Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• unique structure of fullerenes, characterized by a fully conjugated closed-cage structure, containing a mixture of hexagonal and pentagonal rings, have been recognized for the unique electronic [2][3][4], optical [5][6], and mechanical properties [7][8]. Despite the notable achievements in fullerene

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• . Rotations around each bond can also happen and we expect similar steric hindrance effects to appear. Mechanical properties of PBA-linked molecular structure on graphene Here, we discuss possible conformations of the PBA-linked molecule. Would a similar activation barrier-type potential energy surface be

• antibody protein on graphitic material by a linker. The target antigen is introduced onto the sensor chips through antibody/antigen reaction. The present study is concerned with the mechanical deformation of the linker molecule. The mechanical properties of the rotational motion are almost the same whether

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• macroscopic analogs, exhibit mechanical motion between an open and closed conformation in response to stimuli. Such systems constitute an essential component of artificial molecular machines. This review will present selected examples of switchable molecular tweezers and their potential applications. The

• , and molecular machines. In particular, the advent of artificial molecular machines [13][14], consisting of an assembly of molecular components that perform mechanical-like motions in response to specific stimuli, has inspired the development of stimuli-responsive molecular tweezers, which have

• , the incorporation of responsive functionalities into molecular tweezers not only provides significant benefits in catalysis for the development of switchable catalysts but also extends their utility to molecular magnetism, where magnetic switches exploit mechanical motion, and to molecular electronics

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• , but the second fluorination step occurs only after reaction for several days. In the solid phase, mechanical milling of the diketone substrate with solid Selectfluor in the presence of sodium carbonate [13][14], and reaction of ketones with a strong base and an N–F reagent give rise to the

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

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration

• Yipeng Yin,
• Reed Arneson,
• Alexander Apostle,
• Adikari M. D. N. Eriyagama,
• Komal Chillar,
• Emma Burke,
• Martina Jahfetson,
• Yinan Yuan and
• Shiyue Fang

Beilstein J. Org. Chem. 2023, 19, 1957–1965, doi:10.3762/bjoc.19.146

• File 1 for details). To block any hydroxy groups on the surface of CPG that were not capped, including those resulted from mechanical breakage of CPG, before commencing a synthesis, the CPG was subjected to typical capping conditions for 20 minutes. To reduce steric hindrance within the pores of CPG

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

• functionalities, and optimizing the π-conjugated backbone structure of Qxs, significant advancements have been made. These approaches effectively address key concerns and obstacles, resulting in red-shifted absorption and emission maxima, improved nonlinear optical properties, solvatochromism, mechanical

• in emission properties through mechanical stimulation offers exciting possibilities for optomechanical applications [68]. Another notable strategy, performed by Gupta and co-workers, involves fine-tuning of the electron accepting tendency of quinoxaline by incorporating various groups with different

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• is that it is difficult to completely rule out chain transfer to the solvent. Therefore, obtaining very high molecular weight product through solution polymerization is tough. Suspension polymerization is a heterogeneous process and requires the use of a mechanical agitation to mix monomers and

• refractive index from tetravinylsilane, ethanedithiol, and benzenedithiol. Polymers made by thiol–ene polymerization usually have well-ordered molecular networks. This character gives thiol–ene polymers highly tunable mechanical response hence it shows great application potential in additive manufacturing

• type of post-polymerization modification introduces or removes functionalities at polymer chain ends [120]. 3.2 Chemical crosslinking of polymers Chemical crosslinking is a suitable approach to increase chemical resistance [121], mechanical strength [122], and other properties [123] of polymers. In

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

• mechanical bond, such as control over the dynamics of the components upon application of external stimuli. This perspective aims to highlight the relevance of these materials, by pointing out recent examples of photoresponsive materials prepared from a rotaxanated architecture in which motion of the

• -responsive materials; mechanical bond; mechanically interlocked materials; rotaxanes; Introduction Light turns out to be a suitable and tailorable stimulus in order to develop materials showing improved functionalities, such as those of smart materials [1][2][3][4][5]. The characteristics of light which

• azobenzene and ferrocene motifs (Figure 1a). The azobenzene scaffolds play a dual role, both as the engine transforming photoenergy into mechanical motion via trans/cis photoisomerization upon UV light input and as a modulator of the crystalline packing by varying the para-substituent R1, which leads to

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• configuration in a molecule, in short, it is the single most important spectroscopic tool aside from X-ray crystallography to provide an accurate ensemble-guided view of the structure, even conformational dynamics in a molecule. Quantum mechanical/nuclear magnetic resonance (NMR) approaches are used for the

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• difluoromethylphosphonate-containing cyclopropanes in reactions with selected olefins, carried out under mild conditions with good to very good yields, in the presence of CuI, an inexpensive catalyst. As confirmed by quantum mechanical calculations and experimental results, the cyclopropane formation occurs always with a

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• different chemical compositions and controlled physical and mechanical properties. The results obtained after EtOx polymerization in DLG indicated poor control of the polymerization process and the potential presence of undesirable terminations and some other side reactions. Nevertheless, we decided to

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

• solutions were vigorously agitated with a mechanical stirrer. The maximal foam volume is then measured and plotted against the saponin concentration (see Figure 1, above). To measure the foam stability, the foam was recovered and introduced into a graduated cylinder. The liquid volume was measured at

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• for the halogenation of organic substrates. For example, Banerjee and co-workers reported the mono-, di-, and trihalogenation of aromatics by controlling the stoichiometry of the N-halosuccinimide (NXS) and PEG-400 as the grinding auxiliary in a mechanical grinder (Scheme 1a) [3]. N-Halosuccinimides

• ) from an initial mechanical treatment of trichloroheptazine and Na3P, once again highlighting the importance of halogenated organic molecules as building blocks for graphitic heptazine materials (Scheme 4) [8]. Another halogenated molecule, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), proved to be

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

• Jose G. Hernandez Grupo Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 No 52-21, Medellín, Colombia 10.3762/bjoc.18.128 Abstract The formation and scission of chemical bonds facilitated by mechanical force

• time, two main experimental strategies to produce physical and chemical responses in a system when mechanical force is applied have been established. One of them, often called polymer mechanochemistry, relies on the use of polymers to transduce mechanical loads to mechanically sensitive probes

• transduction of mechanical cues with high directionality to the mechanophores [1][2][3][4]. In contrast, ball milling protocols have a more evident effect on the macroscopic level of the system, for instance, by causing comminution, amorphization, polymorphic transformations, structural defects, melting of the

From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• ]. In general, mechanochemistry refers to studying solid-state chemical changes promoted by external mechanical energy, such as grinding or milling. A deeper understanding of its mechanistic aspects laid the basis for further growth in this topic, opening new routes to more efficient mechanochemical

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• the potential applications in optoelectronic devices [1][2][3][4], solid-phase sensing [5], bioimaging [6][7], security [8], and storage devices [9]. The optical and electrochemical properties of the organic emitters can be tuned by external stimuli, such as mechanical force, heat, solvent, acid and

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

• 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

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

• , mechanochemical synthesis using ball milling has attracted considerable attention as an efficient solvent-free synthetic technique [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Notably, the strong mechanical agitation provided by ball milling enables efficient solid-state organic

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• well as the sample collection, and sample preparation for the analytics. For further analysis, long-term studies were carried out to analyze the stability in relation to different storage conditions such as the influence of moisture as well as temperature and mechanical stress. The stability of the

• time to 39 days or 58 days for the immobilized epimerase and aldolase, respectively, is observed when a continuous temperature exposure is applied. The mechanical stress of shaking the immobilized enzyme decreases the stability by about 20% compared to the reference study without shaking. From the

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• mechanical bond, namely from a BINOL-based macrocycle onto the axle. First, they developed [2]rotaxane 27 [52]. Here, the methacrylate-functionalized ammonium salt 25 and the bis-BINOL macrocycle (R,R)-26 give the pseudorotaxane (R,R)-27 through self-assembly. Stoppering of the pseudorotaxane was achieved by

• described in chapter 1, the mechanical bond allows a chirality transfer from a chiral, BINOL-based macrocycle to an achiral thread. Thus, it is conceivable that placing a catalytically active group onto the thread would allow for asymmetric catalysis based on chirality transfer from a BINOL macrocycle. In

• the (1R,2S)-product 45 in high yields and enantioselectivities (78/92/98% ee at +25/−40/−80 °C, respectively). In comparison, a non-interlocked mixture of model catalyst 43 and macrocycle (R)-12 only gave 8% ee at 25 °C, demonstrating the role of the mechanical bond for the chirality transfer (see

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

• ultrasound irradiation, obtaining quantitative yields when compared to the mechanical stirring procedure, thus demonstrating the best efficiency of the method [103]. In 2002, Arai and co-workers reported studies involving epoxidation reactions of menadione (10) using H2O2 as oxidant and a chiral salt derived

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• reactions. Naphthalene is usually hard to undergo Diels–Alder reactions [44][45][46], even though the quantum-mechanical and thermochemical calculations suggest that the reaction is exothermic, which indicates the entropic cost is significant [47]. In 2010, the same group reported another interesting site

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• reactions by ball milling involve the mechanical treatment of at least one solid reagent in the presence of other solid, liquid or gaseous reaction partners or additives [5][6]. Due to the particular reaction conditions in which mechanochemical reactions by milling are carried out, reagents need to exhibit

• stability under environments of mechanical stress, while at the same time enough reactivity to engage in chemical transformations. In the search for solid reagents compatible with mechanochemical techniques, we became interested in evaluating the behavior of N-fluorobenzenesulfonimide (NFSI) under ball