Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

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

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

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

• General: All the reagents/solvents were purchased from commercial suppliers (Sigma-Aldrich, Alfa Aesar, TCI, GLR innovation, Avera, Spectrochem and Across), and used without further purification. Solvents were dried according to standard reported procedures. Pyrrole was used after a fresh distillation

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

• , providing practical guidelines for carbohydrate structural analysis, spanning from the purification to the structural analysis of polysaccharides. MD simulations: Once the 3D glycan structure is built, taking into account the energetically favourable conformations of each constituent disaccharide unit, and

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• purification system. Hydrobromic acid (48%) and deuterium oxide (99.9 atom %) were supplied by Merck. Sample preparation To produce micellar samples, light-responsive PS were shaken with the solvent (50 mM in either H2O or D2O) until homogenous. For samples of higher concentration, AAPTAB was added to water

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

• yields from the same carbon sources through reagent control. Experimental General methods All materials were obtained from commercial suppliers and used without further purification unless otherwise noted. Anhydrous solvents were obtained from Sigma-Aldrich and used directly. Reactions involving air- or

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts

• Ivana Weisheitelová,
• Radek Cibulka,
• Marek Sikorski and
• Tetiana Pavlovska

Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161

• purification. Thus, it significantly improves existing approaches. Keywords: catalysis; deazaalloxazine; flavin; multicomponent approach; one-pot reaction; Introduction Heterocyclic compounds containing pyrimidine and quinoline motifs in their structure, both of natural and synthetic origin, find a wide set

• vary from low to moderate, the reaction starts from commercially available substances and leads to valuable compounds. The procedure is low cost and operationally easy with no need for further purification and opens a new route to the synthesis of powerful, phoredox, flavin-like catalysts, as well as

• Reagents and analytics: Starting materials were purchased from Sigma-Aldrich and Fluorochem. The solvents were purified and dried using standard procedures. Commercially obtained reagents were used as received without further purification unless otherwise stated. The compound structures were drawn and

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

• Moisés Alejandro Alejo Hernandez,
• Katia Pamela Villavicencio Sánchez,
• Rosendo Sánchez Morales,
• Karla Georgina Hernández-Magro Gil,
• David Silverio Moreno-Gutiérrez,
• Eddie Guillermo Sanchez-Rueda,
• Yanet Teresa-Cruz,
• Brian Choi,
• Armando Hernández Garcia,
• Alba Romero-Rodríguez,
• Oscar Juárez,
• Siseth Martínez-Caballero,
• Mario Figueroa and
• Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

• biosynthetic enzymes hold promise as novel entities with untapped bioactive potential. Expression and purification of the CloA1 precursor peptide, CloA2 precursor peptide, and C39 peptidase domain We could not access the producing microorganisms, so the gene sequences reported in public databases (Supporting

• was co-expressed with the corresponding precursor peptide in the same E. coli strain (expected size 150 kDa). The precursor peptides and the peptidase domain of CloPt1 were fused with a 6xHis tag at their N-terminal end for purification purposes (Figure S7 in Supporting Information File 1). After

• purification, we estimated mature peptide and peptidase yields based on SDS-PAGE densitometry between 0.8 and 1.5 g/L of culture for all products. The heat liability of the peptide products challenged the purification, and when trying to perform several purification cycles to increase their purity, we obtained

Ugi bisamides based on pyrrolyl-β-chlorovinylaldehyde and their unusual transformations

• Alexander V. Tsygankov,
• Vladyslav O. Vereshchak,
• Tetiana O. Savluk,
• Serhiy M. Desenko,
• Valeriia V. Ananieva,
• Oleksandr V. Buravov,
• Yana I. Sakhno,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2024, 20, 1773–1784, doi:10.3762/bjoc.20.156

• reaction step for the synthesis and purification of the starting azomethines 9, we cannot propose the Ugi-3CR approach as more suitable compared to the Ugi-4CR approach. The structure of the Ugi bisamides 5–8 were proved by X-ray diffraction study on the example of substance 8c (Figure 2), according to

Synthesis and characterization of 1,2,3,4-naphthalene and anthracene diimides

• Adam D. Bass,
• Daniela Castellanos,
• Xavier A. Calicdan and
• Dennis D. Cao

Beilstein J. Org. Chem. 2024, 20, 1767–1772, doi:10.3762/bjoc.20.155

• sodium hydroxide, followed by acidification with HCl, yielded a mixture of carboxylic acids and anhydrides 5, as evidenced by 1H NMR spectroscopy (Figure S13 in Supporting Information File 1). Gratifyingly, purification of these mixtures was not necessary as they could be used directly for imidization

Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles

• Javier Gómez-Ayuso,
• Pablo Pertejo,
• Tomás Hermosilla,
• Israel Carreira-Barral,
• Roberto Quesada and
• María García-Valverde

Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154

• corresponding pyrrolopiperazinoquinazolines 13 with high yields. Interestingly, despite the acidic medium and high temperatures, the hemiaminal group was conserved, showing the high stability of these systems. On the other hand, the reduction of the N-phenylglycine derivative 10c, used without purification

• dipyrrolopiperazinone 12 quantitatively. In view of the interest of these structures and the poor global yield obtained because of the purification in the first step, we tried the synthesis of these polycyclic systems in a one-pot sequence. In this way, after performing the Ugi reaction for 24 h, the reaction mixture

• , without purification, was treated with caesium carbonate (1 equiv) and heated to reflux for an hour. Gratefully, the dipyrrolopiperazinone derivatives 12 were obtained with high yields and complete diastereoselectivity in an efficient and simple way (Scheme 11, Table 6). The structure of these systems was

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

• purification. Further experimental details are given in Supporting Information File 1. The best result was obtained at 6 F/mol equivalents, giving 47% of quinone 4b (Table 2, entry 4). These experiments, where the reaction mixture was passed through the cell a single time, gave rather low yields. This may be

• acetals. However, the methoxylated products from electrochemical oxidation of chrysen-1-ol (3b) and chrysen-6-ol (3d) rapidly hydrolysed to quinones during purification and could not be isolated. The attempted electrochemical oxidation of naphthalene-1-ol (1b) was unsuccessful; only small traces of

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• . Chromatographic purification was not required post-reaction. Some spiro products exhibited high binding affinity towards DNA, while others showed good cytotoxicity against different cancer cells (A545, MCF-7, HeLa, HL-60, SW480, HepG2, HT-29, and A549) with IC50 values within the micromolar range (2.18–18.54 µM

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

• , purification of the crude product by column chromatography led to the decomposition of compound TP7. Another strategy was devised to obtain the desired triazinephosphonate TP7: The first step was the nucleophilic substitution of the chlorine atoms of triazine 1 by 4-hydroxybenzaldehyde (12), followed by the

• were used as received, without further purification. Solvents and air-sensitive reagents were distilled under a dry nitrogen atmosphere. Dry THF was distilled from sodium benzophenone ketyl. A Nafion N115 film was acquired from FuelCell Store and a 20 wt % mixture in lower aliphatic alcohols and water

• (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

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• for a supporting electrolyte, which is necessary for conventional organic electrolysis, reduces the environmental impact, and facilitates product purification. In addition, using nanoparticles in the catalyst layer, which serve as the electrode, results in a large specific surface area and efficient

Mining raw plant transcriptomic data for new cyclopeptide alkaloids

• Draco Kriger,
• Michael A. Pasquale,
• Brigitte G. Ampolini and
• Jonathan R. Chekan

Beilstein J. Org. Chem. 2024, 20, 1548–1559, doi:10.3762/bjoc.20.138

• additional purification step using an HPLC system (Agilent) with a C18 column (C18 250 × 4.6 mm Luna Omega 5 5 µm C18 100 Å) and gradient of 55–70% B was employed. Structure elucidation of ceanothine B Ceanothine B was analyzed by 1D and 2D NMR in methanol-d4 in 5 mm NMR tubes (Wilmad LabGlass). NMR

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

• 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

• vacuo. In most cases the products were already obtained in sufficiently high purity (>95%) after this work up. If necessary, further purification by silica gel column chromatography can be carried out. Safety considerations: It is known that the combination of inorganic azides and halogenated compounds

• the extracts were then filtered consecutively through a pad of anhydr. sodium sulfate and deactivated silica gel. The solvents were removed in vacuo. In most cases the products were already obtained in sufficient purity (>95%) after this work up. If necessary, further purification can be achieved by

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

• L1000 at 589 nm ([α]D values are listed in deg/(dm(g/cm3)); concentration c is given in g/100 mL). Unless otherwise stated, all chemicals were purchased from commercial suppliers and used without further purification. Dry solvents were obtained from an MBraun-SPS-800 solvent purification system. All

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

• binding of one isomer only. Experimental General experimental details. Commercially available solvents and reagents were used without further purification. Reactions carried out under anhydrous conditions are performed under argon in glassware previously dried in an oven. DMF and THF were previously dried

• with 10% H2SO4 in EtOH and heating about 30 s at 400–600 °C. Column chromatography purification was performed on CombiFlash® Rf+ and RediSep® RF or RF Gold normal phase silica columns (with UV detection at 254 and 350 nm for all azobenzene derivatives), or by flash column chromatography employing

• was stirred at room temperature until total deprotection. The solution was neutralized using Amberlite IR-120 (H), filtered, concentrated and the crude material used without further purification to give the desired product in quantitative yield. (A) Selected monovalent inhibitors for PA LecA and (B

Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

• Simone Gräßle,
• Laura Holzhauer,
• Nicolai Wippert,
• Olaf Fuhr,
• Martin Nieger,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

• 21gd could be isolated in quantitative yield with this technique, avoiding additional purification steps for the azide intermediate without any losses in product formation. The developed procedure was exemplarily transferred to solid-phase synthesis. In quantitative yields, 5-methyl-1H-pyrazol-3-amine

• . It offers the additional benefits of chemistry on solid support: straightforward purification of the resin-bound intermediates by washing steps and a high throughput that allows for faster derivatization. Further research is necessary to establish a protocol for the cleavage of 4-substituted

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• also simplifies product isolation and purification and improves the overall sustainability of the process [23][24]. However; specific reaction requirements ensure efficient and selective utilization of solvents. Marvi and Talakoubi carried out the Cannizzaro reaction [25] using montmorillonite K-10 and

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• minor products and mostly starting material, hence we decided these products were not worth further purification. The minor isomers of the halogenated derivatives were presumably detected but in too low yields to purify. Since 6/6/6-tricyclic diterpenes are known to show cytotoxicity [26], we tested our

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

• precipitation with a hexane–ether mixture and was found to be of sufficient purity for spectroscopic analysis. If desired, the product can be crystallized from an EtOAc–MeOH mixture for further purification. On the other hand, compound 2a has also been previously investigated for its potential covalent prolyl

• transformations is the purification of the synthesized product, since these oils are non-volatile and non-polar. However, in this study, the choice of these materials as green solvents allows convenient isolation of the cycloadducts by precipitation followed by filtration with hexane or diethyl ether. Thus, IMDAF

• . 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

• chromatographic purification due to much lower solubility of 4b compared to 4a. The metal complex of 4b with copper(II) was prepared, because copper(II) exhibited better extraction and separation abilities than cobalt(II) and palladium(II) in the case of Cu-tethered rectangular nanobrackets 1a [11]. Before SWNT

• ) spectroscopies after chromatographic purification. The mass spectrum clearly indicates that the detected mass number is matched with that of 1b. In the absorption spectrum, the absorption bands at 300–340 nm and 430 nm can be assigned to pyrene and dipyrrin moieties for 4b, respectively [18][19]. After

• 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