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Search for "control" in Full Text gives 1461 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO2F2)

  • Xian-Lin Chen and
  • Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

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  • control experiment, SO2F2 is essential for the reaction to proceed (Table 1, entry 2). Encouraged by the preliminary result, we then screened a large variety of conditions as shown in Table 1 in order to improve the efficiency of the transformation. The investigation of the solvent effect revealed that in
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Published 22 Jun 2023

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

  • Brigita Mudráková,
  • Renata Marcia de Figueiredo,
  • Jean-Marc Campagne and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

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  • control of RNA [16]. Moreover, Campagne and co-workers showed that Cu–NHC-catalyzed conjugate additions of dialkylzinc reagents proceed with high enantioselectivities [17][18][19]. Furthermore, this methodology allows iterative access to 1,3-disubstituted motifs that are present in various natural
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Published 16 Jun 2023

Light-responsive rotaxane-based materials: inducing motion in the solid state

  • Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

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  • mechanical bond, such as control over the dynamics of the components upon application of external stimuli. This perspective aims to highlight the relevance of these materials, by pointing out recent examples of photoresponsive materials prepared from a rotaxanated architecture in which motion of the
  • is the functionalization of mesoporous silica nanoparticles with light-responsive rotaxane-based molecular shuttles to control the uptake and release of target molecules [31][32][33][34]. This perspective is focused on recent examples of light-responsive rotaxane-based solid-state materials in which
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Published 14 Jun 2023

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

  • Lukáš Marek,
  • Jiří Váňa,
  • Jan Svoboda and
  • Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

Graphical Abstract
  • MeCN undergoes a ring transformation [1][2] to give 2-phenyl-5-(2-aminophenyl)-4-hydroxy-1,3-thiazole (17') (Scheme 7) under kinetic control, the analogous intermediary hydroxythiazole 7a (Scheme 3) does not decompose into analogous thiazole 7a' due to much worse nucleofugality of the leaving amine
  • thiobenzamide, thioacetamide, and thiobenzanilide. Reaction of N-phenyl- and N-methyl-2-bromo(phenyl)acetamide (4a,b) with thiobenzamide in acetonitrile. Transformation of salt 15 under kinetic and thermodynamic control conditions [1]. Reaction of salt 6a under different reaction conditions. Reaction of salt 2b
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Published 09 Jun 2023

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

  • Yuan-Nan Yuan,
  • Jin-Qiang Li,
  • Hong-Bin Fang,
  • Shao-Jun Xing,
  • Yong-Ming Yan and
  • Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

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  • determine the protein levels of iNOS and COX-2, using GAPDH as a control and dexamethasone (DEX) as a positive reference drug. 1H (600 MHz) and 13C NMR (150 MHz) data of compound 1 (δ in ppm, J in Hz, methanol-d4). 1H (600 MHz) and 13C NMR (150 MHz) data of compounds 2 and 3 (δ in ppm, J in Hz, methanol-d4
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Published 07 Jun 2023

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

  • Joydev K. Laha,
  • Pankaj Gupta and
  • Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

Graphical Abstract
  • purification. Next, in order to determine whether the reaction proceeds via a radical pathway, we performed a control experiment. When substrate 1a was treated with the radical scavenger TEMPO under the optimized reaction conditions, the formation of product 2a was completely suppressed (Scheme 4). This
  • of 1 equiv of K2S2O8 and the corresponding ortho-substituted anilines 3 (1.2 equiv) and stirring at 80 °C for 2 h. Yields correspond to isolated products. Control experiment with TEMPO. Plausible mechanism for the K2S2O8-induced oxidation of N-(arylsulfonyl)benzylamines. Plausible mechanism for one
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Published 05 Jun 2023

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

  • Bastian Jakob,
  • Nico Schneider,
  • Luca Gengenbach and
  • Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

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  • . Among different boronic acid derivatives, we identified aryltrifluoroborates as most promising candidates for the slow generation of the corresponding arylboronic acids under our slightly acid reaction conditions [24]. Therefore, we performed two initial control experiments. The reaction of potassium
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Published 25 May 2023

Photocatalytic sequential C–H functionalization expediting acetoxymalonylation of imidazo heterocycles

  • Deepak Singh,
  • Shyamal Pramanik and
  • Soumitra Maity

Beilstein J. Org. Chem. 2023, 19, 666–673, doi:10.3762/bjoc.19.48

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  • equiv of Zn(OAc)2 was used as an additive (Table 1, entry 12). To check the viability of other acetylating agents, Zn(OAc)2 was replaced with AcOH, generating the desired product in a comparatively lower yield (Table 1, entry 13). Finally, control experiments without a catalyst (Table 1, entry 14
  • reaction conditions, generating the corresponding acetoxymalonylated products 4u–w in good to excellent yields. Several control experiments were performed to gain insights into the mechanistic pathway of this reaction. Firstly, a radical scavenging experiment using the radical scavenger TEMPO was performed
  • under optimized reaction conditions, the acetylated product 4a was produced with excellent conversion (>90%). These results suggest the involvement of compound 5 as an intermediate, and Zn(OAc)2 or AcOH may be effective acetylating agents via generation of acetyl radicals. Control experiments under
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Published 12 May 2023

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

  • Sarot Cheenpracha,
  • Ratchanaporn Chokchaisiri,
  • Lucksagoon Ganranoo,
  • Sareeya Bureekaew,
  • Thunwadee Limtharakul and
  • Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

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  • shown. The isolated compounds were evaluated for their α-glucosidase inhibitory activity [20]. Compounds 1 and 3 exhibited significant α-glucosidase inhibitory activity with IC50 values of 66 and 44 µM, respectively, which showed stronger inhibitory activity than the positive control, acarbose (IC50 178
  • percent inhibition of activity was calculated as (A0 − A1)/A0 × 100, where A0 is the absorbance of control, and A1 is the absorbance with the sample. Acarbose was used as a standard drug and all experiments were evaluated in triplicate. Chemical structures of 1-3 isolated from P. macropterum. Key 1H,1H
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Published 11 May 2023

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

  • Ekaterina A. Lystsova,
  • Maksim V. Dmitriev,
  • Andrey N. Maslivets and
  • Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

Graphical Abstract
  • products 6a,b,e were formed (Scheme 10). These observations are in a full accordance with the studies of similar products of 5-oxa-FPDs II [33][53][54]. We assume compounds 5 to be products of the kinetic control of the reaction, and compounds 3, of the thermodynamic one. In addition, the formation of
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Published 11 May 2023

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

  • Nan Yang,
  • Yi-Yan Zhu,
  • Wei-Xiu Lin,
  • Yi-Long Lu and
  • Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

Graphical Abstract
  • composed of TBTQ-C6, as illustrated in Scheme 1. Due to the electrostatic interaction between the host and guest molecules, pH is considered an influential control factor in regulating the assembly and disassembly of supramolecular nanoparticles, as changes in pH affect the protonation degree of the
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Published 08 May 2023

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

  • Péter Kisszékelyi and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

Graphical Abstract
  • –Jung vinylsilane reagents 33. Kawamura et al. performed zinc enolate trapping reactions using ligand L10, a chiral quinoline-based N,N,P-ligand (Scheme 8A) [35]. The authors have concluded that the strict control of the amount of organozinc reagent added is essential to avoid side-product formation
  • their control experiments and literature mechanistic studies (Chegondi et al.) [84], the role of the base (LiOt-Bu) was considered. Following the Cu-catalyzed conjugate addition of B2pin2, the Michael cyclization is facilitated by the transmetalation of stoichiometric Li base with the Cu enolate (Scheme
  • had low ee values, the trans-products showed better enantioselectivities (up to 78%). Their control experiments suggested that the Ru enolate, formed by the conjugate addition of the alkyne to the enone, plays a significant role in the following aldol reaction. Later, Tian et al. have also employed a
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Published 04 May 2023

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

  • Grédy Kiala Kinkutu,
  • Catherine Louis,
  • Myriam Roy,
  • Juliette Blanchard and
  • Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

Graphical Abstract
  • , not only a unique control of reaction parameters, such as improved mass and heat transfer, but also reduced safety risks and increased reproducibility of the results [29][35][36]. These features should therefore allow us to scale up our directed C3-functionalizations of furfurylimines under safe
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Published 03 May 2023

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

  • Martina Mamone,
  • Giuseppe Gentile,
  • Jacopo Dosso,
  • Maurizio Prato and
  • Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

Graphical Abstract
  • , Table 1). Control experiments were conducted to obtain more mechanistic clues (entries 2–5, Table 1). An experiment revealed how the exclusion of light completely suppressed the process, therefore establishing the photochemical nature of the transformation (entry 2, Table 1). In addition, we confirmed
  • with the α-iodosulfone 2a in the presence of DABCO. Study of scope of the HAS reaction between indoles 1 and α-iodosulfones 2. Yields in parentheses were determined by 1H NMR analyses, using 1,3,5-trimethoxybenzene as an internal standard. Optimization of the reaction conditions and control experiments
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Published 27 Apr 2023

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

  • Alena V. Dmitrieva,
  • Oleg A. Levitskiy,
  • Yuri K. Grishin and
  • Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

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  • level of stereoselectivity induction is important for the evaluation of the chiral templates efficiency. The estimation of the thermodynamically and kinetically controlled stereoselectivity is based on different approaches. The diastereomeric ratio of the products formed under kinetic control is related
  • shown previously [31][37], this difference determines the stereochemical outcome of the reactions performed under thermodynamic control. To determine the conformational changes in the Ni(II) coordination environment induced by the additional tert-butyl group in the o-phenylene moiety, DFT calculations
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Published 27 Apr 2023

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

  • Austin Pounder,
  • Eric Neufeld,
  • Peter Myler and
  • William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

Graphical Abstract
  • reactivity with a few examples failing to provide the desired product when 4-CzIPN was used as the photocatalyst; however, the products were isolated when [Ir(dF(CF3)ppy)2(bpy)]PF6 was used. Based on experimental observations and control reactions, the authors proposed the reaction begins with the
  • the alkoxy group which can finally reductively eliminate the isochromene product. Based on control reactions, the authors proposed the active catalytic species is cationic, as the use of the cationic precatalyst [Cp*Ru(CH3CN)3]PF6 in THF afforded the isochromene as the major product, suggesting a
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Published 24 Apr 2023

Asymmetric synthesis of a stereopentade fragment toward latrunculins

  • Benjamin Joyeux,
  • Antoine Gamet,
  • Nicolas Casaretto and
  • Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32

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  • , France 10.3762/bjoc.19.32 Abstract Latrunculins are marine toxins used in cell biology to block actin polymerization. The development of new synthetic strategies and methods for their synthesis is thus important in order to improve, modulate or control this biological value. The total syntheses found in
  • -induction of the aldol stereocenter by β-alkoxy ketone 9, leading to an (S)-configuration [18][19][20]. This control is supposed to follow a boat transition state A stabilized by a formyl hydrogen bond [30]. It is known to be dependent on the nature of the β-alkoxy substituent, being particularly favoured
  • resulting from a 1,5-anti induction by the nucleophile leading to product 21, and excluding a Felkin–Anh control by the aldehyde. This reaction validates a unique disconnection among latrunculin synthetic strategies and avoids the construction of a 4-acetyl-1,3-thiazolidin-2-one. Finally, this β
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Published 03 Apr 2023

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

  • Robert N. Goldberg,
  • Robert T. Giessmann,
  • Peter J. Halling,
  • Carsten Kettner and
  • Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

Graphical Abstract
  • present as an impurity in most substances and since weighing is often used to determine the amounts of substances, the moisture content of the principal substances used in a study should be reported. If the moisture content is important and can vary, one should report the method used to control and
  • the change in binding of H+(aq) in the biochemical reaction ΔrN(H+), i.e., ΔrH(cal) = ΔrH′° + ΔrN(H+)∙ΔrH°(buffer) [10]. Analogous equations pertain should a Ca2+ or Mg2+ buffer be used. 3.8. Interferences Appropriate control experiments should be performed to make certain that the enzyme or, if it is
  • in a suspension or solution, that an impurity in the enzyme suspension or solution does not interfere with the measurement. Thus, when a spectroscopic method is used for an equilibrium measurement (e.g., in an NAD/NADH coupled reaction), it has been customary to perform a control experiment in which
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Published 15 Mar 2023

Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin

  • János Máté Orosz,
  • Dóra Ujj,
  • Petr Kasal,
  • Gábor Benkovics and
  • Erika Bálint

Beilstein J. Org. Chem. 2023, 19, 294–302, doi:10.3762/bjoc.19.25

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  • processes in the pharmaceutical industry [1][27]. During continuous flow reactions, the target molecules can be produced with better purity, selectivity and in higher yields, as well as in consistent quality due to the precise parameter control, low volume ratio and small quantities. The temperature control
  • easier handling of toxic derivatives and with more precise parameter control. Moreover, the reactions can be performed within a much shorter reaction time than under batch conditions. Tosylation of β-CD under continuous flow conditions. Continuous flow azidation of Ts-β-CD (2). Continuous flow
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Published 09 Mar 2023

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

  • Cécile Alleman,
  • Charlène Gadais,
  • Laurent Legentil and
  • François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

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Published 03 Mar 2023

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

  • Shubham Sharma,
  • Dharmender Singh,
  • Sunit Kumar,
  • Vaishali,
  • Rahul Jamra,
  • Naveen Banyal,
  • Deepika,
  • Chandi C. Malakar and
  • Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

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  • Shubham Sharma Dharmender Singh Sunit Kumar Vaishali Rahul Jamra Naveen Banyal Deepika Chandi C. Malakar Virender Singh Department of Chemistry, Dr B R Ambedkar National Institute of Technology (NIT) Jalandhar, 144027, Punjab, India Central Revenues Control Laboratory, New Delhi-110012, India
  • ) in 86% yield. To find out more information about the mechanistic route of the reaction, we performed a control experiment in the presence of TEMPO as a radical scavenger as depicted in Scheme 6. The reaction of pyrazole-3-carbaldehyde 1, pyrrolidine (A) and elemental sulfur in the presence of 1.1
  • 1C (1.18 g from 1 g, 86%; Rf 0.19 (hexane/EtOAc 90:10, v/v)). Procedure for the synthesis of (5-(4-fluorophenyl)-1-phenyl-1H-pyrazol-3-yl)(pyrrolidin-1-yl)methanethione (1A) through control experiment: In a dry round-bottomed flask, pyrazole-3-carbaldehyde 1 (0.05 g, 0.19 mmol), pyrrolidine (A, 0.015
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Published 02 Mar 2023

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

  • Solomiia Borova and
  • Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

Graphical Abstract
  • polymerization, as evidenced by side products and limited control over the polymerization. However, we could establish that the use of the 2-ethyl-3-methyl-2-oxazolinium triflate salt as an initiator at 60 °C results in polymers with a relatively narrow molar mass distribution and a reasonable control over the
  • challenges associated with this approach. We found that it is critical to use suitable initiator species to exert some control over the polymerization. Nevertheless, CROP of 2-oxazolines in DLG remains plagued with some side reactions at this point, limiting the definition of the obtained polymers. Whether
  • no signals at 6.11–5.92 ppm and 5.93–5.83 ppm, but the appearance of new signals at ca. 1.45–2.00 ppm [46][48]. As a control experiment, DLG was incubated with MeOTf for 4 h at 90 °C. The resulting product was purified by precipitation from cold Et2O. The determination of Mn by SEC analysis was about
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Published 28 Feb 2023

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

  • Sedat Ünal,
  • Gamze Varan,
  • Juan M. Benito,
  • Yeşim Aktaş and
  • Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

Graphical Abstract
  • through either (i) the cationic nature of the CD such as poly-β-CD-C6 or (ii) coating of non-ionic 6-O-capro-β-CD with the cationic polymer chitosan (CS). Uncoated 6-O-capro-β-CD negatively charged NPs were used as control formulation. Results and Discussion Fabrication and in vitro characterization of
  • . As seen in Figure 6, cells were double-stained with calcein AM and ethidium homodimer-1 (EthD-1). The control group consisted of cells incubated only with the medium. Living cells were stained green with the membrane dye calcein AM, while dead cells were stained red with the nuclear dye EthD-1. Both
  • interaction in the control group was not observed in the groups treated with nanoparticles. Similarly, it was determined that incubation with nanoparticles caused a change in the colonization of CT26 cells. Based on the results of both mitochondrial functional activity and microscopic imaging analyses
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Published 13 Feb 2023

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

  • Bram Ryckaert,
  • Ellen Demeyere,
  • Frederick Degroote,
  • Hilde Janssens and
  • Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

Graphical Abstract
  • erythromycin A [18], Woodward famously introduced thianes and ring-fused thianes (dithiodecalins) as building blocks for polyketide chain fragments, in order to be able to exploit their cyclohexane-like conformational behavior in the control of the relative stereochemistry along the polyketide backbone (Scheme
  • its use mainly to reactions with more reactive electrophiles, and often leading to incomplete reactions or the need to precisely control the reaction conditions. Nevertheless, the scope established so far is quite wide as can be seen in Figure 3 for some representative examples of targets, wherein the
  • allowed the assembly of complex terpenoid frameworks. Examples from our research group include various daucanoid and kauranoid terpene scaffolds such as 108, 109, and 110, which can be assembled from dihydrodithiin 3 as a building block in just a few synthetic operations with good to excellent control of
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Published 02 Feb 2023

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

  • Bilge Banu Yagci,
  • Selin Ezgi Donmez,
  • Onur Şahin and
  • Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

Graphical Abstract
  • catalytic aza-Nazarov reaction starting from cyclic and acyclic imines and TMS-substituted α,β-unsaturated acyl chlorides to yield α-methylene-γ-lactam heterocycles with high diastereoselectivities. We also report the results of our detailed mechanistic studies along with the necessary control experiments
  • and control experiments provided valuable insights on the reaction mechanism including the importance of the β-silicon effect and the alkene geometry of the α,β-unsaturated acyl chloride reactants on reactivity, different potential modes of cyclization, and the effect of adventitious water on the aza
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Published 17 Jan 2023
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