Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan 10.3762/bjoc.20.233 Abstract Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to

• at room temperature for 24 h gave the corresponding [1,3]-proton shift adduct (S)-20b in 31% yield (Table 1, entry 1). In this case, the HF-elimination product 21b was also obtained in 16% [37], and the starting material was recovered in 53%. As shown in entries 2–7 of Table 1, the reactions in

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

• for the Cu(I) system indicate that it is not the formation of alkynyl copper intermediate but the formation of active copper vinyl allenylidene intermediate is the rate-limiting step (Scheme 10). Due to the gaseous nature of dimethylamine at room temperature, it needs to be stored in special solvents

Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• until the lipid membrane had completely peeled off from the flask. To remove free catC60 and C60, the resulting suspension was centrifuged at 20,000g at room temperature for 10 min. The supernatant was collected and subjected to more than 20 extrusions using a Mini-Extruder equipped with a 100 nm-pore

• free PyBA. Data analysis, including calculation of the phase transition temperature, was performed using the MicroCal PEAQ-DSC Software. UV–vis absorption measurement UV–vis spectra of DMPC liposomes (1 mM DMPC) with or without catC60 or C60 were measured in PBS(–) using a UV-3600 Plus absorption

• solution (335 µM) was added instead of 10 µM of PBS(–). The solution was subjected to O2 bubbling for 30 seconds and then taken into 50 µL capillary and sealed. The solution was then irradiated with blue LED light for 30 minutes. The capillary was taken into the ESR tube for measurement at room temperature

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• of components and temperature (Table 2). We firstly irradiated with blue LEDs (451 nm) the mixture of the three components in the presence of 1.5 equiv of BrCCl3 for 18 h at room temperature under argon atmosphere (Table 2, entry 1). To our surprise, the reaction provided only traces of the expected

• detrimental (Table 2, entries 4, 5 and 7), while higher temperature improved the efficiency of the process (Table 2, entry 6). Under the optimized conditions we were able to obtain 3a with a 61% isolated yield, which can be considered an excellent result, as it is related to a four-step process (an average

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• in MeOH at room temperature with a short reaction time. Some of them were further functionalized with a 1,2,3-triazole ring via copper-catalyzed azide–alkyne cycloaddition (CuAAC) and deprotected with trifluoroacetic acid. Several hybrids were evaluated against six cancer cell lines, displaying GI50

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

• (4 mol %) and triethylamine (1.5 equiv) in THF (2.5 mL) was added the respective alkyne 5 (2.0 equiv). The reaction solution was stirred at room temperature until 1 was disappeared. The reaction mixture was evaporated and concentrated under reduced pressure. The residue was purified by column

Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores

• Kazuki Kobayashi,
• Shigeyuki Yamada,
• Motohiro Yasui and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225

• diphenylacetylene structure as the π-conjugated core. As a part of our research projects, we have begun to explore diphenylacetylene-based luminescent molecules despite diphenylacetylene not exhibiting fluorescence at room temperature because it undergoes a πσ* excited state that rapidly forms a trans-bend

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• Boltzmann constant, T is the temperature in Kelvin, h is the Planck constant, and R is the gas constant. The enantiomeric excess (%ee) was calculated using Equation 2 [41]. kfav stands for the kinetic rate constant of the most favourable process, and kdefav stands for the rate constant of the less

• = 5.47·104 s−1 for capturing CO2 and k2 = 4.85·10−12 s−1 for capturing the epoxide. Despite the FLP–CO2 adduct being less thermodynamically stable than the FLP–epoxide adduct (−10.1 kcal·mol−1 vs −44.8 kcal·mol−1), the lower activation barrier for the capture of CO2 and the temperature considered (273.0

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• synthesis of E-o-hydroxystilbenes, albeit via a cascade hydrolyzation–decarboxylation reaction at a very high temperature (Figure 2c) [18]. However, a metal-free decarbonylation–oxidation method for benzofuranones is still unprecedented. The earlier report [2] on the Ni-catalyzed decarbonylation–oxidation

• catalyst was essential for this reaction to happen at a higher temperature, and the products were obtained in negligible yields without the catalyst. Our protocol established that the reaction proceeds without the need for a transition-metal catalyst, as well as at a lower temperature. Additionally, the

• temperature proved to be advantageous compared to the reported Ni-catalyzed decarbonylation–oxidation method of benzofuranones [2]. Next, to elucidate the mechanism of the decarbonylation–oxidation reaction of 3-arylbenzofuran-2(3H)-ones 3aa–ka, control experiments were performed. The fact that the reaction

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• Agilent 5977A mass spectrometer. Agilent HP5-MS columns (Agilent Technologies, 30 m × 0.25 mm, 0.25 µm film thickness) were used as stationary phases, and helium was used as the carrier gas. EI-ionization was performed at 70 eV. The temperature program was as follows for both GC–MS and GC–IR: 50 °C (5 min

• capillary temperature was 250 °C, the capillary voltage was 180 V, the source voltage offset was 20 V, and the source voltage span was 30 V. The APCI source gas temperature was 350 °C and the APCI corona discharge was set to 5.0 µA. The scan range was 118 amu to 1522 amu. A direct probe, a small glass rod

• room temperature for 1 h. The solvent was removed with a stream of N2 and the sample was taken up in CH2Cl2 and analyzed by GC–MS [43]. Dimethyl disulfide derivatization: Twenty µL of the sample in a 2 mL GC vial were diluted with pentane (20 µL) and mixed with freshly distilled dimethyl disulfide

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

• the present study to measure the quantity and thermal stability of the water molecules inside the γ-CD we employed differential scanning calorimetry (DSC – Figure 4A) and thermogravimetry (TG – Figure 4B) in the temperature range between 300–440 K. The DSC curve reveals a wide endothermic effect with

• similar to the value experimentally obtained for α-CD (22.1 ± 3.8 and 30.0 ± 2.5 kJ mol−1 H2O for the first and second water release, respectively) [13]. The thermogravimetric curve shows a 10% weight loss in the temperature range 300–450 K, associated with the release of both crystal water inside the

• with a small shoulder at the low temperature peak side. According to the TG analysis, it was estimated that the γ-CD in the present study contains 7 mol of H2O. Several measurements were performed to ensure reproducibility of the results, which proved to be in line with the literature data [17][27][28

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

• minimal change to the materials environment. This allows for structures that are more representative of their typical environment. To achieve this, many specialised cells have been developed to control various environmental parameters including temperature, pressure, irradiation, electromagnetic fields

• such as a change in temperature. Jamieson et al. were able to utilise in situ SANS to characterise the ageing effects of gels formed upon the cooling of hot pyromellitamide solutions [71]. By comparing the fit of the full model to the low-q region only a higher level of hierarchical self-assembly

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine

• Alfiya R. Gimadieva,
• Yuliya Z. Khazimullina,
• Aigiza A. Gilimkhanova and
• Akhat G. Mustafin

Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219

• determined that room temperature is inadequate for fully oxidizing substrates. The optimal oxidation temperature for uracils 1 and 4 is between 60–65 °C, whereas for pyridines 7 and 9 it is 45 °C. Heating the reaction mixture at a temperature higher than the optimum level causes the substrates to be

• overoxidized and leads to destruction of the heterocyclic ring. As a result, the yield of the final products decreases. Furthermore, oxidation is incomplete at temperatures lower than the optimal temperature. The oxidation of MU (1), TMU (4), and pyridine (7) using ammonium peroxydisulfate (APS) was conducted

• classes. Experimental 1H and 13C NMR spectra were recorded on a Bruker Avance III 500 MHz spectrometer at 500.13 MHz (1H) and 125.73 MHz (13C) with 5 mm QNP sensors at a constant sample temperature of 298 K. The solvents were DMSO-d6, D2O, CDCl3 and the internal standard was SiMe4. Chemical shifts in the

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• afforded the known aldehyde 2 in 65% yield [13]. Then, reaction with guanidinium carbonate in DMA at high temperature [12], gave the desired intermediate 2-aminobenzo[h]quinazoline (3). In a final step, classical Buchwald–Hartwig coupling [14][15][16][17] with bromobenzene under the conditions described

• temperature, the mixture was filtered through Celite and washed with EtOAc (2 × 10 mL). The filtrate was evaporated under reduced pressure and the crude product was purified by using 60–120 silica mesh column chromatography using 10–20% ethyl acetate in hexane as eluent afforded target compound 4a (69% yield

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

• Andrey N. Komogortsev,
• Constantine V. Milyutin and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

• of the process time led to decrease of the yield due to partial tarring of the reaction mixture (Table 1, entry 3). Next, we assumed that the investigated reaction can be performed at room temperature. However, stirring under these conditions for 3 h in MeCN didn’t enhance the yield of compound 4a

• (Table 1, entry 7). Then, we tested the investigated reaction in various solvents at room temperature for 24 h. It should be noted that all solvents used had no advantage over MeCN (Table 1, entries 8–11). Thus, the best results for considered recyclization were achieved at stirring of amide 4a in the

• presence of CDI and DBU in MeCN at room temperature for 24 h. The aforementioned optimal conditions were utilized for the synthesis of a wide range of tetronic acids bearing a pyrrolidinone unit (Scheme 3). The presented protocol is of general nature and allows us to prepare the final products with various

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• anode and a foamed Ni cathode, at a constant current of 12 mA in DMSO at room temperature under atmospheric conditions. The reaction has been applied to more than 80 examples, including the late-stage functionalization of natural products and pharmaceuticals, as well as the synthesis and radiosynthesis

• method for the regioselective thiolation of aromatic C–H bonds by activating the thiol rather than the arene [19]. For their developed reaction, Pt electrodes were used in an undivided cell with a mixture of HFIP/DCE 3:1 at room temperature under argon. Late-stage functionalization was demonstrated for

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• details in Supporting Information File 1, Table S1, entries 10–18), it was discovered that a combination of ACN/DMSO/H2O solvent, K2S2O8 oxidant, Ru(bpy)3Cl2·6H2O photocatalyst, and 28–34 °C temperature were the best-suited and optimized reaction conditions. After optimization, our efforts were put

Machine learning-guided strategies for reaction conditions design and optimization

• Lung-Yi Chen and
• Yi-Pei Li

Beilstein J. Org. Chem. 2024, 20, 2476–2492, doi:10.3762/bjoc.20.212

• the platform and addressing safety concerns. On the other aspect, forward reaction prediction normally plays the role of validating the feasibility of a reaction pathway predicted by retrosynthetic models and to further enhance reaction yields by optimizing reaction parameters such as temperature

• factors, such as catalysts, solvents, substrate concentrations, and temperature. In academia, especially, the "one factor at a time" (OFAT) approach, which involves changing one factor while keeping the others constant, is frequently used to examine the effect of individual reaction parameters [13

• vital role in this context; it filters out inaccessible and incompatible conditions, such as high-temperature reactions, high-reactive gases, insoluble solid reagents, and environmentally unfriendly reagents. The examples above illustrate the usefulness of global reaction conditions prediction models

HFIP as a versatile solvent in resorcin[n]arene synthesis

• Hormoz Khosravi,
• Valeria Stevens and
• Raúl Hernández Sánchez

Beilstein J. Org. Chem. 2024, 20, 2469–2475, doi:10.3762/bjoc.20.211

• efficient solvent for synthesizing resorcin[n]arenes in the presence of catalytic amounts of HCl at ambient temperature and within minutes. Remarkably, resorcinols with electron-withdrawing groups and halogens, which are reported in the literature as the most challenging precursors in this cyclization, are

• set at 50% probability level. Resorcin[n]arene synthesis. Scope of resorcin[n]arene synthesis using HFIP. aAll reactions were performed with resorcinol (1.0 mmol), aldehyde (1.0 mmol), and HCl (30 mol %) in HFIP (5 mL) at room temperature, and the yields of the reactions are given as isolated yields

Phenylseleno trifluoromethoxylation of alkenes

• Clément Delobel,
• Armen Panossian,
• Gilles Hanquet,
• Frédéric R. Leroux,
• Fabien Toulgoat and
• Thierry Billard

Beilstein J. Org. Chem. 2024, 20, 2434–2441, doi:10.3762/bjoc.20.207

• compound 2a was observed (Table 1, entry 1). By increasing the amount of DNTFB and DMAP, the yield was doubled but remained low (entry 2 in Table 1) and did not evolve with a higher excess of reagents (entry 3). A reaction at lower temperature to possibly slow down the degradation of the CF3O− anion did

• stirred at room temperature for 2.5 h (unless otherwise stated). Note that a yellowish precipitate is formed during the reaction for high yielding substrates. The reaction is monitored by 19F NMR (PhCF3 as internal standard). At the end of the reaction, the content of the vial is transferred to a

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• sequence from the corresponding chiral 4,4,4-trifluoro-3-hydroxybutyrate at low temperature [27][28][29][30], and 2) t-BuO2Li-mediated transformation of the enoates like 1g at −78 °C [31][32] and, to the best of our knowledge, no report has appeared on the convenient methods applicable to the larger scale

• higher temperature especially in the case of compounds 1e and 1f as well as the high loading of the oxidant in the latter might be due to their higher oleophobicity by possessing longer Rf chains. For all instances, epoxyesters 2 were obtained as single E-isomers, and based on the result obtained by the

• successful employment of amines as nucleophiles for the epoxy ring opening in a highly stereoselective fashion, we next turned our attention to thiols. Optimization of the reaction conditions based on the ones for amines clarified the tendency that the longer reaction time and the higher temperature

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• 94%, initial reactant concentration of 0.5 mol/L, reaction temperature of 40 °C, molar ratio of reactants at 4.4:1, and a residence time of 12.36 minutes. Keywords: continuous flow; kinetic modeling; nitration; reaction optimization; static mixer; Introduction The demand for high-quality

• ]. Guo et al. constructed a continuous flow microsystem for o-xylene nitrification and proved the process safety of by the adiabatic temperature rise of the nitrification reaction and the characteristic heat transfer time of the microreactor [9]. The residence time of the microreactor was reduced by an

• ]. The reaction time and temperature were reduced from >2 h and 80 °C in industrial operation to 10 min and 65 °C in the microreactor with high conversion and selectivity. Since O-methylisouronium sulfate can be dissolved in high concentrations of sulfuric acid, it is expected to construct a homogeneous

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• ], screening of reaction conditions for the substrate 1a was carried out. Constant-current electrolysis of 1a using an undivided cell in the presence of carbon dioxide at room temperature was conducted. The effects of the current density (Table 1, entries 1–3), solvent (Table 1, entries 2, 4, and 5

• in less than 10% yield, determined through 1H NMR analysis, except for Table 1, entries 3 (13%) and 5 (25%). It should also be noted that electrolysis was carried out at room temperature, but the temperature of the reaction mixture increased to 40–50 °C at the end of the electrolysis in every case

• of the electroreductive C(sp3)–O bond cleavage, one additional experiment was carried out as shown in Scheme 5. Constant-current electrolysis of 1a in DMSO with 20 mA/cm2 of current density and 6 F/mol of electricity at room temperature under a nitrogen atmosphere instead of carbon dioxide resulted

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• /prooxidant, and antiradical activity was carried out for the catechols synthesized in this work. Results and Discussion Synthesis The interaction of 3,5-di-tert-butyl-o-benzoquinone with the corresponding thiols in ethanol at room temperature under argon leads to the formation of catechol thioethers 1–3 (69

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• reaction temperature (–5 °C). A slightly different protocol was elaborated for N-Fmoc carbamates 54 using the same catalyst 51. Instead of allylsilanes 49, stannanes 55 were employed and the method proved effective in simple allylation, prenylation, and crotylation (57–59). The yields were also generally

• active catalytic species in COBI-catalysed allylations, chemical equilibria in a solution containing catalyst 72, triflic acid, and aldimine 73 were investigated by low-temperature NMR spectroscopy (Scheme 15). Protonation of oxazaborolidine 70 with triflic acid resulted in an 8.3:1 mixture of 71 and 72

• synthesis of homoallylic amines 117 and showed increased yields and enantioselectivities for aromatic aldehydes. In addition, a simple, ambient-temperature hydrolysis procedure was reported that yielded the unprotected analytically pure homoallylic amines in high yields without the need for chromatographic