Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• distal binding monomers (Db) demonstrated slightly higher affinity for A–U base pairs while one demonstrated slightly higher affinity for the G–C base pair. These results provide insight into the nature of PNA monomer design particularly around linker design and rigidity. Keywords: Hoogsteen hydrogen

• monomer. We reported a similar result for 5-triazolyluracil [28]. However, despite the development of pyrimidine-recognizing bases (P, P9, E, etc.), the sequence selective recognition of any double helical region of RNA remains an elusive problem owing to the difficulties in pyrimidine recognition via a

• % of the final desired monomer 8 was also isolated in the coupling step, presumably due to hydrolysis of the allyl ester in the iron reduction step. The remaining allyl ester 7 was deallylated via Pd(PPh3)4 to afford the monomer 8 in 51% yield. Db2 Synthesis Db2 was prepared through a convergent

Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• synthetic route enabled Siegel and co-workers to determine the first biological target of complanadine A. Screening against a panel of cell surface GPCRs revealed that complanadine A acts as a selective agonist of MrgprX2, while the monomer lycodine showed no significant activity towards this target. This

Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes

• Suvenika Perera,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176

• have studied water-soluble acyclic CB[n] based on methylene-bridged glycoluril monomer–tetramer and found that glycoluril tetramer-derived hosts displayed the highest binding affinity toward hydrophobic alicyclic dications due to enhanced ion–dipole interactions [40][41]. Separately, we studied

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform

• Jie Yan,
• Shaodong Sun,
• Minghao Wang and
• Si Wu

Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159

• monomer to 103 min for the polymer. Linear azobenzene polymer solar thermal fuels Linear azobenzene polymers possess excellent processability and serve as ideal solid-state matrices for photoisomerization [49][50][51][52][53][54][55][56][57], making them suitable candidates for solar thermal fuels

• azobenzene polymer solar thermal fuels: (a) Photoisomerization and thermally induced reverse isomerization of diacetylene monomers. The inset depicts the crystal structure of diacetylene monomer (n = 6, X = N–H) with dashed lines indicating intermolecular hydrogen bonds. Figure 4a was used with permission of

• subject to CC BY 4.0. (b) Schematic illustration of diacetylene monomer photopolymerization and the conjugated polydiacetylene structure. Figure 4b was redrawn from [47]. (c) Photoisomerization of a conjugated azobenzene polymer with a carbazole backbone. Figure 4c was redrawn from [48]. Linear azobenzene

Synthesis of optically active folded cyclic dimers and trimers

• Ena Kumamoto,
• Kana Ogawa,
• Kazunori Okamoto and
• Yasuhiro Morisaki

Beilstein J. Org. Chem. 2025, 21, 1603–1612, doi:10.3762/bjoc.21.124

• , enantiopure [2.2]paracyclophane was used as a chiral monomer to prepare optically active conjugated polymers and cyclic trimers [21], in which π-electron systems were stacked to form zigzag and triangular structures, respectively. The conjugated polymers and cyclic trimers exhibited circularly polarized

• –Hagihara cross-coupling [37][38] of (Sp)-1 with diiodotolane 2 afforded the corresponding ribbon-shaped compound (Sp)-3 in 39% isolated yield. Triisopropylsilyl (TIPS) groups in (Sp)-3 were removed using Bu4NF to afford diyne (Sp)-4 as a monomer in 45% isolated yield. The reaction of (Sp)-4 with

• diiodobenzene 5 using a Pd2(dba)3/PPh3/CuI catalytic system in toluene and Et3N under diluted conditions (monomer concentration = approximately 1.3 × 10−3 M) was performed. The corresponding cyclic dimer (Sp)-6 and trimer (Sp)-7 were detected mainly by thin-layer chromatography (TLC) and separated roughly using

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• initiate the disassembly of the HIM trimer into a HIM monomer [18]. The HIMs were found not to interact with tetrabutylammonium nitrate, signifying a lack of association between the HIM and the bulky cation (tetrabutylammonium) or the non-nucleophilic anion (nitrate). With these observations, and the

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• modular synthesis, acyclic CB[n] can be easily modified synthetically [42][43][44][45][46][47][61]. Acyclic CB[n]-type receptors featuring different length glycoluril oligomers (monomer–pentamer) and different aromatic walls (e.g., naphthalene, anthracene, triptycene) have been studied [42][62][63][64][65

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• its photophysical properties. While a pure sample of the dimer has not yet been isolated, a UV–vis spectrum of Cl2B after 1.75 hours of irradiation in DCM was recorded. The peak corresponding to the remaining monomer was observed, along with a new peak blueshifted by 47 nm compared to the parent

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

• -red region, providing excellent control over molecular weight and polydispersity in the polymerization of various monomers, including methyl acrylate. The authors highlight that under red-light irradiation, the bacteriochlorin catalyst has achieved 89% monomer conversion in just 12 hours, with

• molecular weights closely matching theoretical predictions and low polydispersity indexes. Even with reduced catalyst loadings (down to 10 ppm), the polymerization process has remained efficient, maintaining high monomer conversions and well-controlled molecular weights. What makes this approach

Hydrogen-bonded macrocycle-mediated dimerization for orthogonal supramolecular polymerization

• Wentao Yu,
• Zhiyao Yang,
• Chengkan Yu,
• Xiaowei Li and
• Lihua Yuan

Beilstein J. Org. Chem. 2025, 21, 179–188, doi:10.3762/bjoc.21.10

• polymers (Scheme 1). The terpyridyl group and the pyridinium cation in the AB-type monomer G2 each function as a “sticker” to enable supramolecular polymerization in the presence of the macrocyclic component and zinc ions. The driving force for the recognition involves multiple cooperative interactions

• that by applying the design rules commonly known for metallosupramolecular polymers and macrocycle-mediated dimerization to supramolecular chemistry, we would be able to generate supramolecular polymers with this heterodifunctional monomer, with one end comprising two macrocycles and the other end

• coordinating metal ions. In such supramolecular polymers, orthogonal host–guest and coordination interactions are responsible for polymerization. Host–guest complexation and zinc coordination When forming supramolecular polymers, an AB-type monomer, i.e., the guest G2, is supposed to interact with the

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

• possesses higher HOMO and LUMO energy levels than that of the monomer F1, with a smaller HOMO–LUMO energy gap (3.92 eV for F1 versus 4.11 eV for PH1). The DFT results thus agree pretty well with the fluorescence spectra in solution: G66 shows a fluorescence peak at 470–500 nm, while F6 has peaks located

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• monomer. Since the aggregates were found catalytically inactive, while the monomers in the solution were active, the system acts as a pH-switchable ‘ON–OFF’ organocatalyst. In the case of the enamine-mediated addition of cyclohexanone (62) to 4-nitrobenzaldehyde (7), using 10 mol % of 58 provided up to 99

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• confirmed that a copper–ligand monomer complex exists in the mechanism through nonlinear relationship experiments and kinetic studies (Scheme 17). He et al. [68] developed the regio- and enantioselective monofluoroalkylation of yne-allylic esters using fluorinated malonates as the starting materials, giving

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• parent compounds. Furthermore, fluoroalkenes can be utilized as feedstock for fluoropolymers. Teflon, which is a well-known fluoropolymer with excellent water-repellent and oleophobic properties, is synthesized by polymerizing a monomer called tetrafluoroethylene. As a consequence, convenient and diverse

Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study

• Stiliyana Pereva,
• Stefan Dobrev,
• Tsveta Sarafska,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221

• molecule (O2/O3 side of the truncated cone). These hydrogen bonds have been detected experimentally by NMR: it was supposed that the OH-3 group of one glucose monomer is interacting with the OH-2 group of the neighboring glucose unit [21][22]. Experimental evidence for the involvement of primary hydroxy

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• -assembly across many length scales (Figure 1), allowing for the control of properties through not only chemical modifications on the monomer, but also changes to the gelation process [2]. Whilst this tunability is advantageous in that it allows for a wide range of functionality and applications, this also

Synthesis and reactivity of the di(9-anthryl)methyl radical

• Tomohiko Nishiuchi,
• Kazuma Takahashi,
• Yuta Makihara and
• Takashi Kubo

Beilstein J. Org. Chem. 2024, 20, 2254–2260, doi:10.3762/bjoc.20.193

• unit allows for spin localization at the 10-position of anthracene through C–C bond rotation, resulting in a tail-to-tail σ-dimer (Figure 1b). The σ-dimer exhibits an equilibrium state between the monomer radical and the σ-dimer in solution, and mechano-stimulus-induced C–C bond fission in the solid

• state yields the monomer radical [16][17][18]. Therefore, aromatic hydrocarbon radicals with Ant units possess both stability and reactivity depending on the conditions, giving them high potential for use as reactive catalysts [22][23] and stimuli-responsive sensors [24][25]. To further investigate this

• activation barrier is only 2.94 kcal mol−1 (Supporting Information File 1, Figure S3). Thus, these two structures are likely in equilibrium and rapidly exchange with each other in solution. The energy difference between DAntM dimer (head-to-head σ-dimer) and DAntM radical monomer was also evaluated, showing

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• claimed to be a potential monomer for the preparation of new fluoropolymers [43][44]. Despite the fact that HFO-1132 has been known for a long time, there are no publications that summarize the chemistry of the compound. With this in mind, the main methods for the preparation of (E/Z)-1,2-difluoroethylene

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

• of COFs was further demonstrated by employing the 1,4-diisocyanobenzene (102) monomer, leading to the generation of four COFs 103 in 71–88% yield. The results showed that the synthesized COFs displayed good chemical and thermal stability (Scheme 32). 3.2 GBB-like reactions Basak et al. [68] reported

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• , Tottori University, 4-101 Koyamacho-minami, Tottori city, 680-8552 Tottori, Japan 10.3762/bjoc.20.124 Abstract The synthesis of protected precursors of cyclic β-1,6-oligoglucosamines from thioglycosides as monomers is performed by electrochemical polyglycosylation. The monomer with a 2,3-oxazolidinone

• protecting group afforded the cyclic disaccharide exclusively. Cyclic oligosaccharides up to the trisaccharide were obtained using the monomer with a 2-azido-2-deoxy group. Keywords: cyclic oligosaccharide; electrochemical glycosylation; glucosamine; polyglycosylation; Introduction Electrochemical

• monomers 6 with a 2-deoxy-2-phthalimido (PhthN) group (Table 1). The influence of the anomeric leaving group was not investigated in this study. However, the p-ClC6H4S (ArS) group was used to avoid the exchange of the anomeric leaving group [16]. The monomer 6a (R3 = R4 = Bz) was completely consumed with a

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

• 2,5-furandicarboxylic acid (FDCA), a monomer used for biopolymer production [61]. Other modifications include the use of ortho-substituted aromatic amines as a base in the Cannizzaro reaction and others (Figure 2) [62]. The synthesis of several useful molecular entities [63][64] and synthons of

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• band observed in the SDS-PAGE gel of each homolog is consistent with the expected monomer molecular masses of approximately 21 kDa, several other bands appear (Figure 2A). The banding patterns of each of the homologs are similar to those of Vs NnlA. These higher molecular weight bands are likely not

• from 35.9 to 49.0 kDa, masses consistent with dimers (Table S2 in Supporting Information File 1). The higher oligomer peak was absent in all of these samples. As observed for Vs NnlA, there is no evidence for a significant population of monomer in any of these samples. From these data we conclude that