Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• triphenylamine as donor and dimesitylboron as acceptor linked through a thieno[3,2-b]thiophene (TT) π-conjugated linker bearing a 4-MeOPh group, was designed, synthesized, and fabricated as an emitter via a solution process for an organic light-emitting diode (OLED) application. DMB-TT-TPA (8) exhibited

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• homogeneous reaction. For example, by incorporating a lipophilic side chain [28] on the organocatalyst that does not interfere with its catalytic activity thanks to a linker between the catalyst and lipophilic units. In this way, a significant difference in polarity can be achieved between the catalyst and

• this catalyst easily by incorporating a lipophilic unit, which leads to a drastic increase (5.78 to 28.8) in the logP value of the organocatalyst 2. The recyclable organocatalyst can be divided into three units: the catalytic unit, the linker, and the lipophilic tag with octadecyl chains (Figure 1

• ). The cinchona amine 3 was prepared starting from the naturally occurring quinine [31]. The gained catalyst was demethylated using BBr3 to give alcohol 4. The demethylated cinchona amine was reacted with half-squaramide [9] 5, resulting in demethylated squaramide 6. A short and flexible linker was

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• differentiation of the triplets at δ = 4.18 ppm and δ = 3.78 ppm corresponding to CH2 protons from the pentyl linker, also confirmed by H,H-COSY NMR. Comparison of the 1H NMR spectra of R2 and its components 6 and M2 revealed substantial differences in the chemical shifts of different signals of R1 and 6, M2

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• study raises a concern regarding the performance of dyes with tert-butyl substituted DPQ acceptors, either containing benzene (Qx74) or thiophene (Qx75) as a π-conjugation linker and their benzotriazole analogue. While the incorporation of the Qx enhances the interaction between the donor and acceptor

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• supramolecular architectures [45], e.g., catenanes [73], rotaxanes [74], and catalytic systems [75]. Pelegrino and co-workers reported on crowned porphyrinoids demonstrating interesting photophysical properties [71]. The crown ether part was also demonstrated to play a role of a linker between two porphyrin

• ]. The latter incorporated two dipyrromethane/dipyrromethene units connected through iminoalkyl bridges. The architecture of the macrocycles, and their anticipated dynamic behaviour, wherein two dipyrromethene parts can come closer or further due to the flexibility of the alkyl linker, is reminiscent to

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• these results [37][38]. For several years, our group was interested in preparing multivalent carbohydrate mimetics [39][40][41][42][43] on the basis of efficient coupling reactions of aminopyran and aminooxepane derivatives with suitable linker elements. Hence, the aminopyran derivatives A could be

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• glycan sequences. We showed that, while loading and reaction scale did not significantly influence the AGA outcome, the chemical nature of the linker dramatically altered the isolated yields. We identified that the major determinants of AGA yields are cleavage from the solid support and post-AGA

• purification steps. Keywords: automated glycan assembly; photocleavable linker; polysaccharides; solid-phase synthesis; Introduction Automated glycan assembly (AGA) is a solid-phase method that enables the rapid synthesis of complex oligo- and polysaccharides from protected monosaccharide building blocks

• scale [19], and linkers [20][21] affect the overall yield of solid phase peptide synthesis (SPPS). In the past decades, several supports and linkers have been developed and commercialized for SPPS, enabling a wide range of applications. Solid supports are available with different linker loadings, with

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• linker or pharmacophore group. In fact, more than one hundred FDA-approved drugs are sulfonamide-bearing small molecules. Screening libraries of aromatic and heteroaromatic sulfonamides gave rise to the discovery of multiple physiologically active compounds [27][28][29][30] including important

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• or HBC-like units into one ring system is a straightforward way to generate HBC-based chiral NGs. In general, different HBC units were fused together to form the final chiral structures by connecting with a linker or sharing the same phenyl ring. As shown in Scheme 5, Jux and co-workers synthesized

• the NG precursor 39 by heating dialkyne 38 and tetracyclone 2, which led to two hexarylbenzene units connected by an oxygen linker. Upon treatment of 39 under Scholl reaction conditions (DDQ, TfOH), an oxa-[7]helicene containing chiral NG 40 was obtained in high yield [43]. Meanwhile, they enlarged

• -workers synthesized a helical bilayer NG by using helicene in the initial step as the linker to fuse two HBC units [48]. As shown in Scheme 6, starting from the helical alkyne 54, Sonogashira coupling with 4-tert-butyliodobenzene (55) afforded structure 56 in a 77% yield. Subsequent Diels–Alder reaction

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke–Blackburn–Bienaymé and Ugi reactions

• Oleksandr V. Kolomiiets,
• Alexander V. Tsygankov,
• Maryna N. Kornet,
• Aleksander A. Brazhko,
• Vladimir I. Musatov and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2023, 19, 727–735, doi:10.3762/bjoc.19.53

• 7a–t in 28–72% yield (Scheme 4, Table 1). Having obtained several new compounds containing substituted imidazo[1,2-a]pyridine and peptidomimetic fragments linked by a CH2O linker, we further explored the possibility of synthesizing similar hybrids without a CH2O linker between the two moieties. The

• imidazo[1,2-a]pyridine and peptidomimetic fragments it is better to use acids with a linker between the carboxyl group and aryl ring. This molecular fragment increases the solubility of the whole molecule, which leads to an improvement in the reactivity of the acids, whereas the reactivity of acids 8a and

• manner. A method for the synthesis of the desired compounds was developed, and a small library of 20 Ugi products was prepared. The study also demonstrated that the use of a CH2O linker between the carboxyl group and the aryl ring in the Ugi reaction enhanced the reactivity of the acid component. The

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• ) by alkylation of 1a was patented in 1997 [79]. The process involves the alkylation of iminostilbene (1a) as a critical intermediate step (Scheme 33C). The alkyl halide linker of 148 was further functionalised by reaction with piperazine derivative 149 to give opipramol (5). 6.2 C-Functionalisation

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

• of the etheric oxygen atom and the antibonding orbital of the P=O bond (the stereoelectronic effect), leading to the more stable anti-diastereomer 74 (Scheme 16) [38]. In the phostone 74 was installed a linker 2-(5-aminopentoxy) group via transesterification with benzyl N-(5-hydroxypentyl)carbamate

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• -conjugation of 1,8-bis(dimethylamino)naphthalene (DMAN) fragments through a butadiyne linker and a donor–acceptor aryl–C≡C–DMAN conjugation path. The conjugation path can be “switched” simply by protonation of DMAN fragments. X-ray diffraction, UV–vis spectroscopy and cyclic voltammetry are applied to analyze

• which although conjugated to a third unsaturated center are not conjugated to each other” [16]. It is easy to see that there are two π-conjugation paths in molecules 5: a donor–acceptor conjugation path (Figure 2, highlighted in blue) and the π-conjugation of naphthalene rings through a butadiyne linker

• averaged planes of the naphthalene rings, ∠Cx‒Cy–Cz is the bond angle of the carbon–carbon bonds in the butadiyne linker, Θ is the C2(2′)–C3(3′)–C6(6′)–C7(7′) torsion, N···N is the internitrogen distance in the DMAN fragments, Σ∠N is the sum of the C–N–C angles of the NMe2 groups, and φ is the N1(1′)–C1(1

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• )) and includes a chiral auxiliary, an amino acid, and a bifunctional linker capable to arrange the components in the Schiff base complex. Such templates provide a significant C–H acidity at the α-amino acid carbon and a possibility for recycling of the chiral auxiliaries (for reviews see [5][14][15][16

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• Biotechnology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia 10.3762/bjoc.19.40 Abstract Two novel conjugate molecules were designed: pyrene and phenanthridine-amino acid units with a different linker length between the aromatic fragments. Molecular

• a pH-dependent excimer formation that is significantly red-shifted relative to the pyrene and phenanthridine fluorescence. While the conjugate with a short linker showed negligible spectrophotometric changes due to the polynucleotide addition, the conjugate with a longer and more flexible linker

• exhibited a micromolar and submicromolar binding affinity for ds-polynucleotides and inactivated a mutant of dipeptidyl peptidase enzyme E451A. Confocal microscopy revealed that the conjugate with the longer linker entered the HeLa cell membranes and blue fluorescence was visualized as the dye accumulated

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• a similar synthetic protocol to link porphyrin 71 to a fluorescein 72 through a 1,2,3-triazole linker to form the porphyrin-fluorescein conjugate 73 in 91% yield (Scheme 14). Furthermore, the fluorescence study of conjugate 73 revealed an intramolecular energy transfer between fluorescein and

• -triazole linker significantly influences the charge separation, charge recombination, and photoinduced electron transfer processes. Since, the through-bond distance is approximately the same for all the synthesized ZnP-Tri-C60 conjugates, therefore, the variation in charge separation and charge

• -triazole-ruthenium(II) conjugates 112a,b and 116a,b in 18–20% yield. Their photophysical and electrochemical studies revealed that the orbital energies depend on the ligands/linker, connecting pattern of linkers, and the presence of Zn metal ions in the porphyrin core. Ligand exchange studies also

Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds

• Kah Yean Lum,
• Jonathan M. White,
• Daniel J. G. Johnson,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2023, 19, 107–114, doi:10.3762/bjoc.19.11

• of an ether linker on the pyrazine ring, with a two methylene unit chain length between the heterocyclic core and benzylic substituent, improved the potency of these compounds [16]. Hence, scaffolds 1–3 were then converted into a series of ether-linked triazolopyrazines with phenethyl alcohol or

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• spectra of the dimers possess several features, making them quite different from the spectra of their starting materials. The spectra of the dimers with the urea linker in water contain much fewer distortions in the hydrogen and carbon signals than the spectra of a corresponding azido-compound, so they

• look more like the symmetrical partially methylated compounds without azido group. This phenomenon could be attributed to the increased molecular symmetry after the dimerization with this type of spacer. A methyltriazole ether linker connects the CD moieties in dimers 4, 9, and 10. The aromatic part of

• desymmetrization of the molecule caused by a partial and reversible self-inclusion of the triazole moiety into the CD cavity, as was previously studied in detail for the CD dimers prepared by CuAAC reaction [15]. Although such self-inclusion was not prominent for dimers based on the short propargyl ether linker

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

• Kendra Drayton-White,
• Siyue Liu,
• Yu-Chia Chang,
• Sakashi Uppal and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• interactions [5][6][7]. For example, a binding curve generated for the interaction between an RGD-peptide (C-PEG6-GGRGDGP) and its integrin (α5,β1) target is shown in Figure 4 below. A PEG-linker was added to the RGD-peptide so that the peptide would not be buried in the polymer coating the surface of the

• array, a scenario that would make it unavailable for binding to the integrin receptor in the subsequent analytical experiment. The PEG-6-linker was selected because it was effective and readily available from commercial sources. This linker was functionalized with a cysteine on the end opposite the

• peptides were placed on the array along with a fluorescent dye (LRSC, lissamine rhodamine) that was used to make sure the placement chemistry was working. The array used was coated with the borate ester diblock copolymer (Figure 2), and the peptides were attached to this polymer through a PEG-6 linker in

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• . The tuning of the energy order of the CT and LE states is achieved by oxidation of the PTZ unit into the corresponding sulfoxide, whereas conformation restriction is imposed by introducing ortho-methyl substituents on the phenyl linker, so that the coupling magnitude between the CT and the 3LE states

• minimal impacts on the geometry and the 3LE state energy in the dyad, was rarely explored [8]. We also modified the energy of the CT states by increasing the distance between the electron donor and acceptor by using an intervening phenyl linker between the NI and the PTZ moieties (NI-Ph-PTZ and NI-PhMe2

• -PTZ) [36]. The electronic coupling between the NI and PTZ units differ these two dyads. Finally, in NI-PhMe2-PTZ with methyl substituents, the phenyl linker adopts an orthogonal geometry with respect to the NI moiety, inducing a weaker coupling than that in NI-Ph-PTZ. The photophysical properties of

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• ], or structural motifs in xeno nucleic acids [18]. In continuation of our work on ferrocenoyl-substituted pyrimidine nucleobases [19], we report herewith a combined theoretical and experimental work on purine series. The novelty of these compounds is the carbonyl linker which connects the

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• lifetimes showed a marked increase upon replacement of the nitrogen linker for phosphorus. Nitrogen-linked g-CN showed exciton lifetimes of 4.2 µs, while the introduction of a phosphorus linker in g-h-PCN increases the lifetime to 67 µs, with g-h-PCN300 showing lifetimes of 42 µs. We have also observed a

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• the two dyes: OTK-2 has a cross-conjugated system due to the involvement of the 1,3-phenylene unit as an additional linker, but OTT-2 has a conjugated system. Therefore, it is interesting to reveal the optical and electrochemical properties of (D–π)2-type fluorescent dyes, making a comparison with (D

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

• their catalytic site, while the remaining 7 isoforms of class III, known as sirtuins, are dependent on the NAD+ coenzyme [3][4]. According to current knowledge, HDAC inhibitors usually have several structural subunits: a zinc chelating group, a hydrophobic linker, and a hydrophobic (usually aromatic

• )-ones we have developed an efficient synthesis of hitherto unknown pyrimidine-based hydroxamic acids, wherein the hydroxamic acid residue is attached to the pyrimidine ring by a methylene linker of varying length. The 1H NMR spectra show that the synthesized hydroxamic acids in solution exist as an