Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• ≤ 0.78 µg/mL for levofloxacin as the positive control. Conclusion In conclusion, we have demonstrated that β-keto amides and 2-nitrobenzoyl chloride can be used as convenient precursors to a variety of 4-quinolone derivatives. The described approach is realized in a small number of steps, under mild

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• complex [Cu(dmp)DPEPhos](BF4), well-investigated and used in several photocatalytic reactions [20][21][41], acting as a cost-effective benchmark photosensitizer. Herein, we present a study for the selectivity control of the novel Co(II) catalyst 1, aiming at maximizing the catalytic efficiency, and

• 12.5%, the selectivity towards CO increased up to 40%. Nevertheless, H2 was still the major product. Thus, we decided to use triethylamine instead of TEOA, since a base is necessary for the reduction of CO2, as also demonstrated by control experiments (Supporting Information File 1, Table S4), where in

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• was collected in continuous mode from 2° to 30° (2θ angle) at specific temperatures during the cooling down to room temperature. The temperature was controlled with a TCU2000-temperature control unit (Anton Paar). The absorbance spectra in solution and in spin-coated films were collected with an Ocean

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• with fluorinated or chlorinated compounds, producing Qx14 and Qx15, respectively. This modification aimed to improve the device performance by enhancing aggregation control and optimizing the open-circuit voltage. The introduction of functional groups provided a strategic means to tailor the molecular

• of structural modification, the introduction of various functional groups into Qx derivatives has allowed for the precise control of energy levels, bandgaps, and carrier transport properties. For instance, Sharma et al. fine-tuned the intermolecular charge transfer (ICT) transitions and emission

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• Ar and CF3 groups can localize the negative charge and also provide steric effects to afford stereoselective cycloaddition products with 3:1 to 6:1 dr. The steric hindrance also prevents products 9 from undergoing a second cycloaddition. The control reactions of methyl ketone or benzaldehydes gave

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• ethyl acetate, while using a bulk heterojunction (BHJ) comprised of PM6:Y6. High power conversion efficiencies (PCEs) of 13% were achieved compared to control devices using the standard PFN-Br CIL. Keywords: cathode interlayer materials; green solvent processing; organic photovoltaics; Introduction

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• dissolved initiators in the liquid phase during the process. A suspending agent, e.g., polyvinyl alcohol (PVA), is added to the system to prevent coalescence. The viscosity in suspension polymerization is low throughout the process which brings good heat transfer and temperature control, and therefore well

• radical polymerization is that a limited control of molecular weights and architectures can be achieved due to the slow initiation and rapid termination. In 1956, Szwarc coined the term “living polymerization” in an anionic system [27]. Since then, polymer chemists have been in pursuit for a comparable

• successful nitroxide-mediated polymerization (NMP). In 1993, Georges et al. used benzoyl peroxide (BPO) as the initiator and 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) as the control agent. It was called a bicomponent initiating system containing both stable free nitroxide and a conventional thermal

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• . It was found that the desired product could be obtained in 87% yield (Scheme 4). Next, some control experiments were carried out to study the reaction mechanism. We found that the reaction of compound 3a could not be inhibited by TEMPO and BHT under the standard conditions. Therefore, it is assumed

• that the reaction is not a free radical reaction. Based on the control experiments and previous literature [21], we propose the following possible mechanism, which is shown in Scheme 5. Aluminum trichloride reacts with sodium nitrite to form an intermediate aluminum complex A, which is further

• atmosphere, 90 °C, 24 h. Reaction substrate scope of quinolines. Conditions: 1a (0.1 mmol, 1 equiv), 2 (0.2 mmol, 2 equiv), AlCl3 (0.3 mmol, 3 equiv), NaNO2 (1 mmol, 10.0 equiv), DMAc (1.0 mL), N2 atmosphere, 90 °C, 24 h. Gram scale reaction. Control experiments and possible reaction mechanism. Optimization

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• treatment. The mean percentage of viable cells normalized to the control (solvent alone) is shown with associated standard error (n = 4). Significance was determined using two-tailed T-test analysis, with a significance cutoff of P ≤ 0.05. All significant differences are designated with an asterisk and the

• activity after treatment. The mean percentage of viable cells normalized to the control (solvent alone) is shown with associated standard error (n = 4). Significance was determined using two-tailed T-test analysis, with a significance cutoff of P ≤ 0.05. Only original chelerythrine (P < 0.001) was

• determined to be significantly more potent than the methanol negative control. General route to berberine variants, displaying the numbering system for the berberine ring. Synthesis of new berberine variants. Reductive amination to a secondary amine was followed by cyclization with glyoxal to provide the

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• pyrazolone derivatives with N-thiophthalimides catalyzed by 1 mol % of chiral iminophosphorane organocatalyst was carried out under mild conditions [103]. Solvent control in the procedure can affect the yield of products due to the solubility of the catalysts. Various solvents, such as acetone, ethyl acetate

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• 5 and 8a in 77–88% yields, albeit as poorly selective mixtures of diastereoisomers. This lack of stereocontrol is not surprising, given the well-known difficulty to control the relative configuration between the two adjacent stereocenters created during aldol condensations with zinc enolates

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• reactive and difficult to isolate. The NHC–Cu complex also helps to control the regioselectivity and stereoselectivity of the reaction, which are of high importance in organic synthesis. Overall, the use of NHC–Cu complexes as catalysts for conjugate addition reactions offers a highly efficient and

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• . The reaction mixture was heated at 100 °C until complete conversion of the starting material (via TLC control). Potassium tert-butoxide (505 mg, 4.50 mmol) and 1.50 mL DMSO were then added and the reaction mixture was stirred for an additional 15 min. After cooling the reaction mixture to room

• temperature, NIS (338 mg, 1.50 mmol) and 1.00 mL DMSO were added. After complete conversion (via TLC control), methyl iodide (639 mg, 4.50 mmol) was added and also stirred at room temperature for 5 min. Water was added to the mixture and the aqueous phase was extracted with dichloromethane. The combined

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• mild conditions the benzylation of the alcohol function to yield 7.3. Then, the removing of the tosyl group required a two-step sequence. First, 7.3 reacted with cesium acetate and then the resulting ester was reduced with LiAlH4 to produce 7.4 with control of its stereochemistry. Very recently, a new

• , both enantiomers were reported. For the control of the chirality in position 2 of glycerol, (S)-solketal (17.1) was used as starting material to prepare first the hexadecylglycerol (R)-17.2 which was converted to its enantiomer following a five-step sequence (Figure 17A). First, tritylation and

• ] but to the best of our knowledge, R. Berchtold reported in 1982 the first synthesis in large quantities with a control of the chirality at the sn-2 position (Figure 21) [116]. The synthesis starts from (S)-1,2-isopropylideneglycerol (21.1). The deprotonation of the primary alcohol with sodium amide

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• , radical detection, and other control experiments confirmed that the reaction proceeded through a radical oxidation process. The reaction of most substituted olefins with cyclic ethers afforded the corresponding target products with excellent yields, which provides a simple, novel, and efficient pathway to

• afford allyl ethers. Alkyne C(sp)–H bonds are reactive, and the challenge in the cross-coupling of C(sp)–H and C(sp3)–H bonds is to control chemoselectivity. In this context, Liu et al. reported a Cu(I)/Ga(III)-catalyzed trityl ion-mediated direct CDC of the C(sp3)–H bond of THF with C(sp)–H bonds of

• coordinated with metal catalysts to control the selectivity and improve the reactivity in metal-catalyzed or -mediated reactions. Therefore, controlling the regioselectivity of CDC reactions by directing groups is of great interest [95][96]. Li et al. reported a cobalt-catalyzed CDC between unactivated C(sp2

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• process which involves two consecutives stereoselective reactions. The control of the diastereomeric ratio is, however, difficult to attain as demonstrated by an extensive screening and is always near 50:50 without significant deviations changing the reaction conditions. On the contrary, the use of

• aldehydes other than acetaldehyde generates higher control [11]. It was previously shown that the first stereogenic center formed in the presented cascade process is formed with high control [17]. Therefore, the second carbon–carbon bond forming step, i.e., the organocatalyzed Michael addition of the

• enantiomeric excesses. Unfortunately, the developed methodology is currently limited to aromatic substrates and the formation of one stereocenter is difficult to control, leading to a mixture of two diastereomers. Current efforts in our laboratories are addressing these challenges. Approaches based on the

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• paradigm with photocatalytic ATRA to enable the modular difunctionalization of alkenes under reagent control (Scheme 3). In Stephenson’s photocatalytic ATRA reports, the C–X bond in the product was proposed to be formed through both direct quenching of a transient alkyl radical by halogen atom transfer

• azides for a wide range of both activated (benzylic) and unactivated carboxylic acids. Control reactions support the intermediacy of alkyl radicals and the absence of carbocation rearrangements in a variety of probe substrates disfavor the reaction proceeding via RPC. Intriguingly, no additional oxidant

• literature examples of nitrate oxidation of different transition metals, such as palladium. Control reactions further supported this proposal, including the inability of alternative Fe(III) salts (e.g., FeCl3) to form more than stoichiometric azide product in the absence of added nitrate. We believe this

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• ]quinoxalinoporphyrins 3–8 in 61–68% yields. To authenticate the proposed reaction pathway, a control experiment was carried out by reacting copper(II) 2,3-diamino-5,10,15,20-tetrakis(4-methylphenyl)porphyrin (1) with 2-hydroxynaphthalene-1,4-dione (2) in CHCl3 containing 20 mol % TCA at 65 °C as presented in Scheme 2

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• NADH-analogues are the subject of most studies for recycling sacrificial donors. NADH has been electrochemically recycled but a careful control of pH is required to prevent dimerization reactions [44][45]. For example, Glusac and co-workers recycled BIH and acridine analogues using platinum electrodes

• in acetonitrile with proton donors [45]. They carefully calculated the pKaH of their proton donors and NADH analogues to control the PCET and to prevent side reactions. In another interesting example, NADH was recycled at a copper electrode in aqueous buffers and NADH was found to be more stable in a

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• the biosynthesis of fatty acids in plants, which leads to herbicidal activity [9]. Pyraclonil is used as a protoporphyrinogen oxidase inhibitor for weed control. Such inhibitors not only block the production of chlorophyll and gem in plant pests, but also lead to the formation of highly reactive

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• appreciation and understanding of σ-holes in iodonium ylides, many examples exist where inter- or intramolecular halogen bonding has been invoked to provide a meaningful explanation of unexpected reactivity, of reagent stability, or as a reaction control element. Examples of these include spontaneous

• these preferential outcomes is not understood, and may derive from rapidly equilibrating species (e.g., 2 and 3) reacting under Curtin–Hammett control, from hard/soft principles dictating the Lewis base’s selectivity with either the stronger (e.g., 3) or weaker (e.g., 2) σ-hole, or possibly from other

• ]. However, numerous inconsistencies have been observed when comparing the outcomes of diazo- and iodonium ylide-based metallocarbene reactions, especially during metal-free control experiments, which led researchers to propose alternative, carbene-free reaction pathways for iodonium ylides. This was first

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• potency against cancer cells in the presence of a 3-OH group. Notably, hydrolysis of the C3-acetoxy group in pachymic acid to tumulosic acid increased the activity of the compound compared to the positive control (cisplatin), in some instances [36]. Concomitantly, the oxidation of the hydroxy group at C-3

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• first run, a conversion of 10% was observed after 120 min irradiation time. Running the control experiments gave further insight into the critical components but also a few surprises. As expected, omitting the electrolyte in the photochemical procedure did not affect the conversion (so n-Bu4Br could be

• oxidation of tetrahydrothiophene). Therefore, we performed a control experiment in the presence of an additive with an aromatic moiety to determine its effect on the reactivity of a non-aromatic substrate. Surprisingly, and to the best of our knowledge, never reported before in literature, the addition of 1

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• efficiency and selectivity of the reactions (vide infra, conPET section). Electrolytes have the potential to be i) aqueous-separated and recovered in batch, or ii) decreased, even ultimately eliminated by flow reactors as an engineering control. Regarding purely the chemical reactivity and scope of

• reduction to PC•− ensures higher concentrations that are directly user-influenced. Upon activation, PC1 could successfully reduce various aryl halides generating borylated products in modest to excellent (30–99%) yields. Control experiments confirmed that light, catalyst and DBU as a sacrificial electron

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• , Tokyo, Japan). Plant material The resinous wood of Aquilaria sinensis was purchased from Hainan Xiangshu Agarwood Industry Groud Co., Ltd., July 2018. The material was identified by the Gansu Institute for Drug Control, and a voucher specimen (CHYX0642) was deposited at School of Pharmaceutical Sciences