Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• ethyl esters 5b and 6b is −15.6(2) and −11.5(2)°, respectively, indicating that in the case of methyl esters, the alkoxycarbonyl fragment is less out of plane, causing a greater conjugation with the furan fragment. The possibility of exhibiting fluorescent properties was investigated for tetracyclic

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• , making them more oxidizing. Extended conjugation in cyanins (e.g., 53 and 54) further increases their oxidizing nature at the ground state. Overall, both central substitution and extended conjugation play crucial roles in determining the redox behavior of these dyes. Cyanins with an amino group on the

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• to N1(c)–N4(c), which is due to the localization of the π conjugation in the central part of the molecular skeleton as reported in inverse-type diarylethenes [64]. Figure 1c and the video (Supporting Information File 2) show the photochromic behavior of N4 at room temperature in n-hexane. It was

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• enamine moiety, would afford the corresponding imidate 18 with incorporation of an extended conjugation system. The oxidation-labile nature of the corresponding C11 position in 12 is consistent with the low bond dissociation energies (BDEs) at both the α-position of the nitrogen, as shown in Supporting

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• to Cs-1 (4.37 eV) as calculated at the B3LYP/6-311++G(d,p) level of DFT. The reduced HOMO–LUMO gap of C2-1 can be attributed to the greater conjugation in the essentially flat dibenzotropone moiety. This finding aligns with the fact that the yellow crystal of C2-1 absorbs light of a longer wavelength

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• PH8), with no or little influence of the solvent polarity (Figure 6a). This may suggest that the sigma-bonded F6 and G66 have no conjugation in their ground states, the electron density being located on one triphenylene moiety (see DFT). G66 shows a stronger absorption band than F6, with expected ε

• spectra. Their LUMO electron density maps distribute across to the side arm for F1 (−1.88 eV; −1.78 eV for PH1) and to the other triphenylene core for the dimer G11 (−1.78 eV). The π-conjugation of excited states results in a difference of their HOMO and LUMO energy levels: the fluorine dimer G11

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine

• Alfiya R. Gimadieva,
• Yuliya Z. Khazimullina,
• Aigiza A. Gilimkhanova and
• Akhat G. Mustafin

Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219

• ][19][20]. The catalytic activity of metallophthalocyanines originates from their planar, cyclic structure with a developed π-conjugation system. This makes the fifth and sixth coordination sites of the central metal ion available for coordination with the reactant molecules of the catalytic reaction

• . Additionally, the π-conjugation system facilitates the redistribution of electron density within the reaction complex, thereby lowering the activation barrier of the reaction [21]. The study employed the following oxidation catalysts for phthalocyanines – PcCo, PcFe(II), PcFe(III), PcMn, PcNi, and PcZn. The

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• (Figures S22–25 in Supporting Information File 1) [31]. The absorption band at 524 nm was blue-shifted by 4 nm compared to that of N-phenyl-substituted 1b+-BF4− [15]. This can be ascribed to the lesser conjugation of the core TATA+ unit with the introduced 2,6-dimethylphenyl moieties owing to the more

• Numbers JP22H02067 and JP23K23335 for Scientific Research (B), JP24K08389 for Scientific Research (C), JP23K17951 for Challenging Research (Exploratory), and JP20H05863 for Transformative Research Areas (A) “Condensed Conjugation” and Ritsumeikan Global Innovation Research Organization (R-GIRO) project

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• outer side (in-out-ts), but the thermodynamically stable final product is a regioselective “in-in” adduct, i.e., compound 6a. Optical properties Absorption and emission spectra of 6a were measured in CH2Cl2 (Figure 5). The conjugation is changed and a highly-twisted macrocyle forms by the double azide

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• -planar having π‐conjugation [2][3][4]. Remarkably, these unique characteristics of the truxene scaffold, results in strong π–π stacking ability in addition to the strong electron‐donating capability – hinting for the truxene’s capability as a worthy building block in the advancement of cutting-edge

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• . Because of this conjugation, the aromatic ring at the N of the 1,1-addition product 4 (R = Ar, E = PhS) geometrically isomerizes faster than the NMR timescale, so that the two thio groups of 4 are observed to be equivalent in NMR spectroscopy. In the case of diphenyl diselenide as a representative organic

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Hetero-polycyclic aromatic systems: A data-driven investigation of structure–property relationships

• Sabyasachi Chakraborty,
• Eduardo Mayo Yanes and
• Renana Gershoni-Poranne

Beilstein J. Org. Chem. 2024, 20, 1817–1830, doi:10.3762/bjoc.20.160

• analyze the structure–property relationships of the cc-hPASs. Results and Discussion At first glance, the chemical space of PASs may appear to be quite homogenous. After all, the molecules share certain structural features, such as their multi-ring structures, rigidity, and π-conjugation. Nevertheless

• values become less negative as the molecules increase in size; for the LUMO, Gap, AIP and AEA, the values become smaller or more negative as the molecules increase in size. These trends align with the commonly known effect in polyenes and annulenes, whereby increasing conjugation causes the HOMO to be

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• LUMO orbitals for 3 and 23 and related compounds show reduced orbital densities on their aryl substituents, effectively reducing π-conjugation and raising HOMO–LUMO gaps. There appears little benefit to utilizing highly hindered 2’,4’,6’-triisopropylphenyl groups as in 24 or 2’,4’,6’-tri-tert

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• ], photonics [2], and diagnostics [3]. Their popularity stems from their structural rigidity, potential conjugation with the remaining structure, and the capability to form additional π–π-stacking interactions. Dihalides, in particular, are highly preferred in such applications, enabling the formation of

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• on resin, a GABA residue was attached to the N-terminus of the peptide in order to provide a less-hindered primary amine, enabling an efficient amide conjugation reaction with biscarboxylic acid-substituted C60 derivative 3. Compound 3 was prepared by Prato reaction of C60 and an N-glycine derivative

• of C60–peptide conjugate formation decreased when using fewer equivalents of peptide on resin relative to compound 3, providing as a byproduct the C60–peptide conjugate connected to only one peptide anchor. Based on the optimized reaction conditions outlined above, the conjugation of biscarboxylic

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• compounds allowing for the preparation of porphyrins with different reactive groups such as hydroxy and amino derivatives capable for further functionalization and conjugation of these porphyrins to other substrates. In addition, conjugates containing maleimide or biotin entities in the structure of

• tetrapyrrole compounds [9] since the delivery of a drug at a specific area in the body has vital importance to treat diseases. An alternative approach to solve this problem focused on the postfunctionalization of the porphyrin macrocycle with different linker groups capable for targeting conjugation of these

• porphyrins to other biological substrates and thus facilitate the conjugation with biomacromolecules [10][11]. The modification of the porphyrin periphery with amino-, azido-, epoxy-, hydroxy-, and maleimido-functionalities is usually used for the covalent linkage of the porphyrin to the targeted

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• by the preceding modules (highlighted in purple) [14][16]. Furthermore, the structures of 1 and 2 show a shifted triene portion that is not in conjugation with the carboxylic acid function. NMR studies of off-loaded intermediates with the TE deletion mutant revealed that these double bond shifts are

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

• explored as prospective payloads for antibody-drug conjugation [81][82]. Numerous synthetic approaches have been devised to deliver the cryptophytes skeleton, indicating that the most challenging steps are the regio- and stereospecific macrocyclization and epoxidation [83]. To address these problems, in

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

• . A study confirmed that with appropriate molecular design, the π-conjugation relationship between the donor and acceptor moieties in TCBDs and DCNQs can be retained despite their non-planarity [14]. Diederich et al. synthesized a plethora of push–pull chromophores by employing anilino groups as EDGs

• , engaging in conjugation with the fulvene moiety. Conversely, the reaction of phenyl-substituted DCF 2b with 1 under the same reaction conditions selectively affords the corresponding adduct 3b with 64% yield. In 3b, the anilino group is conjugated with the DCV group rather than the fulvene moiety. This

• variation in the products arises from the difference in the initial reaction step, in particular, whether the nucleophilic attack of the alkyne carbon in 1 occurs at C(6) or C(1) of the DCF framework. This differentiation can be attributed to the efficient electron conjugation between the alkyne and

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• natural product, we performed heterologous expression of the cma cluster. Plasmids named pHKO4-cmaI-D and pTYM3a-cmaG (Figure 2A) were introduced into S. albus by conjugation, resulting in S. albus-cma [20]. S. albus-cma possesses all the cma genes, except for the genes encoding a transporter (cmaF) and a

• . E. coli S17-1 was used for conjugation. Streptomyces albus J1074 was used for heterologous expression. Kutzneria albida JCM 3240 was purchased from the Japan Collection of Microorganisms. Enzymes used for DNA manipulation, including polymerase and restriction enzymes, were purchased from TaKaRa Bio

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

• lack of conjugation between the heterocyclic core of the molecules and their peripherical decorations. Conclusion The synthesis of three CAAC·CS2 and six MIC·CS2 zwitterions derived from aldiminium or 1,2,3-triazolium salts was achieved via a two-step procedure involving the in situ generation of free

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• for use in cutting-edge technologies. In particular, acenes, a subgroup of polycyclic aromatic compounds, are sought-after synthetic targets due to their remarkable optoelectronic properties which stem from their π-conjugation and planar structure. Despite all these promising characteristics, acenes

• exhibit significant stability problems when their conjugation enhances. Various approaches have been developed to address this stability concern. Among these strategies, one involves the incorporation of the biphenylene unit into acene frameworks, limiting the electron delocalization through the

• understanding the correlations between structure and electronic properties, as these units serve as fundamental building blocks in graphite and carbon nanotubes [3]. The limited stability of this particular class of PAHs arises as a key challenge, primarily attributed to their extended conjugation. The longer

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

• values of Ered,onset are comparable with those of recently published compounds containing a dicyanopyridyl moiety as a central electron-accepting core [7]. In case of oxidation potentials (0.96 to 1.04 V) there is only a slight effect of the extended conjugation between the dicyanopyridyl moieties. The

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• charge transport behavior. DFT calculations assisted the interpretation of electron and hole migration mechanism using the frontier orbital energies and the conjugation within the π-system. Results and Discussion The syntheses of 1 and 2 were previously published in [25] and [26], respectively. 1 is a

• literature [24]. It is important to emphasize that the charge carrier mobility of columnar liquid crystals can be improved by five orders of magnitude due to molecular alignment of the film in the device structure [33]. Usually, the π-system conjugation and the frontier orbitals energies dominates the charge

• . While 1 presents majority hole transport, 2 is moderately ambipolar. The electron transport of 2 is around two orders of magnitude higher than 1, which can be associated to the larger conjugation of 2. This work highlights the potential of pyrene-based columnar liquid crystals as electron-transporting