exposition to daylight of a solution of 39 triggered ring contraction with concomitant elimination of sulfur to yield target benzothienothiophene

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• Kazuhiro Okamoto Naoki Shida Mahito Atobe Graduate School of Engineering, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan 10.3762/bjoc.20.27 Abstract Electrochemically generated amidyl radical species produced distinct inter- or intramolecular

• , remarkable inter- and intramolecular chemoselectivities were observed in the hydroamination reaction. We investigated this phenomenon and found that complete inter-/intramolecular chemoselectivity could be achieved by modifying the reaction conditions, despite the presence of both inter- and intramolecular

• current (Figure 2B, blue line). We considered that the inter- and intramolecular chemoselectivities were derived from the pKa of the proton sources. The pre-organization of the amide substrate and phosphate bases is an important process in PCET [13]. Recently, Gschwind et al. published a detailed NMR

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• studied for the first time. In addition to the pronounced tendency of the title compound to form associates with an intramolecular hydrogen bond of the NHN type (new examples with the participation of pyridine rings, including self-associates are shown) and its inertness to amination reactions of the

• 5Н+PicO−, in the cationic part of which a similar intramolecular NHN hydrogen bond is realized [15]. To understand the structure of the resulting complex, we tried to grow its crystals from acetonitrile by co-evaporating solutions of quinoline 5 and chloranil at room temperature. Interestingly, in

• is easily protonated, and its protic salt has been fully characterized as tetrafluoroborate 14H+BF4−. The 1H NMR spectrum of this salt confirmed the symmetrical structure of the heterocyclic cation with a chelated intramolecular [NHN]+ bond, whose proton in CD3CN solution resonates at 17.22 ppm

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• incorporating redox-active tetrathiafulvalene (TTF) residues (Figure 7), known for their ability to form intramolecular π-dimers upon two-electron oxidation [47]. Thus, upon irradiation of the oxidized molecule 24 with 660 nm light, the thermal half-life of the Z-isomer exhibited a significant increase

• , extending from 0.48 seconds to 22 hours at room temperature due to formation of the long-living intramolecular dimeric species. Photochromic N,N'-diacylindigos After the initial report on the photochromic behavior of N,N'-diacetylindigo (9a) in 1954 [37], Wyman and Zenhäusern continued spectroscopic studies

• used in the synthesis of indigo [4]. a) Intramolecular (a = 2.26 Å) and intermolecular (b = 2.11 Å) hydrogen bonds in indigo, b) crystal packing of indigo in the solid state obtained from the single-crystal X-ray diffraction data, CCDC 796873 [12], c) photos of indigo in the solid state and solutions

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• (DBDAPs) is disclosed in this article through a palladium and copper-catalyzed amination (Buchwald–Hartwig (B–H) or Chan–Lam (C–L)) followed by a palladium-catalyzed intramolecular aminocarbonylation with Mo(CO)6 as CO surrogate (to avoid toxic CO handling) of readily available o-phenylenediamines and

• Tsvelikhovsky introduced an efficient synthetic strategy to construct diverse dibenzodiazepinones through a sequential methodology consisting of a B–H coupling between o-carbonylanilines and 1,2-dihaloarene derivatives providing access to key precursors that undergo a tandem amination–intramolecular cyclization

• diverse dibenzodiazepinones via a copper-catalyzed C–N bond coupling between 2-halobenzoates and o-phenylenediamines leading to a key intermediate that undergoes an intramolecular N-acylation to afford the corresponding dibenzodiazepinone structure in high yields (Scheme 1b) [14]. Another innovative

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• methide intermediate 9 upon elimination of the hydroxy group. This highly electrophilic species could trigger a second intramolecular Friedel–Crafts reaction leading to 6. The cyclic connectivity of 6 was determined by bidimensional NMR experiments, incidentally showing a broadening of the signals of

• oxocarbenium 7 and 7’ which exists as a stabilized form including an intramolecular stabilizing interaction between the carbocation and the ester carbonyl group. However, in close agreement with Hess and Baldwin’s values found for the rearrangement of cis-1,3-pentadiene [24], this transition state was high in

• substrates to be submitted to the one-pot tandem transformation (Scheme 5). With only a few exceptions, the presence of ortho (R1), meta (R2), or para (R3) substituents on the benzyl moiety generally allowed the intramolecular Friedel–Crafts reaction, after the first intermolecular one in the presence of

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• physicochemical properties of the family of these compounds that have been investigated is provided to clarify their potential for future applications. Keywords: click chemistry; donor–acceptor conjugate; intramolecular charge transfer; photoluminescence; photoinduced electron transfer; Introduction Push–pull

• , the ensuing RE process yields the corresponding TCBD derivatives. The resulting TCBDs and related products exhibit strong light absorption, resulting from the intramolecular charge transfer (ICT) in the visible region; they also exhibit a rich redox chemistry [11]. In the [2 + 2] CA–RE reaction of

• derivative 39, wherein a DMA–ethynyl group is introduced at the 9-position, with TCNE at 40 °C in THF yielded the corresponding TCBD 40 with 91% yield. Subsequent heating of 40 in toluene at 70 °C led to an intramolecular cyano-DA (CDA) reaction, which quantitatively afforded the CDA product 41 (Scheme 15

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• , Umemoto’s reagent undergoes a homolysis process to generate the trifluoromethyl radical species. The trifluoromethyl radical is trapped by the terminal alkene and forms a relayed radical intermediate 6, which is intercepted by the indole ring realizing an intramolecular cyclization (6-exo-trig). The newly

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• pronounced intramolecular charge transfer [68]. In water, the absorption maxima showed only a small shift of the absorption maxima of 1–4 nm as compared with the ones in acetonitrile (Figure 1B, Supporting Information File 1, Table S1). The absorption spectra of compounds 2a and 2c could not be recorded

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• , ethynylbenzene, or 4-ethynylbenzonitrile yielded compounds 19–21, while two-fold Sonogashira coupling with ((2-ethynylphenyl)ethynyl)triisopropylsilane resulted in compound 22. Desilylation of the alkynes of compound 22 with tetrabutylammonium fluoride (TBAF) and subsequent intramolecular Glaser–Hay coupling of

• Sonogashira couplings of compound 25 with triisopropylsilylacetylene and ((2-ethynylphenyl)ethynyl)triisopropylsilane yielded compounds 26 and 27, respectively. A two-fold, intramolecular Glaser–Hay coupling of compound 27 (after desilylation) was attempted under the conditions that were successful in the

• compound 29 is perpendicular with respect to the herringbone pattern and the related structures (see Figure 10, bottom). Compound 25 packs with an intramolecular distance of 3.41 Å between the planes of the π-systems. Neither compound 26 nor 29 shows π–π interactions in the crystal packing. The large

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• primary adduct A (see Scheme 2) is too short-lived that an intramolecular hydrogen transfer toward 2a (C, in Scheme 2) is occurring [48]. Instead, in case of acrylonitrile another hydrogen bond donor, which is the solvent methanol [49], is necessary to trap intermediate A forming the ion pair D. Finally

• intramolecular proton transfer and the methanol-mediated proton transfer, can occur. It has been described that intermediate B is more stable with enolizable electron-withdrawing groups such as esters [50] when compared to, e.g., a nitrile [49]. Accordingly, the intermolecular proton transfer pathway should be

• more accessible with methyl acrylate than with acrylonitrile. The lower reactivity of acrylamide in chloroform compared to methyl acrylate is in accordance with its lower electrophilicity. The observed rate reduction in methanol suggests the importance of the intramolecular hydrogen transfer pathway

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

• efficient method to synthesize N-acyl carbazoles from readily available iodolium salt and amides via a ring-opening/intramolecular coupling cascade (Scheme 1c) [20][21][22][23][24][25][26][27][28][29][30]. Our group recently explored principle synthetic pathways of hetero- and carbocyclic 5- and 6-membered

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• -dicarbazolyl-3,5-dicarbonitrile. The compounds are synthesized by Sonogashira coupling reactions and characterized by steady-state and time-resolved luminescence spectroscopy. The compounds show efficient intramolecular charge transfer (ICT) from the donor to the acceptor. The photoluminescence (PL) spectra of

• compounds. In general, polyaromatic π-systems with pyridine-3,5-dicarbonitrile fragments demonstrate promising potential for use in organic electronic devices, such as OLEDs. Keywords: charge transport; intramolecular charge transfer; photophysical properties; pyridine-3,5-dicarbonitrile; Introduction The

• peaks of these low-energy absorption bands are collected in Table 1. A similar band was previously observed for REF [5]. On the basis of the results of the theoretical investigations, the low-energy absorption band of REF has been attributed to the intramolecular charge transfer (ICT) caused by electron