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Search for "efficiency" in Full Text gives 1156 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

  • Liyuan Cao,
  • Xi Liu,
  • Xue Zhang,
  • Jianzhang Zhao,
  • Fabiao Yu and
  • Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

Graphical Abstract
  • harvesting efficiency of both the singlet and triplet excitons and thus a high quantum efficiency for the electroluminescence [13]. The TADF emission process involves the reverse intersystem crossing (rISC) from the triplet (T1) state to the emissive singlet (S1) state. A typical molecular structure motif
  • analogous dyads recently, however, the delayed fluorescence lifetimes were much longer (2.0–14.4 μs) as compared to the current dyads [47]. TADF emitters with shorter delayed fluorescence lifetimes are suitable for fabrication of OLED devices, to suppress the efficiency roll-off effect. The photophysical
  • possible relaxation pathway, because the orthogonal geometry of the dyads is beneficial for SOCT-ISC. Previously we have shown that SOCT-ISC occurs for the analogue of NI-PTZ-C5 [39]. In order to study the ISC efficiency of the dyads, we measured the singlet oxygen quantum yield (ΦΔ) of the dyads in
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Published 19 Jul 2023

CO2 complexation with cyclodextrins

  • Cecilie Høgfeldt Jessen,
  • Jesper Bendix,
  • Theis Brock Nannestad,
  • Heloisa Bordallo,
  • Martin Jæger Pedersen,
  • Christian Marcus Pedersen and
  • Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

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  • , are studied as potential CO2 capture agents due to their unique molecular structures and high selectivity towards CO2. In this paper we have investigated binding efficiency of a number of cyclodextrins towards CO2. It is found that the crystal structure of α-cyclodextrin with CO2 has a 1:1
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Published 17 Jul 2023

Linker, loading, and reaction scale influence automated glycan assembly

  • Marlene C. S. Dal Colle,
  • Manuel G. Ricardo,
  • Nives Hribernik,
  • José Danglad-Flores,
  • Peter H. Seeberger and
  • Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

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  • ]. We wondered whether different glycan sequences were more sensitive to the linker structure. Less reactive donors might highlight differences in the linker nucleophilicity [25]. The aggregation of the growing glycan chains is conceivable to be connected to linker flexibility [18]. The efficiency of UV
  • whether methanoloysis on resin could improve photocleavage efficiency. However, when we tested the same procedure on L1, target compound 5b was isolated in only 15% yield. These results strongly suggest that the two linkers perform differently depending on the glycan sequences. Conclusion Taken together
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Published 06 Jul 2023

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

  • Elena Y. Mendogralo and
  • Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

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  • hydrolysis could be a convenient tool for the synthesis of substituted 3-(2-oxopropyl)piperidin-4-ones 5. Using tetrahydrofuro[3,2-c]pyridine 4a as the model compound, we studied the effect of various Brønsted acids, temperature, concentrations, and the nature of the solvent on the efficiency of the reaction
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Published 30 Jun 2023

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

  • Alessio Regni,
  • Francesca Bartoccini and
  • Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

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  • feasible under these conditions, the observed reaction efficiency was poor (14–33% yield). However, on the 1H NMR spectrum, some unexpected signals were observed. The appearance of equilibrating species such as rotamers in the 1H NMR spectrum (see the variable-temperature NMR experiments in Supporting
  • [98]. Reducing the substrate concentration increased efficiency while assisting in avoiding the oligomerization pathways (Table 1, entries 2 and 3). Higher photocatalyst loadings resulted in an increased yield (Table 1, entry 4). Control experiments showed that both the photocatalyst and light were
  • essential for product production (Table 1, entries 6 and 7), despite the fact that the removal of base did not result in a significantly reduced efficiency (Table 1, entry 5). The regioselectivity outcome was explained by the relative stability of the intermediate radicals involved, with strong evidence of
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Published 26 Jun 2023

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
  • %). Notably, the efficiency of this transformation was greatly impacted by the electronic effect on the aromatic rings of the olefins. Alkenes with electron-donating groups on their aromatic rings showed higher yields of the corresponding products as compared to those with electron-withdrawing groups (3af–ar
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Published 22 Jun 2023

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

  • Constantine V. Milyutin,
  • Andrey N. Komogortsev,
  • Boris V. Lichitsky,
  • Mikhail E. Minyaev and
  • Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

Graphical Abstract
  • to 2 h did not affect the yield of pyrimidine 9a (Table 1, entry 8). It is important to emphasize that the use of bases essentially impaired the efficiency of the method (Table 1, entries 9 and 10). Apparently, the addition of a basic reagent does not influence the main process and the decrease in
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Published 07 Jun 2023

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

  • Masahiro Hosoya,
  • Yusuke Saito and
  • Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

Graphical Abstract
  • structure raised the mixing efficiency of a gas–liquid reaction system, and it effectively accelerated the aerobic oxidation of benzyl alcohols to benzaldehydes under continuous-flow conditions. This reactor is a promising device for streamlining aerobic oxidation with high process safety because it is a
  • -tube reactors or fixed bed reactors [17][18][19][20]. To maximize this advantage, the gas–liquid biphasic reaction must be controlled under continuous-flow conditions. This reaction requires high mixing efficiency to assure high mass transfer of the gas to the liquid phase and a consequent high
  • high mixing efficiency throughout the reaction. This complex equipment complicates its versatile application for the scale-up and manufacturing, which leads to higher costs. To address this issue, we turned our attention to the use of porous material, which is widely used for exhaust gas treatment in
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Published 31 May 2023

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

  • Semyon V. Tsybulin,
  • Ekaterina A. Filatova,
  • Alexander F. Pozharskii,
  • Valery A. Ozeryanskii and
  • Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

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  • the extent of π-conjugation and the efficiency of particular donor–acceptor conjugation path in these new compounds. X-ray structures and absorption spectra of doubly protonated tetrafluoroborate salts of the oligomers are also discussed. Keywords: 1,8-bis(dimethylamino)naphthalene; cross-conjugated
  • us to undertake the current study. X-ray crystallography, UV–vis spectroscopy and cyclic voltammetry were applied to analyze the extent of π-electron conjugation and the efficiency of the particular donor–acceptor conjugation path in chromophores 5. Results and Discussion Synthesis The target
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Published 15 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

Graphical Abstract
  • either on harsh reaction conditions or require the preactivation of substrates, which limits their synthetic efficiency. A photocatalytic quaternary C-3 alkylation has also been reported recently (Scheme 1A) [21][22]. During the course of our study, the Wu group reported a solvent-controlled
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Published 12 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
  • makes it suitable for oral drug delivery. However, the aggregation behavior of CS-TPE under alkaline conditions may influence its drug release efficiency. Thus, the development of modified systems with reduced propensity to accumulate should be of interest. Self-assembly behavior of TBTQ-C6/CS-TPE in
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Published 08 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
  • processes rely on the use of a homogeneous metal catalyst at elevated temperatures necessary to cleave the C3–H bond by oxidative addition. These experimental conditions, easily used in the laboratory, are potentially problematic for scale-up due to efficiency and safety issues (related to the high
  • (outside the oven). An improvement in efficiency was then observed when the reaction mixture was preheated to 130 °C for 5 min. Interestingly, only traces of product I2a were observed after 5 min at 130 °C, implying that the Murai reaction was indeed taking place only when passing through the second
  • 150 °C was chosen taking into account the efficiency of the batch reaction between imine 1 and triethoxyvinylsilane (3 equiv) in the presence of 5 mol % of this catalyst at 150 °C, which leads in 5 h to the alkylated imine I2a with a NMR yield of 77% (conv. 100%). Even though the reaction intermediate
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Published 03 May 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

Graphical Abstract
  • ][17][18]). In early works, the chiral tridentate ligand based on (S)-N-benzylproline (L1) was used [19][20]. Though the original Belokon complex derived from N-benzylproline and o-aminobenzophenone showed sufficiently high efficiency and is still the most widely used template, considerable efforts on
  • the modification of the chiral auxiliaries as well as of the other fragments of the tridentate ligand have been made to improve stereocontrolling efficiency and to modify physicochemical properties of the template (such as solubility, lipophilicity, etc). Thus, various substituents (4,5-di-CH3 [21], 2
  • techniques; for details, see Supporting Information File 1); [α]D20 = 2127 (MeOH). To test the stereocontrolling efficiency of the new ligand L7 and to obtain new cysteine Ni–Schiff base derivatives (RCysNi)L7 which are of practical interest, complex (ΔAlaNi)L7 was involved in a nucleophilic addition as
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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

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Published 24 Apr 2023

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

  • Manuel Pedrón,
  • Jana Sendra,
  • Irene Ginés,
  • Tomás Tejero,
  • Jose L. Vicario and
  • Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

Graphical Abstract
  • ; Introduction Transannular cycloaddition reactions (TCRs) are useful for the synthesis of complex natural products and other biologically active compounds with high efficiency and stereoselectivity [1][2][3][4]. There are several different ways in which TCRs can occur, depending on the nature of the starting
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Published 20 Apr 2023

Total synthesis: an enabling science

  • Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 474–476, doi:10.3762/bjoc.19.36

Graphical Abstract
  • constantly needed to improve methods and strategy, keeping in mind the difficulty of performing transformations on highly functionalized compounds, the total synthesis of complex natural products is indeed mature in terms of efficiency, practicality, economy, and scalability. In short, it has become an
  • (biomimetic synthesis) [14]. In addition, total syntheses have also been achieved with enzymes, strengthening the links to biology [15]. Total synthesis is not limited to academic laboratories but rather also pursued in industry, where a particular efficiency and economy of tasks is of paramount importance
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Published 19 Apr 2023

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

  • Louis Monsigny,
  • Floriane Doche and
  • Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

Graphical Abstract
  • . The substitution pattern on the aromatic ring did not affect the reaction efficiency, the meta-substituted derivative 2e as well as the ortho-substituted derivative 2f were obtained in high yields (70% and 63% yields, respectively). It should be noted that the presence of ortho-substituents on the
  • vinylpyridines with electron-donating or electron-withdrawing groups on the aromatic ring were functionalized and 36l and 36m were easily isolated in 73% and 81% yields, respectively. Even an α,β-disubstituted vinylpyridine 35n and the benzoquinoline 35o were smoothly functionalized showing the efficiency of the
  • impact the efficiency of the reaction as illustrated by the synthesis of compounds 44b and 44c. The presence of an electron-donating substituent in the para-position of the directing group was found to be deleterious for the reaction since 44d was obtained in 31% yield while its brominated analog 44e was
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Published 17 Apr 2023

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

  • Nicoleta G. Hădărugă,
  • Gabriela Popescu,
  • Dina Gligor (Pane),
  • Cristina L. Mitroi,
  • Sorin M. Stanciu and
  • Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

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  • , especially by DSC. Both TG–DTG and DSC thermal analyses provide information about the molecular inclusion of guest molecules into the β-CD cavity. Unfortunately, these methods cannot differentiate between the encapsulated components and their entrapment efficiency. However, the goal of the study was the
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Published 28 Mar 2023

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

  • Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

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  • excellent yields using Zn(OAc)2 in a CHCl3/MeOH mixture. Their UV–vis titration study revealed that these host systems exhibit strong anion-binding affinities. Furthermore, with the help of kinetic studies, the absorption efficiency of malachite green dye was investigated by using free-base porphyrins 171a
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Published 22 Mar 2023

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

  • Eric Gayon,
  • Guillaume Lefèvre,
  • Olivier Guerret,
  • Adrien Tintar and
  • Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

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  • to overall processes with a low atom economy, generating a significant amount of chemical waste, and which can be expensive when noble metals such as palladium salts are required (Scheme 1). The high efficiency of transition-metal-catalyzed cross-coupling methods in C–C bond formation processes
  • , using FeCl3 as the catalyst, in order to obtain cross-coupling products with yields between 64 and 83% (Scheme 2a) [11]. Drawing his inspiration from Kochi, Cahiez reported that using N-methyl-2-pyrrolidone or NMP as a co-solvent drastically improved the efficiency of the iron-catalyzed alkyl–alkenyl
  • exogenous N- or P-based ligands, highlighting the efficiency of iron as a credible alternative to noble metal catalysis in cross-coupling chemistry [13]. Cahiez’ pioneering work highlighted the potential of iron catalysis in organic chemistry and generated a new interest for the study of iron-catalyzed
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Published 14 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

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  • , the CS-(6-O-capro-β-CD) nanoparticle formulation had the highest efficiency for both time points against the CT26 cell line. After 48 hours of incubation, the IC50 values of anionic CPT-loaded 6-O-capro-β-CD and CPT-loaded poly-β-CD-C nanoparticles were calculated as 1.23 ± 0.02 µM and 1.35 ± 0.46 µM
  • anticancer efficiency of CPT-loaded nanoparticles on 2D cell cultures According to the results of the conventional 2D cell culture study, the CPT-loaded poly-β-CD-C6 nanoparticle treatment group in CT26 cells had the highest antiproliferative effect after 48 h (Figure 5a). When compared to CPT solution
  • -administration of blank nanoparticles and drug solution was shown to be more efficient in terms of cell survival than the drug solution alone at the end of the 72-hour incubation. The efficiency of drug-loaded nanoparticles is higher than that of co-administered formulations in all three nanoparticle dispersions
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Published 13 Feb 2023

Practical synthesis of isocoumarins via Rh(III)-catalyzed C–H activation/annulation cascade

  • Qian-Ci Gao,
  • Yi-Fei Li,
  • Jun Xuan and
  • Xiao-Qiang Hu

Beilstein J. Org. Chem. 2023, 19, 100–106, doi:10.3762/bjoc.19.10

Graphical Abstract
  • reaction system (Table 1, entry 8). Increasing the amount of acetic acid significantly improved the reaction efficiency delivering product 3aa in 80% yield (Table 1, entry 9). The choice of a suitable catalyst was the key factor for the success of this reaction since only a trace amount of 3aa can be
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Published 30 Jan 2023

Preparation of β-cyclodextrin/polysaccharide foams using saponin

  • Max Petitjean and
  • José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

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  • absence of saponin, by increasing the reaction time from 20 to 45 min (samples 20Pow and 45Pow, respectively), the yield will increase due to a higher crosslinking efficiency of the solventless procedure [38]. A mixture dissolved in water and then freeze-dried (sample 45Liq*) shows a better yield
  • -csp (with no polysaccharide) absorbed more 1-N when saponin is present between 2 ppm and 200 ppm, which is the largest range of higher efficiency for all matrices. For the others, there seems to be no effect in the low 1-N concentration range. Nevertheless, we need to look at the graph insets, which
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Published 24 Jan 2023

NaI/PPh3-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

  • Dan Liu,
  • Yue Zhao and
  • Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

Graphical Abstract
  • replacing the methyl with a phenyl group at the N-arylacrylamide core significantly affected the reaction efficiency from 72% to 34% yield (3pa). Satisfyingly, substrate 1q could successfully undergo decarboxylative cascade cyclization to afford 3qa with 70% yield, which is used as a key intermediate in the
  • similar efficiency, affording oxindole 3aj as a 1:1.1 mixture of diastereomers. Interestingly, this method also enabled the synthesis of the highly sterically demanding oxindole 3ak in good yield when using a tert-butyl N-hydroxyphthalimide ester as the tert-butyl radical precursor. Importantly, a redox
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Published 16 Jan 2023

Inline purification in continuous flow synthesis – opportunities and challenges

  • Jorge García-Lacuna and
  • Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

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  • these tools is provided as a guide to aid researchers in selecting the most appropriate approach for future applications. It is hoped that this perspective contributes to new developments in this field in the context of process and cost efficiency, sustainability and industrial uptake of new flow
  • analysis to control the acid concentration. Good extraction efficiency and purification were achieved for an amine as a test substrate that was contaminated with a minor impurity. Remaining challenges such as time-consuming optimization and the need for several pumps can be overcome through careful
  • heterogeneous fashion. This oftentimes leads to improved green credentials, safety, and sometimes efficiency, especially when it is applied to the downstream process. Commercially available resins, activated charcoal, polymer-supported species that trap spent reagents or side-products as well as related
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Published 16 Dec 2022
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