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Search for "optimization" in Full Text gives 1153 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

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

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

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  • hydrate a. Synthesis of products 6. Reaction conditions: 1 (0.5 mmol), hydrazine hydrate (1.5 mmol, 0.08 g), EtOH (5 ml). Proposed reaction mechanism for the formation of products 6. Synthesis of methylated product 7. Optimization of the reaction conditionsa. Supporting Information Supporting Information
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Published 11 Jun 2024

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

  • Kosuke Yamamoto,
  • Kazuhisa Arita,
  • Masami Kuriyama and
  • Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

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  • this transformation, iodobenzene was successfully converted to the corresponding product 3ka under slightly modified reaction conditions (see Table S1 in Supporting Information File 1 for optimization details). Under the modified conditions, aryl iodides with various electron-donating groups including
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Published 10 Jun 2024
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  • maleamic acid precursors. Optimization of IMDAF cycloaddition using different solvents.a Synthesized tricyclic epoxyisoindole-7-carboxylic acidsa. Supporting Information Supporting Information File 88: Tables S1 and S2, Cartesian coordinates of the optimized structures and copies of NMR spectra.
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Published 06 Jun 2024

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

  • Guoqing Cheng and
  • Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

Graphical Abstract
  • complexation, a significant red-shift of the dipyrrin band to 465 nm was observed due to the metal coordination with the dipyrrin moieties in 4b. To compare the structures of 1a and 1b, they are calculated through geometry optimization with the density functional theory (DFT) method. The alkyl chains at the
  • and their complexes with interlocking structures, respectively, after the geometry optimization with the GFN2-xTB method. The 45 different kinds of SWNTs with length of ≥3.0 nm and diameter range of 0.7–1.2 nm are chosen for the calculation (Table S1, Supporting Information File 1). The relationship
  • (Figure 5b). Computational methods The geometry optimization and frequency analysis of Cu-nanobrackets 1a and 1b were performed at (U)ωB97X-D/6-31+G(d,p)-SDD(Cu) [30][31][32][33] level using the Gaussian 16 program [34], with calculating the pre-resonance Raman activities at 488 nm excitation wavelength
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Published 05 Jun 2024

Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

  • Alina Paffen,
  • Christopher Cremer and
  • Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

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  • 2,8-dimethoxy substitution (PTeZ15) allowed to significantly increase catalytic activity (3aa, 68% after 3 h), still at 1 mol % loading. Encouraged by this trend, which seemed to indicate that the more π-electron-donating substituents increase catalytic activity, we continued structural optimization
  • . Our future research efforts in the area of Te(II) catalysis will likely focus on milder coupling reactions on the one hand, and/or on novel more robust and more active ligand designs on the other. In particular, more investigations will likely be needed regarding the optimization of the possible Te
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Published 04 Jun 2024

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

  • Yong-Chang Zhai,
  • Shimon Oiwa,
  • Shinobu Aoyagi,
  • Shohei Ohno,
  • Tsubasa Mikie,
  • Jun-Zhuo Wang,
  • Hirofumi Amada,
  • Koki Yamanaka,
  • Kazuhira Miwa,
  • Naoyuki Imai,
  • Takeshi Igarashi,
  • Itaru Osaka and
  • Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

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  • differences between t-Bu-FIDO and t-Bu-FIDS, the density functional theory (DFT) method was employed using the B3LYP hybrid functional. The 6-31G* basis set was used for the geometry optimization and frequency calculation. The thiocarbonyl group in FIDS was found to have an out of plane bending vibration
  • , w/w)/PEDOT:PSS/Ag. (b) ITO/ZnO/fullerene:PNTz4T (2:1, w/w)/MoOx/Ag. ITO, indium tin oxide; PEDOT:PSS = poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Optimization of reaction conditions for the treatment of t-Bu-FIDO with Lawesson's reagent.a Reaction of R-FIDO with Lawesson's reagent.a
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Published 31 May 2024

Domino reactions of chromones with activated carbonyl compounds

  • Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

Graphical Abstract
  • chromone. During the optimization of the conditions, the best yields were in many cases obtained when chloride was employed as the leaving group. However, for some other products the yields were slightly better in case of employment of 3-bromochromone. Most of the yields were higher than 70%, in several
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Published 29 May 2024

Synthesis and optical properties of bis- and tris-alkynyl-2-trifluoromethylquinolines

  • Stefan Jopp,
  • Franziska Spruner von Mertz,
  • Peter Ehlers,
  • Alexander Villinger and
  • Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1246–1255, doi:10.3762/bjoc.20.107

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  • ; isolated yields. Optimization of the Sonogashira reaction.a Spectroscopic data of 6a, 9a, 12a, 12c, and 12e in dichloromethane (10−5 M) at 20 °C (λex = 380 nm). Supporting Information Supporting Information File 74: Experimental part.
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Published 29 May 2024

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

  • Naziha Tarannam,
  • Prashant Kumar Gupta,
  • Shani Zev and
  • Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

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  • calculations were performed using Gaussian 16 (revision A.03) [37] and Q-Chem (version 5.4.2) [38], with default tight geometry optimization convergence criteria (10−5 au) and SCF convergence thresholds (10−8 au). All stationary points were characterized by frequency calculations. Throughout this article, only
  • interactions and blue represents repulsive interactions. Additionally, we carried out natural bonding orbital (NBO) analysis using the NBO 3.1 program [42] as implemented in the Gaussian 16 package. The computations are performed at the same level of theory that we chose initially for optimization (M06-2X/6-31
  • noteworthy that optimization with ωB97M-V/6-31+G(d,p) and single point calculations performed with M06-2X and ωB97M-V using the triple-ζ def2-TZVPP basis set provide similar trends for both germacrene and hedycaryol carbocations (the energy comparison plots for the different methods are added in Supporting
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Published 23 May 2024

Two-fold addition reaction of silylene to C60: structural and electronic properties of a bis-adduct

  • Masahiro Kako,
  • Masato Kai,
  • Masanori Yasui,
  • Michio Yamada,
  • Yutaka Maeda and
  • Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

Graphical Abstract
  • 5,6-sila-fulleroid (2d) structures (Figure 6). The optimized structure of 2a was found to be more stable than that of 2c by 19.23 kcal/mol. In contrast, optimization using initial structures of 2b and 2d afforded the structures of 2a and 2c, respectively. Based on these results, the optimized
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Published 22 May 2024

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

  • Manoel T. Rodrigues Jr.,
  • Aline S. B. de Oliveira,
  • Ralph C. Gomes,
  • Amanda Soares Hirata,
  • Lucas A. Zeoly,
  • Hugo Santos,
  • João Arantes,
  • Catarina Sofia Mateus Reis-Silva,
  • João Agostinho Machado-Neto,
  • Leticia Veras Costa-Lotufo and
  • Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

Graphical Abstract
  • the Nazarov reaction, using models already studied in the literature [33][34][35][36][37][38][39][40][41][42][43]. We investigated several conditions, such as the type of catalyst, temperature, solvent, and amount of catalyst (Table 1). Our optimization studies began with the reaction of substrate 9aa
  • , and the dotted line indicates 75% reduction in cell viability. Compounds that reduced cell viability by at least 75% at 5 µg/mL are highlighted in the graph. Previous methods describing decarboxylation reactions of indanones and xanthenones. Optimization of the reaction conditions. Evaluation of the
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Published 21 May 2024

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

  • Akanksha Ashok Sangolkar,
  • Rama Krishna Kadiyam and
  • Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

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  • results will certainly have a remarkable impact for applications in solar energy harvesting and storage. Computational Details The molecular structures of all studied dienes and photoproducts were fully relaxed without any geometrical or symmetrical constraints. The geometry optimization was performed
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Published 13 May 2024

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

  • Tural N. Akhmedov,
  • Ajeet Kumar,
  • Daken J. Starkenburg,
  • Kyle J. Chesney,
  • Khalil A. Abboud,
  • Novruz G. Akhmedov,
  • Jiangeng Xue and
  • Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

Graphical Abstract
  • deep (<−6.0 eV). FMO energies are of great importance not only for the stability but also for device optimization. Raising the HOMO energy level can facilitate hole injection when using Pt electrodes [33], consequently enabling the fabrication of ambipolar devices supporting both hole and electron
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Published 08 May 2024

A Diels–Alder probe for discovery of natural products containing furan moieties

  • Alyssa S. Eggly,
  • Namuunzul Otgontseren,
  • Carson B. Roberts,
  • Amir Y. Alwali,
  • Haylie E. Hennigan and
  • Elizabeth I. Parkinson

Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88

Graphical Abstract
  • the probe was synthesized in good yields, the optimization of the Diels–Alder reaction was undertaken. The Diels–Alder reaction (Figure 3A) was optimized utilizing 3-furoic acid (14) as it fits the requirement of having an electron-withdrawing group in the three position and was an inexpensive
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Published 02 May 2024

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

  • Jingyao Li,
  • Ajay L. Chandgude,
  • Qiang Zheng and
  • Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

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  • . Trimethylsilyl azide is considered as a safe replacement of metal azides. We started the solvent optimization with MeOH and H2O as solvent system at room temperature, however, it did not yield any product even after 3 days (Table 1, entry 1). The use of DMF to improve the solubility of the paraformaldehyde solid
  • was also unsuccessful to increase the product yield. The increased use of microwave conditions in organic synthesis [20] and our previous promising studies on microwave-assisted MCRs [21], motivated us to use microwave conditions for further optimization. Accordingly, we investigated several sets of
  • ). This method is applicable to different amines, isocyanide and acid components including Ugi-4-component and Ugi-tetrazole reactions proving the desired products with low to moderate yields. The Ugi reactions were performed in MeOH at room temperature for 24 hours and without any further optimization
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Published 29 Apr 2024

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

  • Arnaldo G. de Oliveira Jr.,
  • Martí F. Wang,
  • Rafaela C. Carmona,
  • Danilo M. Lustosa,
  • Sergei A. Gorbatov and
  • Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

Graphical Abstract
  • inhibitor (R)-rolipram (5b) [15], and the commercial drug (R)-baclofen hydrochloride (6), used to treat muscle spasticity from spinal cord injury and multiple sclerosis [16]. Results and Discussion Desymmetrization of N-protected 2,5-dihydro-1H-pyrroles Some initial results and reaction optimization Based
  • before. Before exploring the reactivity of the olefin towards other aryldiazonium salts, we performed a brief optimization of the process by testing several other N,N-ligands. Therefore, five other N,N-ligands were evaluated as follows: PyraBox (L2), QuinOx (L3), PyOx L4 and L5, and PyriBOx (L6) (Figure
  • –Matsuda reaction of the protected 2,5-dihydro-1H-pyrroles with aryldiazonium salts catalyzed by a (S)-PyraBox–palladium complex. Optimization of the reaction conditions with tosyl-protected pyrroline 1b.a Supporting Information Supporting Information File 4: Experimental procedures and characterization
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Published 29 Apr 2024

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

  • Jiawei Niu,
  • Yuhui Wang,
  • Shenghu Yan,
  • Yue Zhang,
  • Xiaoming Ma,
  • Qiang Zhang and
  • Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

Graphical Abstract
  • effort was then focused on the optimization of the intramolecular Heck reaction of 5a for making 1,2,3,4-tetrahydroisoquinoline 6a. A systematic evaluation of different catalysts and ligands, solvents, bases, as well as reaction temperatures and times was conducted (Table 1). The Heck reaction of 5a was
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Published 23 Apr 2024

Synthesis and properties of 6-alkynyl-5-aryluracils

  • Ruben Manuel Figueira de Abreu,
  • Till Brockmann,
  • Alexander Villinger,
  • Peter Ehlers and
  • Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

Graphical Abstract
  • carried out by application of the Suzuki–Miyaura cross-coupling. The optimization was carried out with 3a as the model compound (Table 1). The starting material 3a is a sterically hindered system in which the bromine is only partially accessible, due to the large residue. This could be the reason for the
  • . Synthesis of 1,3-dimethyl-5-aryl-6-[2-(aryl)ethynyl]uracils 5a–t. Reaction conditions: 3 (1 equiv), boronic acid (1.2 equiv), Pd(PPh3)4 (5 mol %), NaOH (3 equiv), dioxane/water 5:1, 100 °C, 1 h. aYields of isolated products. Optimization of the reaction conditions for the synthesis of 5a. Photophysical data
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Published 22 Apr 2024

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

  • Jun Kikuchi,
  • Roi Nakajima and
  • Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

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  • iodo(III)azolation using various azoles (a single example of iodo(III)azolation using pyrazole was reported in [28]). Table 1 summarizes the results of the optimization of the reaction conditions for the vinylation of pyrazole (2a) with 1-phenyl-1-propyne (3a) and BXT (1). Upon examination of various
  • . Optimization of reaction conditions.a Supporting Information Supporting Information File 22: Experimental procedures and characterization data of new compounds. Acknowledgements We thank the Central Glass Co., Ltd. for the generous donation of 1,1,1,3,3,3-hexafluoro-2-phenylpropan-2-ol (HFAB). Funding This
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Published 22 Apr 2024

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

  • Ke Jiang,
  • Cheng Pan,
  • Limin Wang,
  • Hao-Yang Wang and
  • Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

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  • -oxyl; BHT = butylated hydroxytoluene. Optimization of reaction conditions.a Scope of naphthols and phenols for the synthesis of 3,4-benzocoumarins.a,b. Scope of ortho-ester-substituted diaryliodonium salts.a Supporting Information Supporting Information File 16: Experimental procedures, LC–MS spectra
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Published 18 Apr 2024

Advancements in hydrochlorination of alkenes

  • Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

Graphical Abstract
  • , cycloheptene (61), when exposed to a concentrated solution of HCl in dichloromethane, did not show any reaction (Table 4, entry 1). Under the same conditions, in the presence of silica gel, they observed 97% conversion and a GC yield of 62% for chloride 62 (Table 4, entry 2). Further optimization identified
  • . Bogers iron-catalyzed radical hydrochlorination. Hydrochlorination instead of hydrogenation product. Optimization of the Boger protocol by researchers from Merck [88][89]. anti-Markovnikov hydrochlorinations as reported by Nicewicz. anti-Markovnikov hydrochlorinations as reported by Nicewicz; rr
  • ). Stereoselective hydrochlorination of hexahydro-1H-indene (33). Hydrochlorination of cycloheptene (61). Hydrochlorination of 1-octene (63). Influence of the HCl gas pressure on the reaction yield. Control reactions for the hydrochlorination reaction of alkene 106. Optimization reactions for the hydrochlorination
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Review
Published 15 Apr 2024

Synthesis and characterization of water-soluble C60–peptide conjugates

  • Yue Ma,
  • Lorenzo Persi and
  • Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

Graphical Abstract
  • details and corresponding spectra for the C60–peptide conjugates 5a–c are shown in Supporting Information File 1. The optimization of the conditions for the reaction between the peptides on resin and fulleropyrrolidine 3 are described in the Results and Discussion section above. These were used to prepare
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Published 12 Apr 2024

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

  • Julien Borrel and
  • Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

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  • discovery and development of the synthesis of homopropargylic azides by the azido-alkynylation of alkenes. Initially, a strategy involving SOMOphilic alkynes was adopted, but only resulted in a 29% yield of the desired product. By switching to a radical-polar crossover approach and after optimization, a
  • high yield (72%) of the homopropargylic azide was reached. Full insights are given about the factors that were essential for the success of the optimization process. Keywords: alkyne; azide; hypervalent iodine; photoredox; trifluoroborate salt; Introduction Homopropargylic azides are important
  • [45]. Herein, we describe our initial effort towards developing an azido-alkynylation of alkenes using the SOMOphilic alkyne approach instead. Then, the optimization of the RPC strategy will be discussed in detail, giving insights into the different steps of the optimization, which were available only
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Published 03 Apr 2024

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

  • Geng-Xin Liu,
  • Xiao-Ting Jie,
  • Ge-Jun Niu,
  • Li-Sheng Yang,
  • Xing-Lin Li,
  • Jian Luo and
  • Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

Graphical Abstract
  • products 4a and 6a (Scheme 6). Both model reactions with diene 2a and allene 5a were proven to be easily scalable without further conditions optimization, delivering unsaturated γ- and ε-AA derivatives 4a and 6a in good yields. Starting from the unsaturated ε-AA derivative 4a, unsaturated ζ-amino alcohols
  • Supporting Information File 1. Optimization of conditions and control experiments.a Supporting Information Supporting Information File 54: Full experimental details, analytical data and NMR spetra. Funding Financial support from the National Natural Science Foundation of China
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Published 27 Mar 2024

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

  • Luan A. Martinho and
  • Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

Graphical Abstract
  • scale-up of the HPW-catalyzed GBB reaction (5.0 mmol) between 2-aminopyridine (1a), 4-nitrobenzaldehyde (2a) and cyclohexyl isocyanide (3) in EtOH under μw heating. Plausible reaction mechanism for the HPW-catalyzed GBB reaction. Optimization of the reaction conditions.a Comparison of reaction
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Published 19 Mar 2024
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