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Search for "DBU" in Full Text gives 303 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Oxetanes: formation, reactivity and total syntheses of natural products

  • Peter Gabko,
  • Martin Kalník and
  • Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

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Published 27 Jun 2025

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

  • Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

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  • two azulene moieties (Scheme 19) [97]. Precursors 148 and 149 were annulated using DBU (1,8-diazabicyclo(5.4.0)undec-7-ene) in NMP (N-methyl-2-pyrrolidone) at 180 °C. The resulting PAHs 150 and 151 were isolated in relatively good yields (40% and 48%, respectively) and exhibited typical azulene-like
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Published 26 Jun 2025

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

  • Jiangfei Chen,
  • Yi-Lin Qu,
  • Ming Yuan,
  • Xiang-Mei Wu,
  • Heng-Pei Jiang,
  • Ying Fu and
  • Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

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  • heteroatom for the synthesis of functionalized oxindoles was also reported in 2013 [3]. In this study, DBU was employed as a ligand and TBHP as an oxidant. A series of ethers, including 1,2-dimethoxyethane, THF, 1,4-dioxane, tetrahydro-2H-pyran, 2,3-dihydrobenzofuran, tetrahydro-2H-thiopyran, and N
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Published 24 Jun 2025

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

  • Betty A. Kustiana,
  • Galuh Widiyarti and
  • Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

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  • with a catalytic base has also been applied to prepare cinnamate esters. For example, Heller and co-workers (2021) synthesized the ester 141 catalyzed by DBU which functioned as a Brønsted base for the alcohol (Scheme 43A) [81]. Impressively, the method could be scaled up to a multigram scale
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Published 28 May 2025

Substituent effects in N-acetylated phenylazopyrazole photoswitches

  • Radek Tovtik,
  • Dennis Marzin,
  • Pia Weigel,
  • Stefano Crespi and
  • Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

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  • further issue, we observed some instability at acidic pH during analysis. Thus, we tested the stability of NAc-PAP-H (1 mM, MeOH, ambient conditions, 2 h) at pH 2, 12, and in the presence of DBU (10−2 M) and found that the acetyl group was lost (cf. Supporting Information File 1, section 2.4). UV–vis
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Published 25 Apr 2025

Recent advances in the electrochemical synthesis of organophosphorus compounds

  • Babak Kaboudin,
  • Milad Behroozi,
  • Sepideh Sadighi and
  • Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

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  • ). Although using other solvents improved the solubility, it reduced the reaction yield. Ammonium thiocyanate is used as a sulfur source in the presence of DBU as a base and n-Bu4NBF4 as an electrolyte. When electron-donating groups were present at the C2-benzene ring, the reaction yield was higher than when
  • the rings contained electron-withdrawing groups. It is suggested that the reaction proceeded via single-electron oxidation of thiocyanate at the anode. DBU was used in the reaction for a simple nucleophilic substitution of phosphonate with a cyanide group in the formed intermediate (Scheme 28). In
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Published 16 Apr 2025

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

  • Maurizio Iannuzzi,
  • Thomas Hohmann,
  • Michael Dyrks,
  • Kilian Haoues,
  • Katarzyna Salamon-Krokosz and
  • Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

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  • , base, solvent, and reagent equivalents to optimize the alkylation reaction for both bromides 4 and 5 (Table 1 and Table 2). For Ni(II) complex of [2.3.5.6F]TfMePhe (6), firstly we screened different inorganic and organic bases (Table 1, entries 1–3) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was
  • identified as optimal delivering a yield of alkylated complex of 60% (Table 1, entry 4). With DBU as base different solvents differing in polarity have been tested. At room temperature, acetonitrile proved best and increased the yield to 88% (Table 1, entry 11). Lowering the temperature to 0 °C led to a
  • final yield of 94%. At these conditions (DBU, MeCN and 0 °C) the base and bromide equivalents were further modified but no further increase in yield could be achieved. Thus, 1.5 equiv DBU with 1.05 equiv alkyl bromide in MeCN at 0 °C have been identified as optimal conditions for the Ni complex
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Published 21 Mar 2025

Formaldehyde surrogates in multicomponent reactions

  • Cecilia I. Attorresi,
  • Javier A. Ramírez and
  • Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

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  • ]. In some cases, the addition of a non-nucleophilic base is needed to neutralize the HCl generated during the reaction (Scheme 20). For example, Yu et al. demonstrated that the reaction yield could be significantly increased when the reaction was performed in the presence of one equivalent of DBU [62
  • ]. They argued that organic bases such as DBU are superior than inorganic bases in improving the yields, probably because of the low solubility of the last ones in the reaction system. In the same way, other bases such as DABCO [64], DBU [66], and TMG (1,1,3,3-tetramethylguanidine) [65][67] were shown to
  • (I)) by reducing the suitable salts (containing Au(III), Co(II), Fe(III), and Ni(II), respectively) at the beginning of the catalytic cycle. The metal in its reduced species (depicted in Scheme 23) activates the C–H bond of the alkyne. After this activation step, a weak base (like DBU, TMG, or even
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Published 13 Mar 2025

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

  • Long K. San,
  • Sebastian Balser,
  • Brian J. Reeves,
  • Tyler T. Clikeman,
  • Yu-Sheng Chen,
  • Steven H. Strauss and
  • Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

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  • organic base such as tetramethylethylenediamine (TMEDA) or 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) [28]. Our initial attempt to apply this method was as follows: A reaction mixture of 9,10-ANTH(Br)2, 10 equiv BnFI, and 10 equiv DBU dissolved in acetone was illuminated with a blue LED for 20 h (see
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Published 07 Mar 2025

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

  • Zahra Noori,
  • Miquel Solà,
  • Clara Viñas,
  • Francesc Teixidor and
  • Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

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  • -1,3-dimethylimidazolinium hexafluorophosphate (ADMP) in the presence of DBU in acetonitrile. This one-pot process enables sequential diazotization and cyclization, leading to the formation of two or three C–N bonds under extremely mild conditions, with excellent tolerance for various functional groups
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Published 21 Feb 2025

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

  • Rituparna Das and
  • Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

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  • in machine-assisted oligosaccharide synthesis. 4-Acetoxy-2,2-dimethylbutanoyl (ADMB) esters were reported by Ensley and co-workers [108] having similar properties with the pivalate group. The facile removal of the C-2-ADMB group with a catalytic quantity of diazabicycloundecane (DBU) in methanol at
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Published 17 Feb 2025

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

  • Zi-Ying Xiao,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

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  • such as DABCO, DBU, triethylamine, and K2CO3 also resulted in the significant reduction of the yields. Therefore, the reaction of MBH nitrile of isatins and arylamines can be simply carried out in toluene at room temperature in the presence of a catalytic amount of DMAP. With the optimized reaction
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Published 06 Feb 2025

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

  • John M. Halford-McGuff,
  • Thomas M. Richardson,
  • Aidan P. McKay,
  • Frederik Peschke,
  • Glenn A. Burley and
  • Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

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  • equiv), DMF, air, rt, 2 h. (iv) Pd(dtbpf)Cl2 (10 mol %), 2-acetylthiophen-3-ylboronic acid (1.2 equiv), K3PO4 (2.0 equiv), iPrOH/H2O 3:4, N2, 85 °C, 16 h. (v) Pd(dtbpf)Cl2 (2.0 mol %), 1-naphthylzinc bromide (1.2 equiv), THF, N2, 45 °C, 16 h. (vi) Cu(OAc)2·H2O (30 mol %), B(OH)3 (2.0 equiv), DBU (2.0
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Published 05 Dec 2024

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

  • Robin Schulte,
  • Dustin Schade,
  • Thomas Paululat,
  • Till J. B. Zähringer,
  • Christoph Kerzig and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

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  • section and complete set of NMR spectra. Funding Financial support was provided by the University of Siegen. R.S. is grateful to the House of Young Talents (University of Siegen) and the Stiftung Nagelschneider for the Ph.D. fellowships. T.J.B.Z. thanks the Deutsche Bundesstiftung Umwelt (DBU) for a Ph.D
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Published 21 Nov 2024

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

  • Ritu Mamgain,
  • Kokila Sakthivel and
  • Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

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  • compound 57 was obtained by treating hypervalent iodine salt 56 with NaNO2 in the presence of DBU as the base (Scheme 23). This salt was also studied for the arylation of sulfur, oxygen, and carbon giving good yields of corresponding products [74]. O-Arylation Arylation of oxygen is a significant chemical
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Published 13 Nov 2024

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

  • Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

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Published 08 Nov 2024

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

  • Yuta Kabumoto,
  • Eiichiro Yoshimoto,
  • Bing Xiaohuan,
  • Masato Morita,
  • Motohiro Yasui,
  • Shigeyuki Yamada and
  • Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

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  • Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan 10.3762/bjoc.20.233 Abstract Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to
  • the NOESY spectrum of the imine (R)-16c, the stereochemistry of the imines (R)-16 was determined as E [36]. Among the imines thus obtained, (R)-16b was used to investigate the optimum reaction conditions (Table 1). Treatment of (R)-16b with 1.2 equiv of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) in THF
  • diethyl ether, toluene, hexane, and cyclohexane, (S)-20b was obtained in 30% to 40% yield and significant amounts of unreacted substrate were still observed, although formation of the byproduct 22b could be generally suppressed. We also examined the reaction using other bases instead of DBU. As shown in
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Published 01 Nov 2024

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

  • Bhaskar B. Dhotare,
  • Seema V. Kanojia,
  • Chahna K. Sakhiya,
  • Amey Wadawale and
  • Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

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  • , entry 10). Other bases like NaOMe, triethylamine, DBU, DMAP, sodium acetate, or DABCO also produced the product in moderate to good yields (42–87%) when used in excess (Table 1, entries 11–16). Interestingly, the reaction did not proceed in the presence of pyridine as a base (Table 1, entry 17). Finally
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Published 21 Oct 2024

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

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

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

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  • fragment in the side chain were investigated. It was shown that the studied process leads to substituted tetronic acids bearing a pyrrolidinone moiety. The application of 1,1′-carbonyldiimidazole and DBU is necessary for implementation of the considered reaction. Based on the performed research a general
  • only in the presence of a strong base (DBU). Results and Discussion The starting allomaltols 3 bearing an amide fragment in the side chain were prepared by reaction of dihydropyranones 5 with appropriate amines 6 applying the previously described method [33][34] (Scheme 2). At first, amide 3a was
  • bases under conditions described earlier for corresponding hydrazides. So, among the employed basic agents (Et3N, DABCO, DBU, DMAP, K2CO3, AcONa) only in the case of DBU the expected recyclization was observed and the target product 4a was obtained in 15% yield. In order to enhance the yield of compound
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Published 14 Oct 2024

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

  • Yutaro Miyashita,
  • Sae Someya,
  • Tomoko Kawasaki-Takasuka,
  • Tomohiro Agou and
  • Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

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  • possibly due to the higher steric congestion by the selection of the other CO2Et moiety. As shown in entries 8 or 9 in Table 4, it was proved that the usage of tetramethylguanidine (TMG) or DBU as the base provided a different stereoisomer as the major component. For the confirmation of its stereostructure
  • , the isolated inseparable mixture of anti,syn-7a and -7b by the reaction of 2b and diethyl malonate was treated with an equimolar amount of DBU in DMSO (rt, 3 h) to furnish products which were identical to the ones obtained in entries 8 or 9 (Table 4). The relative stereochemistry of the isomerized
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Published 25 Sep 2024

From perfluoroalkyl aryl sulfoxides to ortho thioethers

  • Yang Li,
  • Guillaume Dagousset,
  • Emmanuel Magnier and
  • Bruce Pégot

Beilstein J. Org. Chem. 2024, 20, 2108–2113, doi:10.3762/bjoc.20.181

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  • conditions (Table 1, entry 9). Other organic nitrogenous bases were tested (Table 1, entries 10–12). Et3N gave nearly the same result, while DBU seemed less efficient. The use of the inorganic base K2CO3 resulted in poor outcomes. With the optimized conditions in hand, a scale-up was successfully performed
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Published 23 Aug 2024

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

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Published 01 Aug 2024

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

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  • diazo precursor. To achieve this, cholesterol was first esterificated using 2-(4-methoxyphenyl)acetic acid and DCC. The resulting arylacetic ester 12 was then reacted with 4-acetamidobenzenesulfonyl azide (p-ABSA) and DBU in anhydrous acetonitrile to yield the diazo compound 13 in 22% yield. The carbene
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Published 24 Jul 2024

Benzylic C(sp3)–H fluorination

  • Alexander P. Atkins,
  • Alice C. Dean and
  • Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

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  • afforded higher yields and shorter reaction times compared to standard stirring conditions with DBU. When employing substrates bearing secondary benzylic sites in the reaction conditions, the difluorinated products were observed exclusively in high yields. In 2016, Britton and co-workers reported a method
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Published 10 Jul 2024

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

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  • (Table 1, entry 2). It should be noted that application of strong base DBU led to the complex mixture of products (Table 1, entry 5). At the same time basicity of NaHCO3 is not enough for realization of the studied recyclization and in this case the starting hydrazone 3b was isolated unchanged (Table 1
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Published 11 Jun 2024
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