Amino acid-based surfactants: sustainable synthesis and antimicrobial mechanisms

• Rafaela Gomes Bezerra,
• Lourdes Pérez and
• Francisco Fábio Oliveira de Sousa

Beilstein J. Org. Chem. 2026, 22, 1067–1085, doi:10.3762/bjoc.22.85

• related to their antimicrobial activity; b) To describe their possible mechanisms of action in the interaction with microorganisms; and c) To present the novel approaches and perspectives on the use of these innovative molecules. Materials and Methods The methodology for this integrative review was

Synthesis of functionalized, 13-alkyl-substituted coralyne derivatives and investigation of their interactions with duplex and abasic site-containing DNA

• Laurin Beckmann,
• Jason Lennard Kunze,
• Hannah Karola Strunk,
• Maurice Michel and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 1057–1066, doi:10.3762/bjoc.22.84

• : Enzymes (UNG, APE1, NEIL1, NTHL1, NEIL3, OGG1) and mutants were produced as reported previously [59]. General methods The reaction mixtures were stirred with a magnetic stirrer equipped with a stirring bar. The average room temperature (rt) was 22–24 °C. If not stated otherwise, operations were conducted

Synthesis of novel 1,2,4-oxadiazole-isoxazoline hybrids and their in silico potential with adenosine receptors

• Pshtiwan S. Mohammed,
• Mohammed K. S. Dalo,
• Onur C. Yazıcı,
• Muhammet Yildirim and
• Akın Sağırlı

Beilstein J. Org. Chem. 2026, 22, 1033–1047, doi:10.3762/bjoc.22.82

• , such as sulfisoxazole, oxacillin, and acivicin, have been clinically utilized for many years [21][22][23][24][25][26][27][28] (Figure 1). The synthesis of 1,2,4-oxadiazole derivatives can be achieved through various efficient methods, such as the cyclocondensation of amidoximes with carbonyl compounds

• –hydrogen bond; dark-pink region: pi–pi stacked connections. Recent studies for the synthesis of 1,2,4-oxadiazole-isoxazoline hybrids. Synthesis of novel 1,2,4-oxadiazole-isoxazoline lead compounds by 1,3-DC. Synthetic methods for accessing the starting compounds (2a–k, 6a–j). Reagents and conditions: a

Semisynthesis, characterisation, and antibacterial evaluation of a novel lecanoric acid-derived amide library

• Ethan D. Abbott,
• Sasha Hayes,
• Jonathan M. White,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 1023–1032, doi:10.3762/bjoc.22.81

• diffractometer using Cu Kα radiation at 200.0(1) K using an Oxford Cryostream cooling device. The structures were solved by direct methods and difference Fourier synthesis [35]. Hydrogen atoms bound to the carbon atom were placed at their idealized positions and included in subsequent refinement cycles. The

Synthesis and optical resolution of 4,5-diaminohomoadamantane: a promising scaffold for chiral ligands and bioactive compounds

• Polina A. Man’kova,
• Vadim A. Shiryaev,
• Olga S. Podlipnova,
• Marat M. Khisyamov,
• Dmitry S. Nikerov,
• Alexander N. Reznikov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2026, 22, 1013–1022, doi:10.3762/bjoc.22.80

• in clinical practice [64][65][66], as well as auxiliaries and ligands in important asymmetric transformations [67][68][69][70]. Bi- and polycyclic vicinal diamines can also be considered as potential ligands for asymmetric catalysis [71][72][73][74], but little attention has been paid to methods for

• obtaining compounds of this type. Vicinal diamines with an adamantyl substituent I–K have already been obtained [75][76][77][78] and 1,2-diaminoadamantane L has been synthesized by different methods [79][80][81]. For 1,2-diaminonoradamantane M there are even fewer data [82]. Polycyclic vicinal diamines N

Z-Selective semihydrogenation of alkynes via Ni/Lewis acid synergistic catalyzed system using DMF as hydrogen source and solvent

• Lei Kang,
• Haifeng Gao and
• Luo Yang

Beilstein J. Org. Chem. 2026, 22, 1004–1012, doi:10.3762/bjoc.22.79

• the stereoselective semihydrogenation of alkynes a fundamental transformation in synthesis [1][2][3][4][5]. Among available methods, transition-metal catalysis has played a dominant role. The classical Lindlar catalyst remains the most widely applied heterogeneous system [6], yet it suffers from

• . Overall, this work provides a practical and cost-effective alternative to existing semihydrogenation methods and highlights the potential of base metal synergistic catalysis in stereocontrolled synthetic transformations. Experimental All experiments were performed under air. An oven-dried reaction vessel

Rh(III)-catalyzed chelation-assisted C–H activation/annulation of 2-arylimidazolines with cyclic diazo-1,3-dicarbonyl compounds: a novel approach to tetracyclic annulated derivatives of 2,3-dihydroimidazo[2,1-a]isoquinoline

• Ivan Lyutin,
• Grigory Kantin,
• Olga Bakulina and
• Dmitry Dar'in

Beilstein J. Org. Chem. 2026, 22, 997–1003, doi:10.3762/bjoc.22.78

• -heterocycle. Keywords: annulation; 2-arylimidazolines; catalysis; С–H activation; diazodiketones; 2,3-dihydroimidazo[2,1-a]isoquinolines; dimedone; tetraheterocycles; Introduction The advancement of organic synthesis techniques, especially methods for creating nitrogen-containing heterocycles, is essential

• many drug candidates and marketed drugs for the treatment of hypertension [2], diabetes [3], and various central nervous system disorders [4]. Recently, imidazolines that exhibit anticancer activity, like nutlins [5][6], have also garnered a lot of interest. There are numerous general methods for

Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• strategy enables the trans-selective semireduction of unactivated internal alkynes, addressing a limitation in previous methods that typically rely on electronically biased substrates. Moreover, simple substitution of the proton source with HFIP-d1 or iPrOD-d1 enabled efficient trans-selective deuteration

Synthesis of sterically shielded piperidine nitroxides via acid-catalyzed heterocyclization of β-aminoketone derivatives with ketones

• Mark M. Gulman,
• Yurii I. Glazachev and
• Sergey A. Dobrynin

Beilstein J. Org. Chem. 2026, 22, 948–954, doi:10.3762/bjoc.22.74

• Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia 10.3762/bjoc.22.74 Abstract The capabilities of modern methods for the synthesis of sterically shielded piperidine nitroxides with acyclic substituents are largely limited to symmetrical

• of nitroxides and increases their lifetimes in biological systems [12], which makes these radicals promising MRI contrast agents [13], spin probes for in vivo EPRI [14][15] and antioxidant tissue protectors [16]. Existing methods for the synthesis of such sterically hindered piperidine nitroxide

• be prepared by any of the previously used methods. Taking into account the fact that piperidine nitroxides are traditionally used as precursors of nitroxyl radicals of other types, especially the pyrroline and pyrrolidine series, this method may open up new possibilities in the chemistry of nitroxide

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• system development have further expanded the scope and efficiency of copper-catalyzed hydroamination. Despite these achievements, extending these methods to electron-neutral and sterically hindered unactivated alkenes, such as simple aliphatic terminal alkenes and internal alkenes, as well as achieving

A practical CO₂-mediated synthesis of 5,6-carboxylated silicon-rhodamines for targeted probe development

• Dongjie Hou,
• Shaowei Wu,
• Ning Xu,
• Pengjun Bao,
• Wenhao Jia,
• Qinglong Qiao and
• Zhaochao Xu

Beilstein J. Org. Chem. 2026, 22, 915–924, doi:10.3762/bjoc.22.72

• substituent reduces substrate reactivity, thereby diminishing the efficiency of the key ring-closing step and often resulting in low overall yields [45]. Moreover, these methods commonly rely on strongly basic conditions, particularly the use of highly reactive tert-butyllithium, which further reduces their

• operational complexity, safety concerns, and overall cost. Herein, inspired by the limitations of existing methods, we report a direct CO2-mediated carboxylation strategy for the efficient synthesis of 5,6-carboxylated SiR derivatives from brominated SiR precursors (Figure 1c). By introducing the classical

Site-specific labelling of native peptides and proteins: chemical and enzymatic strategies

• Antonio Angelastro,
• Jonathan Bargh,
• Subhajit Guria,
• Victor Laserna and
• Louis Luk

Beilstein J. Org. Chem. 2026, 22, 857–881, doi:10.3762/bjoc.22.67

• and peptide modifications introduce functionalities not achievable through recombinant methods alone, making them vital for fundamental research and biomedical applications [1][2][3][4]. Such chemistry underpins wide-ranging biological investigations including microscopy, proteomic analyses and tissue

• reagents, organic solvents or chaotropic agents must be avoided to preserve protein stability, preventing folding heterogeneity and supporting sustainability. Scalability. For therapeutic and industrial applications, modification methods should minimise waste and curtail costs, reflected in low process

• difference is often not sufficient for site-specific modifications. Consequently, recent effort has shifted towards targeting alternative less-frequent amino acid residues [82], as well as novel mechanisms such as linchpin-directed modifications summarized below. Various chemoselective methods for

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• thiol [22][23][24][25], through nucleophilic aromatic substitution on the catechol ring [26][27], or under electrochemical conditions [28][29][30][31][32]. A number of methods exist for the conversion of sulfides into sulfoxides, proceeding via either oxidative or non-oxidative pathways. The controlled

• catechol moiety were detected. The yields of the target sulfoxides ranged from 42% to 89%. Compounds 3–6 were prepared and characterized as described previously (3, 4, and 6 [23], 5 [42]). The structures of new thioethers 1, 2, 7 and sulfoxides 1a–7a were confirmed by the spectral methods IR-, 1H NMR, 13C

• -R) were studied by cyclic voltammetry (CV) (Table 1). All experimental electrochemical methods and conditions are presented in Supporting Information File 1. In the anodic area, the electrochemical profile of thioethers 1, 2, and 7 exhibit two successive oxidative stages consistent with previous

Synthesis and structural elucidation of a novel bis-spirooxindole from isatin and ethylenediamine

• Irene Moreno-Gutiérrez,
• Josefa L. López-Martínez,
• Sonia Berenguel-Gómez,
• Irene Torres-García,
• Duane Choquesillo-Lazarte,
• Manuel Muñoz-Dorado,
• Miriam Álvarez-Corral and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2026, 22, 813–820, doi:10.3762/bjoc.22.63

• Olex2 [22]. The structure was solved by intrinsic phasing with SHELXT [23] and refined by full-matrix least-squares methods on F2 using SHELXL [24]. Commercially available chemicals were obtained from Scharlau, TCI and Acros and used as received. Synthesis of 25: Isatin (1, 2.98 g, 19.85 mmol, 1 equiv

Knoevenagel condensation of 4,5- and 1,8-diazafluorenes

• Darya S. Cheshkina,
• Christina S. Becker,
• Alina A. Sonina and
• Maxim S. Kazantsev

Beilstein J. Org. Chem. 2026, 22, 803–812, doi:10.3762/bjoc.22.62

• . However, there are currently only limited methods for their synthesis, which are complicated and typically based on modifications of 4,5-diazafluorenone. Herein, we systematically studied the Knoevenagel condensation of both 4,5- and 1,8-diazafluorenes with aromatic aldehydes and evaluated the

Halogenated azobenzene acrylates: from efficient solution photoswitching to stable solid-state photochromic materials

• Martina Vachtlová,
• Michaela Fecková,
• Vítězslav Zima,
• Jan Podlesný,
• Milan Klikar,
• Oldřich Pytela,
• Patrik Pařík,
• Jakub Opršal,
• Eliška Juhaňáková,
• Veronika Chrtová and
• Filip Bureš

Beilstein J. Org. Chem. 2026, 22, 782–794, doi:10.3762/bjoc.22.60

• functionals (Table 3 and Supporting Information File 1, Figures S65–88). Both methods afforded the spectra that are similar in shape but either red or blue-shifted compared to the experimental data. The range-separated CAM-B3LYP functional was used to better describe the excited states and charge-transfer

• character of the investigated molecules. Anyway, both methods confirmed a minor effect of the halogen type, red-shifted λEmax values for monosubstituted E-isomers and the opposite trend for the Z-isomers. TD-DFT calculations revealed the most intense absorption bands of (E)- and (Z)-azobenzenes are

Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• derivatives have been found to be of interest in the development of organic materials with interesting properties [11][12]. The importance of imidazo[1,2-a]pyridines is evidenced by the plethora of recent review articles covering methods for their preparation [13][14][15][16] and functionalisation reactions

• atom, giving rise to benzamides, while Wu and co-workers [31] reported ring-opening to give either benzamides or α-ketoamides. This is in contrast to our own report, where only the oxalamide derivatives 18 were isolated. Two other oxidation methods, IBX and enzymatic oxidation using T. versicolor

• laccase in the presence of TEMPO and O2, were tested on compounds 17 in order to obtain the corresponding aldehydes, but both of these methods also gave rise to the ring-opened products 18. A detailed investigation into the mechanism of this ring-opening reaction was not conducted. However, this failure

Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile

• Melina Goga,
• Hao Zong,
• James Franco,
• Jazmine Prana,
• Rudolph Michel,
• Antonia Muro,
• Elana Rubin,
• Janet Brenya,
• Henk Eshuis and
• Magnus W. P. Bebbington

Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56

• experimental and computational study of the diastereoselectivity of cyclic sulfone synthesis by reaction of Rongalite with doubly electrophilic dienones is presented. Computational methods, including density functional theory, conformational search methods, and internal reaction coordinate methods, have been

• the reactivity of other readily available sulfinate nucleophiles using competition and exchange experiments. Keywords: diastereoselectivity; Rongalite; sulfones; Introduction Sulfonyl groups are widespread in licensed drugs [1]. New methods for the incorporation of sulfonyl groups into organic

• product, we used density functional theory (DFT) and conformational search techniques based on tight-binding methods to find the energetically minimized structure of 7 (see Supporting Information File 1 for details on all computations). The lowest energy structure is depicted in Figure 3. It shows a

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

• the development of 1,3-dipolar cycloaddition over the past decade, examining the reactions of various dipoles, including azomethine ylides, with a wide range of dipolarophiles [22]. In reviews [23][24][25], various methods for the generation of azomethine ylides were discussed in detail, for example

• compounds were reviewed. Rare methods for preparing azomethine ylides using pyridylimines and α-silylimine were described. Electrophilic alkenes, styrene derivatives, and new, previously undescribed unsaturated substrates were frequently used as dipolarophiles. The contribution of our research group to the

• -quinolyl, 2-pyridyl, and 4-pyridyl fragments. It is worth noting that 1-(4-nitrophenyl)-1,3-butadiene (40) and 1,1-bis(2-pyridyl)ethylene (41) also proved to be suitable substrates in this reaction (Scheme 20). It was demonstrated by computational methods (DFT) that electronic effects within the

Anti-invasive and cytotoxic evaluation of a (+)-pinoresinol-based semisynthetic library against glioblastoma

• Chen Zhang,
• Kah Yean Lum,
• Jonathan M. White,
• Paul I. Forster,
• Nicholas Booth,
• Sunita A. Ramesh and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 691–704, doi:10.3762/bjoc.22.54

• collected on a Rigaku XtaLAB synergy diffractometer using Cu Kα radiation at 100.0(1) K using an Oxford Cryostream cooling device. The structure was solved by direct methods and difference Fourier synthesis [36]. Hydrogen atoms bound to the carbon atom were placed at their idealized positions and included

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• efficient macrocyclization methods, including tetracarbonylnickel-promoted cyclization of allylic dibromide [17][18], copper-mediated intramolecular carbene–olefin cyclization [19], titanium-induced intramolecular carbonyl coupling [20], and organozinc carbenoid-mediated intramolecular cyclopropanation [21

• . With the ability to facilely obtain the terpene skeletons such as casbene and germacrene A by this heterologous terpene-producing platform, accessing other casbane- and germacrene-type of natural products and their analogues becomes possible if suitable chemical and enzymatic methods are available for

• ). Supporting Information Supporting Information File 5: Materials, synthetic methods and copies of NMR spectra for all compounds. Supporting Information File 6: X-ray crystal structure of 16. Funding We are grateful to the National Natural Science Foundation of China (No. 82574274) for the financial support.

Harnessing light energy with molecules

• Grace G. D. Han,
• Mogens Brøndsted Nielsen and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2026, 22, 680–682, doi:10.3762/bjoc.22.52

• a key property for characterizing the light harnessing efficiency of a photoswitch. In the article by Volker, Steen, and Crespi [18], a convenient and reliable fiber optic spectroscopic setup for determining this quantum yield is reported and was benchmarked for azobenzene against other methods

Using generative AI to transform peptide hits into small molecule leads

• Joshua Mills and
• Yu Heng Lau

Beilstein J. Org. Chem. 2026, 22, 672–679, doi:10.3762/bjoc.22.51

• experimental co-crystal structure of the bound complex, standard medicinal chemistry principles are used to probe structure–activity relationships (SAR) and determine the key interactions that form a minimal pharmacophore, supported by classical physics-based molecular modelling methods such as molecular

• candidate small molecules for experimental validation in functional assays. Nascent examples of ML approaches In contrast to physics-based models for extracting pharmacophores and predicting small molecule binders, ML methods are now emerging as alternatives for accomplishing these tasks. An early

• tractable, although synthetic accessibility was noted to be somewhat restricted by the highly sp3-rich nature of the generated molecules. New iterations of these methods have since been reported by the authors [23], though experimental validation of predictions remains to be reported at the time of writing

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

• Egor N. Boronin,
• Svetlana E. Kaurkina,
• Milena M. Svetlakova,
• Anton S. Bolshakov,
• Maxim V. Arsenyev,
• Vasilii F. Otvagin,
• Alexey Yu. Fedorov,
• Timothy Noël and
• Alexander V. Nyuchev

Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50

• approaches can be regarded as among the most environmentally sustainable methods for trifluoromethylation. MacMillan and co-workers reported the photochemical trifluoromethylation of arenes and heteroarenes using Ru- and Ir-based photocatalysts together with trifluoromethanesulfonyl chloride (TfCl) in the

Computational prediction of C–H hydricities and their use in predicting the regioselectivity of electron-rich C–H functionalisation reactions

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2026, 22, 603–610, doi:10.3762/bjoc.22.46

• electron-rich C–H functionalisation reactions. Methods Datasets To validate our QM workflow, we use a dataset of 35 experimental C–H hydricities in dimethyl sulfoxide (DMSO, 26 compounds) and acetonitrile (MeCN, 9 compounds) from Parker and co-workers [7]. As 35 C–H hydricities are insufficient to train an

• that evaluates the accuracy of different levels of theory, ranging from semiempirical methods (xTB [16]), composite electronic structure methods (r2SCAN-3c [19]) to DFT methods (M06-2X[21], CAM-B3LYP [22][23]). All methods are evaluated either as single-point calculations or optimization and frequency

• predictive accuracy for sterically demanding carbene insertion reactions, where all current methods underperform. While the ten literature examples discussed here provide promising proof-of-concept evidence, establishing the general utility of hydricity for regioselectivity prediction will require validation