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

• were some issues that held back the universality of this protocol [125]. More recently, in 2022, Kaur et al. utilized CdS nanostructures which possess good Lewis acidity for the heterogeneous catalysis of various organic transformations including the synthesis of BIMs as shown by Chabukswar and his

• research group [126]. Kaur et al. synthesized various CdS nanostructures with differences in their morphology and screened them for their catalytic potential, while avoiding the use of surfactants, which were too difficult to remove from the reaction mixture (Scheme 24). CdS_3a which was a porous and

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

• tetraphenylporphyrintetrasulfonate 132. Recently, Pathak et al. [57] reported the synthesis of porphyrin-lantern-functionalized bright G-quadruplex nanostructures via a “tether and mask” approach in water (Scheme 27). In this study, a large porphyrin dye 133 was first attached to short G-rich sequences and then clicked with azide

Supramolecular approaches to mediate chemical reactivity

• Pablo Ballester,
• Qi-Qiang Wang and
• Carmine Gaeta

Beilstein J. Org. Chem. 2022, 18, 1463–1465, doi:10.3762/bjoc.18.152

• supramolecular nanostructures, displayed aggregation-induced emission (AIE) due to the restricted phenyl-ring rotation of m-TPEWP5 component. Inspired by natural photosynthesis and following an energy transfer process, the supramolecular nanorod assembly was employed as a nanoreactor for a photocatalytic

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• intramolecular phenyl-ring rotations and functioned as an ideal donor. After the loading of eosin Y (EsY) as acceptor on the surface of the assembly of m-TPEWP5 and G, the worm-like nanostructures changed into nanorods, which facilitates a Förster resonance energy transfer (FRET) from the m-TPEWP5 and G

• G guest molecule were involved in the inclusion complex and further self-assembled to form worm-like supramolecular nanostructures, which displayed an AIE effect via restricted phenyl-ring rotation of m-TPEWP5. After that, the negative EsY acceptor was loaded on the positively charged surface of the

Adjusting the length of supramolecular polymer bottlebrushes by top-down approaches

• Tobias Klein,
• Franka V. Gruschwitz,
• Maren T. Kuchenbrod,
• Ivo Nischang,
• Stephanie Hoeppener and
• Johannes C. Brendel

Beilstein J. Org. Chem. 2021, 17, 2621–2628, doi:10.3762/bjoc.17.175

• University Jena, Philosophenweg 7, 07743 Jena, Germany 10.3762/bjoc.17.175 Abstract Controlling the length of one-dimensional (1D) polymer nanostructures remains a key challenge on the way toward the applications of these structures. Here, we demonstrate that top-down processing facilitates a

• methods represent an easily implementable technique toward 1D polymer nanostructures with an adjustable length in the range of interest for perspective biomedical applications. Keywords: distribution; dual centrifugation; filomicelles; self-assembly; ultrasonication; Introduction Cylindrical polymer

• nanostructures in solution have received increasing attention during the last two decades, related to the high surface-to-volume ratio, which is particularly attractive for targeted carrier materials in biomedical applications. In addition, cylindrical drug delivery vehicles appear to be advantageous compared to

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• not rely on specific binding motifs. Here, electrostatic self-assembly was shown to yield a variety of supramolecular nanostructures [4][26][27][28][29][30][31][32][33]. We have built the nanoscale assemblies from polyelectrolytes and multiply oppositely charged molecules based on electrostatic

• understanding and variation of this cycle by synthesizing different derivatives of 4-hydroxyflavylium. Yet, hydroxyflavylium molecules have not been exploited in self-assembly to form water-compatible switchable supramolecular nanostructures that may be responsive to different external triggers such as light

Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides

• Dongsik Yang,
• Hongjian He and
• Bing Xu

Beilstein J. Org. Chem. 2020, 16, 2709–2718, doi:10.3762/bjoc.16.221

• cellular environment. Keywords: acetylation; branched peptides; enzyme; nanostructures; N-terminal; responsive; self-assembly; Introduction Peptides, being able to self-assemble to exhibit emergent properties and functions [1][2][3][4][5], have received considerable attentions recently. For example

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• development of novel drug nanocarrier assemblies. Keywords: aqueous self-assembly; pH-responsive systems; secondary structure; self-assembled nanostructures; solid-phase peptide synthesis; Introduction The self-assembly of small molecules is a ubiquitous phenomenon in nature [1] and also has key

• nanostructures as well as the secondary structures. Results and Discussion Solid-phase peptide synthesis and purification The target octapeptide was synthesized in the solid phase following four steps, including: i) deprotection of the Fmoc protecting group, ii) coupling of an amino acid, iii) cleavage of the

• + moieties. AFM studies at pH 5.5 showed the formation of nanoparticle assemblies, which is in agreement with the loss of the secondary structure (Figure 3b). Similarly, at pH 2.2, PEP-1 also exhibited a structureless CD spectrum and irregular nanostructures (Figure S4, Supporting Information File 1). In

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

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• CLAN – Center for Light Activated Nanostructures, Dipartimento di Scienze e Tecnologie Agro-alimentari, Università di Bologna, viale Fanin 50, 40127 Bologna, Italy Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, via Gobetti 101, 40129 Bologna, Italy INO

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• of the rotaxane system via pseudorotaxane 18. A shorter reaction time, use of small amounts of solvent and the high yield were the advantages over the solvent-mediated synthesis [62]. Macrocycle synthesis The mechanochemical synthesis of sphere-like nanostructures was reported by Severin and co

• -containing [2]rotaxanes [61]. Mechanochemical liquid-assisted one-pot two-step synthesis of [2]rotaxanes under high-speed vibration milling (HSVM) conditions [62]. Mechanochemical (ball-milling) synthesis of molecular sphere-like nanostructures [63]. High-speed vibration milling (HSVM) synthesis of boronic

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• nanostructures described by the empirical formula RSiO3/2, where R represents hydrogen, alkyl, alkenyl, aryl, arylene or their functionalized derivatives. A number of silsesquioxane structures have been reported including random, ladder, cage and partial cage structures. Silsesquioxanes with specific cage

• % (Scheme 22) [44]. Polymers with a weight-average molecular mass in the range from 67000 to 88000 Da were obtained. In the random copolymers obtained, the associative interactions between the particles were shown to result in the formation of ordered nanostructures. TEM micrographs indicate that the

• copolymers assemble into small, randomly oriented lamellae with lateral dimensions of approximately 50 nm and a thickness of ca 3–5 nm that corresponds to twice the diameter of a POSS nanoparticle. With increasing POSS concentration, the nanostructures extend to longer continuous lamellae having lateral

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

• , can be found in nanostructures of low dimensionality with degenerate electronic ground states where any perturbation causes delocalized density fluctuations or density waves, also called collective excitations [25][26]. Often they are found in one- or two-dimensional structures such as graphene or

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• therefore be excluded to ensure the efficient esterification-type reactions with graphene-family materials. Aprotic organic solvents should instead be used as a reaction medium. It is obviously a barrier for the processes with the inclusion of GO or RGO, as these carbon nanostructures’ colloidal stability

A self-assembled photoresponsive gel consisting of chiral nanofibers

• Lei Zou,
• Dan Han,
• Zhiyi Yuan,
• Dongdong Chang and
• Xiang Ma

Beilstein J. Org. Chem. 2018, 14, 1994–2001, doi:10.3762/bjoc.14.174

• glutamic acid skeleton, containing azobenzene as a photoresponsive group and ureidopyrimidinone (UPy) as a connection site, was designed and synthesized. The monomer is capable of forming an organogel in nonpolar organic solvents and different types of nanostructures in other solvents. The state of the gel

• and the chirality of the nanostructures could both be adjusted by subsequent light irradiation at different wavelengths. The helical nanofiber-like morphology was verified in the internal structure of the gel. The performance of this gel was investigated by a series of methods, such as UV–vis

• other interactions. Interestingly, some of them can be assembled into distinctive nanostructures through gel formation [4][5][6]. Various functional nanostructures have shown great potential for applications in many important areas, for example, nanofabrication [5][7][8][9][10], drug delivery [11][12

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• nanostructures. DLS data confirmed this suggestion. In the presence of 10b the size of polydiacetylene vesicles sharply decreases (Table 4 and Supporting Information File 1, Figure S3). This leads to an optimal distance between the diacetylene fragments resulting in a more effective photopolymerization. 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

• Pd catalyst together with a PAA (poly(acrylic acid)) based polymer self-assembled in water [32]. The catalytic activity of the nanostructures was compared to the results achieved with the small molecule analogues of the pincer Pd complex, in a Suzuki–Miyaura coupling. When the reaction of vinyl

Metal-mediated base pairs in parallel-stranded DNA

• Jens Müller

Beilstein J. Org. Chem. 2017, 13, 2671–2681, doi:10.3762/bjoc.13.265

• ], the creation of dynamic and switchable DNA nanostructures [18][19], and an exploitation of their processing by polymerases [20][21][22][23][24]. Most metal-mediated base pairs reported so far have been introduced into canonical antiparallel-stranded nucleic acid duplexes [26], even though the idea of

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

• sources and iron precursors were applied to develop new bio-nanocomposites by mechanochemical milling processes. The proposed methodology was demonstrated to be advantageous in comparison with other protocols for the synthesis of iron oxide based nanostructures. Additionally, mechanochemistry has enormous

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• of mesopores that correspond to the size of the former titania nanostructures [25]. While titanium is removed as gaseous TiCl4, oxygen is extracted as CO, whereby carbon is being partially consumed as well. This partial carbon removal leads to an etching of the carbon framework and an in situ

• pores. This process finally leads to a higher mesopore volume at the expense of a narrower pore-size distribution (Figure 6). The EG ratio does not impact the particle size of the TiO2 nanostructures and thus the pore-size distributions are similar for all investigated materials (average diameter of 8

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

• showed that GAuNPs were still able to recognize specific lectin (peanut agglutinin, PNA) and human galectin-3 (Gal-3), exploiting multiple lactose residues displayed on gold surface. Moreover, due to the presence of the β-cyclodextrin cavity, these nanostructures worked as site-specific delivery systems

Supramolecular frameworks based on [60]fullerene hexakisadducts

• Andreas Kraft,
• Johannes Stangl,
• Ana-Maria Krause,
• Klaus Müller-Buschbaum and
• Florian Beuerle

Beilstein J. Org. Chem. 2017, 13, 1–9, doi:10.3762/bjoc.13.1

• nanostructures. a) Small cavities within the octahedral sites of HFF-1 filled with one CH2Cl2 molecule [57]; b) isolated cavities containing four Et2O molecules for HFF-2 (void spaces are indicated as grey surfaces and most side arms are omitted for clarity, images are created with PyMOL [58]). Face centered

A direct method for the N-tetraalkylation of azamacrocycles

• Andrew J. Counsell,
• Angus T. Jones,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

• be optimised alongside mixing performance [46], and in nanotechnology, where shaking can be used to modulate aggregation so as to favour particular nanostructures [47][48]. Otto and co-workers have investigated the influence of mechanical forces on reactivity in the context of self-replication by

DNA functionalization by dynamic chemistry

• Zeynep Kanlidere,
• Oleg Jochim,
• Marta Cal and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2016, 12, 2136–2144, doi:10.3762/bjoc.12.203

• oligonucleotides an ideal supramolecular scaffold in a wide field of applications [1][2]. In recent years oligonucleotides especially were applied to self-assembly into artificial nanostructures [3][4][5][6][7][8][9]. Preparation of oligonucleotides for new applications requires the introduction of additional