A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• optimised setup was shown to be reasonably stable for continuous runtimes of up to 100 hours. In the last few years, polyacrylonitrile fibres (PANF) along with other synthetic textiles have seized attention in heterogeneous catalysis as supports thanks to their incomparable mechanical properties and low

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• in the use of these compounds. This is quite understandable: compounds with unique optical [2][3][4], electrophysical [5][6][7], mechanical [8][9][10], tribological [11][12][13], sorption [14][15][16][17], and biological properties [18][19][20], and even new dyes and catalysts [21][22][23][24][25

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

• purification steps, the addition of additives or blending with fresh polymers may be included [48]. For this reason, both reextrusion and physical recycling are also referred to as “mechanical recycling”, primary and secondary, respectively [49][50]. However, materials of lower quality and economic value can

• Polyolefins Due to the intrinsic chemical resistance of the hydrocarbon skeleton devoid of functional groups, polyolefins are neither prone to chemical recycling nor biodegradable [131][132]. Hence, they are more commonly repurposed via mechanical recycling, burned or just discarded [133][134

• ]. Depolymerisation of polyolefins usually requires thermal treatments at high temperature [54][135]. 3.1.1 Polyethylene (PE): PE is the most used thermoplastic material today, having a variety of uses in several fields. Applications of PE depend on the mechanical and physical properties (particularly the tensile

Synthesis and physicochemical evaluation of fluorinated lipopeptide precursors of ligands for microbubble targeting

• Masayori Hagimori,
• Estefanía E. Mendoza-Ortega and
• Marie Pierre Krafft

Beilstein J. Org. Chem. 2021, 17, 511–518, doi:10.3762/bjoc.17.45

• increase MB half-lives. The microbubbles were prepared by mechanical agitation using a Vialmix shaker and were characterized by optical microscopy immediately after the preparation and over time. The results show that the incorporation of F-lipopeptides 1–3 led to MBs that are somewhat smaller than those

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• (G'' > G'). Fluids are unable to store mechanical stress. Thus, the storage modulus drops to almost zero. For the cooling process, the change of the moduli mirrors the ones of the heating process (Figure S1b in Supporting Information File 1). We performed concentration-dependent temperature sweeps

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

• Thomas Holmstrøm,
• Daniel Raydan and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229

• mechanical impulse that can increase or decrease the distance between the two lipophilic tails, thus changing the amphiphilic properties of the molecule. Incorporating such molecules into the lipid bilayer of liposomes can result in the decomposition of the whole liposome when the stimuli-responsive

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• differential pulse voltammetry (DPV) and compared to those of their corresponding pseudo[2]rotaxanes. Additionally, we report the synthesis of a novel NDI-[2]rotaxane and study the impact of the mechanical bond on the optoelectronic properties of the NDI unit by CV and spectroelectrochemical measurements

• optoelectronic properties of the TTF unit [35], yet for exTTFC8 the [2]rotaxane shows very similar properties as compared to the free macrocycle [37]. As NDIC8 and the A1·PF6@NDIC8 pseudo[2]rotaxane also reveal distinctly different electrochemical potentials, we investigated the impact of mechanical bonding on

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• chemists represent chemical structures as two-dimensional sketches made up of atoms and bonds, simplifying the complex three-dimensional molecules comprising nuclei and electrons of the quantum mechanical description, is the everyday language of chemistry. This language uses models, particularly of bonding

• , that are not contained in the quantum mechanical description of chemical systems, but has been used to derive machine-readable formats for storing and manipulating chemical structures in digital computers. This language is fuzzy and varies from chemist to chemist but has been astonishingly successful

• “artist’s impression” of a molecule (clozapine) that illustrates the problem. In a puritanical quantum mechanical view, molecules consist of positively charged, and within the Born–Oppenheimer approximation [9] static, nuclei within a cloud of indistinguishable electrons, which are often represented as an

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

•  5). Additional proof of the mechanical bond was provided by 1H DOSY NMR showing the same diffusion for thread and macrocycle signals with a diffusion coefficient of −9.33 m2/s and a hydrodynamic radius of 8.7 Å (see Figure S4 in Supporting Information File 1). Electrochemistry The ferrocene

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• derivatives and are biodegradable, so they are a very promising material from this point of view. In this article a new, green synthesis of nanosponges through a mechanochemical approach is proposed. Mechanochemistry relies on the application of mechanical forces (such as compression, shear, or friction) to

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

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• was proposed for classifying whether the carbon atoms are active or inactive toward electrophilic aromatic substitution [17]. Also, a quantum mechanical approach was introduced to compute ortho-directing groups (DGs) in palladium-catalysed aromatic C–H activation reactions [18]. However, there is a

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• elastomer, and thus dispensing fluid. The elastomer sheets fully embrace the reagent bag, providing mechanical support. In this way, a soft polymer bag can be squeezed at a relatively high pressure: our prototype achieved pumping pressures up to about 1 MPa (10 bar). This type of pressure-driven pump, where

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

• /mechanical stability, and good adsorption capacity. They also contain an ordered porous network that is appropriate for the free diffusion of reactants and reaction products [24]. In this regard, various functionalized SiO2 nanoparticles were employed in diverse organic reactions, including Suzuki–Miyaura

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• radical; visible light; Introduction π-Conjugated polymers are of significant interest as they have the potential to combine the mechanical flexibility and affordability of synthetic polymers with the optical and electronic properties of semiconductors. One of the limitations to this field’s continued

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• J∙s), R is the universal gas constant (1.987 kcal/mol∙K) and T is the absolute temperature in K. Improvement of the Eyring’s equation, incorporating the quantum mechanical tunnelling coefficient, κ, was also used, Equation 4. The quantum phenomenon in this case is the tunnelling of the electrons of

• calculate the quantum mechanical tunneling coefficient by employing the Skodje–Truhlar potential for parabolic potential barriers [91]. In Equation 5 the parameters α = 2π/h∙Im(ν≠) = 5.74672∙1020 J−1 and β = 1/kB∙T = 2.42928∙1020 J−1 are defined through the fundamental constants, ν≠ is the imaginary

Understanding the role of active site residues in CotB2 catalysis using a cluster model

• Keren Raz,
• Ronja Driller,
• Thomas Brück,
• Bernhard Loll and
• Dan T. Major

Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

• melanosporofaciens, which catalyzes the formation of cycloocta-9-en-7-ol, a precursor to the next-generation anti-inflammatory drug cyclooctatin. In this work, we present evidence for the significant role of the active site's residues in CotB2 on the reaction energetics using quantum mechanical calculations in an

• ]. Theoretical quantum mechanical (QM) investigations on the chemistry of terpenes in the gas phase have provided a detailed understanding of the carbocation mechanisms underlying terpene synthase function [25][26][27]. Further, we have used multiscale modeling tools to study the effects of the enzyme

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• dynamic mechanical analyses [30][31][32], NMR spectroscopy [33], and fluorescence spectroscopy [28]. For PMMA, the α-relaxation as slowest relaxation is observed at the glass transition (Tg = 95–110 °C) [34]. It corresponds to long-range conformational changes of the polymer backbone. This relaxation is

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• -catalyzed RCM clipping mechanical bond forming methodology [48]. The 1H NMR spectroscopy in CDCl3 (293 K, 500 MHz) and the fluorescence titration experiments which were done in acetonitrile have demonstrated that the synthesized 1,2,3-triazolium macrocycle 6 was able to bind and sense several anions but the

• between structure topology and mechanical properties [69]. It was argued that carrying out unidirectional 360° rotations, or achieving an all-around mechanostereoselectivity [70] control could be realized by introducing another functional spacer in the [2](3)catenane [71]. Considering that the paths of

• the B24C8 ring to nearby recognition sites are probably kinetically favorable. Thus, this kind of macrocycles can be used as molecular motors [72] with superior structural and mechanical properties and this could lead to an increased understanding of the mechanism of other complicated biological

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• the synthesis and purification of THTAA (3), and report on the results of our investigation based on the quantum mechanical calculations, X-ray structures and electronic absorption spectra of 3 and a number of its derivatives. Results and Discussion Synthesis, purification and chemical modification of

• structures in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication: 3 CCDC 1912951, 6a CCDC 1912953, 7a CCDC 1912952. Quantum mechanical calculations were done with Gaussian 09 software [22] using B3LYP/6-311+G(2d,p) model chemistry. All energies include

Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

• Esther Nieland,
• Oliver Weingart and
• Bernd M. Schmidt

Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197

• help of quantum mechanical calculations involving a combination of low-cost implicit solvation models and hybrid density functionals when including dispersion corrections. Electrostatic potential map at different isodensity values (B3LYP/ def2/TZVP/DGZVP optimized geometries) with a) ρ = 0.0001, and b

Synthesis of a [6]rotaxane with singly threaded γ-cyclodextrins as a single stereoisomer

• Jason Yin Hei Man and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2019, 15, 1829–1837, doi:10.3762/bjoc.15.177

• bond formation, interlocking of the macrocycle is ensured to result in a good efficiency of mechanical bond formation. The synthesis of 1 and 2 is depicted in Scheme 1. To synthesize hetero[n]rotaxanes containing both γ-CD and CB[6], a 1:1 mixture of the anthracene stopper 2 and CB[6] in 50 mM HCl was

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• with the unprecedented utilization of Ertalyte® jars, the mechanical activation allows obtaining the oxidized products from a broad spectrum of initial substrates. We show that the proposed mechanochemical method is definitely safe, performing effectively and inexpensive, thus providing an interesting

• jars manufactured from thermoplastic materials as alternatives to Teflon, having high mechanical resistance, rigidity, and hardness, we were pleased to find that Ertalyte® displayed an excellent performance in the mechanical process. All other parameters being equal, the conversion efficiency improved

• 3-pheny-1-propanol (1a) with N-chlorosuccinimide (NCS) in the presence of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) under mechanical activation conditions [50]. aPercentages of conversion were calculated by GC–MS using an internal reference standard. Hypothesized pathways for the TEMPO

Water inside β-cyclodextrin cavity: amount, stability and mechanism of binding

• Stiliyana Pereva,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2019, 15, 1592–1600, doi:10.3762/bjoc.15.163

• experimental) approaches are sometimes conflicting and contradictory. There is no “standard” method to investigate the complexation behavior of CDs. Thus, in our study a computational quantum mechanical modelling method, namely density functional theory (DFT) was chosen to investigate the electronic structure