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

• in 60% yield. GP-1B (by use of NaClO·5H2O): To a solution of compound 1b [42] (0.2302 g, 1.00 mmol) in 3.0 mL of CH3CN was added NaClO·5H2O (0.3290 g, 2.00 mmol) at 0 °C, and the solution was stirred for 6 h at the same temperature. After the same workup process and purification with silica gel

• in 79% yield after silica gel column chromatography using Hex/AcOEt 6:1 as an eluent. Rf 0.51 (Hex/AcOEt 4:1); 1H NMR (300.40 MHz, CDCl3) δ 0.88 (t, J = 6.9 Hz, 3H), 1.26 (brs, 14H), 1.60 (quint, J = 6.9 Hz, 2H), 2.49 (t, J = 7.5 Hz, 2H), 2.74 (dd, J = 3.6, 17.7 Hz, 1H), 2.83 (dd, J = 9.0, 17.7 Hz

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

• product. After silica gel column purification, the isolated yield of these compounds were 64% and 13%, respectively. Additionally, a radical species, showing an ESR peak pattern distinct from that of the DAntM radical and mainly splitting into five peaks with g = 2.0037, was confirmed (Figure 4, Figure S7

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• silica gel 60 F200) were analyzed under UV light (254 nm). Chromatographic purifications were performed on SDZF silica gel 160. The starting α-oxo ketene N,S-acetals 1 are known compounds [40][41] and easily prepared according to References [40][58]. Typical procedure for the preparation of β-keto

• value of the reaction mixture was adjusted to neutral using a saturated NaHCO3 solution, and the reaction mixture was extracted with CH2Cl2 (3 × 20 mL). The organic solution was dried with anhydrous Na2SO4, and the crude product was purified by column chromatography on 300–400 mesh silica gel (petroleum

• organic solution was dried with anhydrous Na2SO4, and the crude product was purified by column chromatography on 30–400 mesh silica gel (petroleum ether (60–90 °C)/ethyl acetate 20:1, v/v) to give 3a (53.8 mg, 90%). Synthesis of α-keto thioesters and β-keto amides. Synthesis of β-keto thioesters 2

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• purified through silica-gel column chromatography. After successfully synthesizing these easy-to-make yet interesting molecules, they were fully characterized by means of the standard spectroscopic techniques (1H NMR, 13C NMR and HRMS). We are of the opinion that these truxene-based systems will be useful

• . Analytical thin-layer chromatography (TLC) was performed on aluminium plates coated with silica gel by using a suitable mixture of EtOAc and petroleum ether for development purpose. Column chromatography was performed by using silica gel (100–200 mesh) with an appropriate mixture of EtOAc and petroleum ether

• crude product was extracted with ethyl acetate. The combined organic layers were washed with water (2 × 100 mL), dried over anhydrous Na2SO4. After evaporation of the solvent the residue was passed through a silica gel (SiO2) to give the final product as a white powder (7.5 g, 95%). The 1H NMR spectrum

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• was studied and compared in the esterification of methanol or glycerol with oleic acid (1). It was observed that substrate conversion and product yield also depended on the particle morphology. Rope-type propylsulfonic SBA-15 mesoporous silica gel showed the highest catalytic activity in both studied

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• radical, which induces 5-exo cyclization. The following hydrogen abstraction, intramolecular ionic cyclization, and hydrolysis during chromatography on silica gel affords the cyclic amide in good yield. They further applied this radical cyclization reaction as a key step in the synthesis of (±)-α-kainic

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• pyrazoline, which leads to increased yields. In addition to fully substituted pyrazoles, bispyrazoles can also be synthesized [97]. Other Lewis acid catalysts employed in this method include chloride-functionalized silica gel (SiO2Cl) [98] and Sc(OTf)3 [99]. Importantly, all reactions of this method are

Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384

• Marwa Elsbaey,
• Naoya Oku,
• Mohamed S. A. Abdel-Mottaleb and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174

• fractionated on a silica gel column eluting with CHCl3/MeOH mixtures. Allostreptamide was obtained from the eluate with CHCl3/MeOH 2:1 [24]. HPLC-DAD analysis of a less polar fraction, eluted with CHCl3/MeOH 10:1, detected several peaks with characteristic UV absorptions, which were purified by ODS flash

• , and isolation Details on the supplier of Allostreptomyces sp. RD068384, fermentation, extraction, and fractionation are described in Supporting Information File 1. While a CHCl3/MeOH 2:1-eluting fraction by silica gel open column chromatography eventually yielded allostreptamide [24], a less polar

• CHCl3/MeOH 10:1 fraction contained compounds with characteristic UV absorption. This fraction, obtained as 395 mg of brown solid from 4 L culture in A-3M medium, was fractionated by octadecyldimethylsilyl (ODS) silica gel column chromatography with a gradient of MeCN/0.1% HCO2H solution (2:8, 3:7, 4:6

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• moisture-sensitive reagents were performed under a nitrogen or argon atmosphere. Silica gel chromatography was performed using prepacked silica gel columns (RediSep® Rf, Teledyne ISCO). An aluminum block atop a hotplate with a thermocouple was used to heat reactions to the specified temperatures. NMR

A new platform for the synthesis of diketopyrrolopyrrole derivatives via nucleophilic aromatic substitution reactions

• Vitor A. S. Almodovar and
• Augusto C. Tomé

Beilstein J. Org. Chem. 2024, 20, 1933–1939, doi:10.3762/bjoc.20.169

• chromatography (TLC) was carried out on precoated sheets with silica gel (Merck 60, 0.2 mm thick). Preparative TLC was carried out on 20 cm × 20 cm glass plates precoated with a layer of silica gel 60 (0.5 mm thick) and activated in an oven at 100 °C for 12 h. Melting points were determined with a Büchi B-540

• and then it was diluted with CH2Cl2 and water. The organic layer was separated and washed with water and brine. The product was isolated by column chromatography on silica gel using CH2Cl2 as the eluent. Yield: 61%; mp: 278–280 °C; 1H NMR (300 MHz, CDCl3) δ (ppm) 7.62–7.66 (m, 4H), 7.47–7.52 (m, 4H

Electrochemical radical cation aza-Wacker cyclizations

• Sota Adachi and
• Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

• with stirring. The solution was diluted with water and extracted with dichloromethane. The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. Yields were determined by 1H NMR analysis using benzaldehyde as an internal standard (Table 1). Silica gel column

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

• dimethoxylated quinones are somewhat labile but can be purified by rapid silica gel chromatography and stored for a few weeks. The controlled current and anhydrous conditions helped avoiding overoxidation. The substrates leading to p-quinones were more prone to overoxidation. The electrochemical oxidation of

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• (34%) of Nafion perfluorinated resin solution was purchased from Sigma-Aldrich. Purification of reaction products was done by column chromatography on silica gel (230–400 mesh) with the appropriate eluent mixture and using a positive pressure of nitrogen. Spectroscopic characterization The

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• specified. All reactions were performed under nitrogen unless otherwise specified. Analytical thin-layer chromatography (TLC) was performed with Macherey-Nagel silica gel 60 UV254 aluminum plates, and visualization was accomplished by UV light (254 nm or 365 nm) or by staining with phosphomolybdic acid and

• heating. Flash column chromatography was performed using Macherey-Nagel silica gel 60 (230–400 mesh). Deuterated solvents were purchased from Cambridge Isotope Laboratories. UV–vis spectroscopy UV–vis measurements were performed on an Agilent Cary 60 UV–vis spectrophotometer with a quartz cuvette of 1 cm

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• predominately considered to be stable to isolation conditions, secondary and tertiary suffer from the elimination of HF, especially in the presence of silica gel or glass vessels. Therefore, benzyl fluorides have been derivatised, for example in C–O, C–N and C–C bond-forming reactions [18][19][20], thereby also

Primary amine-catalyzed enantioselective 1,4-Michael addition reaction of pyrazolin-5-ones to α,β-unsaturated ketones

• Pooja Goyal,
• Akhil K. Dubey,
• Raghunath Chowdhury and
• Amey Wadawale

Beilstein J. Org. Chem. 2024, 20, 1518–1526, doi:10.3762/bjoc.20.136

• temperature. The crude reaction mixture was purified by silica gel (230–400 mesh) column chromatography (petroleum ether/EtOAc as the eluent) to give the product 3 or ent-3. Selected examples of drugs and bioactive molecules bearing a pyrazole core. Single crystal X-ray structure of ent-3ba (CCDC 2234286

Tetrabutylammonium iodide-catalyzed oxidative α-azidation of β-ketocarbonyl compounds using sodium azide

• Christopher Mairhofer,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1510–1517, doi:10.3762/bjoc.20.135

• were recorded on an Agilent QTOF 6520 spectrometer with an ESI source. Melting points are recorded using a Büchi M-560 apparatus and are reported uncorrected. TLC was performed on Macherey-Nagel pre-coated TLC plates (silica gel, 60 F254, 0.20 mm, ALUGRAM® Xtra SIL). Preparative column chromatography

• was carried out using Davisil LC 60 Å 70-200 MICRON silica gel. All chemicals were purchased from commercial suppliers and used without further purification unless otherwise stated. General α-azidation procedure Sodium azide (7.8 mg, 120 µmol, 1.2 equiv) and TBAI (7.4 mg, 20 µmol, 20 mol %) were

• diluted with 8 mL dichloromethane and extracted with 5 mL of sat. aq NaHCO3. The aqueous phase was then extracted twice with 10 mL of DCM. The organic layer and the extracts were then filtered consecutively through a pad of anhydr. sodium sulfate and deactivated silica gel. The solvents were removed in

Towards an asymmetric β-selective addition of azlactones to allenoates

• Behzad Nasiri,
• Ghaffar Pasdar,
• Paul Zebrowski,
• Katharina Röser,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1504–1509, doi:10.3762/bjoc.20.134

• and EtOAc), concentrated under reduced pressure, and subsequently purified by preparative TLC (silica gel, heptanes/EtOAc 4:1) to obtain the products 2 in the given yields and enantiopurities. Details for the parent compound 5a (details for the other targets can be found in Supporting Information File

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• through alumina or molecular sieves-containing cartridges using a solvent purificator MBRAUN SPS-800. All the reactions with azobenzene-containing substrates were carried out in the dark. Reactions were monitored by TLC on Silica Gel 60F-254 plates with detection by UV (254 nm or 365 nm) or by spraying

• silica gel (60 Å pore size, 40–63 µm). 1H and 13C NMR spectra were recorded on a JEOL ECS-400 spectrometer or on Bruker Avance 300 and 400 spectrometers. Structural assignments were made with additional information from gCOSY, HMBC, and gHMQC experiments. High-resolution mass spectra (HRMS) were

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• purified by column chromatography on silica gel to give product 4. In the case of reacting with 3-NO2 bearing 2f, 2-benzylphenol 5f was partially obtained together with normal product 4fa. 4-CN substituted 2o generated 2-benzylphenol 5o exclusively. Synthesis of aniline derivatives from 2-cyclohexenones or

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• . Louis, MO), or Acros Organics (Thermo Fisher Scientific, Geel, Belgium) and used without further purification. Thin-layer chromatography was performed using silica gel (60 F254, Merck, Darmstadt, Germany) plates. Melting points were recorded by Büchi melting point B-540 apparatus (Büchi Labortechnik AG

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• Sigma-Aldrich Co., Nacalai Tesque Co., Tokyo Chemical Industry Co., Ltd., FUJIFILM Wako Pure Chemical Industries, Ltd. All organic solvents are purchased from Nacalai Tesque Co., FUJIFILM Wako Pure Chemical Industries, Ltd. and were used without purification unless indicated otherwise. The silica gel 60

• N (spherical, neutral) was purchased from Kanto Chemical Co., Ltd. All reactions were performed in oven-dried glassware unless stated otherwise and were monitored by TLC using 0.25 mm silica gel plates with UV indicator (70F-254). Commercial HiPco (purchased from Carbon Nanotechnologies Inc., with

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• environment. Acetonitrile (99.9%) was bought from Avra Chemicals Private Ltd. and used without any further purification. Selenium dioxide and a range of reactants were purchased from Sigma-Aldrich. TLC was performed using silica-gel-coated aluminum sheets (TLC silica gel 60 F254). 1H, 13C, and 77Se NMR (500

• in a different round-bottom flask, and the solvent was evaporated in a rotary evaporator. The resulting solid was dissolved in DCM, and silica gel was added to the DCM layer. This slurry was subjected to column chromatography on silica gel (100–200 mesh) using petroleum ether and ethyl acetate as

• solid. The filtrate was evaporated and column-chromatographed on silica gel (100–200 mesh) using petroleum ether and ethyl acetate as an eluent. The initial yellowish orange fraction containing N1,N2-bis(2-methoxyphenyl)oxalamide, collected with 22% ethyl acetate, was recrystallized from a chloroform

Introduction of peripheral nitrogen atoms to cyclo-meta-phenylenes

• Koki Ikemoto and
• Hiroyuki Isobe

Beilstein J. Org. Chem. 2024, 20, 1207–1212, doi:10.3762/bjoc.20.103

• overnight to give 3a in 6% yield (272 mg, 0.592 mmol) after the extraction. The latter was purified by silica gel short path and GPC (column: YMC-GPC T30000-40 + T4000-40 + T2000-40, eluent: CHCl3, flow rate: 30 mL/min) to give 3a in 1% yield (52.8 mg, 0.115 mmol) and 3b in 3% yield (118 mg, 0.193 mmol). In

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• accompanied by mono-adduct 2 (22% yield) by silica gel flash column chromatography using mixed solvents of hexane/CH2Cl2 by changing the ratios of volumes from 10:1 to 3:1. In thin-layer chromatography (TLC) analysis using silica gel, the Rf values are 0.55 for 2 and 0.33 for 3, respectively, with hexane