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Search for "solvent-free" in Full Text gives 211 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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

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  • much greener as compared to methanol, it was chosen as the solvent to study the reaction scope. The use of water or solvent-free conditions resulted in much lower reaction yields (Table 1, entries 14–16). Next, the scope of the reaction was investigated with a range of 2-aminopyridines/2-aminothiazoles
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Published 19 Mar 2024

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

  • Periklis X. Kolagkis,
  • Eirini M. Galathri and
  • Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

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  • , lowering its LUMO energy, by withdrawing electron-density through a variety of covalent interactions. Green and sustainable approaches Solvent-free processes Alternative processes, that limit environmental pollution and toxic byproducts, came to the forefront of research for the introduction of novel
  • and viability of these synthetic protocols, organic chemists have been opting towards the use of greener catalysts and solvents in drug development. Chemists dream to perform reactions under solvent-free conditions, which provide a greener approach towards organic transformations. Nowadays, the use of
  • solvent-free reaction conditions has been introduced as a popular alternative to common organic solvents for many different organic transformations. The lack of an organic solvent can result in improved yields and reaction rates, more facile work-up processes and reduced waste, which are among the goals
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Published 22 Feb 2024

Catalytic multi-step domino and one-pot reactions

  • Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

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  • -aminopyrazoles with azlactones under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium, is described by the Fisyuk group [13]. A further facile one-pot process toward a new series of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrin analogues is described
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Editorial
Published 08 Feb 2024

Synthesis of 7-azabicyclo[4.3.1]decane ring systems from tricarbonyl(tropone)iron via intramolecular Heck reactions

  • Aaron H. Shoemaker,
  • Elizabeth A. Foker,
  • Elena P. Uttaro,
  • Sarah K. Beitel and
  • Daniel R. Griffith

Beilstein J. Org. Chem. 2023, 19, 1615–1619, doi:10.3762/bjoc.19.118

Graphical Abstract
  • secondary amine according to our previously described, solvent-free protocol [12][13]. The resulting iron complex 6 was demetallated upon irradiation with UV light [14] to give the deconjugated olefin 7. We then hoped to forge the desired bicycle 8 (Table 1) via a 6-exo-trig Heck cyclization, drawing on the
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Published 23 Oct 2023

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

  • Fatemeh Doraghi,
  • Seyedeh Pegah Aledavoud,
  • Mehdi Ghanbarlou,
  • Bagher Larijani and
  • Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

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  • cyclization and sulfenylation promoted by AlCl3. Dialkyl disulfides 47 were also well tolerated in this Lewis acid-mediated sulfenylation reaction in solvent-free conditions at room temperature. In the same year, a three-component reaction between highly substituted cyclopropanes 49, sulfonamides 25 and N
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Published 27 Sep 2023

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp3)–H to construct C–C bonds

  • Hui Yu and
  • Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

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  • 2010, Schnürch et al. utilized Fe(NO3)3 as the catalyst and TBHP (tert-butyl hydroperoxide) as the oxidant to realize the CDC of C(sp3)–H/C(sp2)–H bonds under solvent-free conditions (Scheme 21) [82]. However, the desired coupling products were obtained in low to moderate yields. The C–H oxidative
  • -catalyzed CDC reaction of N-methylaniline with ethers. Fe-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds. Fe-catalyzed hydroalkylation of α,β-unsaturated ketones with ethers. Solvent-free Fe(NO3)3-catalyzed CDC of C(sp3)–H/C(sp2)–H bonds. Alkylation of disulfide compounds to afford tetrasubstituted alkenes. Fe
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Published 06 Sep 2023

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

  • Vladislav Yu. Shuvalov,
  • Ekaterina Yu. Vlasova,
  • Tatyana Yu. Zheleznova and
  • Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

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  • ) under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium (t-BuOK/DMSO). The fluorescent properties of the synthesized compounds were studied. 4-Arylpyrazolo[3,4-b]pyridin-6-ones luminesce in the region of 409–440 nm with a quantum yield of 0.09–0.23
  • ]pyridones 3 obtained by this method vary widely [31][32][33]. Solvent-free reactions are convenient from both economic and environmental points of view. We obtained tetrahydro-1H-pyrazolo[3,4-b]pyridinone 3a by heating 5-aminopyrazole 1 with azlactone 2a in the absence of solvent at 150 °C in 62% yield
  • obtained under solvent-free conditions followed by the addition of t-BuOK in DMSO, the yield of pyrazolo[3,4-b]pyridin-6-one 4a was higher (73%, Table 1, entry 5) than when performing the reaction in a solvent (60%, Table 1, entry 6). Therefore, this procedure was used for the synthesis of compounds 4b–i
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Published 02 Aug 2023

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

  • Dileep Kumar Singh and
  • Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

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  • . Furthermore, many solvent-free reactions and solid-supported reagents are becoming increasingly popular in organic synthesis. Moreover, in order to increase the product yield, different green catalysts were used in the synthesis of numerous organic and bioorganic molecules while reducing the amount of excess
  • procedure is explained in the first section, and the green protocol is covered in the second (Figure 2). The second section is further divided into three subsections that covers the various eco-friendly green processes used, such as, (i) reactions in water, (ii) solvent-free reactions, (iii) microwave
  • -assisted reactions in water, solvent-free conditions and in other organic solvents. Clauson–Kaas reaction and its mechanism The Clauson–Kaas reaction refers to the synthesis of various N-substituted pyrroles via an acid-catalyzed reaction between aromatic or aliphatic primary amines and 2,5
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Published 27 Jun 2023

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

  • Konstantin Lebedinskiy,
  • Volodymyr Lobaz and
  • Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

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  • methylated primary rim based on the remarkable methylation ability of methyl tosylate with relatively mild bases at solvent-free conditions has been developed. It has been proved that using Lewis acid in the phosphine imide reactions with CDs can increase the reactivity of some low-reactive compounds, giving
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Published 25 Nov 2022

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

  • Koustav Singha,
  • Imran Habib and
  • Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

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  • tosyl halogenides. Solvent-free chlorination reaction of imidazole N-oxides. Multicomponent reaction of imidazole N-oxides 28 with Meldrum’s acid (26) and aldehydes. Multicomponent reaction of imidazole N-oxides with CH-acids and aldehydes. Reaction conditions: aThe mixture of 2-unsbstituted imidazole 1
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Published 22 Nov 2022

Polymer and small molecule mechanochemistry: closer than ever

  • José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

Graphical Abstract
  • -free ball milling has enabled to surpass the insolubility and recalcitrant reactivity of cellulose [36][37], chitin [38][39], and lignin (Figure 2) [40][41]. In addition to allowing solvent-free reactions, mechanical forces generated inside ball mills can depolymerize biomass through cleavage pathways
  • remediation, the degradation of dye pollutants (e.g., rhodamine) has been accomplished using BaTiO3 as a mechanophore in solution with ultrasonication [52] or under solvent-free ball milling reaction conditions [56]. These reports complement recent studies on piezocatalysis, such as on chain-growth
  • complementary reactivity, as discussed above. Depolymerization of biomacromolecules by mechanical force In addition to the manipulation of manufactured polymers, ball milling techniques have also been reported to facilitate the depolymerization of biopolymers [35]. On the one hand, the implementation of solvent
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Published 14 Sep 2022

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

  • Blaine G. Fiss,
  • Georgia Douglas,
  • Michael Ferguson,
  • Jorge Becerra,
  • Jesus Valdez,
  • Trong-On Do,
  • Tomislav Friščić and
  • Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

Graphical Abstract
  • explored herein the use of solvent-free, room temperature mechanochemistry to access phosphorus-linked carbon nitride with repeating heptazine units, which were found to show improved photochemistry over pristine graphitic carbon nitride (g-CN). Additionally, the effect of a 1-hour annealing period at 300
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Published 12 Sep 2022

Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

  • Jin Yang,
  • Dang-Wei Qian and
  • Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

Graphical Abstract
  • catalyst through a similar transformation under solvent-free conditions [44]. Recently, Zhang’s group disclosed a cesium carbonate-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence and extended the phosphorus source from phosphate to phosphonate [45]. Despite of these important advancements
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Published 09 Sep 2022

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

  • Dharmendra Das,
  • Akhil A. Bhosle,
  • Amrita Chatterjee and
  • Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

Graphical Abstract
  • mechanical grinding or milling, has garnered massive interest among chemists owing to its green attributes like solvent-free, clean, atom economic, and time-efficient, and has been identified by the IUPAC as one of 10 world-changing technologies [47]. While milling has received more focus, the simpler form
  • automated grindstone chemistry [50]. Notably, a few mechanochemical methods are available for aromatic halogenation using NXS (Scheme 1d) [51][52][53]. However, the solvent-free protocol reported by Mal and co-workers requires several hours for halogenation [51], whereas Ghafuri and co-workers’ method
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Published 09 Aug 2022

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry

  • Koji Kubota,
  • Emiru Baba,
  • Tamae Seo,
  • Tatsuo Ishiyama and
  • Hajime Ito

Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86

Graphical Abstract
  • high yields. Notably, all experimental operations could be performed in air, and did not require the use of large amounts of dry and degassed organic solvents. The utility of this method was further demonstrated by gram-scale synthesis under solvent-free, mechanochemical conditions. Keywords: ball
  • , solvent-free palladium-catalyzed borylation process applicable for a wide range of aryl halides would greatly improve the practicality of the desired arylboronic acid derivatives. Nechaev et al. reported the first solvent-free protocol for the palladium-catalyzed Miyaura–Ishiyama borylation of aryl
  • serve as reactants and solvents (neat liquid conditions). In addition, a long reaction time (12 h) is required to complete the reaction [15]. A general and efficient solvent-free borylation protocol that can be applied to liquid as well as solid aryl halides remains undeveloped. Recently
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Published 18 Jul 2022

Synthesis of odorants in flow and their applications in perfumery

  • Merlin Kleoff,
  • Paul Kiler and
  • Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

Graphical Abstract
  • be extracted from grapefruits or prepared by, e.g., oxidation of (+)-valencene (7) (using toxic di-tert-butyl chromates), which is isolated from the essential oil of oranges [9]. In 2014, Neuenschwander and Jensen reported a flow setup for the catalyst and solvent-free oxidation of (+)-valencene (7
  • ) to (+)-nootkatone (8) under catalyst and solvent-free conditions in a segmented flow. Enzyme-catalyzed acetylation of isoamyl alcohol (9) in a biphasic n-heptane/water mixture utilizing a CorningTM Low Flow reactor. Esterification of alcohols by transesterification, catalyzed by immobilized
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Published 27 Jun 2022

Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides

  • Petar Štrbac and
  • Davor Margetić

Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75

Graphical Abstract
  • conditions (temperature) and the inability to control the elimination process [17]. The objective of this work was to establish whether the 1,2-debromination with the Zn/Ag couple could be carried out under solvent-free conditions in a ball mill and whether the tedious Zn/Ag couple preparation procedure [18
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Published 24 Jun 2022

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

  • Dajana Barišić,
  • Mario Pajić,
  • Ivan Halasz,
  • Darko Babić and
  • Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

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  • protocol for the ortho-halogenation of acetanilide with NXS (X = Cl, Br, I) using Pd(OAc)2 as precatalyst in the presence of p-toluenesulfonic acid (TsOH) as an additive under solvent-free conditions [49]. Recently, Mal and Bera reported the utilization of NXS (X = Br, Cl) as bifunctional reagents for the
  • solvent-free synthesis of phenanthridinones via a cascaded oxidative C–N coupling followed by a halogenation reaction [50]. Only recently, our group carried out a detailed synthetic and mechanistic study of the mechanochemical PdII-catalyzed bromination of unsubstituted azobenzene (L1) by N
  • in the para position occurred in the absence of the added PdII catalyst and additives, in the ortho position to the substituent, which is typical for the products of electrophilic aromatic substitution. In addition, an additive- and solvent-free protocol without the added PdII catalyst was developed
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Published 15 Jun 2022

DDQ in mechanochemical C–N coupling reactions

  • Shyamal Kanti Bera,
  • Rosalin Bhanja and
  • Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

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  • -Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a commonly known oxidant. Herein, we report that DDQ can be used to synthesize 1,2-disubstituted benzimidazoles and quinazolin-4(3H)-ones via the intra- and intermolecular C–N coupling reaction under solvent-free mechanochemical (ball milling) conditions. In
  • . Keywords: ball mill; 1H-benzo[d]imidazole; C(sp2)–H amidation; DDQ; mechanochemistry; quinazolin-4(3H)-one; Introduction The reawakening approaches to use solvent-free and environmentally benign conditions in organic synthesis have facilitated new opportunities [1][2][3][4]. The research area of
  • mechanochemistry [5][6] mainly focuses on conducting synthetic transformations in solid-state or solvent-free conditions. Mechanochemistry is one of the emerging avenues in chemistry that can make the world more sustainable by following the “Twelve Principles of Green Chemistry” [2]. Mechanochemistry is one of the
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Published 01 Jun 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

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Published 11 Apr 2022

Synthesis of 5-unsubstituted dihydropyrimidinone-4-carboxylates from deep eutectic mixtures

  • Sangram Gore,
  • Sundarababu Baskaran and
  • Burkhard König

Beilstein J. Org. Chem. 2022, 18, 331–336, doi:10.3762/bjoc.18.37

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  • of 5-unsubstituted dihydropyrimidinones from β,γ-unsaturated ketoesters in low melting ʟ-(+)-tartaric acid–N,N-dimethylurea mixtures is reported. This solvent-free method is very general and provides easy access to 5-unsubstituted dihydropyrimidinone-4-carboxylate derivatives in good yields
  • . Keywords: green protocol; mild conditions; no additional catalyst; solvent free; triple role of melt; Introduction In recent years, dihydropyrimidinones (DHPMs) and their derivatives have attracted considerable attention due to the multifaceted pharmacological properties of this class of compounds [1][2
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Published 22 Mar 2022

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

  • Surendran Amrutha,
  • Sankaran Radhika and
  • Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

Graphical Abstract
  • dendrimers were grown on graphene nanosheets for catalyzing the reaction using highly active Pd-Co bimetallic nanoparticles under copper and solvent-free conditions at room temperature. K2CO3 was found to be the suitable base which provided a relatively good yield (Scheme 28) [41]. The graphite sheets could
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Published 03 Mar 2022

New advances in asymmetric organocatalysis

  • Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 240–242, doi:10.3762/bjoc.18.28

Graphical Abstract
  • nitromethane to β-silyl α,β-unsaturated carbonyl compounds catalyzed by bifunctional squaramide catalysts are effective under solvent-free conditions [26]. Zhai and Du demonstrated that asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins are efficiently
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Published 28 Feb 2022

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

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

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

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Published 04 Nov 2021

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

  • Akhil K. Dubey and
  • Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

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  • -unsaturated carbonyl compounds catalyzed by bifunctional squaramide catalysts has been developed. This methodology offers both enantiomers of β-silyl nitroalkanes in good to excellent yields (up to 92%) and enantioselectivities (up to 97.5% ee) under solvent-free conditions at room temperature. Control
  • experiments reveal that the presence of a β-silyl group in the enones is crucial for high reactivity under the optimized reaction conditions. Keywords: β-silyl α,β-unsaturated carbonyl compounds; β-silyl nitroalkanes; chiral organosilanes; organocatalysis; solvent-free synthesis; Introduction
  • organosilanes [29][37][38], we present herein an organocatalyzed conjugate addition reaction of nitromethane to β-silyl enones to afford chiral β-silyl nitroalkanes (Scheme 1). Notably, the developed method was not only carried out under solvent-free conditions at room temperature but was found to be tolerant
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Published 27 Oct 2021
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