Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• , 861.08866. HOMO levels of unsaturated substrates and LUMO levels of fullerenes computed at the B3LYP/6-31G(d) level of theory. HPLC profiles of themal [2 + 2]reaction of Li+@C60 with substrate 1 (a) and 2 (b) in o-dichlorobenzene at room temperature. HPLC profiles of 5a (a) and 5b (b) before and after

• +) reference couple. Working electrode: Pt, counter electrode: Pt, reference electrode: Ag/Ag+ in acetonitrile, solvent: o-dichlorobenzene, supporting electrolyte: 50 mM TBAPF6. Reaction mechanisms of thermal and photoinduced [2 + 2] cycloaddition on C60 [19][22][23]. Thermal [2 + 2] reaction of Li+@C60 TFSI

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

• 78.5 (C-4’), revealed the presence of a 2,4-di-O-methylpyranose substructure. Furthermore, an HMBC, δH 3.48 (H-6”)/δC 78.7 (C-4”), along with typical chemical shifts and coupling constants from C-1” to C-5” obtained in CD3OD (Table 2), indicated the presence of a 4-O-methylpyranose substructure. The

• Figure 3. Consequently, the relative configuration of the THP ring was determined to be 3S*,5S*,7S*. For the 2,4-di-O-methylpyranose moiety, the two large coupling constants in CD3OD, 3JH-1’/H-2’ (7.8 Hz) and 3JH-2’/H-3’ (9.0 Hz), indicated that H-1’, H-2’, and H-3’ were in the axial position. The two

• NOESY correlations in CDCl3, δH 3.45 (H-7’)/δH 4.87 (H-1”) and δH 3.45 (H-7’)/δH 4.23 (H-5a”), revealed that the methoxy group at C-4’ was in the equatorial position and H-4’ was in the axial position. The 2,4-di-O-methylpyranose moiety was identified as 2,4-di-O-methylxylose. For the 4-O-methylpyranose

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• cyclases responsible for DMOA-derived compounds. To achieve this goal, we first aimed to establish a production system for the 4-desmethyl analogue of (6R,10′R)-epoxyfarnesyl-DMOA methyl ester by utilizing the polyketide synthase FncE, the prenyltransferase FncB, the O-methyltransferase InsA1, and the FAD

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• furnished good results for the HPW-catalyzed GBB-3CR with yields greater than 63% (5m–o). It is always important to point out the limitations of a given method and in our case, we did have some. Purification by column chromatography became necessary since product isolation by precipitation was not effective

Introduction of a human- and keyboard-friendly N-glycan nomenclature

• Friedrich Altmann,
• Johannes Helm,
• Martin Pabst and
• Johannes Stadlmann

Beilstein J. Org. Chem. 2024, 20, 607–620, doi:10.3762/bjoc.20.53

• ). Attempt at an application to O-glycans The short, but varied core-region of O-glycans do not lend themselves to the proglycan logic as much as N-glycans. However, its application is possible as demonstrated in an article on chondrocyte glycans [56]. The branches to the core structures can be dealt with in

• much the same way as N-glycan antennae. It appears, however, that the particular core type has to be specified as shown in Figure 12. The very simple and frequently occurring O-glycans T-, Tn- and Sialyl-Tn-antigen may be exempted from such attempts. Likewise, will the rarer core types be left out for

• . Proglycan annotation of oligomannosidic and some hybrid-type N-glycans. Plant and insect N‐glycans. Since the xylose strongly indicates plant N‐glycans, a simplified annotation, possible with the macro‐term “La” for the Lewis A determinant, may be used (grey font). Provisional outline of how O-glycans with

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• , such as medium-chain alcohol dehydrogenase (CpDCS), esterase (CpDCE), P450 and O-methyltransferase (CpOMT1) (Figure S37). Through genome excavation and analysis of Penicillium shentong XL-F41, a significant difference was discovered between the key enzymes involved in the formation of product compound

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• Michael O. Akintubosun Melanie A. Higgins Department of Biological Sciences, The University of Alabama, 3314 Science and Engineering Complex, Tuscaloosa, AL 35487, USA 10.3762/bjoc.20.51 Abstract Hygromycin A is a broad-spectrum antibiotic that contains a furanose, cinnamic acid, and

• scyllo-inositol but can have reduced activity on ᴅ-chiro-inositol, ᴅ-glucose, ᴅ-xylose and 4-O-benzyl-myo-inositol [12][13][15][16][17]. However, scyllo-inositol dehydrogenases are active on scyllo-inositol and myo-inositol to a lesser extent [16][18]. Altogether, this suggests that Hyg17 can accommodate

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• the αKG-dependent dioxygenase have been analyzed in detail due to its relatively small molecular weight and the low costs of its cofactors: αKG, ascorbic acid, and iron ions. The αKG reacts with iron and molecular oxygen to form the highly reactive Fe(IV)=O via oxidative decarboxylation. This active

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• conformation 1, 2, and the conformation at the saddle point, we measured the dihedral angles and the distance between two hydrogen atoms using Xcrysden [10]. (a) Molecular structure of 1-pyrenebutanoic acid succinimidyl ester (PASE). The black, white, red, and blue balls represent C, H, O, and N atoms

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

• (namely furan-2(5H)-ones, tetrahydrofurans and pyrans spiro-conjugated with the succinimide ring) has been developed. The protocol consists of Rh(II)-catalyzed insertion of heterocyclic carbenes derived from diazoarylidene succinimides (DAS) into the O–H bond of propiolic/allenic acids or brominated

• 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

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• a terminal phenanthroline receptor substituent was synthesized. Upon irradiation in acetonitrile or DMSO with light of 436 nm, they underwent Z–E isomerization of the C=C bond, followed by very fast N→O migration of the acyl group and the formation of nonemissive O-acylated isomers. These isomers

• light and H+ or sequential addition of Fe2+ and AcO− ions. Keywords: fluorescence; molecular switches; N→O acyl rearrangement; naked eye effect; photochromism; Introduction Photochromism is defined as the reversible transformation of a molecular entity between different forms, having different

• inverse photochromism), such as merocyanine forms of spiropyrans and spirooxazines, azomethine imines, thioindigoid dyes and N→O acylotropic systems [12][13][14][15]. Recently, they have been actively used to create next-generation molecular switches, materials with new properties (in particular, color

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• quantities of the most active compounds for advanced biological testing. Pleasingly, our four-step approach using a potassium O-ethyl dithiocarbonate-mediated formation of thio intermediates 11a–c (thiol–thione tautomers) with subsequent sulfur removal using iron powder in acetic acid [19] proceeded smoothly

• target affinity (pI50 5.7), whereas compound 13c, bearing an o-tolyl substituent, provided insufficient control of three weeds, i.e., ALOMY, POAAN, and LOLRI (Table 2, entry 6), in line with a surprisingly weak target affinity (pI50 4.5). Remarkably, 6-bromo-5-(2-fluorophenyl)-2,3-dihydro[1,3]thiazolo

• marginal effects against ALOMY_R and LOLSS_R. Whilst 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines 7c and 13b showed weak to moderate efficacy against ALOMY_R (strongly dependent on the application rate), o-fluorophenyl analogue 7b exhibited strong control of this resistant, commercially important grass weed

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

• ligands and a halide-induced ligand rearrangement (HRI) [81]. For example, when two symmetric Rh(I) complexes, one with P,O and one with P,S ligands, are subjected to the addition of halide anions, a rearrangement is observed by ligand exchange from the symmetric [Rh(P,O)2], [Rh(P,S)2] complexes to the

• dissymmetric [Rh(P,O)(P,S)] complex. This rearrangement allows access to tweezers with two different arms with two types of weak sites of different reactivities. This HRI reaction was first used to access simple dissymmetric rhodium(I) tweezers such as 38 with different aromatic arms [82], 39 with Zn/Mg

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

• recently developed series of bisbiphenylphosphine ligands, RP(o-biphenyl)2 (R = OPh, Ph, t-Bu) [36][37]. When urea alkene 1a (0.1 M, CD2Cl2) was treated with 1 mol % LAuOTf, where L = PhOP(o-biphenyl)2 (4a), PhP(o-biphenyl)2 (4b), t-BuP(o-biphenyl)2 (4c), the fastest rate to form 3a was observed with the

• ligand with the greatest π-acceptor character and weakest donor character, namely L = PhOP(o-biphenyl)2 (Table 1) [38]. Notable amounts of scatter and a narrow range of observed rates, however, reveal the differences to be relatively minor (Table 1, entry 1, krel(4a/4c) = 3.6). Nevertheless, each

• by identifying a more Lewis acidic gold. To determine whether benzamide (1c) cyclization could be made efficient with appropriate combination of ligand and MeOH we surveyed rates with (PhO)P(o-biphenyl)2AuOTf (4a) and JackiephosAuNTf2 (6a, Table 5). Benzamide rates remain slow but gains can be

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• rotated to maximize the distances between the lone pairs of the electron-rich fluorine and oxygen atoms. Usually, one of the fluorine atoms lies in a syn orientation to an oxygen (e.g., 3f has an F–C–C–O dihedral angle of 15.6°) creating a dipole. This dipole appears to aid crystal packing by forming weak

• ); ref codes IZICEA [47], XOPZEK and XOPZIO [48]) are known. Interestingly, in contrast to the previously described acyclic structures no OH···O(H) hydrogen bonds are present in structure 5e – the molecules are linked by OH···O(NO2) interactions. Discussion Keto–enol tautomer studies have shown that DBM

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• -domains could attenuate the virulence of pathogens. 5’-O-N-(Aminoacyl or arylacyl)sulfamoyladenosine (AA-AMS) is a bisubstrate small-molecule inhibitor of the A-domains of NRPSs. However, the bacterial cell permeability of AA-AMS is typically a problem owing to its high hydrophilicity. In this study, we

• mycobactin from Mycobacterium tuberculosis [6]. 5′-O-Sulfamoyladenosine (AMS), a bioisosteric analog of an AMP intermediate, has been used as a non-hydrolysable scaffold for developing A-domain inhibitors. Moreover, 5′-O-[N-(salicyl)sulfamoyl]adenosine (Sal-AMS) and its derivatives show potent inhibitory

• , Supporting Information File 1). After washing, the wells were incubated with an anti-His6 tag antibody and subsequently with a horseradish peroxidase-conjugated secondary antibody. The amount of GrsA bound to ʟ-Phe-AMS-biotin was determined by measuring the absorbance of o-phenylenediamine dihydrochloride at

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• the C=O bond. Thus, an innovative approach on nanocatalysis was introduced, incorporating solid grinding in catalyst-free conditions with the challenge of a high catalyst loading and lack of aliphatic aldehydes or ketones being utilized as substrates for the formation of their respective BIMs [118

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

• photochemical instability, as evidenced by their low N–O bond dissociation energy (BDE ≈ 42 kcal/mol) [28], the reliance on toxic tin hydrides as reductants and the undesired radical recombination with reactive 2-pyridylthiyl radicals that leads to (alkylthio)pyridine byproducts [26]. More recently, N

• -hydroxyphthalimide (NHPI) esters (3) have emerged as convenient alternatives to Barton esters (Scheme 1) due in part to their ease of synthesis and greater stability (N–O BDE ≈ 75 kcal/mol) [28]. Their use as radical precursors was first described by Okada and colleagues in 1988 [29], who showed that C(sp3)-centered

• transfer complexes with a donor species 6 or via LUMO lowering activation with Brønsted and Lewis acids 7 (Scheme 2B), collectively offering a number of variables to influence their reactivity. Upon reduction, RAEs give rise to a radical anion 8 with a weakened N–O bond (BDE < 70 kcal/mol) [33]. While

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• short-term heating of the melted reactants at 220–250 °C is described, and the compounds were characterized by means of single-crystal X-ray crystallography, NMR, UV–vis, and IR spectroscopy, as well as cyclic voltammetry. The reaction with o-amino-, o-hydroxy-, and o-mercapto-substituted arylamines

• widened the scope and provided an access to derivatives of N,O- and N,S-heteropentacyclic quinoxalinophenoxazine, triphenodioxazine and oxazinophenothiazine systems. Keywords: 3H-phenoxazin-3-one; fluorescence; molecular structure; pentacyclic heterocycles; synthesis; Introduction 3H-Phenoxazin-3-one

• structure, 3H-phenoxazin-3-ones can easily be accessed through oxidative couplings of o-aminophenols [3][4] or N-aryl-o-benzoquinone imines [5][6]. Further, they can serve as efficient precursors of pentacyclic N,O-heterocyclic compounds that possess promising properties for application in fluorescent

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• data of 1 allowed identifying characteristic 1H and 13C signals very similar to those of unguisin B (2) [1][5], the difference being the replacement of the Phe-4 in 1 by Val-4 in 2. This assignment was confirmed by observation of HMBC correlations from δH 7.98 (NH) and δH 8.44 (NH) to C=O (δC 173.1

• ) and from δH 2.93 and 3.01 (H2-β) to C=O (δC 171.1) (Figure 3), together with key NOESY interactions between the NH signals at δH 7.98↔8.44↔8.14. The absolute configuration of 1 was assigned by Marfey’s method [14]. Comparison of the retention time by LC–MS between the derivatized 1 as well as the

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• , these substructures occurred in many different contexts, such as blood group H, LacdiNAc, or the Sda motif, and particularly in sequences resembling O-glycans, milk oligosaccharides, and glycosphingolipids. At first glance, these two binding specificities may seem unconnected, indicating a rather

• in which its preferred binding motifs occur (O-glycans, milk glycans, GAGs) are absent from most plants, including melons. We thus hypothesize that the role of this lectin might be to recognize non-self epitopes, such as for protection against pathogens, which is a common function in plant lectins [3

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

• precursors of S- and Se-inserted HBCs. The subsequent Scholl reaction allowed the formation of four new C–C bonds, but failed to afford the fully cyclized chalcogen-embedded HBC whatever the conditions tested, presumably due to large strain in line with the size of S and Se atoms as compared with O. The

• reducing agent, O-extrusion takes place with concomitant ring contraction to give the corresponding PBI 6f, isolated in 63% yield after oxidative quenching and work-up. Contrary to photo- or thermal activation, it is important to note that the mechanism for O-extrusion involves in this case the dianion of

• injection were investigated as stimuli to trigger O-extrusion. Moresco, Peña and co-workers thus designed diepoxytetracene precursor 56, displaying an oxabicyclo moiety at each extremity (Scheme 15) [83]. The latter was prepared in one step via a double Diels–Alder reaction between furan and 2,6

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• and Discussion We started our study by testing the cycloaddition of N-tosyl-tethered bisalkyne 1a and C70 (Scheme 2) using our previously optimized reaction conditions for the C60 derivative [33]: that is, using 10 mol % of a mixture of [Rh(cod)2]BF4 and Tol-BINAP in o-dichlorobenzene (o-DCB) and

• group was substituted by a mesyl substituent and BIPHEP was used as a model phosphine ligand instead of Tol-BINAP to reduce the computational cost. The calculations, conducted at the B3LYP-D3/cc-pVTZ-PP(SMD=o-DCB)//B3LYP-D3/cc-pVDZ-PP level (see full computational details in Supporting Information File

• isomers. B3LYP-D3/cc-pVTZ-PP(SMD=o-DCB)//B3LYP-D3/CC-pVDZ-PP Gibbs energy profile of the [2 + 2 + 2] cycloaddition between our model diyne 1a and C70. Comparison between α- and β-reaction pathways. Black line: α-pathway. Grey line: β-pathway. Molecular structures correspond to the α-pathway. [Rh] = [Rh

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

• ; Introduction Proton-coupled electron transfer (PCET) enables the generation of various radical species under ambient conditions (Figure 1, top) [1]. In PCET processes, hydrogen bond formation between weak bases and acidic X–H bonds (X = N, O, C) is a key step, which is followed by concerted proton- and

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

• (Figure 2) as a fully conjugated analog of acenaphthene 5 by classical methods were unsuccessful (Supporting Information File 1, Table S2). In all experiments, the starting compound remained unchanged or bound into a sparingly soluble precipitate even in high-boiling solvents such as o-dichlorobenzene or

• 5. As the XRD study of the crystals showed (Figure 3), the molecular and crystal structure of the isolated compound is strongly dominated, on the one hand, by intra- and intermolecular hydrogen bonds with the participation of N, Cl, and O heteroatoms (forming an endless slightly corrugated ribbon