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

• from the scientific world [97][98]. In 2008, the first application of nanocatalysis for the synthesis of BIMs was introduced by Shailaja and her research group, utilizing a ceria/vinylpyridine nanocomposite as the catalyst [99]. After repeated studies and experiments on the reaction between indole (11

• ) and benzaldehyde (31), methanol emerged as the optimum solvent with the isolated product yield approaching 98%, after 1 hour, when 69 mg of the nanocomposite were added to the reaction mixture [99]. The recovery of the nanocatalyst was feasible by simple filtration and it was found that its catalytic

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• arising from hydrogen bonding and π–π stacking interactions. In contrast, when 75 is incorporated into a nanocomposite with polystyrene serving as the matrix, luminescent properties are observed [141]. Photoinduced intramolecular energy and electron transfer Exploiting the electron-accepting property of

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

• latter with salts of Pd(II) and Co(II) in ethylene glycol and water at pH 11 afforded the desired PdCo nanoparticles-3D graphene nanocomposite. The catalyst was then studied in the Sonogashira coupling reaction of arylacetylenes and aryl halides in the presence of various bases and solvents. The maximum

• halides with terminal acetylenes in the presence of Co nanoparticles. Sonogashira coupling reaction of aryl halides with phenylacetylene in the presence of Co nanoparticles. PdCoNPs-3DG nanocomposite-catalyzed Sonogashira cross coupling of aryl halide and terminal alkynes. Sonogashira cross-coupling of

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

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

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

• . 5.2.2. Injectable nanocomposite cryogels: Nanocomposite cryogels comprise a typical cryogel with nanoparticulate fillers incorporated into the structure. Addition of nanoparticles is often conducted to impart specific properties, such as improving mechanical properties or provide therapeutic properties

• such as antimicrobial properties. A work reported by Koshy et al. in 2018 was testing the use of injectable nanocomposite cryogels for versatile protein-drug delivery [37]. Injectable and porous cryogels were prepared using a bio-orthogonal click chemistry crosslinking approach with alginate employing

• pore size range was between 50–300 μm, and small concentrations of laponite found in the gel wall helped with sustained release of a number of proteins with diverse properties [37]. Injectable nanocomposite cryogels have also appeared in research as a method to combat cancer. Bauleth-Ramos et al. used

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• copolymer (Ps-b-PCL). a) DSC thermogram of photoinduced synthesis of nanocomposite networks (heating rate: 10 °C/min). b) FTIR spectra of Alk-5, Az-3 monomers and the corresponding cross-linked polymer. (a, b) TEM images of cross-linked polymer at two different magnifications, c) HAADF-STEM image and d) the

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• nanostructured metal oxides were tested as catalysts for PET glycolysis. Thus, a graphene oxide (GO)–Mn3O4 nanocomposite (Table 3, entry 5) [220] and silica NPs-supported Mn3O4 [221] resulted in a good yield of BHET (>90%), however, at a high reaction temperature. A zinc manganite spinel ZnMn2O4 gave BHET in 92

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• nanocomposite, carbon nanocomposite, and magnetic nanocomposites and their catalytic uses in CuAACs will be helpful to the community of scientists working in industry and scholarly laboratories, respectively. This review aims to cover recently published reports from 2014 to 2019 presenting synthetic routes and

• , copper nanoparticles-decorated three-dimensional graphene (3D graphene/Cu nanocomposite 87) was reported as a catalyst to perform Huisgen 1,3‐dipolar cycloadditions. Therein, the GO material was mixed with EDA to produce a stable suspension that was transferred to a teflon‐lined autoclave. After heating

• 24 h to produce a precipitate that was gathered and washed with water and ethanol (Scheme 18). It should be noted that 5.0 mol % of the 3D graphene/Cu nanocomposite 87 were sufficient to generate a high yield of the desired products in EtOH/H2O (1:1) at 70 °C. To screen the recyclability of 87, the

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• contributes to an efficient aqueous reaction [119]. The preparation of catalytic nanocomposite hydrogels has been widely reviewed [56][114]. Several examples showing their utility as nanoreactors for various reactions such as coupling, oxidation and reduction reactions have been reported [43][114][118]. Wei

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• reaction conditions. In 2016, Wang and co-workers reported the thiocyanation reaction of indoles with TiO2/MoS2 nanocomposite as heterogeneous photoredox catalyst and molecular oxygen as terminal oxidant (Scheme 27) [62]. They propose that the efficiency of their reaction is due to a separation of

• nanoscale MoS2. The scope of the reaction is quite similar to Li’s report [60]. The photocatalyst nanocomposite was reused in eight consecutive cycles with only slight decrease in activity. Yadav et al. developed a metal-free photoredox-catalyzed α-C(sp3)–H thiocyanation reaction for tertiary amines (Scheme

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• the recovery and reuse of the catalytic system, a magnetically separable nanocomposite could represent a breakthrough in the scientific community [51]. Therefore, our research group has focused on the investigation of the aforementioned oxidation and alkylation reactions, using heterogeneous catalysts

• nanocatalyst, the XPS experiments results revealed a band at 462 eV (Ti 2p3/2), which confirmed the presence of TiO2 on the surface of the nanocomposite (Figure 2C). Additionally, the deconvoluted C 1s XPS spectra of the obtained materials exhibited two different contributions associated to the presence of C–C

• /C=C and C–O bonds. Also, the O 1s XPS spectra for the Fe2O3-PS4 and Fe2O3-PS4-MNP nanomaterials displayed two different peaks attributed to O–C and O–Fe, while for the TiO2-Fe2O3-PS4 nanocomposite contained three contributions related to O–C, O–Ti and O–Fe (see also Supporting Information File 1

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• used in C−C or C−N cross-coupling reactions [44][45][46][47]. We have recently shown that uniformly dispersed Ni NPs that are free of agglomeration can be embedded in RGO sheets (Ni/RGO). This very stable Ni/RGO nanocomposite enhances the reduction rate of Cr(VI) species to Cr(III) in the presence of

• conversion to the thioether, the catalytic system contains a significant amount of Ni(II) species embedded with RGO in addition to Ni(0) NPs. Therefore, assuming that Ni(II) species having embedded with RGO can also be used as the catalytic system, we prepared a new nanocomposite [Ni(OH)2/RGO (30 wt %)] [48

• ) species, which then undergoes oxidative addition to the aryl halide forming a Ni(III) species, as proposed previously [19]. Conclusion In conclusion, we have shown that a RGO-supported Ni(0) nanocomposite (Ni/RGO-40) with average size (≈11–12 nm) Ni NPs display high catalytic efficiency for C–S cross

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

• Qing Yin,
• Qi Chen,
• Li-Can Lu and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

• (5.14 × 10−3 s−1) derived from the slope of the curve in Figure 5b. The active factor ka (ka = k/m, m is the total mass of catalyst) is considered as a suitable way to judge the activity of the catalyst [49]. As reported, the ka of AgNPs/C composite is 1.69 s−1 g−1 [50], the Fe3O4@SiO2–Ag nanocomposite

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• nanocomposite, carrying either a targeting agent towards E. coli pili and an antibacterial polymer, resulted able to bind E. coli specifically and to kill the attached bacteria, by enhancing the local concentration of biocidal agent on the bacterial surface [90]. GAuNPs find interesting application also in the

Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters

• Élise Euvrard,
• Nadia Morin-Crini,
• Coline Druart,
• Justine Bugnet,
• Bernard Martel,
• Cesare Cosentino,
• Virginie Moutarlier and
• Grégorio Crini

Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172

• cationic dyes. Zhang et al. [4] studied the removal of cobalt and 1-naphthol onto magnetic nanoparticles containing cyclodextrin and iron and Yang et al. [5] proposed a new nanocomposite adsorbent for the simultaneous removal of organic and inorganic substances from water. Here, we propose to use a single

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

• Vincent M. Rotello

Beilstein J. Org. Chem. 2016, 12, 1638–1646, doi:10.3762/bjoc.12.161

• nanocomposite materials, including regular structures using diblock copolymers [25][26] and nanoparticle–protein [27][28] and nanoparticle–nucleic acid composites [29]. Concurrently with our 3D self-assembly, we pursued the use of nanoparticles for surface modification. This research has focused on the use of

• used to "pin" arginine-capped nanoparticles to oil droplets comprised of fatty acids. This trick worked remarkably well, providing ~150 nm nanocapsules. These capsules were unstable in serum however. Reaching back to our nanocomposite work, we were able to use bricks and mortar assembly of anionic

Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

• Kazuaki Kato,
• Daisuke Matsui,
• Koichi Mayumi and
• Kohzo Ito

Beilstein J. Org. Chem. 2015, 11, 2194–2201, doi:10.3762/bjoc.11.238

• Kazuaki Kato Daisuke Matsui Koichi Mayumi Kohzo Ito Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan 10.3762/bjoc.11.238 Abstract A significantly soft and tough nanocomposite gel was realized

• silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young’s modulus increased with silica content. Gelation did

• not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for <20% compression strain, indicating an infinite stable network without physical cross

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• novel nanocomposite catalyst AuNPs@HS-CNC. The uniform, fine AuNPs were made by the reduction of HAuCl4 solution with thiol (HS-) group-functionalized CNC films. The AuNPs@HS-CNC nanocomposites were examined by X-ray photoelectron spectroscopy (XPS), TEM, ATR-IR and solid-state NMR. Characterizations

• suggested that the size of the AuNPs was about 2–3 nm and they were evenly distributed onto the surface of CNC films. Furthermore, the unique nanocomposite Au@HS-CNC catalyst displayed high catalytic efficiency in promoting three-component coupling of an aldehyde, an alkyne, and an amine (A3-coupling

• ) either in water or without solvent. Most importantly, the catalyst could be used repetitively more than 11 times without significant deactivation. Our strategy also promotes the use of naturally renewable cellulose to prepare reusable nanocomposite catalysts for organic synthesis. Keywords: A3-coupling

SbCl₃-catalyzed one-pot synthesis of 4,4′-diaminotriarylmethanes under solvent-free conditions: Synthesis, characterization, and DFT studies

• Ghasem Rezanejade Bardajee

Beilstein J. Org. Chem. 2011, 7, 135–144, doi:10.3762/bjoc.7.19

• , inks, crayons, typewritten ribbons, and photoimaging systems [1][2][3]. These compounds have been employed as dye precursors in nanocomposite preparations [4], in photoresponsive polymers [5], and as the thermal iniferter (initiator–transfer–terminator agent) in pseudo-living radical polymerizations [6