Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold

• Henry S. T. Smith,
• Ben Giuliani,
• Kanchana Wijesekera,
• Kah Yean Lum,
• Sandra Duffy,
• Aaron Lock,
• Jonathan M. White,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90

• scaffold for aminations with 14 commercially available primary amines. Reacting scaffold 1 with excess primary amine at room temperature for 16 h generated the desired amine analogues in respectable yields (18–87%) and high purity (≥95%) following chromatography workup. The structures of the 14 previously

• ]triazolo[4,3-a]pyrazine (compound 1; Scheme 1) according to the approach previously described by Korsik et al. [10] was performed, but without reflux, in order to compare the yield obtained for the aminated product under our further modified conditions (neat phenethylamine only, room temperature; Scheme 1

• column chromatography (and additionally by HPLC for the toluene reaction), the reactions also gave comparable yields of compound 2 (70% for toluene/silica and 82% for only phenethylamine at room temperature). Only the tele-substituted product was observed in either reaction mixture, consistent with

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• second-sphere coordination of [AuBr4]− and two α-CDs, accounts for the co-precipitation of α-CD·[Rb(OH2)6]+[AuBr4]− and α-CD·[Cs(OH2)6]+[AuBr4]−. Improvements of the method for the precipitation of gold in the form of {α-CD·[K(OH2)6]+[AuBr4]−}n were further investigated, namely the effect of temperature

• and ratio of α-CD that was added to the salt solution [40]. Studies at different temperature values demonstrated that the precipitate is less soluble as the temperature decreased and thus the gold extraction was optimal at 0 °C. Tests with excess stoichiometries of α-CD (2:1, 3:1, 4:1, 5:1) showed

• of precipitating gold from a solution even when it is found in low concentrations and the possibility of operating at ambient temperature. Lab-scale tests with e-waste recovery show promising extraction yields. Future developments will further optimize parameters and scale up the procedure

A versatile route towards 6-arylpipecolic acids

• Erich Gebel,
• Cornelia Göcke,
• Carolin Gruner and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

• amount of water was added to activate the boronic species and to dissolve the inorganic base under otherwise inert conditions. The reaction mixture was then stirred at room temperature overnight. Under these conditions, a variety of boronic acids with different steric and electronic properties was

Salen–scandium(III) complex-catalyzed asymmetric (3 + 2) annulation of aziridines and aldehydes

• Linqiang Wang and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1087–1094, doi:10.3762/bjoc.21.86

• procedure [16]. General procedure for the synthesis of ethyl 2-(oxazol-2-yl)alkanoates 3 Sc(OTf)3 (9.8 mg, 0.02 mmol) was added in a dried 10 mL reaction tube, then it was heated to 220 °C and dried at 220 °C for 2 h under oil pump vacuum. After gradually cooling to room temperature, the chiral salen ligand

• with a syringe and the mixture was stirred at 55 °C for 24 h. After gradually cooling to room temperature and removal of the solvent under reduced pressure, the crude residue was purified by basic aluminum oxide column chromatography with petroleum ether/ethyl acetate 1:10 to 3:7 (v/v) as eluent to

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• excellent yield (Scheme 2) [32]. The formed anhydride 3 was smoothly converted to the amide at room temperature. This method provides a green approach by allowing cinnamic acid derivatization in water as a benign solvent. Similarly, Rajendran and Rajan (2023) reported a one-pot transamidation of cinnamamide

• cinnamamides 13, 77, 99, and 371 in good yields via the active palladium–hydride species 372 (Scheme 81A) [137]. The Z-to-E-selectivity could be effectively tuned by changing the solvent and temperature from CH3CN to DMF and rt to 80 °C, respectively. Similarly, Wang and co-workers (2023) employed Pd to

Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

• Valentina Benazzi,
• Arianna Bini,
• Ilaria Bertuol,
• Mariangela Novello,
• Federica Baldi,
• Matteo Hoch,
• Alvise Perosa and
• Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

• dissolved or suspended in water, and the resulting mixture transferred to an autoclave and treated at a temperature ranging 140–200 °C; the treatment yields CDs with an amorphous structure. The synthetic procedure, as well as the structural and morphological characteristics of these materials, have been

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

• problems in the future and prepare organic radicals for the challenges in emerging quantum technological applications. Review Triarylmethyl monoradicals The importance of symmetry in triarylmethyl radicals Gomberg’s radical is unstable at room temperature and dimerizes quickly to a closed-shell molecule

• mixture of right- and left-handed propellers can be resolved by chiral high pressure liquid chromatography (HPLC) into the P- and M-enantiomers, respectively [40][41]. However, due to the low racemization barrier of only about 22 kcal mol−1, the enantiomers racemize within minutes at room temperature. TTM

• )methyl (TTBrM) radical exhibits λem = 593 nm and ϕ of 0.8% (in dichloromethane-solution, at room temperature) [50][51]. Functionalization of TTM in the para-position has also been achieved with a pseudo-halide, namely a nitrile group. While the absorption and emission spectra are slightly

Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• ester 29 gave pyrrolo-β-carboline 30 in excellent yield (Scheme 7). Our attempts for the selective saturation of the pyrrole ring of 30 by catalytic reduction were unsuccessful. When the hydrogenation was carried out under mild conditions (ambient temperature, 15 bar H2) in the presence of PtO2.H2O

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• equivalent of commercial iodomesitylene diacetate (CAS [33035-41-5]) and 1 equivalent of MsOH (Table 1, entry 4). Here, it was necessary to maintain a temperature of 0 °C, as vigorous bubbling and rapid decomposition occurred when the reaction was initiated at room temperature. In all cases (Table 1), only a

• delivering product (Table 2, entries 1 and 3–5). With our standard conditions of stirring substrate with 1.5 equivalents of PhI(OH)(OTs) in CH2Cl2 at room temperature, the yield of product markedly suffered with N-isopropoxy carbamate substrate 3 (Table 2, entry 2). Here, we hypothesize that the increased

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• , with values of 16%, 14%, and 14%, respectively. The lowest values were obtained for molecules 5a and 5b (7% and 6%, each). Remarkably, compound 5e demonstrated minimal luminescence in nearly all solvents at room temperature. This behavior has been previously reported and is believed to be due to strong

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• 10 was unequivocally determined through X-ray crystallographic analysis (ORTEP drawing, Scheme 4). Further optimization by elevating the reaction temperature did not noticeably alter the ratio of 32 and 33 (Table 1, entries 8 and 9). Moreover, attempts to apply interrupted Nazarov cyclization with

Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines

• Muhammad Hasan,
• Anatoly A. Peshkov,
• Syed Anis Ali Shah,
• Andrey Belyaev,
• Chang-Keun Lim,
• Shunyi Wang and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74

• , when performed at room temperature, proceeded with lower efficiency compared to the reaction at 70 °C, leaving some of the starting 1H-pyrazole-3-carbaldehyde (14a) unreacted. Propargylamide 15a was selected as a model substrate to optimize the reaction conditions for the intramolecular

• temperature to 90 °C and the catalyst loading to 10 mol % enabled full conversion of 15a and improved the yield of product 16a (Table 1, entries 2 and 3). The use of other silver salts including AgBF4, Ag(NTf)2 and AgNO3 did not lead to improved results, with Ag(NTf)2 being particularly ineffective (Table 1

• temperature. cConducted on a 2.0 mmol scale. dConducted on a 1.5 mmol scale. Scope of the silver(I) triflate-catalyzed synthesis of pyrazolo[1,5-a][1,4]diazepines. Conditions: Unless otherwise specified, the reactions were run on 0.2 mmol scale using 20 mol % of AgOTf in dioxane (1 mL). The reactions were

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• literatures focusing on key regulatory factors for product divergent formation, in which controlling chemical selectivity primarily relies on ligands, metal catalysts, solvents, time, temperature, acids/bases, and subtle modifications of substrates. To gain a deeper understanding of the mechanisms underlying

• review systematically examines, how these multidimensional control elements (including ligands, metal catalysts, solvents, time, temperature, acids/bases, and subtle modifications of substrates) synergize to achieve predictable product diversification. In addition, mechanistic insights are discussed

• (cod)Cl]2 and the Carreira chiral phosphoramidite ligand (S)-L10, along with the addition of 3,5-dichlorobenzoic acid as an additive in MeOH at room temperature, the reaction proceeded smoothly for 10 hours to yield the aminated product 51. Interestingly, when the reaction was quenched after 6 minutes

Cu–Bpin-mediated dimerization of 4,4-dichloro-2-butenoic acid derivatives enables the synthesis of densely functionalized cyclopropanes

• Patricia Gómez-Roibás,
• Andrea Chaves-Pouso and
• Martín Fañanás-Mastral

Beilstein J. Org. Chem. 2025, 21, 877–883, doi:10.3762/bjoc.21.71

• product in 70% yield with 83:17 dr by decreasing the reaction temperature to 50 °C (Table 2, entry 4). Under the same optimal conditions, compound 8 could be transformed into cyclopropane 17 in 61% yield with 81:19 dr (Table 2, entry 5). It is important to note that (2,2-dichlorovinyl)cyclopropanes

Chitosan-supported CuI-catalyzed cascade reaction of 2-halobenzoic acids and amidines for the synthesis of quinazolinones

• Xuhong Zhao,
• Weishuang Li,
• Mengli Yang,
• Bojie Li,
• Yaoyao Zhang,
• Lizhen Huang and
• Lei Zhu

Beilstein J. Org. Chem. 2025, 21, 839–844, doi:10.3762/bjoc.21.67

• (acac)2) and chitosan-supported on CuSO4 (CS@CuSO4) were explored, and the results showed that CS@CuI was the most effective catalyst (Table 1, entries 7−11, 65−89% yields). To further enhance the reaction yield, the reaction temperature was increased to 90 °C, and the target product 3a was obtained in

Substituent effects in N-acetylated phenylazopyrazole photoswitches

• Radek Tovtik,
• Dennis Marzin,
• Pia Weigel,
• Stefano Crespi and
• Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

• thermodynamic properties, we decided to perform an Eyring analysis of two representative PAPs. We chose NAc-PAP-CN and NAc-PAP-OMe, which lie on two different ends of the Hammett plot and hence should reveal the difference in relaxation mechanism. We measured the temperature-dependency of their relaxation rates

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• , the hydride addition of DIBAL-H to allene 1a catalyzed by 5 mol % IPrCuCl as the optimal catalyst selectively generated the allylaluminum intermediate 2a with >98% conversion [30]. Subsequent addition of one equivalent of TsCN to 2a in a single vessel at room temperature proceeded regioselectively

• scope for the formal hydrocyanation with 1,1-disubstituted and 1,1,3-trisubstituted allenes was examined (Scheme 3). All reactions were performed in the presence of 5 mol % IPrCuCl to generate the allylaluminum reagents in situ, followed by cyanation at room temperature for 30 min. This method

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• . Electricity can perform the oxidation and reduction process by exchanging electrons on the electrode surface in a region called the double layer (DL) [12]. Unlike traditional methods that require high temperature, pressure, and external oxidants, electrochemistry is an efficient and energy-saving approach

• yield was observed with increased reaction temperature. 2-Isocyanobiaryl compounds showed better reactivity when they contained electron-withdrawing groups. Diarylphosphine oxides containing a methyl group reacted well under standard conditions, regardless of their position. Mechanistic studies showed

• undivided cell at room temperature, and three different electrodes, graphite, platinum, and glassy carbon (GC), were examined during the reaction. The best result was obtained when platinum electrodes were used as the anode and cathode. Although the reaction was less efficient in undivided cells, increasing

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• BINOL phosphate/Ca(OiPr)2. In the presence of two equivalents of TMSCN, complex 4 gave a quantitative conversion to the product 2, whereby the phosphoric acid BIPO4-H ligand 3 did not catalyze this hydrocyanation. At room temperature, a nearly full conversion can already be achieved within 2–12 hours

Copper-catalyzed domino cyclization of anilines and cyclobutanone oxime: a scalable and versatile route to spirotetrahydroquinoline derivatives

• Qingqing Jiang,
• Xinyi Lei,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2025, 21, 749–754, doi:10.3762/bjoc.21.58

• moderate yield (Table 1, entry 6). Conducting the reaction at room temperature (rt) instead of the optimal elevated temperature resulted in a lower yield (Table 1, entry 7). Increasing the reaction temperature to 100 °C did not improve the yield (Table 1, entry 8). Having established the optimal reaction

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• obtained in general procedure B was dissolved in dichloromethane and cooled to 0 °C under argon atmosphere. Then, triphenylphosphine and carbon tetrabromide were added and stirred at room temperature for two hours. Afterwards, the entire mixture was loaded on a silica gel column and eluted with 100

• % dichloromethane. General procedure D. In a manner similar to [11], the product obtained in general procedure B, methanesulfonyl chloride, and triethylamine were dissolved in dichloromethane and stirred overnight at room temperature. After reaction control and 100% consumption of the starting material, the entire

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

• temperature overnight. Afterwards, the mixture was centrifuged (4400 rpm, 10 min) to pellet excess insoluble C1. An aliquot of the supernatant and a solution of dimethyl malonic acid as a non-binding internal standard of known concentration were transferred to an NMR tube followed by collection of a 1H NMR

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• -branched amino acids. Results and Discussion Aromatic amino acids First, we concentrated our efforts on synthesizing the aromatic, fluorinated amino acids (Scheme 2). The corresponding alkyl bromide precursors were commercially available. We screened a broad range of reaction conditions such as temperature

• identified as optimal delivering a yield of alkylated complex of 60% (Table 1, entry 4). With DBU as base different solvents differing in polarity have been tested. At room temperature, acetonitrile proved best and increased the yield to 88% (Table 1, entry 11). Lowering the temperature to 0 °C led to a

• (II) complex of bisTfMePhe have differed significantly. Here, sodium hydride (NaH) was identified as optimal base leading to a yield of 85% when using DMF as solvent at 0 °C to room temperature (Table 2, entry 4). Testing different base equivalents, solvents, solvent mixtures and temperatures didn’t

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• synthesis underscore the robustness and reliability of this copper-mediated transformation in creating stereochemically complex molecules. Mechanistic investigations revealed several key factors controlling the stereochemical outcome of these transformations. The extremely low temperature (−100 °C) during

• temperature led to a significant decrease in dr values, suggesting partial racemization. This observation highlights the importance of careful experimental handling of [RCu·ZnX2·L] species {X = Br, Cl; L = P(OEt)3}, where both temperature control and reaction time must be precisely managed to maintain

• optimization revealed LiOt-Bu and diphenyl phosphate as the optimal metal alkoxide and leaving group, delivering the desired product 32 in high yield and high enantioselectivity at room temperature with only 2 mol % catalyst loading. The scope of this transformation proved to be remarkably broad. In addition

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• conditions at room temperature, and 2.0 F charge (if not otherwise noticed) with current density of 12 mA/cm2 was passed through the colorless reaction solution. The resulting clear, colorless (sometimes pale yellow) solution was concentrated under reduced pressure and the crude product was purified by