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

• -soluble C60 and C70 derivatives by covalently attaching biocompatible water-soluble polymers, such as polyethylene glycol (PEG) [37][38] and PVP [39]. Although these C60– and C70–polymer conjugates revealed high water-solubility, it was found that they, especially the PEG conjugates, formed micelle-like

• C60–peptide conjugates in this study. In addition to the water solubility introduced by the peptides, these conjugates have a superior biocompatibility compared to those with synthetic polymers, such as PEG and PVP. We utilized the previously reported biscarboxylic acid derivative 3, which was

• a similar peptide (GABA-(Lys)5-peptide-PEG) on resin for the reaction with compound 3. Initial trials, using 2-(1H-7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU) and N-methylmorpholine (NMM), respectively, as a coupling reagent and a base, and 5 equiv of peptide on

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

• Fe3O4@PEG-SO3H complex were added in ethanol for a time period of 5 to 10 minutes, yielding 88–98% of isolated product with only aromatic aldehydes showing a meaningful reactivity (Scheme 23) [122]. In 2022, Boroujeni et al. employed a Cu(II) complex coated in Fe3O4@SiO2 nanoparticles which worked as an

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• ), did not give rise to any diffraction. Multiple layer plate or needles clusters were obtained in the presence of PEGs, but only showed weak diffraction (≈3.5 Å). Finally, in the presence of 20% PEG 8K, 0.2 M MgCl2, and 0.1 M Tris HCl pH 8.5, single diamond-shaped crystals were obtained after 1–2 days

• were used and led to more than 30 hits after one to three days. Pill-like crystals were obtained with high salt concentration that could be reproduced by hand in the laboratory. Plates and needles clusters were obtained with PEG containing solutions. For CMA1-Nter, protein at a concentration of 2.9–3.5

• mg/mL was crystallized using hanging drop and vapor diffusion methods with a 2 µL drop in 1:1 ratio at 20 °C. Bipyramidal single crystals were obtained after one or two days in a solution containing 10–12% PEG Smear Medium, 0.1 M MES pH 6.5, 1× divalent (5 mM of CaCl2, MgCl2, CsCl2, CdCl2, NiCl2, and

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

• synthesis of N-substituted pyrroles 29 in the yields of 85–97% using squaric acid as catalyst. In this reaction, various amines 28 and 2,5-DMTHF (2) were reacted in greener solvents like water, deep eutectic solvent (DEC) and polyethylene glycol (PEG) under thermal or ultrasonic irradiation (Scheme 13a

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

• biomedical applications, in particular as an alternative to the hydrophilic poly(ethylene glycol) (PEG), which is the polymer of choice for many biomedical applications due to its high solubility, low cytotoxicity and biocompatibility [3][4][5][6][7][8][9]. However, an ongoing discussion about pre-existing

• K. HFIP was supplemented with 3 g/L potassium triflate, and the flow rate was adjusted to 0.50 mL/min. Calibration was performed using PEG standards with molar masses ranging from 0.1–1,000 kg/mol. Before every measurement, samples were filtered through 0.2 µm PTFE filters, Roth (Karlsruhe, Germany

• typically set from 1000 m/z to 7000 m/z. After parameter optimization, the instrument was calibrated with PEG standards depending on the m/z range of the individual sample. Samples were prepared with sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) as matrices using the dried-droplet spotting

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

• Kendra Drayton-White,
• Siyue Liu,
• Yu-Chia Chang,
• Sakashi Uppal and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• interactions [5][6][7]. For example, a binding curve generated for the interaction between an RGD-peptide (C-PEG6-GGRGDGP) and its integrin (α5,β1) target is shown in Figure 4 below. A PEG-linker was added to the RGD-peptide so that the peptide would not be buried in the polymer coating the surface of the

• array, a scenario that would make it unavailable for binding to the integrin receptor in the subsequent analytical experiment. The PEG-6-linker was selected because it was effective and readily available from commercial sources. This linker was functionalized with a cysteine on the end opposite the

• peptides were placed on the array along with a fluorescent dye (LRSC, lissamine rhodamine) that was used to make sure the placement chemistry was working. The array used was coated with the borate ester diblock copolymer (Figure 2), and the peptides were attached to this polymer through a PEG-6 linker in

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

• José G. Hernández Bochum, Medellín, October 2022 ORCID® iDs Lars Borchardt - https://orcid.org/0000-0002-8778-7816 José G. Hernández - https://orcid.org/0000-0001-9064-4456 a) Mechanochemical PEG-400-assisted halogenation of phenols and anilines using NXS. b) Halogenation of azobenzenes with NXS

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

• catalyst-free halogenation of phenols and anilines via liquid-assisted grinding using PEG-400 as the grinding auxiliary. A series of mono-, di-, and tri-halogenated phenols and anilines was synthesized in good to excellent yields within 10–15 min in a chemoselective manner by controlling the stoichiometry

• of N-halosuccinimides (NXS, X = Br, I, and Cl). It was observed that PEG-400 plays a key role in controlling the reactivity of the substrates and to afford better regioselectivity. Almost exclusive para-selectivity was observed for the aromatic substrates with free o- and p-positions for mono- and

• reaction time, and mild reaction conditions are a few noticeable merits of this environmentally sustainable mechanochemical protocol. Keywords: automated grinding; chemoselectivity; mechanochemistry; N-bromosuccinimide; PEG-400; regioselectivity; stoichiometry-controlled halogenation; Introduction Aryl

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

• materials to inductively heat up glass reactors. For the Biginelli reaction solubility of the starting urea (22) as well as the products 24a and 24b were an issue being overcome by using a solvent mixture of PEG/DMF 1:1. Also the proline-catalyzed asymmetric Mannich reaction was achieved with cyclohexanone

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• , Saugus, MA, USA). The DART ion source was operated with helium gas (approximately 4.0 L/min flow rate), the gas heater (350 °C), and the source grid (350 V). The data acquisition range was from m/z 50 to 1000. Polyethylene glycol (PEG 600) was used for the exact mass calibration. General synthetic

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

• catalysis. The catalytic activity of Co@imine-POP was investigated in a Sonogashira coupling of bromobenzene and phenylacetylene under different reaction conditions. The optimized reaction conditions were found to be 1.7 mol % of the Co@imine-POP catalyst, PEG as solvent and 80 °C reaction temperature

• , recyclable, and selective for the coupling between aryl halides and phenylacetylene in PEG as the solvent (Scheme 22). The effect of various reaction parameters such as solvent, base, temperature, and catalyst loading was assessed by the model reaction between bromobenzene and phenylacetylene. Optimization

• studies revealed PEG-200 and K3PO4 as suitable solvent and base, respectively. Aryl halides with electron-donating and electron-withdrawing groups afforded the corresponding products in good yields with 0.15 mmol of catalyst in PEG at 60 °C. A three-component coupling of alkyne with a heterogeneous

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• bond from β-NQS. Method A: NaOH, EtOH/H2O, 40 °C, 2 h; Method B: t-BuOK, PEG-300, rt, 6–10 min. C=C bond formation from β-NQS and substituted acetonitriles. Funding Fellowships granted by CNPq (301873/2019-4 and 306011/2020-4), CAPES (Financial Code 001), and FAPERJ (E-26/203.191/2017, E-26/202.800

Stepwise PEG synthesis featuring deprotection and coupling in one pot

• Logan Mikesell,
• Dhananjani N. A. M. Eriyagama,
• Yipeng Yin,
• Bao-Yuan Lu and
• Shiyue Fang

Beilstein J. Org. Chem. 2021, 17, 2976–2982, doi:10.3762/bjoc.17.207

• synthesis of monodisperse polyethylene glycols (PEGs) and their derivatives usually involves using an acid-labile protecting group such as DMTr and coupling the two PEG moieties together under basic Williamson ether formation conditions. Using this approach, each elongation of PEG is achieved in three steps

• – deprotection, deprotonation and coupling – in two pots. Here, we report a more convenient approach for PEG synthesis featuring the use of a base-labile protecting group such as the phenethyl group. Using this approach, each elongation of PEG can be achieved in two steps – deprotection and coupling – in only

• one pot. The deprotonation step, and the isolation and purification of the intermediate product after deprotection using existing approaches are no longer needed when the one-pot approach is used. Because the stepwise PEG synthesis usually requires multiple PEG elongation cycles, the new PEG synthesis

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

• hydrogels could also be adjusted by varying the ratio of CBMA to GelMA which gives it a high degree of customisability. The use of cryogels in neuroscience applications is gaining interest due to their soft and spongey properties [80]. Newland et al. recently reported on the use of injectable PEG/heparin

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• masses. Subsequently, both polymers were characterized regarding their structure. For this purpose, size exclusion chromatography (SEC) was performed revealing a molar mass of Mn = 11,400 g/mol for P1 and Mn = 17,400 g/mol for P2 with respect to a PEG-standard. The SEC traces of both polymers are

• reported in literature [23]. During cooling, the reformation of the perylene domain was also observed. Finally, P2 featured a second endothermic transition at 13 °C, which is based on the melting of the short PEG-block [24]. Furthermore, both polymers were characterized via rheology and dynamic mechanical

• second phase transition of the PEG moieties observed in the DSC. Nevertheless, at 150 °C, P2 also shows the clear broadening of bands, which is consistent with the very similar positions for the perylene π–π interaction signal in the DSC. All these findings clearly support that at increased temperatures

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

• Janina-Miriam Noy,
• Fan Chen and
• Martina Stenzel

Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148

• cells. When TPP was conjugated to the pMPC PISA particles more cellular uptake as well as better spheroid penetration were observed, while TPP on PEG-based PISA had only little effect. It was hypothesized that TPP on the micelle surface may not be accessible enough to allow mitochondria targeting, but

• result in more bioactive PISA nanoparticles [28]. Therefore, the relative short MPC block (p(MPC17-co-PENAO4), MP2 ) was selected, which was reacted with MMA in water–methanol to yield nanoparticles of around 76 nm (Table 1). In order to identify a matching nanoparticle of similar size with a PEG surface

• attachment of TPP-COOH to the micelle variants resulted in an increase in hydrodynamic diameter from approximately 85 nm to 136 nm for the PEG micelles and from 75 nm to 138 nm for the zwitterionic counterparts. However, no major change in dispersities was detected and well-defined nanoparticles (PdI < 0.078

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

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• synthesis of fully decorated 1,2,3-triazoles 162, 164, and 166 was reported by Ackermann et al. via intramolecular oxidative C–H arylation of 1,2,3-triazoles 161, 163, and 165 using a reusable palladium catalyst in PEG, Pd@PEG, under O2 atmosphere. The main advantages of this strategy include i) a versatile

• methodology for aerobic C–H activation; ii) PEG as green and recyclable reaction medium; and iii) a reusable palladium catalyst complex [65]. Fully functionalized 1,2,3-triazolo-fused chromenes 162, 164, and 166 were regioselectively prepared in moderate yield. The isoindoline-fused triazoles 164 were

• ]triazoles 166 were also prepared through the cyclodehydrogenative arylation of 165. It was demonstrated that the Pd and PEG mixture could be reused for further cycles, and only a catalytic amount of the copper source, pivalic acid, and the substrates needed to be added [65]. As shown in Scheme 44, this

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• −1 to 3710 cm−1 relying on pendant hydroxy groups of the PEG structure, the signal at 1719 cm−1 is corresponding to the C=O group stretching and the more pronounced intensities from 980 cm−1 to 1202 cm−1 are attributed to C–H bending and C–O stretching vibrations. Consequently, all FTIR spectra

• overall interpretation is that the condition variety did not drastically affect ESR results of each sample. HGCM-PEGMEMA has the highest ESR in every condition that is in good agreement with the nonionic and highly flexible structure of PEG that can resist electrolytes and pH stimuli. On the other hand

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• challenging. In an effort to target LNPs composed of an ionizable cationic lipid (DLin-MC3-DMA), cholesterol, the phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), and 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 (DMG-PEG 2000) to particular cell types, as well as to generate

• lipid, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol, and PEG-lipid, each with an essential role in the design (Figure 1). These lipids promote the effective distribution of the LNP in vivo as well as aid in effective cargo release from the endosome [1][37]. To this end, we herein

• mixture of DLin-MC3-DMA, DSPC, cholesterol, and 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 (DMG-PEG 2000). Lipids were first extruded and then complexed with negatively charged aptamers annealed with fluorescently tagged complementary DNA oligonucleotides (GP160:A-1 or CCR5:G-3) to

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

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

• penetrating properties, such as the transactivator of the transcription (TAT) peptide. Moreover, peptides being smaller than the antibodies generally induce a lower immunogenicity [15][16][17]. Micro- and nanocarriers are often covered by poly(ethylene glycol) (PEG) stealth coatings that significantly enhance

• occurrence of side reactions due to reactive groups introduced during PEG to lipids (or peptides) connecting reactions [23][24][25]. In particular, the PEG layer grafted on the surface of certain nanocarriers restricts the exposure of functional peptides [26][27]. Novel ligand-grafted lipids have been

• proposed for the preparation of functional drug carriers for clinical applications [25][28][29]. In order to alleviate the steric hindrance effect of PEG chains, a novel spacer consisting of alternating serine–glycine sequences (SG)n was introduced between the ligand and lipid within the molecular