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

• (Figure 2B). An innovative design links the two ends together with an ethylene glycol linker (Figure 2C), which reduced the unfavorable loss of entropy by converting the binding event from a trimolecular to a bimolecular process [34][35][36]. The new bis-PNAs (Figure 2C) showed about two orders of

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

• . This method was then extended to ketone, tosyl, and phthalimide groups on alkyl azides to produce the desired triazole derivatives. The ethylene glycol-, phenylalanine-, and glucose-derived azides were also good candidates to furnish the triazole derivatives. This protocol provides access to various

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

• primary amide C=O stretching vibration of the amide group. The strong signals at 1558 and 1404 cm−1 are originated from amine N–H bending and scissoring –CH2– vibrations, respectively. At last, the poly(ethylene glycol) methyl ether methacrylate (PEGMEMA)-based network displays O–H stretching from 3106 cm

• % aqueous solution, Merck), magnesium chloride (MgCl2, 99%, Merck), melamine (99%, Sigma-Aldrich), poly(ethylene glycol) dimethacrylate (PEGDMA, Mn 550, Sigma-Aldrich), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA, Mn 300, Sigma-Aldrich), potassium chloride (KCl, 99%, Merck), rhodamine B (RhB

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

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• moieties, such as a tetrose (ʟ-α-threofuranose, TNA [48]), and hexoses (e.g., hexitol, HNA [49]; altritol AtNA [50]; xylol XyNA [51]), or cyclohexene (CeNA [52]), a morpholino moiety (PMO [53]), and an acyclic, chiral glycol linker (GNA [54]), to generate so-called xeno nucleic acids (XNAs [55][56]). In

• at the PS2 nucleotide sites of an siRNA duplex sense strand increase the thermal stability of the duplex to levels comparable to the unmodified variant, it also further improved the binding affinity to the Ago2 protein, hypothesized to be in part caused by a superior hydrophobic effect [92]. Glycol

• nucleic acid Glycol nucleic acid (GNA) with its chiral, acyclic three-carbon backbone linked by phosphate is the simplest phosphodiester-based nucleic acid analogue (Figure 1D). It contains one stereocenter allowing for the synthesis of either (S)-GNA or (R)-GNA where chirality is fixed by use of either

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

• 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

• -3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] and observed that their LNP–DNA aptamer was able to deliver target siRNA into osteoblasts via macropinocytosis, increasing bone formation in vitro and in rodents [47]. In 2017, Kim et al. used a postinsertion method to incorporate an aptamer

A chromatography-free and aqueous waste-free process for thioamide preparation with Lawesson’s reagent

• Ke Wu,
• Yichen Ling,
• An Ding,
• Liqun Jin,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2021, 17, 805–812, doi:10.3762/bjoc.17.69

• scaling up the preparation of two pincer-type thioamides, we have successfully developed a convenient process with ethylene glycol to replace ethanol during the workup, including a traditional phase separation, extraction, and recrystallization. The newly developed chromatography-free procedure did not

• , we herein reported an efficient work-up procedure of applying LR by utilizing ethylene glycol to decompose the compound A (Figure 2). With a combination of some usual operations, such as, phase separation, extraction and crystallization, the desired thioamide products were efficiently obtained in

• reckoned that converting compound A to a more polar derivative could probably be a breakthrough. As common knowledge, the more polarized alcohols over EtOH are those diols or polyols, while MeOH was previously ruled out. Ethylene glycol, a basic chemical and the simplest diol, is slightly soluble in

[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

• formed. In fact, a series of spirocyclopentalydenemethanofullerenes 190–193 were obtained by the reaction of C60 with lithium salts of tosylhydrazone (Scheme 34) [154]. Spiromethanofullerene 194 was prepared on the basis of monoethylene glycol tosylhydrazone. Hydrolysis of the former resulted in 6,6

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

• developed, using a solvent or molecular hydrogen as cleaving agents [81]. The main solvolytic process include: hydrolysis (water) alcoholysis (methanol, ethanol, 1-butanol, 2-ethyl-1-hexanol, phenol) glycolysis (ethylene glycol (EG), 1,2-propanediol (PD), 1,3- and 1,4-butanediol (BD)), diethylene glycol

• (DEG), dipropylene glycol (DPG)) aminolysis (2-aminoethanol, 3-amino-1-propanol, ethylenediamine). Advantages of catalytic processes are obvious and can be witnessed in the hydrolysis and the glycolysis reactions of poly(ethylene terephthalate) (PET) [82][83]. Representative data are reported in

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

• -Dipalmitoylphosphatidylcholine (DPPC, >99%) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DPPE-PEG2000, >99%) were purchased from Avanti Polar Lipids (Alabaster, AL, USA) and used without further purification. Perfluorohexane came from Fluorochem (>98%). A HEPES (N-2-(hydroxyethyl

Regioselective chemoenzymatic syntheses of ferulate conjugates as chromogenic substrates for feruloyl esterases

• Olga Gherbovet,
• Fernando Ferreira,
• Apolline Clément,
• Mélanie Ragon,
• Julien Durand,
• Sophie Bozonnet,
• Michael J. O'Donohue and
• Régis Fauré

Beilstein J. Org. Chem. 2021, 17, 325–333, doi:10.3762/bjoc.17.30

• quantified by submitting samples removed from the reaction to the oxidative action of sodium periodate at 0 °C and registering the absorbance at 530 nm (under alkaline conditions) [23][37][38][43]. Importantly, it is vital to include a stoichiometric amount of ethylene glycol to avoid further oxidation of

• solution was preincubated at 40 °C before AnFaeA addition. Aliquots (25 µL) were stopped by cooling (at 0 °C) every 6 min over a 24 min period and mixed with 45 µL of a cooled 10 mM NaIO4 solution (pH 2.0). After being kept for 5 min at 0 °C throughout, 45 µL of ethylene glycol were added, followed by 135

• . Negative controls containing all of the reactants except the enzyme were always included in order to monitor and correct for spontaneous hydrolysis of the substrate. Control reactions containing 12, 11 and 4NTC without enzyme, and 4NTC without both enzyme and ethylene glycol were also prepared. Alternative

Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders

• David Straßburger,
• Svenja Herziger,
• Katharina Huth,
• Moritz Urschbach,
• Rainer Haag and
• Pol Besenius

Beilstein J. Org. Chem. 2021, 17, 97–104, doi:10.3762/bjoc.17.10

• of rigid supramolecular polymers. Since multivalent sulfated supramolecular structures mimic naturally occurring L-selectin ligands, the corresponding affinity was evaluated using a competitive SPR binding assay and benchmarked to an ethylene glycol-decorated supramolecular polymer. Keywords: L

• . Both amphiphiles were synthesized using a convergent and modular strategy as shown in Scheme 1. The Newkome-type [33] dendritic dodeca(ethylene glycol) moiety 3, equipped with a 6-aminohexanoic acid spacer was synthesized as reported previously [34]. Using this building block in the subsequent HBTU

• I was purified by size exclusion chromatography. In order to synthesize the sulfated, functionalized supramolecular building block II, we made use of the selective heterofunctionalization of trimesic acid. By replacing one of the solubilizing dodeca(ethylene glycol) moieties with an azide group

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• trimethylsilyl cyanide (TMSCN) in poly(ethylene glycol) (PEG) solution. The advantages of the sonochemical versus the conventional α-(arylamino)acetonitrile synthesis are the significantly shorter reaction time (30 min instead of 72 hours), the higher purity and the easier separation of the product that

• using “green” solvents, for example, low vapor pressure solvents such as ionic liquids [3], low volatile solvents such as glycerol, ethylene glycol and its oligomers, or nontoxic water solvent, as well as in heterogeneous media under solvent-free conditions [4]. Other advantages induced by sonication

• , ferrocene or benzene units was screened by the Salmonella mutagenicity assay (Ames test) [28] using S. typhimurium TA98 and TA100 strains. Results and Discussions Ultrasound-assisted synthesis The Strecker reaction between (hetero)aromatic aldimines and TMSCN in poly(ethylene glycol) (PEG)–water medium [18

Synthesis of purines and adenines containing the hexafluoroisopropyl group

• Viacheslav Petrov,
• Rebecca J. Dooley,
• Alexander A. Marchione,
• Elizabeth L. Diaz,
• Brittany S. Clem and
• William Marshall

Beilstein J. Org. Chem. 2020, 16, 2739–2748, doi:10.3762/bjoc.16.224

• -temperature operation. The sample temperature was calibrated against neat ethylene glycol and neat methanol standards. Selective inversion experiments at subambient temperature effected the selective inversion with iBURP shapes [25]. The spin–lattice relaxation time T1 for each site was determined with

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• /bjoc.16.219 Abstract Gold nanoparticles covered with a mixture of ligands of which one type contains solubilizing triethylene glycol residues and the other peripheral zinc(II)–dipicolylamine (DPA) complexes allowed the optical detection of hydrogenphosphate, diphosphate, and triphosphate anions in

• binding of these anions to the immobilized receptor units strengthened their interaction with a simultaneously present bis(imidazolium) ion, which in turn caused nanoparticle crosslinking [16][17]. Our group recently showed that a mixed monolayer-protected AuNP containing solubilizing triethylene glycol

• receptors based on other scaffolds [22][23][24][25]. To test whether this binding motif induces AuNP crosslinking, we synthesized nanoparticles containing peripheral zinc(II)–DPA complexes together with a solubilizing triethylene glycol-based ligand in different ratios and studied their interaction with

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• glycol to afford monocyclic acetal 53 with less hindered keto-group in respectable yield. Since the introduction of powerful electron-withdrawing groups such as fluorine atom(s) in any material changes its behavior significantly, in this regard, Sakurai’s group installed six fluorine atoms at the

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• obtained in a lower yield (52%) but high diastereoselectivity, similar to those previously reported [59][61]. The authors also explored the PKR in a catalytic version based on a biphasic system of ethylene glycol/toluene, which generally enhanced both yields and stereoselectivities, as well as simplifying

• purification of the products [66]. This methodology (7 mol % catalyst, atmospheric CO pressure, and 15% v/v of ethylene glycol in toluene) was shown to be suitable for substrates bearing differing fluorinated groups, as well as one example with a phenyl-substituted alkyne, giving rise to products 54 in good

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

• strand), that combined the components into a single structure. The T1–T4 strands were connected with the platform by polythymidine or hexaethylene glycol linkers, which provided flexibility of SDFS. All nucleotide sequences are presented in Table S2 of Supporting Information File 1. A calculation of the

• biological material. SDFS main components and its work model. A) Schematic representation of the SDFS structure. Dotted lines indicate hexaethylene glycol linkers in T1 and T4, and polythymidines linker in T2 and T3; Dz1 and Dz2 – deoxyribozyme sequences. B) The detailed structure of the Dz catalytic core

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

• multitriazole products in polyethylene glycol as a green solvent at room temperature (Scheme 10). The authors proposed that sodium ʟ-ascorbate acted as a reducing agent in the reduction of Cu(II) to Cu(I). Aromatic/aliphatic terminal acetylenes and benzyl bromides bearing electron-rich and electron-deficient

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• (Scheme 3). Cascade regio- and stereoselective reactions of thiaselenole 1 with water and ethylene glycol resulted in the formation of the first representatives of the new family of polyfunctional 2,3-dihydro-1,4-thiaselenines [41]. The regioselective nucleophilic substitution reactions in thiaselenole 1

Why do thioureas and squaramides slow down the Ireland–Claisen rearrangement?

• Dominika Krištofíková,
• Juraj Filo,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2019, 15, 2948–2957, doi:10.3762/bjoc.15.290

• was isolated in 58% when the reaction was carried out in dimethyl ethylene glycol (Table 5, entry 6). However, Ireland–Claisen rearrangement of ester 1c did not proceed in 2,2,2-trifluoroethanol, ethyl ʟ-lactate or in 2-butanone. Interestingly, the best yield of acid 3c (95%) was obtained when the

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• better conjugation with the 4AP substituent at the C4 carbon of the BTD heterocyclic core. The ionic nature of the structure in combination with a hydrophilic anion (MeSO3−, methanesulfonate) and the presence of the hydrophilic domain (triethylene glycol monomethyl ether) make the dye a water-soluble BTD

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

• one case, phenol PEG (poly(ethylene glycol) was grafted together with pyridine imine phenol, affording dendrimers stochastically functionalized on the surface, but all having precisely 12 fluorophores in the internal structure [59]. Another way to induce solubility in water consists in having

• fluorescence of the dendrimer was not induced by TPA but classically by one photon. The last example of biological uses concerns a second generation dendrimer built with the fluorophore shown in Scheme 6 at the level of the first generation and having triethylene glycol chains as terminal functions (Figure 11

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• reported by Boul et al. Reactions occur between a pentafulvene and dicyanoethylenecarboxylate or tricyanoethylenecarboxylate [189]. Polymerisation and dynamer formation via Diels–Alder cycloaddition between fulvene groups in polyethylene glycol bis(fulvene) and bis(tricyanoethylenecarboxylate) derivatives

• [190]. Preparation of hydrogels via Diels–Alder cycloaddition with fulvene-conjugated dextran and dichloromaleic acid-modified poly(ethylene glycol) [191]. Ring-opening metathesis polymerisation of norbornene derivatives derived from fulvenes and maleimides to furnish facially amphiphilic polymers

Analysis of sesquiterpene hydrocarbons in grape berry exocarp (Vitis vinifera L.) using in vivo-labeling and comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC–MS)

• Philipp P. Könen and
• Matthias Wüst

Beilstein J. Org. Chem. 2019, 15, 1945–1961, doi:10.3762/bjoc.15.190

• consisted of a 30 m × 0.25 mm i.d. × 0.25 µm df DB-WAX Ultra Inert (Agilent Technologies, Bellefonte, PA, U.S.A.) as a high polar primary column with poly(ethylene glycol) as stationary phase coupled to a 1.7 m × 0.10 mm i.d. × 0.10 µm df MEGA-17 MS FAST (MEGA s.n.c., Legnano, MI, IT) moderately polar