Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• . Reaction optimization studies.a The effect of Hantzsch esters and other reaction parameters.a Supporting Information Supporting Information File 4: Full experimental details and characterization data of all compounds. Funding We are grateful for the financial support provided by the National Nature

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• )aminoaniline.a Optimization of the Chan–Lam coupling conditions between o-phenylenediamine (1a) and 2-bromophenylboronic acid (7).a Substrate scope of the one-pot synthesis of dibenzodiazepine using via Chan–Lam coupling/carbonylative intramolecular cyclization.a Supporting Information Supporting Information

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• , in the sole presence of MgSO4, no reaction was observed (Table 1, entry 6). Furthermore, Yb(OTf)3 or ZnCl2 mainly resulted in aldehyde 3 (Table 1, entries 7 and 8), while AlCl3 performed well with an 83% yield of 4 (Table 1, entry 9). This optimization validated the expected tandem sequence of

• and aromatic nucleophiles in the one-pot transformation. aNot determined (mixture with unidentified products). Reaction optimization toward 4 (see also Scheme 2). Supporting Information Crystallographic data of compound 6 were deposited in the Cambridge Crystallographic Data Center under the CCDC

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• . Reaction conditions: 1a (0.2 mmol), 2 (0.8 mmol), Cu(OAc)2·H2O (20 mol %), K2CO3 (0.2 mmol), DMSO (1.0 mL), stirred under air at 100 ºC for 12 h. Isolated yield. Further substrate scope investigations and gram-scale application. Control experiments and proposed mechanism. Optimization of the reaction

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• most suitable CF3 radical source. Further optimization involved screening the substrates’ ratios, which revealed that an excess of substrate 1a resulted in improved yields. Finally, experimenting with anhydrous DCM as the solvent showed that anhydrous conditions were not necessary for the reaction

• derivatives. UV–vis spectra of substrates; [1a] 0.33 M, [2a] 0.11 M. Selected works for the construction of dihydropyrido[1,2-a]indolones and current methodology. Substrate scope of the cascade reaction. Radical trapping experiment. Plausible reaction mechanism. Optimization of reaction conditions.a

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• ). Structure of dimer 5B-Cs•+ found in the metadynamics, however, is not a minimum and leads to dimer 3B-Cs•+ upon geometry optimization. C–C distances of the new bonds are within the range 1.53–1.71 Å. For dimer 1-Cs•+, the two distances are equivalent (1.587 Å) as they are the six distances for HPR-Cs

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• this study. On the other hand, despite higher L/D, the CNT orientation in the film prepared from the dispersion was comparable to the previous study. This suggests that further optimization of the deposition process is necessary to create highly oriented CNT films. Results and Discussion To prepare

• consistent with the Onsager theory. On the other hand we found that the order parameter of the DWCNT film, obtained from the LC dispersion, was nearly identical to that of the film composed of lower L/D SWCNTs [23]. Further optimization of experimental conditions, including viscosity of the dispersion and

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• -diaminoacrylonitriles 1 with heteroaryl azides (HetN3) 2 [16] leading to 5-amino-1,2,3-triazole-4-N-heteroarylcarbimidamides 3 (Scheme 1C). Results and Discussion Optimization of the reaction of amidine 1a with azide 2a We initiated the study by investigating a model reaction involving the cycloaddition of 3-amino-3

• (method A)a; 1 (0.5 mmol), 2 (0.5 mmol), NaOH (0.5 mmol), EtOH (2 mL), 0 °C → rt, 30 min (method B)b. Proposed mechanism for the formation of triazoles 3. Optimization of the reaction of amidine 1a with 6-azidopyrimidine-2,4-dione 2a.a Cytotoxicity index (IC50 ± SE) in µM of the studied compounds on human

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• iodane. bphenoxazines 3b–e required a higher reaction temperature of 135 °C. Optimization of reaction conditions.a Supporting Information Supporting Information File 22: Experimental part. Funding Funding for NC was provided by DFG project NA955/3-1.

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• anion. Subsequently, we extended the method to different internal and terminal alkynes. Finally, we studied the reaction in the electrogenerated BF3/BMIm-BF4 system, comparing the results with those obtained with the chemical route (BF3·Et2O). Results and Discussion Optimization of the reaction

• reused up to five times, without adversely affecting the reaction yields. Screening of different ionic liquids as media for the hydration of diphenylacetylene After the optimization of the reaction conditions in BMIm-BF4, different ILs were considered as alternative solvent (Table 2 and Table 3). All the

• BMIm-BF4 catalysed by BF3·Et2O (blue) and by electrogenerated BF3 (orange). Anodic oxidation of tetrafluoroborate anion. Optimization of the reaction conditions for hydration of diphenylacetylene (1a)a. Structure of the ILs used as solvent for the hydration reaction of diphenylacetylene (1a). Hydration

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• . The high thermal stability is profitable for the preparation of stable and durable OLED devices. Computational chemistry Ground-state geometry optimization of DMB-TT-TPA (8) was performed using density functional theory (DFT) calculations with the Gaussian 16 software at the B3LYP/6-31G (d,p) level

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• ). Unfortunately, also the generation of H2 increased with the concentration of HFIP, lowering the selectivity to 55%. Nevertheless, these results are promising, and further optimization studies are necessary to achieve high efficiencies and selectivity at the same time. Conclusion We presented a novel Co(II

• the selectivity towards the two electron-reduction product of CO2, carbon monoxide. We successfully achieved a selectivity of 97% with the use of TEA (12.5%) instead of TEOA. The following optimization studies allowed us to tune the efficiency for CO production with a maximum TON of 86, after 15 h of

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• basis sets, 6-311++G(d,p), was employed for geometry optimization. The effect of continuum solvation was incorporated by using the polarizable continuum model (PCM). Enthalpies and Gibbs free energies were obtained by adding unscaled zero-point vibrational energy corrections (ZPVE) and thermal

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• emerged as a promising class of heterocyclic compounds for charge transport applications, owing to two crucial factors. Firstly, their structural diversity enables precise customization of molecular structures, allowing for fine-tuning of their properties and optimization of performance for specific

• and optimization, Qx polymer acceptors are expected to evolve into high-performance materials for organic electronics. Quinoxalines as NFAs Fullerene acceptors have long dominated OSCs until the emergence of NFAs; nonetheless, researchers have attempted to improve fullerenes and address their

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• atmosphere, 90 °C, 24 h. Reaction substrate scope of quinolines. Conditions: 1a (0.1 mmol, 1 equiv), 2 (0.2 mmol, 2 equiv), AlCl3 (0.3 mmol, 3 equiv), NaNO2 (1 mmol, 10.0 equiv), DMAc (1.0 mL), N2 atmosphere, 90 °C, 24 h. Gram scale reaction. Control experiments and possible reaction mechanism. Optimization

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• screening different bases. In our optimization, we discovered, when morpholine was used in excess as a base, it generated fully substituted 1,2,3-triazole cycloaddition products with morpholine at the C-4 position instead of forming 5-fluorotriazoles. The fully substituted 1,2,3-triazoles are typically

• -difluoroalkenes and the co-elution of the aniline byproducts during column chromatography with the desired products affected the overall yield of the reaction. For a complete optimization list with all conditions that were screened, see Supporting Information File 1. With the optimized conditions in hand, we

• , which is five times the usual reaction scale used in substrate scope screening or optimization experiments (Figure 6). In this scale-up experiment, we obtained the product with 57% yield , which is slightly lower than 70% using 1-(2,2-difluorovinyl)-4-methylbenzene (1, 154 mg, 1 mmol, 1 equiv), 4

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• for 24 h at 60 °C. Comparison of physicochemical properties of selected DES used in this study. Optimization of Knoevenagel conditions.a Comparison to other reported methods for 5-benzylidenerhodanine synthesis. Structures and observed antioxidant activity expressed as % DPPH scavenging.a Supporting

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• atoms, presenting a challenging and time-consuming task for geometry optimization calculations and screening via DFT methods. Recent advancements have introduced fast semi-empirical DFT methods such as xTB [15], which enable their use in preliminary screening for molecular dynamics or searching for

• reactive sites (aISS), for example, in the formation of supramolecular complexes [16]. The particularly fast GFN-xTB methods work well in geometry optimization, which is the most time-consuming step of the DFT calculation. There have also been developments in DFT methods concerning the energy distribution

• complexes. Following the initial optimization of the geometry of the R[4]A molecule and the corresponding amine using the GFN2-xTB method in DMSO and CHCl3 with the analytical linearized Poisson–Boltzmann (ALPB) [20] solvent model, it was subjected to the aISS procedure. This involved interaction site

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• previous studies of reaction mechanism analysis [16][44]. Vibrational frequency calculations at the same level of theory with optimization were performed to verify that each local minimum has no imaginary frequency and that each TS has only a single imaginary frequency. Conformational search was done with

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• –H bonds.a Optimization of the air-promoted 1,4-addition of dialkylzinc reagents onto N-(tert-butanesulfinyl) α-(aminomethyl)acrylates. Supporting Information Supporting Information File 94: General information, characterization data, chemical correlation, and copies of NMR spectra

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• we examined the influence of the ligand tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) which has been identified by Sharpless et al. [58] as a very beneficial component in CuAAC reactions. After comprehensive optimization, we found that the addition of 0.2 equiv of this ligand not only

• reductive ring openings of bis(1,2,3-triazole) derivative 21 to divalent carbohydrate mimetics with hydrogen under palladium catalysis or with samarium diiodide did not proceed cleanly and need further optimization. Earlier approaches to multivalent carbohydrate mimetics B, D or F based on enantiopure

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• mmol), NiBr2(dtbbpy) (0.04 mmol), Hantzsch ester (0.6 mmol), Piv2O (0.6 mmol) and H2O (1.2 mmol) in DMAc (4.0 mL) was irradiated by purple LEDs for 7 h. Isolated yields are presented. aThe reaction was performed in a 1.0 mmol scale. Optimization of the reaction conditions.a Supporting Information

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• -substituted imidazole derivatives from MBH adducts. Proposed mechanism for the allylation of imidazole with alcohol 4a. Allylation of imidazole derivatives 2a,b with cyclic MBH adducts 4 and 5. Optimization of the reaction conditions of imidazole (2a) with acyclic MBH 1a. Michael addition of imidazole (2a

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• alternative to toluene. The use of chloroform (Table 2, entry 2), as in our previous report [17], showed an improvement on selectivity, however, toluene was chosen as a more benign solvent. After further optimization of the acidic resin, stoichiometry, concentration, temperature, and reaction time (see

• nitronate to the α,β-unsaturated iminium ion, should be tackled to improve the diastereocontrol. All efforts to discriminate the two faces of the nitroenolate during the addition proved unproductive during the optimization, therefore, a potential epimerization was envisaged during the course of the reaction

• organocatalytic cascade reaction developed by Enders. Acetaldehyde dimethyl acetal (6) as an acetaldehyde surrogate to effect a triple organocatalytic cascade reaction. Enders reaction with acetaldehyde.a Selected optimization reaction conditions.a Supporting Information Supporting Information File 34

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• ]chromeno[2,3-h]quinoxalinoporphyrins 3–8. For the optimization of the reaction conditions, a model four-component reaction of copper(II) 2,3-diamino-5,10,15,20-tetra(p-tolyl)porphyrin with 2-hydroxynaphthalene-1,4-dione (2), benzaldehyde and dimedone was carried out in the presence of 20 mol % p

• ]chromeno[2,3-h]quinoxalinoporphyrin 3. Optimization of the reaction conditions for the synthesis of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrin 3.a Supporting Information Supporting Information File 186: Characterization data, 1H and 13C NMR spectra of newly prepared porphyrin products