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Search for "scaffold" in Full Text gives 658 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

  • Hao Guo,
  • Yu-Fei Ao,
  • De-Xian Wang and
  • Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

Graphical Abstract
  • ], cucurbiturils [24][25], and cavitands [26][27] have been widely applied. While these conventional macrocycles can usually enable a confinement effect or serve as a supporting scaffold, they do not contain definite catalytic sites in their cyclic skeletons. When required, an additional catalytic functional group
  • was commonly introduced through in-situ, noncovalent inclusion/encapsulation in the cavity or by covalent, post-functionalization of the macrocyclic scaffold. The encapsulated catalytic group could occupy the space for substrate entering, or has a risk to be squeezed out of the cavity under complex
  • catalytic conditions. On the other hand, the covalently pendant catalytic group may reside far away from the center of the cavity. On the other hand, we envisaged by use of tailored building units already containing definite catalytic sites to directly form a macrocycle scaffold could provide a different
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Published 02 May 2022

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

  • Sayan Pramanik and
  • Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

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  • and operational simplicity through one pot reaction. Keywords: chemoselective conjugate reduction; dispirocyclopentanebisoxindole scaffolds; metal-free; one-pot operation; reductive cyclization; Introduction There is a vast demand of the structurally complex spirooxindole scaffold which is an
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Published 27 Apr 2022

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

  • Saika Izumi,
  • Prasannamani Govindharaj,
  • Anna Drewniak,
  • Paola Zimmermann Crocomo,
  • Satoshi Minakata,
  • Leonardo Evaristo de Sousa,
  • Piotr de Silva,
  • Przemyslaw Data and
  • Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

Graphical Abstract
  • , the one-less number of donor units in the molecular scaffold led to lower solubility in organic solvents and thermal stability, presumably due to the less steric hindrance around the π-extended conjugated acceptor unit with the unsymmetric molecule structure. The OLEDs fabricated with the D–A emitter
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Published 25 Apr 2022

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

  • Md Imran Hossain,
  • Md Imdadul H. Khan,
  • Seong Jong Kim and
  • Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

Graphical Abstract
  • prevalent scaffold in biomedical research and drug discovery programs. We also proposed a plausible mechanism for the selectivity of the [3 + 2]-cycloaddition reaction to produce 3,4,5-trisubstituted isoxazoles. Not to be overlooked are our optimized reaction conditions for the dimerization of hydroximoyl
  • . Meanwhile, some of the starting material 2l remained unreacted and we suspected the lower solubility of compound 2l in water was responsible for the low yield of the reaction. Since trifluoromethyl-substituted isoxazoles are an important and prevalent scaffold in biomedical research and drug discovery
  • similar 3,4,5-trisubstituted isoxazole structure to the synthesized compounds in this report. In addition, we optimized the reaction conditions to produce trifluoromethyl-substituted isoxazoles, a prevalent scaffold in biomedical research and drug discovery programs. We also proposed a plausible mechanism
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Published 22 Apr 2022

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

  • Robin Schulte and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41

Graphical Abstract
  • because the parent system does not operate in the spectrum of the sunlight. Therefore, the efficient and purposeful functionalization of the norbornadiene scaffold is an important and challenging task in this field. Specifically, earlier approaches for the synthesis of norbornadiene derivatives are mainly
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Published 01 Apr 2022

Amamistatins isolated from Nocardia altamirensis

  • Till Steinmetz,
  • Wolf Hiller and
  • Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

Graphical Abstract
  • -type siderophores. Structurally, compounds 1–5 are closely related to formobactin [10], brasilibactin [23], nocardimicin [24], and terpenibactins [15]. While the core scaffold of these natural products is conserved, they differ in the length of their fatty acid residues, their methylation pattern, and
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Published 30 Mar 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

Graphical Abstract
  • dictate the position of the metal centers, we reasoned on the possibility to design a novel generation of diametric phosphine gold(I) cavitands exploiting a calix[6]arene scaffold characterized by a 1,2,3-alternate conformation. As working hypothesis, this geometry would segregate two catalytically active
  • calix[6]arene scaffold, we carried out the synthesis of three monomeric gold catalyst analogues A’,B’,C’(AuCl). The synthesis of these compounds was performed using the previously optimized protocol, starting from a 4-(octyloxy)aniline intermediate (Scheme 2). Subsequently, due to the general interest
  • parental macrocycles A,B(AuCl)2, that arise from the proximity of the two gold(I) nuclei to the calix[6]arene scaffold. Although just preliminary, these results indicate that the conformational properties of this class of macrocycles can influence the selectivity in gold(I)-catalyzed cycloisomerization of
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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

Graphical Abstract
  • scaffolds with versatile medicinal properties, including anti-Alzheimer, anti-inflammatory, anticancer, antidiabetic, and antileishmanial activity [1]. Since the first synthesis of paullones (scaffold A in Figure 1) in 1992 [2], and disclosure of their Cdk inhibiting potential, several other analogues were
  • From a retrosynthetic point of view, we followed three main pathways, in order to accomplish the synthesis of scaffold C. The first retrosynthetic route (a) started with an alkyl halide precursor, which was expected to afford scaffold C after ring-closure reaction at position 2 of the indole ring [23
  • -oxobutanoate (Scheme 1). To construct scaffold C by route (a) we first tried to synthesize 3-(2-nitrophenyl)indole by Heck reaction of indole and o-iodo-nitrobenzene [25]. However, in this case we obtained an isomeric mixture of 3- and 2-(2-nitrophenyl)indole in a 3:1 molar ratio, quite difficult to separate
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Published 26 Jan 2022

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

  • Soumyadip Basu,
  • Sauvik Chatterjee,
  • Suman Ray,
  • Suvendu Maity,
  • Prasanta Ghosh,
  • Asim Bhaumik and
  • Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

Graphical Abstract
  • (NPs) and therefore automatically increases the dispersibility of the catalyst throughout the medium, resulting in a higher catalytic activity [23]. 1,4-DHPs are considered one of the most useful molecular scaffolds in medicinal chemistry. The scaffold is the main constituent of several crucial drugs
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Published 25 Jan 2022

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

  • Ruan Carlos B. Ribeiro,
  • Patricia G. Ferreira,
  • Amanda de A. Borges,
  • Luana da S. M. Forezi,
  • Fernando de Carvalho da Silva and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

Graphical Abstract
  • -hydroxynaphthoquinomethanes [110]. These reactions were carried out by method A described above, and the stereochemistry was attributed to the E-isomer (Scheme 19). Conclusion Compounds containing the 1,2-naphthoquinone scaffold represent a class of natural and synthetic substances with important biological activities and
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Published 05 Jan 2022

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

  • Jiang-Song Zhai and
  • Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

Graphical Abstract
  • scaffold. Selected examples of bioactive spirobarbiturates. The screened organocatalysts. X-ray crystal structure of 3ae (displacement ellipsoids are drawn at the 50% probability level). Known strategies and conceptual advance of this contribution. Substrate scope of 2-isothiocyanato-1-indanones. The
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Published 04 Jan 2022

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

  • Hendrik Gruß,
  • Rebecca C. Feiner,
  • Ridhiwan Mseya,
  • David C. Schröder,
  • Michał Jewgiński,
  • Kristian M. Müller,
  • Rafał Latajka,
  • Antoine Marion and
  • Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

Graphical Abstract
  • this purpose, tryptophan halogenases RebH and Thal were applied for the generation of ʟ-7-bromo- and ʟ-6-bromotryptophan, respectively. As a peptide sequence, we chose the β-catenin-binding domain (CBD) of axin as a benchmark system (PDB ID 1QZ7) [75]. Axin is a scaffold protein playing an essential
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Published 03 Jan 2022

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

  • Rodolfo H. V. Nishimura,
  • Thiago dos Santos,
  • Valter E. Murie,
  • Luciana C. Furtado,
  • Leticia V. Costa-Lotufo and
  • Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

Graphical Abstract
  • ) with relevant biological activities, is recognized as a privileged scaffold in medicinal chemistry [3][4]. Among important quinazoline derivatives, 4-anilinoquinazolines have been widely investigated as antitumor agents because they can inhibit some receptor tyrosine kinases (RTKs) expressed by
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Published 22 Dec 2021

First total synthesis of hoshinoamide A

  • Haipin Zhou,
  • Zihan Rui,
  • Yiming Yang,
  • Shengtao Xu,
  • Yutian Shao and
  • Long Liu

Beilstein J. Org. Chem. 2021, 17, 2924–2931, doi:10.3762/bjoc.17.201

Graphical Abstract
  • , ensuring the smooth progress of the total synthesis of hoshinoamide A. With the tripeptide 7 in hand, we went on to construct the peptide scaffold (Scheme 3). When tripeptide 7 was subjected to Pd-catalyzed hydrogenation conditions [16], the benzyl group was selectively cleaved to generate 8. Treatment of
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Published 15 Dec 2021

Iron-catalyzed domino coupling reactions of π-systems

  • Austin Pounder and
  • William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

Graphical Abstract
  • would give the oxindole scaffold. Hydrogen abstraction would regenerate the reduced iron catalyst and produce the final product. Two years later, Zhou and co-workers expanded the reaction for the synthesis of substituted isoquinoline-1,3(2H,4H)-dione derivatives 64 (Scheme 10) [81]. Both laboratories
  • of functional groups with neither EDGs nor EWGs altering the reactivity of the acrylamide. Once synthesized, the authors demonstrated the oxindoles could be transformed into fused indoline–heterocycle frameworks in good yield, an attractive scaffold found in many biologically active compounds [119
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Published 07 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

Graphical Abstract
  • , according to Temel and co-workers who studied a similar scaffold, namely, 4-bromo-2-((quinoline-8-yl)methyl)phenol [27], no imine–hemiaminal tautomer peak transition was observed for the Schiff bases 3. In general, there were slightly significant changes in the transitions according to the changes in the
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Published 01 Dec 2021

Synthesis of new pyrazolo[1,2,3]triazines by cyclative cleavage of pyrazolyltriazenes

  • Nicolai Wippert,
  • Martin Nieger,
  • Claudine Herlan,
  • Nicole Jung and
  • Stefan Bräse

Beilstein J. Org. Chem. 2021, 17, 2773–2780, doi:10.3762/bjoc.17.187

Graphical Abstract
  • [3,4-d][1,2,3]triazines and their derivatives, for example, were reported to function as anticancer compounds [28][29][32], herbicides [19][20][21], antimicrobials [18], and pest control agents [35]. Several possibilities have been reported to gain the scaffold of pyrazolo[3,4-d][1,2,3]triazines
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Published 22 Nov 2021

Me3Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

  • Krishna M. S. Adusumalli,
  • Lakshmi N. S. Konidena,
  • Hima B. Gandham,
  • Krishnaiah Kumari,
  • Krishna R. Valluru,
  • Satya K. R. Nidasanametla,
  • Venkateswara R. Battula and
  • Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

Graphical Abstract
  • ] receptors. They are useful in the synthesis of phosphorescent materials [22][23][24], fluorosensors [25]. and also found as chiral ligands in a variety of transition metal catalysts [26][27][28][29][30]. Given the pharmacological promiscuity of this scaffold, extensive efforts from different groups led to
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Published 16 Nov 2021

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

  • Alemayehu Gashaw Woldegiorgis and
  • Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

Graphical Abstract
  • synthesis of atropisomeric heterobiaryls 2.1. Synthesis of atropisomeric arylindoles The indole scaffold is found in many natural products, drugs, and bioactive molecules. Moreover, the introduction of axial chirality into the indole scaffold is receiving attention due to its widespread use [45][52]. In
  • bioactive molecules and chiral catalysts [62][63][64], the construction of this scaffold has recently become valuable and attracted the attention of chemists [2][64]. In this context, Shi and co-workers reported a new strategy for the enantioselective synthesis of axially chiral naphthylindoles via the
  • scaffold for a variety of natural products, bioactive compounds and pharmacological agents [79] as well as for a variety of chiral phosphine ligands [80]. As a result, the preparation of axially chiral arylpyrroles has been one of the most important areas of investigation in synthetic chemistry. In the
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Published 15 Nov 2021

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

  • Ilya A. P. Jourjine,
  • Lukas Zeisel,
  • Jürgen Krauß and
  • Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

Graphical Abstract
  • presently discussed as a therapeutic option for fighting Ebola and SARS-CoV-2 viruses [12]. Modifications of the tilorone scaffold resulted in compounds having cytokine-inducing [13], antitumor [14], and telomerase-inhibitory effects [15]. Further synthetic fluorenones and polyfluoren(on)es show attractive
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Published 02 Nov 2021

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

  • Dušan Đ. Škorić,
  • Olivera R. Klisurić,
  • Dimitar S. Jakimov,
  • Marija N. Sakač and
  • János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

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  • MDA-MB-231 cells was noticeable with compounds 7 and 15. Interestingly, the introduction of tetrazole into the B-ring of cholic acid scaffold increased activity toward MDA-MB-231 cells dramatically (IC50 of 12 = 82.42 μM vs IC50 of 24 = 5.18 μM). Further, tetrazole 14 showed strong and selective
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Published 20 Oct 2021

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

  • Luke O. Jones,
  • Leah Williams,
  • Tasmin Boam,
  • Martin Kalmet,
  • Chidubem Oguike and
  • Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

Graphical Abstract
  • cell proliferation and waste exchange, e.g., in a scaffold for tissue engineering applications [3]. Novel biomedical and biotechnical applications of cryogels can also be found in controlled drug delivery, carriers for cell immobilization, sensors, bioseparation, purification, and wound dressing [4][5
  • current literature, despite the importance of it for applications such as scaffold materials [29]. A recent review article by Savina et al. highlights biodegradable cryogels and their applications, including a variety of biocompatible polysaccharide-based cryogels [8]. 3. Stimuli-responsive cryogels
  • of the size, porosity, and geometry of the final product tailored to the requirements of the individual patient, e.g., potential scaffold fabrication from cryogels in tissue engineering [63]. It is extremely important to consider the viscosity and injectability of the material for limitations on
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Published 14 Oct 2021

Enantioselective PCCP Brønsted acid-catalyzed aminalization of aldehydes

  • Martin Kamlar,
  • Robert Reiberger,
  • Martin Nigríni,
  • Ivana Císařová and
  • Jan Veselý

Beilstein J. Org. Chem. 2021, 17, 2433–2440, doi:10.3762/bjoc.17.160

Graphical Abstract
  • structures of many biologically important compounds. An important example of such heterocycles are 2,3-dihydroquinazolinones which scaffold can be found in various compounds exhibiting pharmacological properties [1][2][3][4][5][6]. Some of them are currently used to treat numerous diseases, such as the
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Published 16 Sep 2021

Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4-c]carbazoles via domino Diels–Alder reaction

  • Ren-Jie Fang,
  • Chen Yan,
  • Jing Sun,
  • Ying Han and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2021, 17, 2425–2432, doi:10.3762/bjoc.17.159

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  • 3-(indol-3-yl)-1,3-diphenylpropan-1-one gave the expected indole-substituted chalcone A, which comprises the desired 3-vinylindole scaffold as the reactive diene. In the meantime, the carbonyl group of the chalcone is protonated to give the activated dienophile in the presence of p-toluenesulfonic
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Published 16 Sep 2021

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

  • Sumana Mandal,
  • Raju D. Chaudhari and
  • Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

Graphical Abstract
  • materials. For example, Zhang et al. showed that refluxing anilide 177 in presence of a catalytic amount of Hg(OAc)2 and 90% formic acid gave the tricyclic heterocyclic scaffold 178 [113]. It involved a two-step process with the rearrangement of the primary cyclization products (Scheme 53). In 2013, Lin et
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Published 09 Sep 2021
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