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

• equiv of isatin with a 50% excess of the α-CF3-substituted imine in toluene at room temperature in the presence of 10 mol % of organocatalyst 138 for times between 1 and 80 h. The reaction exhibited a broad scope in the isatin carbonate derivatives with high to excellent enantioselectivities (89–99

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• nucleophilic catalyst. Test reactions between cyclohexenone and thiomalonate 1 conducted in toluene at room temperature indicated the formation of the product with high conversions and efficiencies (Scheme 2). Application of epi-aminoquinine (AQ-1) in combination with 2-fluorobenzoic acid (system A) led to the

gem-Difluorination of carbon–carbon triple bonds using Brønsted acid/Bu₄NBF₄ or electrogenerated acid

• Mizuki Yamaguchi,
• Hiroki Shimao,
• Kengo Hamasaki,
• Keiji Nishiwaki,
• Shigenori Kashimura and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2024, 20, 2261–2269, doi:10.3762/bjoc.20.194

• (NMR) yield, in which trifluorotoluene (CF3C6H5) was used as an internal standard. The use of Tf2NH (5 equiv or 10 equiv) and Bu4NBF4 (5 equiv) in CH2Cl2 at room temperature gave the corresponding product 2a in up to 83% yield (Table 1, entries 1–5). The use of CF3COOH did not yield 2a at all (Table 1

• Bu4NBF4 was not effective (Table 1, entries 11 and 12). Finally, investigations of the amount of Bu4NBF4 and the reaction temperature demonstrated that conditions including Bu4NBF4 (9 equiv) and room temperature gave the best result (Table 1, entries 13–17). Based on the above investigation, we decided to

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• partially azidated poly(vinyl chloride) (PVA-N3) was prepared by stirring poly(vinyl chloride) and NaN3 in DMF at room temperature overnight. Measurements NMR spectra were recorded using a JEOL mode Al300 (300 MHz) at room temperature. Deuterated chloroform was used as the solvent unless otherwise stated

• only one imaginary frequency corresponding to the reaction coordinate. Synthesis of 6a To a solution of 5 in CH2Cl2, two equivalents of benzyl azide were added and the mixture was stirred at room temperature for 12 h. Evaporation of the solvent quantitatively yielded the target compound. 1H NMR (CDCl3

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

• , but its effective realization is limited by the need for both a solvent as well as a supporting electrolyte to allow for the flow of current through the reaction. Although some imaginative options have been reported, they tend to be quite limited in scope. Room temperature ionic liquids (RTILs) were

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

• –80%) along with their preliminary photophysical (absorption, emission and time resolved fluorescence lifetime) properties. The condensation reaction for assembling the required DPMs were catalyzed with trifluoroacetic acid (TFA) at 0 °C to room temperature (rt), and the stable dipyrromethanes were

• 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

• different equivalents (2 equiv for 12, 6 equiv for 15 and 9 equiv for 17) at 0 °C under N2 atmosphere. The red reaction mixture was stirred for 30 min at 0 °C, and further stirred at room temperature for 1 to 6 hours. After the reaction completion (TLC monitoring), the mixture was poured gradually into

Diastereoselective synthesis of highly substituted cyclohexanones and tetrahydrochromene-4-ones via conjugate addition of curcumins to arylidenemalonates

• Deepa Nair,
• Abhishek Tiwari,
• Banamali Laha and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2024, 20, 2016–2023, doi:10.3762/bjoc.20.177

• from curcumins and arylidenemalonates is reported. This strategy works in the presence of aqueous KOH using TBAB as a suitable phase transfer catalyst at room temperature. The functionalized cyclohexanones are formed as major products in moderate to excellent yields with complete diastereoselectivity

• base (KOH) and a phase-transfer catalyst (PTC) in a biphasic medium (toluene–H2O) at room temperature, leading to highly functionalized cyclohexanones and tetrahydrochromenones as major and minor products, respectively, in moderate to high yield and excellent diastereoselectivity. Results and

• Discussion Initially, the reaction of 1a with 2a was carried out with 3.0 equiv of aq KOH as base and toluene as a solvent in the presence of 20 mol % tetrabutylammonium bromide (TBAB) as a phase-transfer catalyst at room temperature for 24 h (Table 1, entry 1). To our delight, the formation of double

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

• ]. In addition to this, AAPTAB has a high thermal half-life at room temperature (5.7 years [19]), meaning there is no significant contribution from thermal Z–E isomerisation over the course of these experiments. Using in-situ UV- and visible-light irradiation with SAXS, here we measure the intermediate

• to the AzoTAB, as seen in similar amphiphilic systems [30][31]. In the case of ionisation, both stereoisomers would be expected to be affected equally. In comparison to Azo, the AAP moiety is much more stable as the Z isomer, with a thermal half-life of 5.7 years at room temperature [13]. This means

• (10 and 90 wt %), and the samples were heated to 60 °C, whilst stirring until homogenous. Samples were left to cool to room temperature whilst stirring. For the photoisomerisation studies using UV–vis absorbance spectroscopy, samples were irradiated to the PSS in a custom-built LED light box with UV

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

• reaction conditions. For instance, the use of lithium perchlorate as supporting electrolyte in acetonitrile at room temperature in a divided cell equipped with two platinum electrodes led exclusively to diazines 131 in good yields. In contrast, when the electrolysis was conducted in methanol containing

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

• Masahiro Terada,
• Zen Iwasaki,
• Ryohei Yazaki,
• Shigenobu Umemiya and
• Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

• reaction conditions were further examined (see Supporting Information File 1 for details). Although the yield of 3m was improved to 19% (Table 3, entry 2) by increasing the temperature of the premixing zone from room temperature to 50 °C and reducing the flow rate from 24 mL/h to 6 mL/h (light irradiation

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

• -substituted indazole analogs in 44% and 40% yields, respectively, by treating compound 6 with methyl iodide and potassium carbonate in dimethylformamide (DMF) at room temperature for 17 h [40]. Other works have shown poor selectivity when 6 and other isomers similar to 6 were reacted with isopropyl iodide and

• % at room temperature to 89% when warmed to 50 °C. No information was provided to justify any N2-selectivity or the lack thereof. Should an N2–Cs+–O ion pair exist, this could reasonably account for all the reported results presented herein (vide infra). Additionally, using Cs2CO3 in dioxane provided

• no products at room temperature (see Table 1) presumably due to the low solubility of Cs2CO3 in dioxane. They also provided a single example of a Mitsunobu reaction utilizing n-pentanol, dibutyl azodicarboxylate (DBAD), and PPh3. Therefore, there is still a great need to develop an operationally

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

• synthesis of highly fluorescent DPP derivatives through straightforward nucleophilic aromatic substitution reactions with thiols and phenols. These nucleophilic substitutions occur at room temperature and manifest a remarkable selectivity for the 4-position of the pentafluorophenyl groups. Both symmetrical

• performed in dry DMF at room temperature, in the presence of a base (K2CO3 or Cs2CO3). Room temperature was chosen due to the observed rapid degradation of the starting material at elevated temperatures. The work described herein allowed us to assess the potential of DPP 2 as a novel platform for obtaining

• , 2.8 mmol) and NaH (11.2 mmol) in DMF (60 mL) was stirred at 0 °C under a nitrogen atmosphere for 30 min. At this temperature, and under vigorous stirring, a solution of pentafluorobenzyl bromide (1.7 mL, 11.2 mmol) in DMF (8 mL) was added dropwise. The mixture was stirred for 24 h at room temperature

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• protocols [70][71]. In these experiments, compounds 6b and 6i proved to be unstable under on-DNA conditions as they failed to form esters 8b and 8i. Closely related structures, such as α-aminobenzothiazol-2-ylacetic acid is known to undergo decarboxylation at room temperature [72]. Compound 8t underwent

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

• using 2-alkenylbenzamide derivatives as substrates (Scheme 1). Results and Discussion We began by exploring the reaction of N-methoxy-2-(prop-1-en-2-yl)benzamide (1a) with PISA (1.5 equiv) in anhydrous acetonitrile at room temperature under argon atmosphere. 4-Methylisoquinolinone 2a was the sole

• were as follows: 1.5 equivalents of PISA and 4 Å MS in anhydrous CH3CN (0.1 M of 2a) under argon atmosphere at room temperature for 20 min. With the optimal reaction conditions in hand, we explored the scope of the method by testing various 2-alkenylbenzamide derivatives 1 (Scheme 2). When R1 was ethyl

• of 3-methylisoquinolinone as follows: reacting 1.1 equivalents of PISA in HFIP (0.1 M of 1a) containing 2.5 equivalents of H2O at room temperature for 20 minutes (Scheme 3). The general applicability of PISA in wet HFIP solvent was studied. When R1 was ethyl, isopropyl, cyclopropyl, or hydrogen

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

• appropriate alkene (0.20 mmol), TFA (0.20 mmol), and CH3CN (0.4 mL) were added to a solution of Bu4NOTf/1,2-DCE (0.10 M, 3.6 mL) while stirring at room temperature. The resulting reaction mixture was electrolyzed at 1 mA using a CF anode (10 mm × 10 mm) and a Pt cathode (10 mm × 20 mm) in an undivided cell

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

• high yields of the target compounds. When stored individually or in solution at room temperature, the acids 4 gradually decompose and undergo decarboxylation and other accompanying processes. The example of acid 4a demonstrates the possibility of easy amidation to form new β-lactam derivatives 3s and

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

• discussed in more details in chapter 2). Another recent article on the use of Brønsted acids has been reported by Vilapara et al., who employed for the first time etidronic acid (1-hydroxyethane-1,1-diphosphonic acid, HEDP) as a green catalyst. Reactions were efficient at room temperature [11]; although the

• -free conditions at room temperature for 2 h [16]. Although thiamine had already been reported to be effective in other chemical transformations and its role in carbonyl activation in vivo through its thiazole ring is well known, no mechanism of action in the GBB condensation was proposed by the authors

• et al. reported the first biocatalytic GBB reaction using lipase [21]. The model reaction depicted in Scheme 2 (R = t-Bu) was tested in ethanol at room temperature with various enzymes, where Candida antarctica lipase B (CALB) and Aspergillus niger gave best results, affording 3 in 63% and 64% yields

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

• mL urea buffer (8 M urea, 100 mM NaH2PO4, 10 mM Tris-base), pH 8.0, frozen at −80 °C, and then thawed at room temperature. The cell lysate was clarified by centrifugation and incubated with 1 mL Ni-NTA resin (Qiagen). The precursor protein was purified using the standard protocol from Qiagen for

• GraphPad (version 8.0.2). Atomic force microscopy AFM characterization was conducted using a MultiMode 8-HR (Bruker). Samples containing S. epidermis at an OD600 > 1 were incubated with the lanthipeptides at room temperature for 1 and 5 hours. Subsequently, 9 µL of the samples were combined with 1 µL of a

• 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

• efficient separation from the excess Selectfluor and its byproduct. Reducing the amount of Selectfluor to 2.5 equivalents and the reaction time to 24 hours (Table 2, entry 2) resulted in a similar high yield of difluoroiodane 6. The reaction also proceeded well at either room temperature for 24 hours (Table

• afford iodoalcohol 14 in 93% yield. In the final step iodoalcohol 14 underwent an oxidative fluorination with Selectfluor at room temperature to deliver methyl(trifluoromethyl)fluoroiodane 15 in a good 68% yield after recrystallisation from toluene. Although bis(trifluoromethyl)fluoroiodane 19 has been

• charged to a dry Schlenk flask under a nitrogen atmosphere. The flask was sealed and heated to 40 °C for 24 hours. After cooling the reaction mixture to room temperature, the solvent was removed in vacuo to afford a crude orange solid. The orange solid was extracted with dry dichloromethane (3 × 5 mL

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

• possibilities for subsequent post-transformation reactions. The synthesis of the target Ugi bisamides 5–8 was carried out at room temperature in ethanol with stirring for 24–48 hours (depending on the type of starting material) with a yield of 54–93% (Table 1). It is worth noting that the Ugi-4CR reaction also

• corresponding amide 10. The expected fact that the amides 10 could not be formed from the ketobisamides 12 (Table 3) was also confirmed; stirring the latter in MeCN or EtOH in the presence of HCl at room temperature or under heating did not lead to formation, not even to the appearance of traces of the amide

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

• procedure. Thus, initially the amine 3 (1 equiv) was added to a solution of the arylglyoxal 1 (1 equiv) in methanol and the mixture was stirred for 15 min. Then, the acid 2 (1 equiv) and the isocyanide 4 (1 equiv) were added and the reaction was stirred at room temperature for 24 h. Fortunately, after the

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

• . HCl and 3–4 drops of water. The mixture was stirred at room temperature for 0.5 h and poured into ice water (5 mL). The precipitated quinone was filtered off, thoroughly washed with water, and dried under vacuum to yield the pure product. General procedure C: combined electrochemical oxidation and

• hexafluorophosphate ([NBu4] [PF6]) solution in acetonitrile. The solvent was dried and degassed using N2 prior to each experiment. All experiments were conducted at room temperature. All redox potentials were calibrated against ferrocene/ferrocenium (Fc/Fc+) redox couple. Cyclic voltammograms of PAPs first scan at

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

• tolylhydrazonoyl chloride derivative 54 [35]. The reaction conducted in the presence of silver acetate at room temperature, achieved yields of 78–81% of the 16-spiropyrazolines 55a,b (Scheme 17). 6-Spiroimidazoline steroids In 2015, Dar’s group reported a small library of spiroimidazo[1,2-a]pyridines obtained