Search results
Search for "B" in Full Text gives 3269 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Synthesis of triazolo- and tetrazolo-fused 1,4-benzodiazepines via one-pot Ugi–azide and Cu-free click reactions
Beilstein J. Org. Chem. 2025, 21, 2202–2210, doi:10.3762/bjoc.21.167
- methods for the synthesis of tetrazoles [25][26][27][28], the Ugi–azide reaction is a good approach for constructing 1,5-disubstituted-tetrazoles (1,5-DS-T) [29][30][31]. This scaffold can be subsequently linked to 1,2,3-triazole [32], 4H-chromen-4-one [33], pyrrolo[3,4-b]indolizine [34], and other
Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings
Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166
- systematically. According to different types of five-membered rings, the electrochemical construction of five-membered rings from alkynes are mainly classified into the following categories: (a) construction of indoles, (b) construction of isoindolinones and indolizines, (c) construction of oxazoles and
- ] generated [Cp2Fe]+ along with cathodic reduction of MeOH to H2 and MeO− acting as a base. Deprotonation of 1a using MeO− produced the anion A, which underwent single-electron transfer (SET) with [Cp2Fe]+ to give the nitrogen-centered radical B with regeneration of [Cp2Fe] [164][165][166][167][168][169][170
- ][171][172]. Then, the 6-exo-dig cyclization of B obtained the vinyl radical C [173] that proceeded cyclization with the aryl species to form the radical D. Eventually, the rearomatization of D by eliminating one proton along with electron afforded 2a. This protocol, proceeding smoothly without noble
C2 to C6 biobased carbonyl platforms for fine chemistry
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- asymmetric hydrogenation process of α-hydroxy ketones opens up a new pathway for the production of chiral terminal 1,2-diols (Scheme 23) [98]. Kini and Mathews reported the synthesis of novel oxazole derivatives such as 6-(substituted benzylidene)-2-methylthiazolo[2,3-b]oxazol-5(6H)-one by reacting 1
- % yield (Scheme 42, path b) [131]. 5-Acetamido-2(5Н)-furanone is obtained in 20–40% yield when acetamide reacts with 5-bromo- or 5-ethoxy-2(5H)-furanone [132][133][134][135], while 5-acetamido-2(5Н)-furanone and 5-benzoylamido-2(5H)-furanone were obtained in 48% and 55% yield, respectively, by reaction of
- phosphorus oxide catalyst (VPO), furoic acid was also found to be a key intermediate (Scheme 44, route b) [149]. A photocatalytic access to succinic anhydride from furoic acid using catalytic porphyrin H2TPP in the presence of O2 and light was also reported [150]. Yang and Lv reported the oxidation of
The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products
Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164
- the presence of Fe(dpm)3/Ph(iPrO)SiH2 proceeded smoothly to furnish the tetracyclic product 39 in 56% yield with 2.5:1 ratio. Finally, removal of the acetonide and the Bn protecting group completed the total synthesis of (+)-aplysiasecosterol A (6). Total synthesis of (+)-cyrneine A, (−)-cyrneine B
- ][26][27][28][29][30]. In 2018, the group of Han accomplished the total synthesis of (+)-cyrneine A (7), (−)-cyrneine B (9), (−)-glaucopine C (10), and (+)-allocyathin B2 (8) by a collective manner [31]. In their synthetic route, an enzyme-catalyzed desymmetric enantioselective reduction of 1,3
- (Scheme 3) [31][32]. Oxidation state adjustment of 48 led to the ketone 49. Starting from this common intermediate, firstly, base-promoted double bond migration and oxidation at the γ-position gave tertiary alcohol 50. Deprotection of acetyl in 50 followed by selective oxidation delivered (−)-cyrneine B
Multicomponent reactions IV
Beilstein J. Org. Chem. 2025, 21, 2082–2084, doi:10.3762/bjoc.21.163
- , September 2025 Number of publications by year on multicomponent and one-pot reactions (A) and multicomponent reactions alone (B) accessed by Web of Science on June 16, 2025.
Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B
Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162
- reported structures of alkaloids aspera chaetominines A and B have been synthesized. Moreover, the four-step synthesis of the reported structure of aspera chaetominine B generated another diastereomer that was converted in one-pot to (–)-isochaetominine C, which turned out to be the revised structure of
- aspera chaetominine B. Keywords: epoxidation; selective epimerization; stereodivergent synthesis; structural revision; tandem reaction; Introduction In contemporary organic chemistry, due to the widespread application of modern separation and analytical techniques, the structural elucidation and
- endophytic fungus from the liverwort Heteroscyphus tener (Steph.) Schiffn. [30]; (–)-versiquinazoline H (9), isolated from the gorgonian (Pseudopterogorgia sp.)-derived fungus Aspergillus versicolor LZD-14-1 [31]; as well as 5) aspera chaetominines A and B (12 and 13), isolated from marine sponge associated
Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design
Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161
- Daniil V. Khabarov Valeria A. Litvinova Lyubov G. Dezhenkova Dmitry N. Kaluzhny Alexander S. Tikhomirov Andrey E. Shchekotikhin Gause Institute of New Antibiotics, 11 B. Pirogovskaya Street, Moscow 119021, Russia Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov
- [2,1-b]quinazoline-6,12-dione) and its derivatives are particularly noteworthy as they demonstrate multiple biological activities, including antibacterial, antitumor, antifungal, antiviral, anti-inflammatory, antileishmanial, antiplasmodial, etc. [18][19]. The structurally isomeric class – pyrimido
Bioinspired total syntheses of natural products: a personal adventure
Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160
- proposal is that toussaintine C was isolated as a racemic mixture, and sarglamides A and B are derived from one enantiomer of toussaintine C while sarglamides C–E are derived from the other one. The Diels–Alder cycloadditions are basically proceeded through endo-selectivity. The isopropyl group in α
Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform
Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159
- energy-storage capacity of solar thermal fuels“, Nature Chemistry, vol. 6, pages 441–447, published by Springer Nature, 2014, reproduced with permission from SNCSC). This content is not subject to CC BY 4.0. (b) RGO templating. Figure 3b was used with permission of The Royal Society of Chemistry, from
- subject to CC BY 4.0. (b) Schematic illustration of diacetylene monomer photopolymerization and the conjugated polydiacetylene structure. Figure 4b was redrawn from [47]. (c) Photoisomerization of a conjugated azobenzene polymer with a carbazole backbone. Figure 4c was redrawn from [48]. Linear azobenzene
- Wiley and Sons. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This content is not subject to CC BY 4.0. (b) Structure of the UV–vis solar-thermal cell. Figure 5b was adapted from [59], A. K. Saydjari et al., “Spanning the Solar Spectrum: Azopolymer Solar Thermal Fuels for Simultaneous UV
Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid
Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158
- -triazoles, salicylaldehydes, and pyruvic acid were studied under different reaction conditions. In particular, it was found that the three-component reaction of an equimolar mixture of 5-amino-3-methylthio(methoxy)-1,2,4-triazole 1a,b, salicylaldehydes 2a–f, and pyruvic acid (3) under conventional heating
- -aminotriazoles 1a,b having pronounced electron-donating substituents (methylthio- and methoxy groups). On the other hand, the MCR of the reagents 1a, 2a–c and 3 under ultrasonic irradiation for 2 h at room temperature (25 °C) (Scheme 3) afforded a mixture of 5-(2-hydroxyphenyl)-2-(methylthio)-7-((3-(methylthio
α-Ketoglutaric acid in Ugi reactions and Ugi/aza-Wittig tandem reactions
Beilstein J. Org. Chem. 2025, 21, 2021–2029, doi:10.3762/bjoc.21.157
- -methylisoxazol-3-yl)-5-oxo-2,5-dihydro-1H-pyrrol-3-yl]acetic acids II (Scheme 1, pathway B). Subsequently, a four-component Ugi reaction of compounds II with temperature-controlled formation of diastereomers of peptidomimetics III was also studied [52]. Taking into account all mentioned above, this work is
- isocyanide (4) in a molar ratio of 1:2:2:2 in MeOH and subsequent stirring at a temperature of 45 °C for 24 hours led to the formation of N1,N5-bis(2-(tert-butylamino)-1-(4-chlorophenyl)-2-oxoethyl)-N1,N5-bis(4-chlorophenyl)-2-oxopentanediamide (6a) in 55% yield (Scheme 2, pathway B; Table 2). Compounds 5
- prepare new quinoxalinone derivatives, we studied a tandem combination of Ugi/aza-Wittig reactions involving α-ketoglutaric acid and o-azidoanilines. First, 5-((2-arylazido)(1-aryl-2-(tert-butylamino)-2-oxoethyl)amino)-4,5-dioxopentanoic acids 8a,b,d,f–h were synthesized by the reaction of KGA (1
Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics
Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156
- isosurface is 0.001. Absorption spectra and geometric overlays corresponding to Wigner-sampled geometries of 1 (a), 3 (b), and 5 (c) with XMS-CASPT2(8,9)/ANO-S-VDZP. Minimum energy path using XMS-CASPT2(8,9)/ANO-S-VDZP for 1 (a), 3 (b), and 5 (c). The dots on the graphs correspond to the S0 (black), S1 (red
- depicted. σCN bonds plotted against each other for 1 (b), 3 (c), and 5 (d). The solid multicolor lines on each plot show the bond lengths over time, and the dots represent the S1/S0 surface hopping points for each trajectory. (a) Geometrical parameters. Plots show trajectories for a 1 ps NAMD simulation
- with CASSCF (8,9)/ANO-S-VDZP, monitoring C–C-bond formation, H–C–C–C dihedral angle, and relative energy for 1 (b), 3 (c), and 5 (d). The energy is relative to the lowest total energy of each trajectory. The red trajectories return to reactant, the green trajectories form retained housane, the blue
Measuring the stereogenic remoteness in non-central chirality: a stereocontrol connectivity index for asymmetric reactions
Beilstein J. Org. Chem. 2025, 21, 1995–2006, doi:10.3762/bjoc.21.155
- molecule is characterized by the absence of mirror planes and centers of inversion. Central chirality arises when four distinct substituents (a, b, c, and d) are arranged tetrahedrally around a central atom (Scheme 1A). Non-central chirality – such as axial and planar chirality – are becoming increasingly
- can be generated from achiral starting substrates by various means that assemble the four distinct substituents (a, b, c, and d) (Scheme 1D). In the case of central chirality, the differentiating substituents are often directly attached to the newly formed stereocenter. By contrast, for non-central
- chirality, the pairs of substituents (a and b, c and d) are separated in space because the stereogenic scaffolds span multiple atoms. Consequently, bond cleavage and formation occur at positions that are distant from the stereogenic elements and remote from the actual points of differentiation among the
Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis
Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154
- an internal nucleophile (O-, N-) and reductive elimination affords the arylated product 8 and regenerates the Cu(I) catalyst. The added base (B:) traps the H+, generated in this catalytic cycle. In the case of tert-butyl esters (7: R = COOt-Bu) an equivalent of isobutylene gas is released as a side
- mmol/mL. bNo reaction at 60 and 120 °C. cSame result at 120 °C. Synthesis of lactone and pyrrolidine derivatives. Conditions: ac7e = 0.1 mmol/mL. bReaction conditions modifications: a) 1.2 equiv I-1, CuCl (5 mol %), 60 °C, 3 h, c7f = 0.3 mmol/mL; b) 3.0 equiv I-1, CuCl (10 mol %), 70 °C, 3 h, c7g = 0.1
Photochemical reduction of acylimidazolium salts
Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153
- suitably electrophilic substrate at the carboxylic acid oxidation level provides an acylazolium species B, which typically reacts directly with nucleophiles or may first be transformed into the corresponding enolate derivative. Regardless of the individual pathway, NHC-catalyzed reactions of this type
- offer many synthetic advantages while the wide availability of chiral NHCs can also allow for high levels of enantioselectivity. As effective enamine and active ester derivatives, Breslow and acylazolium intermediates A and B typically react via classical two-electron polar mechanisms, however, recent
- applications, are underway in our laboratory. (a) Combining N-heterocyclic carbene (NHC) organocatalysis with photoredox catalysis for radical–radical coupling reactions. (b) This work: light-mediated reduction of acylimidazolium species 1 with the tertiary amine DIPEA or the simple silane HSiEt3. Initial test
Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization
Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152
- synthetically challenging because of the tricyclic ring system, spiroketal moiety (B, C-ring), and instability arising from dehydration of the hydroxy groups. Prior approaches to (±)-4 have shown the feasibility of accessing this target molecule. Blair [7] and Sulikowski [8] reported the total synthesis of
Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis
Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151
- norlignans hyperione A and ent-hyperione B was reported by the Deska group (Scheme 4) [33]. The synthesis commenced with a two-step conversion of ketone 22 to alkyne 23. Pd-catalyzed Tsuji-type reaction with zinc reagent 24, followed by acetonide hydrolysis, furnished allenic diol 25. Treating allenic diol
- . Alcohol 28 was obtained from 27 in two steps, and was subsequently converted to hyperione A (30) and ent-hyperione B (31) by refluxing in toluene with Shvo’s catalyst 29. Notably, the authors found that hyperione A (30) could be obtained in higher yield and enantiopurity from alcohol 28 via a two-step
- includes two enzymes, CAL-A and CAL-B [35][36]. Although a previous report [27] indicated that the desymmetrization of prochiral diol 2 with CAL was ineffective, the Shishido group prepared optically active compound (S)-11 via CAL-catalyzed asymmetric transesterification of the structurally similar diol 10
Rhodium-catalysed connective synthesis of diverse reactive probes bearing S(VI) electrophilic warheads
Beilstein J. Org. Chem. 2025, 21, 1924–1931, doi:10.3762/bjoc.21.150
- estimation of the yield of each product (Figure 2, panel B). It was found that many reactions involving alcohol- (e.g., C1–5, C8, C11 and C14) and indole- (e.g., C3, C12 and C15) containing co-substrates yielded intermolecular products, whilst those involving nitrile-containing co-substrates (C9 and 10) and
- subsequently used. Panel B: yields, estimated by evaporative light scattering detection, of reactions involving combinations of substrates, co-substrates and catalysts (dash: <2% estimated yield). Highlighted combinations (green boxes) were selected for mass-directed purification. aMultiple intermolecular
- substrates D1–5 of general structure 2 bearing S(VI) electrophiles. Panel A: Overview of synthesis (see Table 1 for details of synthesis of individual substrates). Panel B: Substrates that were prepared. Synthesis of α-diazoamide substrates of general structure 2 bearing S(VI) electrophiles (see Scheme 1
Synthesis of N-doped chiral macrocycles by regioselective palladium-catalyzed arylation
Beilstein J. Org. Chem. 2025, 21, 1917–1923, doi:10.3762/bjoc.21.149
- bromide (see Supporting Information File 1). Subsequent Buchwald–Hartwig reaction with 1,3-dibromo-7-tert-butylpyrene (2) gave the [2 + 2] macrocyclic precursors 3a,b as the major product in 16%/10% yields, and trace amounts of higher oligomers as detected by mass spectrometry. Notably, compounds 3a,b
- % and 90%, respectively. For MC2, four C–C bonds are formed between the dichlorobenzene units and tert-butylphenyl groups, generating two dihydroindolo[2,3-b]carbazole subunits. In contrast, there is only one newly formed C–C bond between the dichlorobenzene unit and one pyrene moiety for MC1
- planar dihydroindolo[2,3-b]carbazole subunits orienting upwards with a dihedral angle of 75° and two pyrene units downwards (Figure 2b). Besides, the central cavity is highly symmetric, and the shortest diameters are determined to be 4.34 Å and 4.99 Å, respectively. In contrast to MC2, MC3 shows an
Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs
Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148
- or aziridine fragments. Dose–response curves for the cytotoxic effects of glycidyl esters of phosphorus acids 1–3 on human cell lines. (A) Human skin fibroblasts (HSF), (B) prostate cancer cells (PC-3), and (C) breast cancer cells (MCF7) were treated with diglycidyl methylphosphonate (1, red
Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules
Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145
- interactions with the enehydrazine intermediate, which is essential for achieving high levels of stereocontrol. Using the optimal catalyst CPA 1, a series of aza[6]helicenes 3a,b was synthesized with excellent enantioselectivity and high yield. However, this method demonstrated notably reduced efficiency and
- demonstrated the successful construction of planarly chiral macrocycles with 12- to 14-membered ansa chains with high enantioselectivity when using NH2 as the directing group (see 33a,b). However, extending the ansa chain to 15 members led to the loss of planar chirality due to insufficient steric hindrance to
- for the asymmetric synthesis of saddle-shaped inherently chiral dibenzo[b,f][1,5]diazocines 72 via CPA catalysis [55]. In the presence of CPA 7 (10 mol %) and the corresponding 2-acylaniline 73 (20 mol %) as co-catalysts, the asymmetric dimerization of 2-acylbenzo isocyanates 71 allowed access to
Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction
Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144
- catalysis via the rational functionalization of MOF pores. Schematic representation of the modulation of MOF pore environments. A) de novo synthesis of several MOFs requiring the multistep synthesis of different organic linkers. B) Synthesis of several frameworks from a single parent MOF using post
- -synthesis modification (PSM). A) Schematic representation of the reaction of KSU-1 with aliphatic isocyanates and the estimated conversions at –OH and –NH2. B) The corresponding 1H NMR spectra of the MOF reaction products digested in a solution of D2SO4 in DMSO-d6. A) Schematic representation of the
- reaction between benzaldehyde and malononitrile to form benzylidenemalononitrile (BMN). B) Representative 1H NMR spectra for the reaction of benzaldehyde and malononitrile in toluene with dodecane as internal standard, analyzed after 30 minutes. Graphical representation of the Knoevenagel catalysis results
Photoswitches beyond azobenzene: a beginner’s guide
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- forward and backward isomerisation can occur simultaneously. Moreover, some unwanted photochemical side reactions ΦS can occur, as shown in the Equation 4: A is one state of the photoswitch, B the second state, and B’ a generic degradation product. Fatigue resistance measures how many times the
- be synthesised through oxidation of aminoheteroarenes 12 (Scheme 4A) or reduction of nitroheteroarenes 13 (B). Bayer–Mills coupling (Scheme 4C) is suitable for both symmetric and asymmetric targets, usually in acidic conditions. Basic conditions [14] are more effective with very electron-poor
- aromatic amines. Another strategy for both symmetric and asymmetric targets is the azo coupling of a diazonium salt 15 (Scheme 5A) with a nucleophile, which can be a (hetero)aromatic 16 [29] (B), a lithiated ring 19 [39] (C), or a precursor 20a,b [29][32][40] (D). In case of more than one reactive position
[3 + 2] Cycloaddition of thioformylium methylide with various arylidene-azolones in the synthesis of 7-thia-3-azaspiro[4.4]nonan-4-ones
Beilstein J. Org. Chem. 2025, 21, 1791–1798, doi:10.3762/bjoc.21.141
- product. Next, using the revealed optimal reaction conditions, we studied its scope on a variety of arylidene-azolones 1–4 (Scheme 3). We also tried to apply both proposed approaches (methods A and B) to the series of derivatives 5. In contrast to the results obtained previously for N-benzylazomethine
- would be of help in further drug design of spirocyclic scaffolds. Single crystal X-ray analysis for the compounds 6e (A), 7d (B), 8e (C) and 9e (D). Atoms are shown as thermal ellipsoids at 50% probability. All hydrogen atoms, except the one at the stereogenic center, are omitted for clarity. Synthetic
Synthesis of chiral cyclohexane-linked bisimidazolines
Beilstein J. Org. Chem. 2025, 21, 1786–1790, doi:10.3762/bjoc.21.140
- nucleophilically attacks the phosphonium in A to generate intermediate B by loss of triphenylphosphine oxide and triflic acid. The nucleophilic sulfonamide in B intramolecularily attacks the generated imine moiety in B to form intermediate C, in which triflic acid may protonate the imine moiety in B to assist the
Other Beilstein-Institut Open Science Activities
