Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins

• Zhongwei Hua,
• Nan Liu and
• Xiaohui Yan

Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68

• , novel pharmaceutical systems, such as liposomes, microcapsules, and nanoparticles, were adopted to enhance the stability and bioavailability of these compounds [13][14][15]. To find a sustainable way of supplying crocins, researchers have developed various approaches to produce them, including plant

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• catalytic arrangements of the most enantioselective catalysts, including anchoring on polystyrene beads [8][9], magnetic nanoparticles [10], or block copolymers composed of PEG-poly(Glu) [11]. These modifications have facilitated the recycling of the catalysts, offering numerous advantages, including

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

• [96]. Nanocatalysis Nanocatalysis has emerged over the last decades as a sustainable and green field of organic catalysis that offers unparalleled opportunities for chemical transformations that were previously deemed unfeasible. The use of nanoparticles, compounds with a cross section of less than

• , Rahimizadeh et al. proposed the use of the nanometal oxide TiO2, which was already reported as an effective nanocatalyst for the promotion of various organic transformations [100]. TiO2 nanoparticles are non-toxic, inexpensive and reusable compounds that are synthesized through a sol–gel method. This method

• of Fe3O4 nanoparticles (Scheme 15) [101][102]. This organic–inorganic hybrid material was synthesized by the immobilization of the dodecatungstovanadophosphoric acid (HPA) on TPI-Fe3O4 with N-[3-(triethoxysilyl)propyl]isonicotinamide (TPI), acting as the linker for the heterogeneous catalyst, while

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• formation of silver nanoparticles (AgNP) on the cathode's surface [116] (Scheme 35B). The use of this Ag-doped cathode led to slower mass transport and minimized side reactions caused by rapid reduction of RAEs, thereby avoiding substrate decomposition and enhancing reaction yields (Scheme 35B). Furthermore

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

• wormlike nanoparticles. In rotaxanes, the utilization of metal–ligand bonding involving CuI is a common strategy for immobilizing a thread moiety within a macrocycle. However, the efficacy of such a bonding is compromised when catalysts are used in stoppering reactions, e.g., the copper-catalyzed azide

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• -based nanoparticles [58][59]. But although these classes of compounds have been intensively studied and already contributed significantly to the field of PDT, there is still a demand for novel DNA-photodamaging ligands that could be applied for specific purposes, e.g., to improve efficacy or to limit

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• surface properties of the aromatic micelles (PA-R)n and their host–guest composites including nanocarbons in water. The ZP of self-assembled nanoparticles evaluates their structural stability in solution against aggregation through electrostatic repulsion [25]. Solutions of the micelles in Milli-Q water

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• featuring monodentate [44][45], chelating bidentate [46][47][48][49][50][51][52][53][54][55], or bridging bidentate NHC·CS2 ligands [45][51][52]. Small bimetallic clusters [51][52][56], coordination polymers [57], self-assembled monolayers [58], and nanoparticles [45] based on these zwitterions were also

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• achieved, for example, by immobilizing the catalysts to a solid support [15], e.g., silica gel [16][17][18], organic polymers [19][20][21], magnetic nanoparticles [22][23], or by membrane separation, e.g., using organic solvent nanofiltration (OSN) [24][25][26], which methods can be easily implemented in

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• compound with the donor polymer PM6 to create BHJ nanoparticles and employed it in the hydrogen evolution reaction. This approach substantially reduced trap density, increasing the hydrogen evolution rate by 2–3 times compared to conventional inorganic/organic hybrid photocatalysts [30]. Computational

• ). The charge transfer efficiency and device performance of Qx33 was improved by aligning its LUMO energy level with the conduction band edge of the TiO2 nanoparticles. This strategic approach highlights the importance of optimizing energy level alignment for efficient charge transport in DSSCs [40

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• multifunctional catalytic system 142 incorporating ruthenium nanoparticles (RuNPS) and an NHC–Cu–Cl complex supported on silica (Scheme 56). The catalyst, Ru@SiO2–[Cu(NHC)] was successfully applied to a one-pot tandem A3 reaction of an aldehyde, alkyne, and secondary amine followed by hydrogenation of the

• the A3 reaction is catalyzed by the NHC–Cu complex while the selective hydrogenation is catalyzed by Ru(0) nanoparticles. The versatility of this tandem catalytic approach was established by using a wide range of substrates. Furthermore, the catalytic activity and selectivity remained fairly constant

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

• -functionalization method using a benign and naturally occurring glutathione and magnetic ferrite nanoparticles by sonication in water at room temperature. Furthermore, using this organocatalyst, various N-substituted pyrroles were prepared by reacting various amines 56 with 2,5-DMTHF (2) in water at 140 °C under

• of reaction. Mahmoudi and Jafari [85] reported the preparation of a new on magnetic nanoparticles sulfonic acid-supported catalyst with maghemite coating as a magnetically recyclable catalyst Fe3O4@-γ-Fe2O3-SO3H. This heterogeneous catalyst is used for the synthesis of N-substituted pyrrole

Cyclodextrins as building blocks for new materials

• Miriana Kfoury and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2023, 19, 889–891, doi:10.3762/bjoc.19.66

• science that require high performance with minimal environmental impact. They are involved in the construction of interlocked molecules (rotaxanes and catenanes), supramolecular polymers, artificial enzymes, hydrogels, metal–organic frameworks, supramolecular solvents, fibers, nanotubes, nanoparticles

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

• 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

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

• , PR China 10.3762/bjoc.19.45 Abstract We synthesized a new tetraphenylethylene-modified chitosan bioconjugate, CS-TPE, that shows the aggregation-induced emission effect. It can self-assemble into fluorescent polymeric nanoparticles in an aqueous solution at pH 5.3 either alone or with the water

• -soluble bowl-shaped six-fold carboxylated tribenzotriquinacene derivative TBTQ-C6 via host–guest binding. The spherical nanoparticles formed by CS-TPE amphiphiles or TBTQ-C6/CS-TPE supra-amphiphiles disintegrated under alkaline stimulation at pH 10.4 and the dispersion of the aggregates after the collapse

• in the presence of TBTQ-C6 was greatly improved. In addition, the fluorescence of CS-TPE was significantly enhanced by introducing TBTQ-C6, and remained relatively stable with variations in pH for both CS-TPE and TBTQ-C6/CS-TPE. Such pH-responsive supramolecular spherical nanoparticles with stable

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

• microwave irradiation conditions. The prepared nanoparticles from free-base PPCs showed colorimetric aqueous pH sensing, which suggests that the PPC nanoparticles could serve as chemical sensing applications. In 2008, the Crossley’s group [59] reported the synthesis of a ‘capped’ porphyrin 142 forming a

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

• nanoparticles were screened for the thioamidation of pyrazole-3-carbaldehyde. The desired thioamide-conjugated pyrazole 1C was afforded in 30% yield, as the starting substrates were not completely consumed even after 24 hours of reaction time (entry 13, Table 1). On the basis of the experimental results above

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• proved to be a potent reaction medium in catalytic hydrosilylation [53], hydroamination and hydroarylation [54], as well as for the synthesis of nanoparticles [55][56]. Results and Discussion Ionic liquids 1–6 were synthesized via a three-step procedure starting from commercially available aniline

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

• , and furthermore in vivo antitumoral and antimetastatic efficacy in early and late-stage colon cancer models and biodistribution after single dose oral administration. This study was carried out to further elucidate oral camptothecin (CPT)-loaded amphiphilic cyclodextrin nanoparticles for the local

• -loaded polycationic-β-cyclodextrin nanoparticles caused reduced cell viability in CT26 and HT29 colon carcinoma spheroid tumors of mice and human origin, respectively. In addition, the release profile, which is one of the critical quality parameters in new drug delivery systems, was investigated

• mathematically by release kinetic modeling for the first time. The overall findings indicated that the strategy of orally targeting anticancer drugs such as CPT with positively charged poly-β-CD-C6 nanoparticles to colon tumors for local and/or systemic efficacy is a promising approach. Keywords: colorectal

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

• dressings. This saponin possesses two large hydrophilic parts, surrounding the aglycone [30]. The association chitosan–saponin can show other functions for medicinal purposes, and anticancer nanoparticles made of chitosan loaded with saponins have been prepared by Nair and Jayakumar [31], and even

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

• of these two different experimental approaches in the development of mechanochemical reactions. For example, Li and co-workers showed that piezoelectric nanoparticles such as BaTiO3 and ZnO could trigger water electrolysis under ultrasonication [53]. Sonication caused deformation of, or strain on the

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• sophisticated platforms such as metal nanoparticles, all of which have been reviewed thoroughly in the literature [4][5][6][7][8]. However, the methods referenced so far display one or more of the following setbacks: involvement of harsh oxidants or reductants, use of expensive metal catalysts, need for

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• synthesis; nanoparticles; Introduction Several decades ago, inductive heating was introduced as an indirect technique in various applications, including industrial manufacturing, synthetic chemistry [1][2][3], and medicine (Figure 1) [4][5][6][7]. Compared to microwave heating [8][9], the other major

• ferromagnetic or ferrimagnetic nanoparticles into these materials. For this purpose, superparamagnetic iron oxide nanoparticles (SPION) are most commonly used, of which the main forms are magnetite (Fe3O4) and its oxidized form maghemite (γ-Fe2O3). Although cobalt and nickel are also highly magnetic materials

• parameters are critical to the heat release of magnetic nanoparticles and can vary for different particle types. Coercivity is an inherent property of magnetic nanoparticles that reaches a maximum at a critical diameter of magnetic nanoparticles from multidomain to single domain structures. In hysteresis

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

• catalyst (Table 1, entry 14) [60]. Other less common oxidizing agents have also been used for the oxidation of 2-methylnaphthalene (16) to produce menadione (10). Sulman and co-workers, for instance, achieved the oxidation of 10 using peracetic acid as oxidant in the presence of gold nanoparticles

• also reported the oxidation of 2-methylnaphthol (17) using molecular oxygen in the presence of gold nanoparticles as catalyst and the best yield of menadione (10) was obtained using 1.5% Au/TiO2 as catalyst (57%, Table 2, entry 9), while the best conversion of 17 was furnished using 1% Au/C-2 catalyst

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

• emphasis given to green strategies. This is the first review on iron- and cobalt-catalyzed Sonogashira coupling reactions which comprehends literature up to 2020. Keywords: C–C bond formation; cobalt; green reaction; iron; nanoparticles; Sonogashira; Introduction The palladium-catalyzed cross-coupling

• , but their efficiencies were found to be lower than that of 1,10-phenanthroline. Metal impurities in FeCl3·6H2O were detected by using ICP mass spectrometry. Lipshutz and co-workers prepared nanoparticles from inexpensive iron(III) chloride containing reusable palladium in ppm level and XPhoS as ligand

• for the effective Sonogashira coupling under aqueous conditions (Scheme 3) [22]. The coupling reaction was catalyzed by the nanoparticles in water between room temperature and 45 °C. Notably, the amount of Pd was below the detection limit. The reaction done in the presence of 1000 ppm of Pd ligated