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

• pathway involving hydrogen abstraction from water yielding 4, and a major pathway involving oxygen addition to the central carbon to afford 1,2-dioxetane (DOT) intermediate. Usually, DOT derivatives are known to readily decompose [38], and this DOT intermediate is also considered to decompose upon C–C and

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• are not well described yet. To date, standard conditions have mainly been used for CFPS, with little systematic testing of whether conditions closer to intracellular conditions in terms of viscosity, macromolecules, inorganic ions, osmolarity, or water content are advantageous. Also, very few non

• -physiological conditions further extend the parameter space in which CFPS can be performed. This extension would be highly desirable for a coupled CFPS and enzyme assay, where, e.g., an organic solvent is used to solubilize poorly water soluble substrates for the enzyme. In this study, we therefore aim to fill

• some of the gaps in the consideration of the general physical properties and potential effects on the performance of Escherichia coli-based CFPS. We use technical additives, such as water-soluble macromolecular polymers and salts, which are commonly used as deep eutectic solvents (DES) and extend the

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

• Haifeng Yu Wanting Zhang Xuejing Cui Zida Liu Xifu Zhang Xiaobo Zhao College of Chemistry, Baicheng Normal University, Baicheng, Jilin 137000, China 10.3762/bjoc.20.190 Abstract An eco-friendly selective hydrolysis of chain α-oxo ketene N,S-acetals in water for the switchable synthesis of β-keto

• thioesters and β-keto amides is reported. In refluxing water, the hydrolysis reactions of α-oxo ketene N,S-acetals in the presence of 1.0 equiv of dodecylbenzenesulfonic acid effectively afforded β-keto thioesters in excellent yield, while β-keto amides were successfully obtained in excellent yield when the

• synthetic method for the preparation of β-keto thioesters and β-keto amides remains imperative. Organic reactions in water are an important and exciting research topic of green chemistry because water as a solvent exhibits fascinating features, such as low cost, good environmental compatibility, nontoxicity

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• constant current conditions with sacrificial tin electrodes resulted in 50% conversion to the allylation product and starting material after passing 2.5 F/mol of current. This poor conversion could be significantly improved by adding 10 volume percent of water to the reaction mixture, which also visibly

• decreased the viscosity. While complete conversion was still not achieved (67% conversion), it was a considerable improvement. Using glassy carbon electrodes with two equivalents of tin(II) chloride under a constant potential of 2 V, but still in CC/EG with 10 volume percent water, resulted in further

• recycling (Table 8). As with TBAB/EG, the allylation of p-anisaldehyde with allyl bromide was conducted using 2 equivalents of tin(II) chloride in CC/EG with 10 volume percent water at a constant potential of 2 V until 2.5 F/mol of current had been passed through the reaction. The product and unreacted

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

• to a mixture of 60 mL acetic acid and 30 mL concentrated HCl, then the reaction mixture was stirred for 16 h at 100 °C. The creamy precipitate (4.7 g, 80%) was obtained after pouring the reaction mixture into crushed ice, washed with water, acetone and dichloromethane (DCM), then dried under vacuum

• atmosphere. The flask was cooled to 0 ºC, and stirred vigorously after that n-BuBr (11.30 mL, 105.12 mmol) was slowly added to the RB-flask, and the mixture was stirred for 24 h at room temperature (rt), until the reaction completed (TLC monitoring). Then the reaction mixture was quenched with water, and the

• 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

O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• , was found to be 67–129 Å2 for all compounds except products 4 and 2e. None of the compounds penetrate the BBB (blood–brain barrier) except for seleno-2p and desulfurized product 7. Regarding water solubility, we can conclude that all compounds are either soluble or moderately soluble. For more details

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

• and changes in the reaction kinetics. The non-covalent immobilisation of chiral organocatalysts can also be carried out within deep eutectic solvents (DESs). Very recently, a cinchonidine-squaramide organocatalyst was immobilised in three types of natural DESs, namely betaine/sorbitol/water, betaine

• /xylitol/water, and betaine/mannitol/water [74]. In these systems, the recyclability of the organocatalyst was investigated and several reaction cycles were performed using the same DESs and organocatalyst. For example, in the Michael addition of methyl 2-oxocyclopentane-1-carboxylate and trans-β

• -nitrostyrene, the recyclability of the organocatalyst in the betaine/sorbitol/water DES system was demonstrated up to 10 cycles without any significant decrease in yield (up to 99%) or stereoselectivity (up to 96% ee). Encapsulation is an irreversible method and the only catalyst immobilisation process that

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

• interface, and a wide range of analysis tools for studying complex biomolecular systems. AMBER provides various force fields, specifically optimised for simulating biological molecules, as lipids (lipids21) [57], proteins (ff14SB) [58], water molecules (TIP3P) [59], general organic molecules (gaff2) [60

• ) sample the glycan conformational space; ii) investigate how the glycan behaves in a solution (if the MD is performed in explicit solvent), describing carbohydrate–water interactions; iii) monitoring the intramolecular interactions. Usually, this information has to be further validated by performing

• , water network prediction, and 3D-QSAR. GRID 2021 introduced a new interface aimed at structure-based design. It enables users to explore binding sites using classic GRID MIFs, encompassing 74 different chemical types. Additionally, it offers a new molecular probe for generating MIFs specific to

Cage-like microstructures via sequential Ugi reactions in aqueous emulsions

• Rita S. Alqubelat,
• Yaroslava A. Menzorova and
• Maxim A. Mironov

Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179

• redissolution in water resulted in colloidosomes with large holes on the surface. Varying the cross-link density during the Ugi reaction made it possible to obtain structures with different hole sizes. Keywords: carboxymethylcellulose; chitosan; colloidosomes; Pickering emulsions; Ugi reaction; Introduction

• emulsions. The polystyrene particles were treated with sulfuric acid to form a surface layer of sulfonated polystyrene. These particles were then used to produce Pickering emulsions, which were transformed into large-pore structures when treated with an alcohol/water mixture [12]. Another method involves

• polysaccharides [18]. Therefore, to stabilize such structures, the Ugi reaction in water was chosen, for which this particular pH value range is optimal [19]. The amino groups of chitosan and the carboxy groups of CMC reacted with each other and formed a stable structure that was no longer sensitive to changes in

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

• -hydroxypyrazoles 143 and not tautomeric 3-pyrazolones. Alternative access to alkynones can be achieved by nucleophilic addition of lithiated alkynes to N-substituted phthalimides 145, followed by ring opening to give, upon the addition of water, the corresponding 3-hydroxyindolines. These intermediates are in

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

• lipid tail length in the Z isomer [26]. Notably, these authors observed that the X-rays themselves also induced Z–E isomerisation in Azo-lipids, which they attributed to the X-ray radiolysis of water, which produces radicals and reactive species that can catalyse Z–E conversion [27]. This effect was

• greater using low-energy X-rays (8 keV) due to their greater photoabsorption in water, thus leading the authors to conclude that higher energy (≈36 keV) should be used for future small-angle X-ray scattering (SAXS) experiments on photoswitchable systems. However, this may not always be achievable

• . With comparison to the rate of Z–E isomerisation on addition of acid to the PS systems, we show that factors beyond the production of protons (H+) upon X-ray radiolysis of water may have an effect to produce the large, rapid structural changes observed using SAXS. To conclude, we create a set of

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• prepared prior to the electrolysis through the condensation of 2-hydrazinopyridine 13 and various aromatic, aliphatic and α,β-unsaturated aldehydes 14. The electrooxidative transformation was performed under constant current at 7 mA in a mixture of acetonitrile and water under heating. From a mechanistic

• the presence of iodide anion as electromediator. An important challenge is to avoid the competitive formation of the corresponding methoxy(phenylazo)alkane [46][47] or carbonyl compound [48] upon SET anodic oxidation of the hydrazone and subsequent reaction with methanol or water, respectively. In

• thiocyanation of ketene dithioacetals, Wang and Yang et al. mentioned one example of thiocyanation of benzaldehyde-derived hydrazone 120 using potassium thiocyanate as a source of thiocyanate radical. The electrolysis was conducted in the presence of two equivalents of water in acetonitrile with lithium

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

• monitored by TLC. The solution was diluted with water and extracted with EtOAc three times. The organic layer was washed with brine and evaporated to dryness to afford bismethylated derivative of 1 (1a, 1.9 mg, 88% yield). DFT methodology Prior to the calculations of the molecular properties of compounds 2

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

• cesium carbonate (766 mg, 2.352 mmol) followed by the necessary tosylate (1.5 equiv). The resulting mixture was stirred for 2 hours at 90 °C. The mixture was poured into EtOAc (500 mL) and washed with water (100 mL) and brine. The organic layer was dried and concentrated, the obtained residue was

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

• 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

• and water. The organic layer was then separated and washed with brine and water. The products were isolated by preparative TLC using CH2Cl2/hexane mixtures as the eluent. Compound 3a. Yield: 51%; mp 274–276 °C; 1H NMR (CDCl3, 300 MHz) δ (ppm) 8.43 (AA’XX’, J = 6 Hz, 4H), 7.68 (AA’BB’, J = 8.7 Hz, 4H

Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• zwitterionic water-soluble hypervalent iodine reagent (phenyliodonio)sulfamate (PISA). In water, PISA is strongly acidic, and the pH value can reach 2.05 in a saturated aqueous solution. With PISA, various indoles have been synthesized via C–H amination of 2-alkenylanilines involving an aryl migration

• product in the reaction, with a yield of 86% in 20 minutes (Table 1, entry 1). Encouraged by this result, we added additives to the reaction with the aim of further increasing the chemical yield of 2a. When 1.5 equivalents of water were added to the reaction, the yield of 2a dropped to 79% (Table 1, entry

• migration and reductive elimination, along with the release of iodobenzene and sulfamic acid. Cyclization of protonated G takes place to afford the intermediate H. Finally, release of water and β-proton elimination produces the rearranged product 3a (Scheme 8). Conclusion In summary, we reported the

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

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• -methoxyethylamine. Attempts to obtain directly 2-oxoazetidine carboxylic acid (or its decarboxylation product) or its trifluoroethyl ester by running the synthesis with water or trifluoroethanol were also unsuccessful. Acylation of the π-excessive double bonds of N-alkylindole and dihydropyran by the in situ

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• catalyst was tested only with 5-aminopyrazole 4, and no comparison with a “classic” GBB reaction can be made, the authors compared HEDP with other catalysts on the same substrates, demonstrating that HEDP in MeOH/water was superior for yields, mildness, and less hazardous conditions (Scheme 3). Longo et al

• . 1.3 Compartmented and enzyme-mediated reactions Compartmentation of reaction media has already found many applications in chemistry. Amphiphilic molecules can associate in water to nanometer-sized micelles, above a certain critical concentration. Such micelles are characterized by a lipophilic core

• and a hydrophilic corona and can serve as heterogeneous systems for solubilizing hydrophobic chemicals in water. By concentrating reactants in nanometer-sized vessels, their reactivity is altered, and reaction rates are often accelerated. As a result, mild reaction conditions can be achieved

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

• , water), which has become a common method for the synthesis of these derivatives [3][22][25][30][31][32][33]. In our previous studies [14][15][16][17][18][19] we have shown that the 5-aryl and 7,8-substitutients of the pyrimido[4,5-b]quinoline core have a significant effect on the photocatalytic activity

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

• 0.1% w/v poly-ʟ-lysin solution in water (Sigma-Aldrich) and immediately deposited onto freshly cleaved mica to be incubated for 10 min at room temperature to allow adsorption. The surface was then rinsed using 600 µL of ultrapure 0.2 µm filtered water and slowly dried using compressed air. Imaging was

Oxidative fluorination with Selectfluor: A convenient procedure for preparing hypervalent iodine(V) fluorides

• Samuel M. G. Dearman,
• Xiang Li,
• Yang Li,
• Kuldip Singh and
• Alison M. Stuart

Beilstein J. Org. Chem. 2024, 20, 1785–1793, doi:10.3762/bjoc.20.157

• rate of decomposition was reduced significantly (green line in Figure 3). The hydrolysis of the four hypervalent iodine(V) fluorides was also investigated in acetonitrile-d3 by adding 5 equivalents of water. All four compounds decomposed to their corresponding iodosyl compounds and the order of

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

• chlorine atom in the chlorovinyl fragment to the hydroxy group, probably under the influence of water (Figure 4). It is worth noting that the synthesis of Ugi bisamides 5–8 (Table 1) yielded compounds 10 and ketobisamide 12 in some cases. For example, in the Ugi reaction involving benzyl isocyanide (4b

• moiety under the influence of water. The appearance of HCl in these cases was identified by the specific odor and detected by pH measurements. It is likely that this catalytic amount of HCl is enough for the conversion and formation of the amides 10. To confirm the influence of HCl and its necessity to

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

• control of the current [32][33][34]. Early studies on the electrochemical oxidation of phenols revealed that the oxidation passes through a phenoxonium ion and forms acetals in methanol but quinones in the presence of water [35][36][37]. However, the reaction is sometimes accompanied by the formation of

• shown), where methanol further served as nucleophile. Some THF was needed to improve the solubility of some of the substrates. Acidic conditions (Table 1, entry 5) or methanol/water (Table 1, entry 6) gave a complex mixture with overoxidized products. Although the desired oxidation is a 4-electon

• flowrate of 100 µL/min. The current was increased from 1 mA to 13 mA to increase the electron equivalents from 1 F/mol to 8 F/mol at a potential of 1.7–3.0 V. The crudes, after evaporation of the solvents, were further hydrolysed with a mixture of HCl, acetic acid, and water to release the quinones before

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

• spirosteroids was underscored by the synthesis of spironolactone [3] (Figure 1), which plays a pivotal role in edema treatment. Aldosterone, implicated in water and salt retention in conditions such as congestive heart failure, hypertension, nephrosis, liver cirrhosis, and toxemia of pregnancy, prompted the

• –water–NaOAc mixture. Spiro heterocycle 99 was obtained in 52% overall yield as a single product (Scheme 29). The reaction mechanism was elucidated based on the hard and soft acid and base theory. Spiro-1,3,4-thiadiazoline steroids In 2006, Mazoir et al. [56] reported the synthesis of 4α,14α-dimethyl-5α