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

• polymerization of organic molecules is an important strategy for the preparation of functional materials, such as conducting polymers [1][2][3][4][5]. Electrochemical reactions can be controlled by electric potential or current, electrodes, and electrolytes, which are not available in conventional chemical

• reaction time and rate is possible under electrochemical conditions [11][12][13]. We have been interested in the preparation of cyclic oligosaccharides under electrochemical conditions and electrochemical conversion of linear oligosaccharides of glucosamine into the corresponding cyclic oligosaccharides by

• rate: 7.5 mL/min, recycle numbers: 3) to obtain pure cyclic oligosaccharide 16 (0.125 mmol, 79.7 mg, 62%). Preparation of cyclic oligoglucosamines a) via intramolecular glycosylation and b) via polyglycosylation and intramolecular glycosylation. Proposed reaction mechanism of the formation of 1,6

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

• synthesis of medicinally useful molecules (Scheme 23) [90]. The Cannizzaro reaction has also been applied to the preparation of mandelic acid-based synthons, which gain potential importance in the synthesis of prostaglandins, cephalosporins, and homatropine [65][66][67][68][69]. Synthesis of useful

Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor

• Kazuyuki Sato,
• Satoki Teranishi,
• Atsushi Sakaue,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai,
• Hiroyuki Takeda,
• Tatsuo Kinashi and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118

• preparation of the Grignard reagent followed by the homo-coupling reaction. Various conditions were examined and biphenyl (3b) was obtained in 85% yield in a one-pot reaction, when bromobenzene (5b) was treated with 1.5 equiv of Mg (turnings, grade for Grignard reaction) under reflux conditions of THF for 24

• , since the preparation of Grignard reagents derived from haloarenes with Mg in situ requires heating for a long time, we decided to use heating conditions for the one-pot homo-coupling reaction. Most homo-coupling products were obtained in this reaction, although the product yield decreased when using

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• participation of hydrazones attract special attention. This reaction is a general method for the preparation of 1,2,3-triazoles bearing various substituents at position 2. Wherein, depending on the type of starting heterocycles various functional derivatives are formed. So, the well-known Boulton–Katritzky

• undergo base-promoted Boulton–Katritzky rearrangement to appropriate 1,2,3-triazoles 4 (Scheme 1c). Based on the performed investigation a general approach to the preparation of corresponding terarylenes with a 3-hydroxy-4-pyranone unit was designed. Results and Discussion The starting ketones 1 were

• hydrazones. Further, the obtained hydrazones undergo Boulton–Katritzky recyclization to the corresponding 1,2,3-triazoles. Based on the performed study a convenient approach for the preparation of 1,2,3-triazole derivatives with 3-hydroxypyran-4-one unit was designed. It was shown that the proposed method

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

• preparation of compound 2a are given in Table S2 (Supporting Information File 1). As can be seen from the table, most of these methods use toxic and volatile organic solvents, and the duration of the associated intramolecular exo-[4 + 2] reaction is quite long. In the scope of this study, the structures and

• reactions, which are a useful strategy for the preparation of many natural compounds and various organic intermediates, can be safely carried out under more environmentally friendly conditions. Experimental All reagents and solvents were purchased from Merck (Merck, Darmstadt, Germany), Sigma-Aldrich (St

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• trimethylchlorosilane. A direct preparation of 6a by reaction of dianion 7 with trimethylchlorosilane is not possible, because the silylation occurs at the terminal carbon atom of the dianion. (2,4-Dioxobutylidene)phosphorane 8 also represents a synthetic equivalent of dianion 7 [23]. However, reactions of such

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• , competent cell preparation, and transformation were performed as described previously [42]. Protein expression and purification The alpG gene was amplified by PCR from S. ambofaciens ΔΔalpW genomic DNA using primers 5’-ggaattccatATGGAAGGGACAACGGCGGACAC-3’ and 5’-cccaagcttTCAGCGGGCGGGGCCGAA-3’, digested with

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• ][8][9][10][11][12]. The interest in the preparation of functionalized indanone derivatives has increased enormously, and many synthetic methods have been developed, including Friedel–Crafts cyclization reactions [13], cyclization of acetylenic derivatives [14], ring contractions and ring expansions

• ], Reformatsky reaction [65], azalactone synthesis [66], nitro reduction [67][68], epoxide rearrangement, thiourea guanylation, and others [69][70]. In this article, we describe a simple and direct protocol for the preparation of indanones through a classical Nazarov reaction catalyzed by bismuth(III) triflate

• . In addition to the synthetic simplicity, the moisture stability of bismuth triflate allows the protocol to be carried out under ambient atmospheric conditions. Results and Discussion Preparation of β-ketoesters We initiated our studies with the preparation of the β-ketoesters, which were synthesized

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• medium). Then, the α- or β-anomer of salt 21 was converted to 2-cyanoethoxy derivative 22 using 3-hydroxypropionitrile and TBTU. This was further transformed into the required phosphoramidite 23 as individual α- or β-anomer, which was used in the preparation of modified DNA sequences on a DNA synthesiser

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• significant importance as reactive building blocks in polymer and materials chemistry. Their preparation primarily relies on established synthetic methods using molecular bromine or N-bromosuccinimide, known for their reliability and effectiveness. However, from a sustainability perspective, these methods

• process, the residual halogen (if any) can decompose hydrogen peroxide into molecular oxygen (Equation 4) [45]. Over the years, various peroxide-bromide processes have been developed based on this chemistry. In particular, significant attention has been given to the preparation of benzyl (mono)bromides

• %. The aryl-cored bromides featuring both core and side chain halogens (1c, 3c, and 4c of Figure 3) are also of interest for the chemical community. The preparation of these polybromides can be ideally approached with two synthetic strategies: first-benzylic-then-ring or first-ring-then-benzylic

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• , 2H), 9.34–9.36 (d, J = 8 Hz, 2H); 13C NMR (125 MHz, DMSO-d6 + TFA) δ 126.8, 127.8, 136.8, 138.3, 139.0, 147.9, 155.8; HRESIMS: [M + H]+ calcd for C16H8N6O2, 317.0787; found, 317.0776. Chemical structures of H-bonding N-heteroacenes synthesized by Miao et al. and Bunz et al. (a) [22][23]. Preparation

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• are versatile reagents that exhibit a range of reactions, both in the presence and absence of metal catalysts. In this study, we developed efficient synthetic methods for the preparation of aryl(TMP)iodonium(III) carboxylates, by reaction of (diacetoxyiodo)arenes or iodosoarenes with 1,3,5

• compared to trifluoroacetic acid, TfOH, HBF4, and p-TsOH, present a wider substrate scope, including acid-sensitive groups, in the preparation of diaryliodonium(III) salts. While the counterion exchange of diaryliodonium(III) chloride with silver acetate was reported [20], this method required heating

• design diaryliodonium(III) salts including a commercially available and inexpensive auxiliary group to achieve efficient preparation of the salts and a high degree of chemoselectivity for transferring the required aryl group. Electron-rich aryl ligands derived from anisole, mesitylene, and particularly

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• the high synthetic value, significant efforts have been devoted to developing methods for the preparation of the tetrazole scaffolds, in particular recently through multicomponent reactions (MCRs) and mostly Ugi and Passerini reactions [7][8][9]. Traditionally, due to its charged nature the tetrazole

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• tetrazolyl-1,2,3,4-tetrahydroisoquinoline 8a in 74% isolated yield which is higher than the one-pot Ugi/Hecke reaction to give product 6b (58%). Under the alternative one-pot reaction conditions involving an N-alkylation step, the substrate scope was explored by the preparation of 10 derivatives 8a–j (Scheme

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• was performed on Merck Silica gel 60 (particle size 63–200 μm). Solvents for extraction and column chromatography were distilled prior employment. Representative method for the preparation of starting materials 5-Bromo-6-chloro-1,3-dimethyluracil (2). Uracil 1 (22.9 mmol; 4.00 g) was dissolved in

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• group in the product can be leveraged as a versatile synthetic handle, allowing for the preparation of hitherto inaccessible types of densely functionalized N-vinylazoles. Keywords: alkynes; azoles; cross-coupling; hypervalent iodine; Introduction N-Functionalized azoles are prevalent in bioactive

• natural products and pharmaceutical agents, including antifungal drugs [1][2][3], and hence their selective preparation has attracted considerable attention from the synthetic community. Compared to methods for the de novo construction of azole heterocycles, direct functionalization of the azole N–H bond

• iodonium salts [9], which usually occurs with the retention of the stereochemistry of the vinylating agents (Scheme 1a). Nonetheless, this approach is not necessarily suited for the stereoselective preparation of densely substituted N-vinylazoles because preparing the requisite multisubstituted vinylating

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• assay as described above. Preparation of NNG and 2-NAE degradation samples Triplicate samples containing 2 mM 2-NAE or 350 µM NNG, 40 µM titanium citrate with or without 20 µM Vs NnlA in deoxygenated 23 mM tricine at pH 7.5 were incubated overnight at 21 °C. Phylogenetic tree Homologs of the Variovorax

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• reports of Karban et al. (Scheme 2) [19]. We envisaged that these hexose-derived building blocks with a 2,5-anhydro bond such as 5 could be useful materials for the construction of C-nucleosides such as formycin A (Figure 1) [22][23][24]. The preparation of C-glycosides usually involves the creation of

• , with the exo-hemiacetals favoured due to steric interactions between the substituents and alcohol, while the attempted preparation of 12b led only to complex mixtures (Scheme 2). The products of the reactions were characterised by 1D and 2D NMR, and X-ray crystallography of members from each class was

• 10a–c, preparation of 10d–f, and X-ray structure of 10e. Rearrangement reactions for 10a–f promoted by SOCl2. Reactions of allylic alcohols 15 and 18 with SOCl2. Appel reactions of dioxabicyclo[3.2.1]octan-4-ols 10a,e,f and 15. Some transformations for the skeletal rearrangement products 11a and 12a

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• -sensitive substrates. Another challenge, shared with Nicewicz's method [90], is the preparation of arylacridine 159 in a single step from the relatively expensive 9-chloroacridine through Pd-catalyzed cross-coupling with 2-chlorophenylboronic acid. Additionally, for large-scale reactions, a flow reactor is

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• compounds allowing for the preparation of porphyrins with different reactive groups such as hydroxy and amino derivatives capable for further functionalization and conjugation of these porphyrins to other substrates. In addition, conjugates containing maleimide or biotin entities in the structure of

• )sensitizers that are efficient for both PDT and boron neutron capture therapy (BNCT) [27][39]. The preparation of compounds with dual therapeutic efficiency is of great importance since they improve the therapeutic effect of sensitizer by the action on the different cellular sites. Here, we report the

• ][17][18][19][20][21][22][23][24][25][26][27]. In order to prepare boronated PSs of A3B-type the employed synthetic strategy included the preparation of monoazido-substituted tris(pentafluorophenyl)porphyrin 2 by the reaction of porphyrin 1 with sodium azide (molar ratio 1:1.9) in DMF at ambient

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• requires effective and economical preparation methods [5]. In the synthesis of these natural products and their analogs, macrocyclization through linear precursors, the key step in the general routes, was typically accomplished via conventional chemical methodologies [6][7], keeps presenting an obstacle

• aforementioned NPRS macrocycles, the synthesis of macrocylic polyketides and PKS/NRPS hybrids is more challenging due to the absence of a streamlined preparation strategy such as solid-phase peptide synthesis (SPPS). In enzymology studies, it was common to hydrolyze the cyclic natural products in order to obtain

• then transformed into aldehyde 31 through several protecting group adjustments and the corresponding alcohol and Ley oxidation. After the preparation of 33 using Evans syn-aldol condensation as a critical step, 34 was produced by thioester formation, desilylation, and allylic oxidation. Incubating 34

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• Information File 1). Preparation of fatty acid methyl ester (FAME) derivatives 0.1 mg of 1 or 2 were hydrolyzed with 6 M HCl at 110 °C overnight. The obtained hydrolysates were freeze dried, resuspended in 100 µL of methanol, and then treated with 100 µL of trimethylsilyldiazomethane, and the mixtures were

• held for one minute, increased to 230 °C at a rate of 10 °C/min, and then held at 230 °C for six minutes. Preparation of 2-alkenyl-4,4-dimethyloxazoline (DMOX) fatty acid derivatives 0.2 mg of 3–5 were hydrolyzed with 6 M HCl at 110 °C overnight. The obtained hydrolysates were treated with 250 µL of 2

• library preparation with a Ligation Sequencing Kit (SQK-LSK 109), following the 1D genomic DNA by ligation protocol. The library was applied to a MinION flowcell (FLO MIN106 R9.41revD) operated by the MinKNOW (20.06.9) software, and then processed by Guppy basecaller (4.0.11) in the high accuracy mode. As

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• structures for the Henry reaction. The preparation of 5-isopropyl-5-methyl-2-(pyridin-2-yl)imidazolidin-4-one derivatives and their application in asymmetric Henry reaction [5]. Asymmetric Henry reactions of various aldehydes with nitromethane catalysed by copper(II) complexes of ligands Ia–c. Asymmetric

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• preparation of 2-chloro-4-sulfonylquinazolines 8 (Scheme 3). The starting material 7 underwent SNAr reactions with sodium sulfinates and the C4-substituted products 8a,b were isolated [24]. The complete conversion was achieved in DMF or DMSO. In the case of sodium dodecylsulfinate, the reaction stopped at 70