Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

• Simone Gräßle,
• Laura Holzhauer,
• Nicolai Wippert,
• Olaf Fuhr,
• Martin Nieger,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

• suitable for single-crystal X-ray diffraction could be obtained and confirmed the product structure with the presumed regioisomer (Scheme 3). A library of over 50 triazole products 21aa–vg was successfully synthesized with yields ranging from 28% to quantitative, combining four different pyrazole-carbon

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• intramolecular Cannizzaro reaction while accomplishing the synthesis of the bicyclic core structure of proposed ottelione A (47) [85]. Commencing from the Diels–Alder adduct 48, an enzymatic desymmetrization of the reduced diol 49 formed the enantiopure 50 (ee >99%). A cascade of reaction sequences delivered the

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• spectroscopy and high-resolution mass spectrometry. Moreover, X-ray analysis was used for confirmation of structure of compound 4g (Figure 1). A plausible mechanism of the studied rearrangement is presented in Scheme 5. At first, anion A is generated from starting hydrazone 3 under action of base. Next

• obtained the recyclized product 6a (Scheme 6), whose structure was confirmed by 1H, 13C NMR spectroscopy, high-resolution mass spectrometry and X-ray analysis. Based on the aforementioned reaction we have synthesized a set of pyrazolylisoxazoles 6 (Scheme 7). The proposed mechanism of investigated

• recyclization. The structures of one example of the 1,2,3-triazole derivatives and one synthesized pyrazolylisoxazole were established by X-ray analysis. The X-ray crystal structure of compound 4g (CCDC 2343878). Synthesis of various triazole derivatives using Boulton–Katritzky rearrangement. Synthesis of

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• energies of the neutral products. In the cyclization of 2, protonation at C6, results in a C7 tertiary cationic intermediate (A2+) where C2 is only 1.65 Å away from C7 (Figure 2B); this structure can be viewed as protonated 5 or 6 with a strongly hyperconjugated C2–C7 bond [21]. Reducing this

• [22]. An X-ray structure of 9 allowed us to solve its absolute configuration and measure the C2–C7 distance to be 3.31 Å. This distance matches reasonably well with the calculated distance, 3.36 Å, of the lowest energy conformer of 9. Calculation of the proposed 6,7-epoxy derivative of 2, which was

• , Supporting Information File 1). The lowest transition state for a Cope rearrangement, a chair–chair structure at 29.3 kcal mol−1, originates from a DD (down–down orientations of the methyl groups on the 10-membered ring) conformer that is 3.2 kcal mol−1 higher in free energy than the most dominant conformer

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• moiety in N-furfuryl-N-benzylmaleamic acid, formed by acylation of N-benzyl-N-furfurylamine with maleic anhydride, adopts a favorable conformational structure thanks to two activating electron-withdrawing groups and participates in the formation of the corresponding IMDAF product in oil medium rapidly

• the bis structure are in equilibrium with maleamic acid precursors (Scheme 3) complicates the interpretation of their 1H and 13C NMR spectra. The existence of these precursors is clearly demonstrated by both their 1H and 13C NMR spectra (Supporting Information File 1). It should be noted that in the

• , 47.03, 45.86; Anal calcd for C16H15NO4 (285.30): C, 67.36; H, 5.30; N, 4.91; found: C, 67.30; H, 5.26; N, 4.86. Reaction yields after seven uses of SSO and average recovery of the oil. Coupling constants of selected protons in compound 2a and its optimized geometric structure. Possible mechanism for the

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• interlocked structure is formed, the concentrated extract (e-SWNTs) was washed thoroughly with dichloromethane by sonication and filtration to remove unlocking host molecules. The resulting SWNTs (i-SWNTs) were demetallized with dithiothreitol (DTT) and washed to afford the pristine SWNTs (p-SWNTs). As shown

• . The plotting of Raman spectra and calculation of the molecular cavity were accomplished with the help of Multiwfn [35]. VMD [36] was used for the modeling of (n,m)-SWNTs and the structure visualization. Molclus [37] was used for the modeling of Cu-nanobrackets@SWNTs complexes. The binding energies of

• -nanobrackets 1b. DFT-optimized structure of Cu-nanobrackets (a) 1a and (b) 1b. The yellow regions indicate their spherical cavities. (c) Experimental and calculated results of Raman spectra of 1b (λex = 488 nm). For calculation, Raman activity was transferred to Raman intensity (298.15 K, the full width at

Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

• Alina Paffen,
• Christopher Cremer and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

• in the structure, or else at different positions, in order to establish how their redox catalytic reactivity might be affected. Indeed, we learned recently that amino-arenes possess some level of redox catalytic activity by themselves, in the absence of a Te-center [34], and therefore wished to

• elected at this point to keep the cyclic phenotellurazine structure of the catalyst in the hope of increased catalytic robustness, especially in view of further increasing substitution. Next, we therefore tested methoxy-substituted PTeZ2, a successful catalyst structure which we recently developed for the

• cross-dehydrogenative coupling of indoles [33], in the same benchmark reaction. To our satisfaction, PTeZ2 proved to be the most active catalyst so far in this study (3aa, 99% after 3 h). In order to further optimize the catalyst structure, we then reduced the catalytic loading by one order of magnitude

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• -withdrawing substituents. Computational studies with density functional theory revealed the unique vibrations of the thioketone group in FIDS. The molecular structure of FIDS was confirmed by single-crystal X-ray analysis. Bulk heterojunction organic solar cells using three evaporable fullerene derivatives

• significant scientific interest since its discovery by H. W. Kroto in 1985 [1]. Due to their distinctive spherical structure and electron-deficient properties, fullerene derivatives have found applications in various fields, including photovoltaics [2][3][4][5], biomedicine [6][7][8], and electron

• . Additionally, the ketone structure acts as a Lewis base, resulting in a passivation effect on Pb2+ [19]. In this study, we designed and synthesized indano[60]fullerene thioketones (FIDSs) with various para-substituents. The vacuum-deposition performance and thermal stability of FIDS were assessed by both

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• type of product is formed in the reaction of 3-formylchromones with (2,4-dioxobutylidene)phosphoranes [37]. The yields were in a range of 33 to 82%. No clear trend was observed for the yields depending on the structure of the diene and the chromone. Similar to unsubstituted diene 6a, dienes containing

• of the carbonyl group adjacent to the ester, due to the electron-withdrawing effect of the latter. The yields were generally good to very good and no trend was observed depending on the structure of the chromones. 1,3-Diphenylacetone Similarly, reaction of 1,3-diphenylacetone (4) with 11a,d afforded

• benzophenones 22a,b in moderate yields (Scheme 8) [38]. Again, no trend was observed depending on the structure of the chromones. 1,3-Bis(silyloxy)-1,3-butadienes The reaction of 11a–c with 1,3-bis(silyloxy)-1,3-butadienes 6a–h, catalyzed by Me3SiOTf, afforded products 23a–j with excellent diastereoselectivity

Synthesis and optical properties of bis- and tris-alkynyl-2-trifluoromethylquinolines

• Stefan Jopp,
• Franziska Spruner von Mertz,
• Peter Ehlers,
• Alexander Villinger and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1246–1255, doi:10.3762/bjoc.20.107

• steady state absorption and fluorescence spectroscopy which give insights of the influence of the substitution pattern and of the type of substituents on the optical properties. Keywords: alkynes; catalysis; fluorescence; heterocycles; palladium; Introduction Quinoline is a well-known core structure

• is applied as antimalarial agent and furthermore as a bitter flavour component. Mefloquin [5] and ciprofloxacin [6], on the other hand, are synthetic compounds containing a fluorinated quinoline and quinolone core structure and are used as antimalarial and antibacterial agents, respectively (Figure 1

• group, could not be isolated at all, since the reaction resulted in an inseparable mixture of several products. The structure of 6b could be independently confirmed by X-ray crystallography (Figure 2). Both phenyl rings are found to be twisted in an angle of approximately 45° from the quinoline core. As

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• of non-planarity [40], where the helical structure allows for mixing between the singlet and triplet π,π*-states [41][42]. In addition, the insertion of heteroatoms such as nitrogen further enhances ISC due to a spin-orbit coupling between n,π*-states and π,π*-states [40], as stated by El Sayed’s

• rule [43]. However, helicenes have not been broadly considered as potential photocatalysts or sensitizers or their applications were unsuccessful [44]. Recently, one of our groups exploited the highly reducing polyaza[7]helicene (Aza-H, see Scheme 1 for its structure) for sulfonylation/arylation three

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• of quinones having exceptional radical-stabilizing abilities. The best example in nature is the radical pathway in the catechol oxidation process [56][57][58]. The structure of o-anisidine resembles catechol as it has two adjacent electron-donating functions (NH2 and OMe). For o-anisidine, the amine

• )cyclohexa-2,5-diene-1,4-dione (compound 10). Single-crystal X-ray crystallographic studies The ORTEP diagram of oxamide 3 is shown in Figure 1. Compound 3 crystallized in a monoclinic crystal system in the P21/n space group. The single-crystal X-ray structure of compound 3 was reported with the space group

• a monoclinic crystal system in the space group P21/c. The structure was similar to the structure of oxamide 3 (Figure 2). The hydrogen of the NH unit was concealed by the oxygen atoms of the C=O and OMe units. Consequently, it did not engage in intermolecular hydrogen bonding. Due to the planar

The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• , representing the easygoing generation of a collection of small-molecules essential for structure–activity relationships (SAR). The isocyanide-based Ugi reaction is one of the most resourceful tools and still broadly studied MCR, generating multifunctional libraries of α-aminoacylamide derivatives, or Ugi

• excellent yields (up to 99% yield). Some selected compounds were screened against five human solid tumor cell lines: lung (A549), breast (HBL-100 and T-47D), cervix (HeLa) and colon (WiDr). Preliminary SAR studies have revealed the preference of the N-benzylisatin structure over the 3,3-protected-oxindole

• and Figure 2). Like the oxindole scaffold, 1,2,3-triazole is also considered a privileged unit in drug discovery since compounds having this structure have a broad spectrum of biological activities, and have been widely used to create anticancer drug candidates [24][25]. The copper-catalyzed azide

Introduction of peripheral nitrogen atoms to cyclo-meta-phenylenes

• Koki Ikemoto and
• Hiroyuki Isobe

Beilstein J. Org. Chem. 2024, 20, 1207–1212, doi:10.3762/bjoc.20.103

• structural features of nitrogen-doped [n]CMPs. The crystal molecular structures of 3a and 3b are shown in Figure 3. The hexagonal macrocyclic structure of 3a showed a chair-like conformation with alternating biaryl dihedral angles showing +/– values. The octagonal structure of 3b exhibited a saddle-like

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• quinone structure. Consequently, we redirected our focus towards alternative, more electron-rich substrates. In a preceding investigation, we identified that the bifunctional enzyme JadH proficiently converted prejadomycin (9) to 8, a compound demonstrated to spontaneously oxidize to 1 under aerobic

• spectrometry (HRMS) analysis of 10 ([M − H]− calcd for C18H12O5, 307.0612; found, 307.0607, Figure S4, Supporting Information File 1) suggested a possible identity as hydroquinone–kinobscurinone [11]. However, attempts to elucidate the chemical structure of 10 were not successful due to the inherent

• -independent reactions failed to occur. It is plausible that 1 lacked the capability to reductively activate molecular oxygen owing to the quinone structure. In these instances, FADH2/FMNH2 were deemed necessary as cofactors for AlpJ-family oxygenases. These findings uncover a noteworthy substrate-controlled

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• and hedycaryol were prepared from their corresponding SMILES string using the RDKit library [30]. Electronic structure calculations on these carbocations were performed using the hybrid DFT functional M06-2X [31] and with the range-separated hybrid meta-GGA functional ωB97M-V [32] with the 6-31+G(d,p

• Information File 1). The NCI plot analysis for the other two sets of carbocations E–L are presented in Supporting Information File 1 (Figure S2). Among them G has the highest Gibbs free energy. Inspection of its geometry and corresponding NCI plot reveals that it has the most puckered structure of all the

• to repulsive and yellow represents slightly attractive interactions. The bottom two plots are side views of the cations and emphasize the relatively puckered structure of B compared to A. NCI plots for F and H hedycaryol cations. The C+···OH distances (Å) are shown in black. Correlation plot relating

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• 305-8577, Japan 10.3762/bjoc.20.100 Abstract The addition reaction of C60 with silylene 1, a silicon analog of carbene, yielded the corresponding bis-adduct 3. The structure of 3 was determined by single-crystal X-ray structure analysis, representing the first example of a crystal structure of a

• atoms of the C60 carbon cage, eight methyl, and three methine carbon signals of the Dip group were observed. These spectral features are consistent with the structure of 3 as the e isomer of bis-adducts with Cs symmetry. The plane of symmetry includes one silirane ring and bisects another silirane ring

• ions of 3. Finally, the structure of 3 was established by single-crystal X-ray structure analysis. The ORTEP diagram of 3 is presented in Figure 5 with the selected bond lengths and angles collected in Table 1. The cage C–C bond lengths of the addition sites are C1–C9: 1.623(2) Å and C21–C40: 1.6282(19

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• is a report by Rajesh and Prajapati from 2015 [79]. In this work, the authors aimed at obtaining substituted β,β-indanones, and the decarboxylation step was a mandatory part of the methodology, with no interest in controlling the process. The indanone core is a privileged structure, as it is often

• may drive further structure–activity relationship studies to identify indanone targets of pharmacological interest. Conclusion In summary, we developed a simple and efficient methodology for the Nazarov reaction of aryl vinyl ketones, leading to 3-aryl-2-ethoxycarbonyl-1-indanones and 3-aryl-1

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

• resistance to the most reactive 1,3-carbons of the furan ring. A combination of experimental and computational studies clarifies the impacts of these sterically congesting substituents on each molecule’s electronic structure. We further studied the reaction rates of 1,3-diarylisobenzofurans with the strong

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• accelerated by enzymes. These enzymes share a similar mechanism of cytosine deamination and a similar tertiary structure. Despite this similarity, individual enzymes are selective for the corresponding cytosine-containing substrates with little or no cross-reactivity. Cytosine deaminase, which is present in

• cytosine deamination for A3 and CDA [50][59][60][61][62][63][64]. The fact that dZ (IIc), FdZ (IId) and diazepinone 2'-deoxyriboside (IIIb) used in the same DNA sequence had a differing inhibitory effect on individual A3 under identical conditions means that the structure of the cytidine analogue

• and a structure of proposed phosphinine deoxyribosides Va–c. V0 of A3A mimic-catalysed deamination of 5'-dTTTTCAT in the absence (no inhibitor) and presence of inhibitor at the concentration indicated. Conditions: 400 µM of the substrate 5'-dTTTTCAT, 8 µM or 32 µM of ODN containing α- or β-anomer of

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

• of a benzylic hydrogen atom from the substrate by Br•, to give HBr and a structure-stabilised carbon-centred radical, which may react with Br2 to give the brominated product, thus regenerating Br• that is able to sustain the chain process. In the absence of light (left side of Figure 1), the reaction

• aryl/benzyl polybromides are also well known. Looking at this subject, the number of found reaction hits (role = reagent) for the structure “as drawn” provides a quantitative measurement of the synthetic usefulness of these halides. This work focuses on the application of the peroxide-bromide method to

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• impose a serious limitation for their practical applications [8][9][10][11][12][13]. It is believed that the rational design of the molecular structure can assist to endow all the necessary properties in a single photoswitch [14]. Therefore, engineering of novel photochromic couples with an intention to

• attempts to search the TS structure instead resulted in a distinct TS geometry than that involved in thermal back conversion. The optimized geometry of the TS for the Id system along with the important geometrical parameters are shown in Figure 3. Analysis of the geometrical parameters reveals that the TS

• Figure 7. As mentioned earlier, the dissociation of the two newly formed σ-bonds proceeds in a highly asynchronous mechanism. Therefore, initially, only one of the two σ-bonds denoted as α bond in the photoproducts (Figure 7) dissociates to form a TS structure having singlet biradicaloid. Subsequently

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• -bonding dicyanopyrazinoquinoxaline (DCPQ) suspensions with excess potassium hydroxide, resulting in moderate to good yields. Both families of compounds were analyzed by UV–vis and NMR spectroscopy, where the consequences of hydrogen bonding capability could be assessed through the structure–property

• phase within these systems [24]. These molecules are particularly intriguing as they bear resemblance to Głowacki’s compounds discussed above. Reported here is a robust structure–property relationship study of these types of molecules with a particular interest in their optoelectronic properties

• dicyanopyrazinoquinoxalines (DCPQs) 1a–7a and subsequent mild one-step synthesis of hydrogen-bonding dihydropyrazinoquinoxalinedione (DPQDs) 1b–7b. The structure–property relationships have been established within and between the two families using optical measurements. Moreover, the incorporation of H-bonding functionality

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

• Luca Julianna Tóth,
• Kateřina Krejčová,
• Milan Dejmek,
• Eva Žilecká,
• Blanka Klepetářová,
• Lenka Poštová Slavětínská,
• Evžen Bouřa and
• Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

• still scarce. Recently, many studies have been focusing on drug repurposing or screening libraries of already approved biologically active compounds [16][17]. This approach might represent a very promising strategy in the case of targeting the coronaviral RdRp due to the highly conserved structure of

• the benzoxazole ring-opening reaction, namely 16. Simplification of the hit molecule: synthesis of pyridone derivatives We decided to simplify the relatively large structure of HeE1-2Tyr (1) in order to obtain smaller, more accessible inhibitors with similar or better properties. The employed novel

• antivirals. Structure of HeE1-2Tyr (1) and of the derivatives synthesized in this work. Analysis of inhibitory activity against SARS-CoV-2 RdRp using primer extension assay. A) Gel-based polymerase assay with a constant concentration of fluorescently labeled template/primer RNA (0.5 µM) and the polymerase

Spin and charge interactions between nanographene host and ferrocene

• Akira Suzuki,
• Yuya Miyake,
• Ryoga Shibata and
• Kazuyuki Takai

Beilstein J. Org. Chem. 2024, 20, 1011–1019, doi:10.3762/bjoc.20.89

• localized at edges [2]. The presence of edges greatly modifies the electronic structure of nanographene, which strongly depends on the geometry of the edges [3][4][5]. Edges at the periphery of nanographene sheets consist of two kinds of geometry: zigzag edges and armchair edges. The presence of the zigzag

• . Ferrocene (FeCp2) is a “sandwich” compound where the two cyclopentadienyl (Cp or C5H5-) rings sit above and below the Fe2+ ion [16]. The electronic structure of FeCp2 satisfies the 18-electron rule, so this compound is stable due to a closed L-shell structure in view of the atomic orbitals of Fe and it is a

• diamagnetic molecule (S = 0, no spin magnetism) compared with other metallocenes [17]. However, FeCp2 is easily oxidized to a monovalent cation, the electronic structure of which is magnetic (S = 1/2). Electron spin resonance (ESR) spectroscopy revealed the spin magnetism of cationic FeCp2 accommodated in