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

• , no reaction was observed with indazoles and furans using the first two conditions, requiring the formation of the ketoesters 4j and 4r first, followed by the functional group interconversion (FGI) with NH2OH·HCl (Scheme 6, blue and green sections). The Riley oxidation of the furanyl derivative 2j

Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• in line with the green chemistry requirements [24]. To test the assumption, the preparative oxidation of amine A1 was performed in the potentiostatic mode at 1.6 V (vs Ag/AgCl, KCl(sat.)) in a two-compartment cell in DMF; sodium tosylate was used as a supporting electrolyte. After a charge

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

• adducts. An intriguing study is reported by Porcal et al. [35] in which they evaluate the use of 5-hydroxymethylfurfural (5-HMF, 23). Nowadays, the need to move towards more sustainable protocols is impending and the emphasis on green chemistry and on the use of renewable carbon sources is huge. Indeed

• reaction conditions. The authors performed the optimization study using 5-HMF (23), 2-aminothiazole (24) and tert-butyl isocyanide (5, Scheme 10). Inspired by a procedure reported by Demjén et al. [37], they found the best conditions using EtOH as a green solvent, trifluoroacetic acid (TFA, 20 mol %) or Yb

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

• mechanism, see Supporting Information File 1). Such results with previous reports on DMSO acting as a methine source in the synthesis of heterocyclic compounds [35][36] are opening a new avenue for the green synthesis of non-substituted 5-deazaalloxazines in a pseudo MCR fashion. Conclusion In summary, we

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

• (blue line), dry CDCl3 with 2.4 equivalents of dry pyridine (green line), and dry CDCl3 (red line). Order of hydrolytic stability for the four hypervalent iodine(V) fluorides. Examples of fluorination using hypervalent iodine(III) reagents 1 and 2. Preparations and reactions of hypervalent iodine(V

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

• = green, N = blue, and O = red. a) Absorption and b) emission spectra of the compounds dissolved in CH2Cl2. Cyclic voltammograms of the compounds collected on ca. 1 mM solutions of the analyte in CH2Cl2 with 0.1 M Bu4NPF6 as electrolyte. The major y-axis tick mark spacing corresponds to 5 μA. Structural

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

• estitmation of the HOMO/LUMO energies to shed more light on this transformation. The easy separation of the supporting electrolyte from the product will allow recycling and makes this a green transformation. Keywords: acetal formation; cyclic voltammetry; flow electrochemistry; green oxidation; polycyclic

• synthesis of polycyclic aromatic quinones by anodic oxidation as a green alternative to our previous synthesis with SIBX [18]. Results and Discussion The electrochemical reactions were performed in the Flux module of the Syrris automated modular flow system [40] which provides a controlled geometry with a

• cations B and C which have only one Clar sextet with two alternative positions. Conclusion The electrochemical oxidation of polycyclic aromatic phenols to quinones represents a green alternative to chemical oxidants. Hydrogen gas evolution can be handled by recycling of the reaction mixture through the

Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ³-iodanes

• Thomas J. Kuczmera,
• Pim Puylaert and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

• formation of a) an alkoxy-NHI which is causing a significant downfield shift of the protons in alpha-position (orange) compared to the free alcohol 2 (blue) and b) oxidation of p-tolylmethanol (3a, blue) to the aldehyde 4a (green) and carboxylic acid 4a’ (red). Reaction conditions: An equimolar mixture of

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• advance and are not recycled in the system. The amino acids are methylated either prior to tRNA binding or after. The efficiency of incorporating unnatural amino acids is lower, but Merryman and Green have demonstrated that an excess of tRNA can overcome this problem [47]. When attempting to incorporate

• core peptide is coloured in orange. Methylation of the backbone is highlighted in green. B) Three-dimensional structure of the OphMA homodimer, PDB ID: 6TCS (https://doi.org/10.2210/pdb6tsc/pdb) [99]. Overview of the protein architectures and core peptide compositions of borosin N-MTs as defined by

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

• electrolysers that allow the generation of green hydrogen [12][13]. The technology behind these electrochemical devices still relies on the membrane as a key component that defines the applications and the conditions to its use [14]. Both fuel cells and water electrolyser devices depend on proton exchange

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

• bioactivities including analgesic, sedative, and cytotoxic [12][13][14]. In order to identify new potential burpitides, we searched the NCBI Sequence Read Archive (SRA) for Streptophyta (all land plants and most green algae) transcriptomes that could be assembled and examined with a custom hidden Markov model

• color-coded to show localization of various molecules. Molecules in red are new to this study and predicted by MS/MS fragmentation. Ceanothine B was isolated and its structure confirmed by 1D and 2D NMR. Correlations are indicated as follows: red lines – COSY, green lines – TOCSY, pink arrows – NOSEY

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

• total heat released as a function of total ligand concentration for the titration shown in the upper panel. The solid line represents the best least-square fit to experimental data using a one site model. (A) Enthalpy–entropy compensation plot of compounds 1–5 from ITC analysis. The dotted green line

• crystalline complexes. The protein is represented by orange ribbon, His53 by lines, and calcium by green sphere. Synthesis of photoswitchable LecA inhibitors. Reagents and conditions: (i) DMC, Et3N, H2O, −10 °C to rt, 8 h, 50% for 7, 40% for 10; (ii) BrCH2CH2NHBoc, K2CO3, DMF, 60 °C, 15 h, 91% for 8, 80% for

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

• Lu Li Na Li Xiao-Tian Mo Ming-Wei Yuan Lin Jiang Ming-Long Yuan National and Local Joint Engineering Research Center for Green Preparation Technology of Biobased Materials; School of Chemistry and Environment, Yunnan Minzu University, Kunming, China 10.3762/bjoc.20.130 Abstract A catalyst- and

• of anilines through Brønsted acid or transition-metal-promoted conversion of 2-cyclohexanone oximes [15][16][17][18] (Scheme 1, (2)). Moreover, Strauss and co-workers described a green, multicomponent reaction of aromatic aldehydes, 2-cyclohexenone and amines to afford 2-arylmethyl N-substituted

A comparison of structure, bonding and non-covalent interactions of aryl halide and diarylhalonium halogen-bond donors

• Nicole Javaly,
• Theresa M. McCormick and
• David R. Stuart

Beilstein J. Org. Chem. 2024, 20, 1428–1435, doi:10.3762/bjoc.20.125

• that we studied here revealed an opposite trend (Scheme 4b, orange, yellow, blue, and green dots). The halogen-bond length decreased with increasing van der Waals radii of X and the trend was more pronounced for monovalent halogen-bond donors. This is exemplified by halogen-bond complexes of the

• hypervalent phenyl(mesityl)haloniums 9 and 10 (X = Cl and Br) to negative E(r) values for the heavier haloniums 11 and 12 (X = I and At, Scheme 5, green bars). Uchiyama previously suggested that the diarylchloronium 9 has a “breakdown of the hypervalent bond” [43], and our data suggest that the interaction

• halogen-bond donors are clustered into hypervalent 1–8 (Scheme 6b, green dots), monovalent aryl 26–28 and 30–32 (Scheme 6b, orange dots), perfluorophenyl 33–36 (Scheme 6b, yellow dots), and imidazolium 37–40 (Scheme 6b, blue dots) linear correlations with similar slopes are observed for p-orbital

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• Md Azadur Rahman Hirofumi Endo Takashi Yamamoto Shoma Okushiba Norihiko Sasaki Toshiki Nokami Department of Chemistry and Biotechnology, Tottori University, 4-101 Koyamacho-minami, Tottori city, 680-8552 Tottori, Japan Center for Research on Green Sustainable Chemistry, Faculty of Engineering

Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation

• Akanksha Chhikara,
• Fan Wu,
• Navdeep Kaur,
• Prabagar Baskaran,
• Alex M. Nguyen,
• Zhichang Yin,
• Anthony H. Pham and
• Wei Li

Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122

• Akanksha Chhikara Fan Wu Navdeep Kaur Prabagar Baskaran Alex M. Nguyen Zhichang Yin Anthony H. Pham Wei Li Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States 10.3762/bjoc

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

• of α-hydroxycarboxylic acids [47]. They are also used in the development of different nanoparticle preparations and other reactions for synthesis of bioactive compounds [48][49][50]. Green synthesis methodologies, such as microwave-assisted [51][52][53] and ultrasound-assisted reactions [54] are

• established techniques in green chemistry due to their potential benefits in terms of reduced reaction times, increased yields, and the ability to perform reactions under milder conditions than traditional methods. The Cannizzaro reaction, being a useful synthetic tool, has also been explored in this regard

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• heightened by the current energy crisis and the adverse impacts of industrialization. The development of green and energy-efficient methods in organic chemistry that use renewable sources of starting materials is considered highly sustainable [1][2][3]. Radical reactions have profound applications in organic

• promote green chemistry principles. In this regard, in 2019, Banerjee et al. published a review article on the generation of acyl radicals in the presence of visible light [22]. Therein, they discussed the various ways in which visible light can generate acyl radicals from different organic molecules to

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

• , chloroform, etc. Despite recent efforts by 'green chemists', synthetic chemists still use these traditional toxic organic solvents in many of their reactions, even though safer alternatives are available. However, in addition to the harmful effects of these petrochemical solvents on the environment, the

• prediction that their resources will run out in the near future has led 'green chemists' to explore solvents that can be derived from renewable resources and used effectively in various organic transformations. In this context, we have shown for the first time that the 100% atom-economical tandem Diels–Alder

• Diels–Alder reactions and can be used repeatedly without significant degradation. These materials also allow the reaction to be completed in less time, with less energy consumption and higher yields. Keywords: biobased solvent; epoxyisoindoles; furanics; green chemistry; intramolecular Diels–Alder

Oxidative hydrolysis of aliphatic bromoalkenes: scope study and reactivity insights

• Amol P. Jadhav and
• Claude Y. Legault

Beilstein J. Org. Chem. 2024, 20, 1286–1291, doi:10.3762/bjoc.20.111

• Amol P. Jadhav Claude Y. Legault Department of Chemistry, Centre in Green Chemistry and Catalysis, Université de Sherbrooke, Québec J1K 2R1, Canada 10.3762/bjoc.20.111 Abstract We have developed an operationally simple method for the synthesis of dialkyl α-bromoketones from bromoalkenes by

• Green Chemistry and Catalysis (CGCC), and the Université de Sherbrooke.

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• air-saturated solution (red spectrum) and used it to separate the signal that only stems from the oxidative quenching step (green spectrum). This correction likely overestimates the contribution of the two-photon process to the radical cation signal in the presence of 4CP, considering that quenching

• (blue) and phosphorescence (green) spectra measured at 77 K in MeOH/EtOH (4:1). B) Transient absorption spectra of 25 µM (initial ground-state absorbance at the laser wavelength, 0.2) Aza-H in Ar-saturated (black) and air-saturated (red) MeCN/H2O (9:1) recorded after 250 ns and the difference spectrum

• . Mechanistic LFP experiments of 25 µM Aza-H with 4CP in MeCN/H2O (9:1) after 355 nm laser pulses. A) TA spectra recorded after 250 ns of solely Aza-H in air-saturated solution (red), in Ar-saturated solution with 200 mM 4CP (blue) and the difference spectrum of both (green). Inset: Kinetic traces of Aza-H with

The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• ]. Carboxylic acids 2 and aldehydes/ketones 3 used in the Ugi4CR. GI50 range plot against human solid tumor cell lines of investigated α-acetamide carboxamide isatin hybrids. Green most potent, yellow intermediate, red less potent. (A) Library of isatin-based α-acetamide carboxamide oxindole derivatives

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

• on the 0.0067 e·Å−3 isosurface for the electron density. Response towards acid treatment with nitrogen-doped CMPs. (a) Absorption spectra of 3a (CHCl3, 2.3 × 10−6 M) in the absence (black) and presence of trifluoroacetic acid (green: 4.3 × 10−2 M, blue: 2.1 × 10−1 M, red: 4.2 × 10−1 M). (b

• ) Absorption spectra of 6 (CHCl3, 1.9 × 10−6 M) in the absence (black) and presence of trifluoroacetic acid (green: 4.3 × 10−2 M, blue: 2.1 × 10−1 M, red: 4.2 × 10−1 M). Syntheses of 3a and 3b. Supporting Information Supporting Information File 50: Experimental and copies of spectra. Supporting Information

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• electron density (ρ) and the reduced-density gradient (RDG, s). The NCIplot provides qualitative information, and it can successfully map real-space regions where non-covalent interactions are prominent. The resulting plots have a color scheme of red–green–blue scale, where red represents attractive

• are represented by dark shades. 6-6 bicyclic molecules are colored purple, 5-7 bicyclic molecules with the carbocation present on the seven membered ring in green, and 5-7 bicyclic molecules with the carbocation on the five membered ring in brown. NCI plot for A (left) and B (right). Blue corresponds

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• synthesizing amines, the borrowing hydrogen approach is becoming increasingly popular in catalysis since this method provides an excellent example of a green chemistry and atom-efficient reaction [31][32][33]. This section focuses on manganese-catalyzed C–N bond formation reactions via BH or HA using alcohols