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Search for "donor" in Full Text gives 831 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Regioselectivity of the SEAr-based cyclizations and SEAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

  • Jonali Das and
  • Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

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  • V. Electrocyclization of V followed by loss of proton from the intermediate VI afforded the corresponding cyclopenta[e]indol-6-ones 35a,b. While involved in the synthesis of 9H-fluorenes and 9,10-dihydrophenanthrenes through intramolecular arylative ring-opening of indole-tethered donor–acceptor
  • regioselective cyclization of an indole-tethered donor–acceptor cyclopropane. Indole C5 regioselective epoxide–arene cyclization. Funding We acknowledge the financial supports received from DST-SERB, New Delhi (Grant No. CRG/2018/003021) and Council of Scientific and Industrial Research (CSIR), New Delhi (Grant
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Published 08 Mar 2022

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

  • Peterson de Andrade,
  • Sanaz Ahmadipour and
  • Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

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  • 3a–h were tested at 1.0 mM in the presence of the donor substrate MUNANA (0.1 mM) along with pyridoxal phosphate (PLP, Ki = 7.3 mM) [35] and 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA) [36] as positive controls for TcTS and neuraminidase, respectively. Surprisingly, the results showed
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Published 17 Feb 2022

Diametric calix[6]arene-based phosphine gold(I) cavitands

  • Gabriele Giovanardi,
  • Andrea Secchi,
  • Arturo Arduini and
  • Gianpiero Cera

Beilstein J. Org. Chem. 2022, 18, 190–196, doi:10.3762/bjoc.18.21

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  • devised a new family of triphosphine calix[6]arene gold(I) complexes (Figure 1c) [30]. These cavitands are able to form (pseudo)rotaxane species, by threading viologen-based guests, with a conformational control operated by the sulfonamido hydrogen-bonding donor domain [31][32]. Furthermore, their
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Published 10 Feb 2022

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

  • Irina Kuznetcova,
  • Felix Bacher,
  • Daniel Vegh,
  • Hsiang-Yu Chuang and
  • Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

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  • challenge and practical synthesis is still missing in the literature. Its accessibility may enrich the arsenal of available tools for enzyme inhibitor design by increasing the number of hydrogen bonding donor and acceptor groups at the same side of the backbone, which may result in a tight binding with
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Published 26 Jan 2022

Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

  • Sandeep Kumar,
  • Jyotirmoy Maity,
  • Banty Kumar,
  • Sumit Kumar and
  • Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

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  • ) immobilized on polyacrylate (Lewatit), commonly known as Novozyme® 435 and Thermomyces lanuginosus lipase immobilized on silica, commonly known as Lipozyme® TL IM in different organic solvents, such as THF, acetonitrile, toluene, acetone, DIPE and 2-Me-THF. Vinyl acetate was used as acetyl donor at
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Published 11 Jan 2022

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

  • Jun-Xian Gou,
  • Yang Luo,
  • Xi-Nan Yang,
  • Wei Zhang,
  • Ji-Hong Lu,
  • Zhu Tao and
  • Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

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  • : cucurbiturils; melamine; Schiff base; silver ion; Introduction Schiff bases [1] are usually synthesized by the condensation of amines and active carbonyl compounds, endowing them both nitrogen and oxygen donor atoms [2][3][4][5]. Schiff bases are not only easy to coordinate with various transition metal ions
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Published 17 Dec 2021

Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

  • Tanmoy Halder and
  • Somnath Yadav

Beilstein J. Org. Chem. 2021, 17, 2915–2921, doi:10.3762/bjoc.17.199

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  • the hitherto not synthesized above trisaccharide repeating unit containing two ᴅ-galactose and one N-acetyl-ᴅ-galactosamine moieties. The linear synthesis of the target oligosaccharide was first carried out via a linear [1 + (1 + 1 = 2)] assembly of a galactopyranose donor with a GalpNTroc–Galp
  • for further conjugation to other moieties towards the synthesis of vaccine conjugates by removal of the anomeric PMP group. This has been previously demonstrated by removal of the anomeric PMP group, conversion to a glycosidic donor, and further conjugation to either linkers or amino acids by several
  • described in Scheme 2. With the monosaccharide building blocks in hand, the galactosamine donor 6 was coupled with galactose acceptor 7 by activation of the thioglycoside using N-iodosuccinimide (NIS) in the presence of TMSOTf to afford the desired disaccharide β-ᴅ-GalpNHTroc-(1→4)-α-ᴅ-Galp (4) in 85% yield
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Published 13 Dec 2021

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

  • Ettore Crovini,
  • Zhen Zhang,
  • Yu Kusakabe,
  • Yongxia Ren,
  • Yoshimasa Wada,
  • Bilal A. Naqvi,
  • Prakhar Sahay,
  • Tomas Matulaitis,
  • Stefan Diesing,
  • Ifor D. W. Samuel,
  • Wolfgang Brütting,
  • Katsuaki Suzuki,
  • Hironori Kaji,
  • Stefan Bräse and
  • Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

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  • separation of the HOMO and LUMO on donor and acceptor, respectively, will result in an S1→S0 transition with predominantly charge transfer (CT) character. Highly twisted donor–acceptor architectures are typically employed to realize small ΔEST [4][8]. SOC can be enhanced by ensuring that the nature of the S1
  • acts as a weak, planar, and rigid donor [11][12][13][14]. Examples of compounds incorporating an ICz unit include reports from Xiang et al. with the emitters IndCzpTr-1 and IndCzpTr-2 [11], and Maeng et al. with the emitter TRZ-TPDICz [12] (see Figure 1). In the doped film, IndCzpTr-1 and IndCzpTr-2
  • , but efficiency roll-off was significant, with EQE at 100 cd m−2, EQE100, of 11.0% and 15.3% for the OLEDs with IndCzpTr-1 and IndCzpTr-2, respectively. The addition of two phenyl units on the ICz in TRZ-TPDICz increased the donor strength and led to ΦPL of near unity (96%) and a much shorter τd of
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Published 08 Dec 2021

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

  • Samet Poyraz,
  • Samet Belveren,
  • Sabriye Aydınoğlu,
  • Mahmut Ulger,
  • Abel de Cózar,
  • Maria de Gracia Retamosa,
  • Jose M. Sansano and
  • H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

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  • ligands that could coordinate several metal centers with the aid of sulfur, nitrogen or oxygen donor atoms that allow multiple bindings [13]. Moreover, compounds bearing a –C(O)NHC(S)– moiety and their metal complexes have assorted biological and pharmacological properties such as anti(myco)bacterial
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Published 02 Dec 2021

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

  • Inaiá O. Rocha,
  • Yuri G. Kappenberg,
  • Wilian C. Rosa,
  • Clarissa P. Frizzo,
  • Nilo Zanatta,
  • Marcos A. P. Martins,
  • Isadora Tisoco,
  • Bernardo A. Iglesias and
  • Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

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  • substituent or polarity of the solvent (behavior in CHCl3, MeOH, and DMSO is quite similar). Notably, one can highlight compound 3bb (R = Ph, R1 = 5-NEt2) which transitions vary significantly with the change in polarity of the medium (4–24 nm), and this may be due to the donor diethylamino group attached to
  • effect of the diethylamino group (donor group) [14][28][29]. Moreover, these results should indicate a negative possibility of excited state intramolecular proton transfer (ESIPT) phenomena occurring (in protic MeOH solvent and low values of Stokes shifts), being only a direct influence of the
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Published 01 Dec 2021

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

  • Umesh P. Aher,
  • Dhananjai Srivastava,
  • Girij P. Singh and
  • Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

Graphical Abstract
  • -oxathiolane intermediates 65 and 66 could be controlled well (Scheme 22). The glycolaldehyde dimer 64 and 1,4-dithiane-2,5-diol (3q) were reacted in the presence of TEA and the acyl donor phenyl acetate. The presence of CAL-B allowed the formation of the intermediate 66 and ultimately the corresponding
  • 73. These acted as hemithioacetal substrate and acyl donor, respectively. CAL-B was further utilized for the subsequent intramolecular cyclization of hemithioacetal intermediates 75 and 76. Screening of base additives showed that good results could be obtained by addition of 4-methylmorpholine (74
  • stereoselectivity during β-selective glycosidic bond formation. The general pathway for glycosidic bond formation (Figure 4) shows that the glycoside donor moiety has to be activated using an appropriate activator to form an oxonium ion. The attack of a nucleobase (glycosyl acceptor) may occur on either side of the
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Published 04 Nov 2021

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

  • Viera Poláčková,
  • Dominika Krištofíková,
  • Boglárka Némethová,
  • Renata Górová,
  • Mária Mečiarová and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

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  • itself, in which the carboxylic function acts as an ancillary hydrogen-bond donor for the direction of one of the reagents [9]. Amines serve as basic units and nucleophilic components capable of carbonyl compounds activation via enamine or iminium ion formation [10][11]. In particular, pyrrolidine became
  • compounds with heterocyclic substituents are of high biological and medicinal relevance [34][35]. Therefore, we have decided to evaluate sulfinylurea and thiourea catalysts C1 and C2 also with (E)-2-(2-nitrovinyl)furan (9) and (E)-3-(2-nitrovinyl)pyridine (11) as Michael acceptors. As Michael donor, we
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Published 25 Oct 2021

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

  • Pratibha Sharma,
  • Raakhi Gupta and
  • Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

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  • ][5][6][7]. The reaction involving a nitrogen-based nucleophile as the Michael donor is known as the aza-Michael reaction (aza-MR). In view of its ability to introduce a nitrogen-containing functionality at the β-position of an activated alkenyl- or alkynyl-substrate, over the years, it has developed
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Published 18 Oct 2021

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

  • Robin Klintworth,
  • Garreth L. Morgans,
  • Stefania M. Scalzullo,
  • Charles B. de Koning,
  • Willem A. L. van Otterlo and
  • Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

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  • formation or retention of an exo double bond in a 6-ring derivative. Reactions which involve the loss of an exo double bond will be favored in the 6-ring as compared to the corresponding 5-ring derivative” [69]. Since the presence of a proton donor even as weak as acetic acid was deleterious for
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Published 13 Oct 2021

Visible-light-mediated copper photocatalysis for organic syntheses

  • Yajing Zhang,
  • Qian Wang,
  • Zongsheng Yan,
  • Donglai Ma and
  • Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

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  • oxidized RuIII, which subsequently accepts an electron from an external donor (D) to form the ground-state catalyst RuII. This type of reaction mechanism is an oxidative quenching cycle (OQC). Alternatively, the lower energy SOMO of the excited state RuII* can accept an electron from an external donor
  • acceptor A or receives electrons from a donor D. In the OQC pathway, the excited state CuI* transfers an electron to the acceptor A and is oxidized to CuII. Subsequently, CuII accepts an electron from the donor D to form the ground-state CuI (Scheme 2). However, reports that the excited state CuI* receives
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Published 12 Oct 2021

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

  • Najeh Tka,
  • Mohamed Adnene Hadj Ayed,
  • Mourad Ben Braiek,
  • Mahjoub Jabli and
  • Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

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  • their partially hydrogenated analogues, even though they were used as electron-donor groups for OLED applications [42][43]. On the other hand, tetrahydroacridines have received much attention in medicinal chemistry, due to their ability to inhibit topoisomerase enzymes and block the DNA transcription
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Published 20 Sep 2021

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

  • Songeziwe Ntsimango,
  • Kennedy J. Ngwira,
  • Moira L. Bode and
  • Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

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  • substituents in a range of positions. In all cases at least one methoxy substituent was positioned ortho- to the biaryl axis. The other aromatic ring had to contain an oxime ester, which would form an iminyl electron donor, as shown in Scheme 2. As illustrated substrates 13a–f were accessed using the Suzuki
  • electron donor iminyl radical. In fact, iminyl radicals have been identified and studied by EPR spectroscopy in a number of related processes involving oxime derivatives [14]. As an example utilizing substrate 14d, intermediates such as the iminyl radical 17a and the ring closed intermediate 17b (Figure 3
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Published 08 Sep 2021

Synthesis of O6-alkylated preQ1 derivatives

  • Laurin Flemmich,
  • Sarah Moreno and
  • Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

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  • class-I riboswitch [1]. This riboswitch acts as a ribozyme by using 7-aminomethyl-O6-methyl-7-deazaguanine (m6preQ1) as methyl group donor; it catalyzes self-methylation of a specific cytidine in the aptamer binding pocket, yielding N3-methyl cytidine (m3C) under release of 7-aminomethyl-7-deazaguanine
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Published 02 Sep 2021

Halides as versatile anions in asymmetric anion-binding organocatalysis

  • Lukas Schifferer,
  • Martin Stinglhamer,
  • Kirandeep Kaur and
  • Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

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  • a field. Thus, the use of the halide in the catalyst–anion complex as both a mere counter-anion spectator or an active nucleophile has been depicted, along with the new trends toward additional noncovalent contacts within the HB-donor catalyst and supramolecular interactions to both the anion and
  • studies revolved around hydrogen bond donor catalysts and their application in N-acyliminium ion reactions. At this point, the mechanistic proposal, albeit speculative, was based on the hypothesis that neutral chloroamide structures I were the reactive intermediates in the reaction. Under this premise, H
  • catalysts and asymmetric methodologies, a few innovative nonchiral alternative H-donor or halide-binding organocatalysts, like, e.g., tridentate phosphoramides [41], onium salts [42] such as Berkessel's pyridinium systems [43], or Huber's bis-iodo imidazolium [44] and neutral bridged 2,6-diiodo‐3,4,5
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Published 01 Sep 2021

Photoredox catalysis in nickel-catalyzed C–H functionalization

  • Lusina Mantry,
  • Rajaram Maayuri,
  • Vikash Kumar and
  • Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

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  • photocatalyst. [PC] = photocatalyst, A = acceptor, D = donor. Proposed catalytic cycle for the photoredox-mediated HAT and nickel catalysis enabled C(sp3)‒H arylation. Proposed mechanism for photoredox nickel-catalyzed α-amino C‒H arylation with aryl iodides. Proposed catalytic cycle for the C(sp3)−H arylation
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Published 31 Aug 2021

Chemical syntheses and salient features of azulene-containing homo- and copolymers

  • Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

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  • region. Also, the protonated polymer 61 showed strong fluorescence at 480 nm with a large Stokes shift of 155 nm. In 2015, Zhang, Liu, and co-workers [36] reported the synthesis of conjugated donor–acceptor (D–A)-type azulene-dithienyldiketopyrrolopyrrole (DPP) polymers 69, 71, and 72. The synthesis of
  • donor for organic PV cells and the blend of thin-film 69 with PC71BM showed a power conversion efficiency (PCE) of 2.04%. In 2018, Gao and co-workers [37] reported the synthesis of conjugated polymers containing 2,6-connected azulene units in the polymer backbone. The key monomer, N,N’-bis(2
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Published 24 Aug 2021

Constrained thermoresponsive polymers – new insights into fundamentals and applications

  • Patricia Flemming,
  • Alexander S. Münch,
  • Andreas Fery and
  • Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

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  • polymers, such as PDMAPS and its structural analogues [88][89][90][91], and on the other hand, polymers with strong hydrogen acceptor and donor units, like the uncharged PNAGA [92][93][94][95][96], show a pronounced UCST. In contrast, the solubilization process of a polymer with LCST behavior is an
  • irradiation as well as by host molecule (α-cyclodextrin) complexation [278]. Due to the high number of proton acceptor/donor sites, ureido-modified copolymers such as poly(allylamine-co-allylurea) are also becoming more and more important. The critical phase transition temperature can often be finely tuned
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Published 20 Aug 2021

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

  • Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

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  • Friedel–Crafts fashion (Scheme 10a) gave 82 with moderate to good product yields, respectively [69][70]. A similar work by Janosik involved strongly basic conditions at low temperature with bis(phenylsulfonyl)sulfide (83) as the sulfur donor (Scheme 10b) [73][74]. Disulfides are also important reagents
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Published 19 Aug 2021

Progress and challenges in the synthesis of sequence controlled polysaccharides

  • Giulio Fittolani,
  • Theodore Tyrikos-Ergas,
  • Denisa Vargová,
  • Manishkumar A. Chaube and
  • Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

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  • group on the glycosyl donor and the acceptor for the stereoselective formation of the β(1–3) linkage (Figure 4) [132]. Interestingly, oligomers bearing several 4,6-O-benzylidene groups show anomalously small coupling constants for some of the C-1 hydrogens. NMR [133] and X-ray [134] studies revealed
  • glycosylation method was also employed to access different branched structures having β(1–3)- and β(1–6)-linked Glc appendances on a β(1–3) backbone [136]. To date, the longer β(1–3)-glucans [137][138] were obtained using a 2-O-acylated donor, to ensure β-selectivity, followed by deacylation and use of the
  • approach was efficient in solid phase as well as in solution phase synthesis. The participating (S)-(phenylthiomethyl) benzyl chiral auxiliary at the C-2 position of the glucosyl donor permitted the solid phase synthesis of a branched pentaglucan having a α(1–3) branch on an α(1–6) backbone [174]. Boron
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Published 05 Aug 2021

Development of N-F fluorinating agents and their fluorinations: Historical perspective

  • Teruo Umemoto,
  • Yuhao Yang and
  • Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

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Published 27 Jul 2021
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