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

• physicochemical interplay between the architecture of the polymer assembly and the resulting thermoresponsive switching behavior will be in the foreground of this consideration. Keywords: lower critical solution temperature (LCST); responsive coating; smart material; thermoresponsive polymer; upper critical

• -assembly due to their structure consisting of hydrophilic and hydrophobic units [110][111][112][113]. In the case of rather large corona blocks compared to the core-forming blocks, such structures are usually star-shaped and spherically composed of many individual chains by noncovalent interchain

• absolute length of the block copolymer and the relative length of the blocks to each other and the glass transition temperature. If a block is composed of a thermoresponsive polymer, the amphiphilic character and self-assembly ability can be altered by changing the temperature. The thermoresponsive block

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• approach (also known as fragment coupling) allows connecting pre-assembled oligosaccharide blocks. To decrease the synthetic time required for the chemical synthesis of polysaccharides, automated techniques have been developed [28][29][30][31]. Automated glycan assembly (AGA) connects monosaccharide BBs on

• a solid support following a linear approach (Figure 1D). Cycles of glycosylation and selective deprotection are iteratively performed to access the desired polysaccharide with full control over the length and the monosaccharide sequence [32]. Upon completion of the assembly, the desired product is

• of the self-assembly of cellulose chains at the active site of the enzyme suggested that diffusion of the aggregated molecules and the monomers around the active center dictates the DP that can be obtained by enzymatic polymerization [70][71]. This could be the reason causing enzymatic reactions to

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• multicomponent reaction (IMCR) [31]. The enantioenriched hemiacetals 5 were obtained using the Jørgensen catalyst 7 as previously described by Rueping et al. [32]. This approach enables the rapid assembly of complex natural product hybrids 6 including up to four different molecular fragments, such as

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• amine functionalities in their neutral, i.e., non-protonated form. Regarding synthetic strategies, both the use of amine group functionalized phosphoramidites, i.e., functionalized monomeric building blocks, as well as conjugation with amine groups after completion of the ON assembly, are being

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

• Christin Walther,
• Pamela Baumann,
• Katrin Luck,
• Beate Rothe,
• Peter H. W. Biedermann,
• Jonathan Gershenzon,
• Tobias G. Köllner and
• Sybille B. Unsicker

Beilstein J. Org. Chem. 2021, 17, 1698–1711, doi:10.3762/bjoc.17.118

• contribute to the overall (E)-β-caryophyllene emission from the tree. To identify terpene synthase genes potentially involved in volatile terpene formation in Cladosporium, we sequenced the transcriptome and performed a de novo assembly of the obtained reads. A TBLASTN analysis with Aspergillus terreus

• aristolochene synthase (pdb 20A6) as query and the de novo assembly as template revealed two genes with high similarity to other fungal TPS genes. The genes were designated CxTPS1 and CxTPS2. For functional characterization, the complete open reading frames of CxTPS1 and CxTPS2 were amplified from cDNA, cloned

• library was prepared, and PolyA enrichment was performed before sequencing on an IlluminaHiSeq 3000 sequencer (Max Planck Genome Centre, Cologne, Germany) with 25 Mio reads, 150 base pairs, paired end. Trimming of the obtained Illumina reads and de novo assembly were both performed with the program CLC

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

• hairpin structure in the 5’-UTR of an mRNA, which inhibited ribosome assembly and suppressed mRNA translation in vitro and in cells [119]. This study was the first demonstration of the biological effect of binding of M- and P-modified PNAs to dsRNA in live cells. Recent work from our labs [120

Copper-mediated oxidative C−H/N−H activations with alkynes by removable hydrazides

• Feng Xiong,
• Bo Li,
• Chenrui Yang,
• Liang Zou,
• Wenbo Ma,
• Linghui Gu,
• Ruhuai Mei and
• Lutz Ackermann

Beilstein J. Org. Chem. 2021, 17, 1591–1599, doi:10.3762/bjoc.17.113

• : benzhydrazides; copper; 3-methyleneisoindolin-1-one; removable directing group; Introduction Inexpensive copper-promoted oxidative C−H activations [1][2][3][4][5][6][7][8][9][10][11] have been recognized as competent tools for the efficient assembly and late-stage functionalization of organic molecules due to

• (Cq), 129.3 (CH), 128.7 (CH), 127.3 (CH), 127.3 (CH), 126.5 (Cq), 123.8 (CH), 119.8 (CH), 114.3 (CH), 107.8 (CH), 106.4 (CH), 36.7 (CH3); HRESIMS (m∕z): [M + H]+ calcd for C21H18N3O, 328.1444; found, 328.1439. Assembly of 3-methyleneisoindolin-1-one via 3d transition metal-mediated/catalyzed oxidative

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• composite with platinum nanoparticles stabilized with poly(acrylic acid) [113]. Such a catalytic system, obtained by layer-by-layer self-assembly with the addition of poly(diallyldimethylammonium chloride) on the indium tin oxide surface, provided hydrogen formation in photoelectrolytic cycles with a

Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings

• Ivan P. Mosiagin,
• Olesya A. Tomashenko,
• Dar’ya V. Spiridonova,
• Mikhail S. Novikov,
• Sergey P. Tunik and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2021, 17, 1490–1498, doi:10.3762/bjoc.17.105

• , attempts to assemble this framework using Pd-catalyzed intramolecular arylation of compounds C' (X = Br, I) failed [17]. In this work, we report an effective method for the assembly of pyrido[2,1-a]pyrrolo[3,4-c]isoquinoline and related frameworks via a free radical cyclization of pyrrolylpyridinium salts

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• the assembly of complex molecules from relatively simple and inexpensive materials/reagents in a single operation. The reaction continues to be an interesting and profitable field of research with high impact on synthetic organic chemistry [17][18]. Many of the existing protocols rely on an acid

Antiviral therapy in shrimp through plant virus VLP containing VP28 dsRNA against WSSV

• Santiago Ramos-Carreño,
• Ivone Giffard-Mena,
• Jose N. Zamudio-Ocadiz,
• Alfredo Nuñez-Rivera,
• Ricardo Valencia-Yañez,
• Jaime Ruiz-Garcia,
• Maria Teresa Viana and
• Ruben D. Cadena-Nava

Beilstein J. Org. Chem. 2021, 17, 1360–1373, doi:10.3762/bjoc.17.95

• entry, binding and assembly of the virion. Previous studies have shown that silencing these structural proteins in WSSV challenge assays, increases shrimp survival [10][11][17][18][19][20][21]. The VP28 glycoprotein plays an important role in systemic infection by interacting with cell membrane proteins

• assembling. SDS-PAGE was used to verify the integrity of the capsid protein. In vitro assembly of VLPs-dsRNAvp28. Dissociated CCMV CP and dsRNAvp28 were mixed in a mass ratio of 6:1 (CP/dsRNA) and dialyzed overnight against RNA assembly buffer (50 mM NaCl, 10 mM KCl, 5 mM MgCl2, 50 mM Tris-HCl, pH 7.2) at 4

• °C. The samples were acidified by dialysis in virus suspension buffer (50 mM sodium acetate, 8 mM magnesium acetate, pH 4.5) for at least 4 hours. Then, to disrupt the empty capsids, the sample was dialyzed against an RNA assembly buffer. The VLP-dsRNAvp28 was then purified and concentrated by

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

• represents a family of materials where variety of synthetic routes can be applied to form photoactive matter with altered properties, i.e., monomer supramolecular assembly to attain a monomer complex prior to carbonization results in enhanced porosity and photoactivity since ordered structures are formed

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

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• architecture based on C–I···N and C–I···π interactions was formed through halogen bonding in the lattice of self-assembly of meso-tetraarylporphyrins [7]. In recent years there has been a strong uprising interest for substituting hydrogen-bonding motifs with their halogen-bonding counterparts. This is due to

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

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

• ’-flouronated base; italics and underlined = 2’-O-methyl base Complementary DNA A-1: (Cy5/AGG CTA TCT AGA ATG TAC) G-3: (Cy5/TCT ATC AAT CTA TCA) Peptide synthesis, purification, and characterization Peptide assembly was carried out by solid-phase peptide synthesis in standard solid-phase extraction filtration

[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

• (Scheme 33). Сoordination of these compounds with ruthenium(II) leads to a donor–bridge–acceptor assembly of complexes with various lengths, 187–189. It is believed [153] that the photophysical and electrochemical properties of the complexes presented are promising for the formation of charge-separated

• the starting material for synthesizing adduct 204 (Scheme 39) [123]. A synthesis and a self-assembly of flavin-functionalized fullerene derivative 205 consisting of [60]PCBM and isoalloxazine moieties attached at both ends of a linear 12-carbon aliphatic spacer, based on the same acid (Scheme 40), was

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

• Naohiro Horie,
• Takao Yamaguchi,
• Shinji Kumagai and
• Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

• Support™ T 40s (GE Healthcare) was used as a solid support. The amidite solution was dehydrated. The standard synthesis cycle was used for the assembly of the reagents except that the coupling time was extended to 16 min. The synthesis was carried out in the trityl-on mode. The oligonucleotides were

Hydrazides in the reaction with hydroxypyrrolines: less nucleophilicity – more diversity

• Dmitrii A. Shabalin,
• Evgeniya E. Ivanova,
• Igor A. Ushakov,
• Elena Yu. Schmidt and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2021, 17, 319–324, doi:10.3762/bjoc.17.29

• hydrazides appeared to be good recyclization agents as was exemplified by the assembly of 1,4-dihydropyridazines 4ab and 4ag from 4-methylbenzohydrazide (2b) and acetohydrazide (2g) in 69% and 54% isolated yields, respectively. In contrast, the recyclization of hydroxypyrroline 1a with electron-deficient 4

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

• building blocks for the ternary electrostatic self-assembly, forming well-defined supramolecular assemblies with tunable sizes of 50 to 500 nm. Due to the network of possible chemical reactions for the anthocyanidin and the excited-state dissociation of the photoacid upon irradiation, different ways to

• particles, and information on the molecular structure was gained by UV–vis spectroscopy. Isothermal titration calorimetry (ITC) provided information on the thermodynamics and interaction forces in the supramolecular assembly formation. Keywords: electrostatic self-assembly; hydroxyflavylium

• ; multiswitchable; photoacid; polyelectrolyte; Introduction Supramolecular nanoscale assemblies responding to multiple stimuli are highly desirable in various fields including transport systems, sensors, and optoelectronic applications [1][2][3][4][5][6][7][8]. Self-assembly into supramolecular structures and

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

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

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• of functional photocatalytic systems [16][17]. The diversity of crown ether-based photocatalytic reactions is relatively low, involving mainly photocycloaddition reactions. Saltiel and co-workers reported the regiospecific intermolecular [2 + 2]-photocycloaddition based on a supramolecular assembly

• electron donor, respectively (Figure 3). A benzo-18-crown-6 derivative was connected to the porphyrin ring, which could form a supramolecular complex with fullerene through dipole interactions. The formed supramolecular self-assembly resulted in a high energy-transmission efficiency (over 97%) between the

• BODIPY and the zinc porphyrin. The excited zinc porphyrin further transferred the electron to the fullerene, yielding a charge-separated state, with a long lifetime of 23 µs, indicating the charge stabilization of the supramolecular assembly. Thus, an artificial photocatalytic system that can mimic the

Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding

• Subrata Nath,
• Alexander Kappelt,
• Matthias Spengler,
• Bibhisan Roy,
• Jens Voskuhl and
• Michael Giese

Beilstein J. Org. Chem. 2021, 17, 124–131, doi:10.3762/bjoc.17.13

• of iodofluorobenzene derivatives with nitro-cyanostilbenes is reported. The systematic variation of the fluorination degree and pattern indicates the relevance of the halogen bond strength for the induction of liquid crystalline properties. The modular self-assembly approach enables the efficient

• interactions, which allow for dynamic responses to external stimuli [1]. In addition, the self-assembly of the complementary molecular entities provides an easy access to functional systems and enables recyclability and self-healing properties of the materials [2]. With respect to the formation of

• with the theoretical data and confirms that the formation of thermally stable halogen bonding induces the liquid crystalline properties of the assemblies. We suppose that the formation of the halogen-bonded assembly expands the mesogenic core and yields a more balanced ratio of rigid and flexible

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

• Research Center of Electron Microscopy, Freie Universität Berlin, Fabeckstr. 34a, 14195 Berlin 10.3762/bjoc.17.10 Abstract The synthesis of a sulfate-modified dendritic peptide amphiphile and its self-assembly into one-dimensional rod-like architectures in aqueous medium is reported. The influence of the

• -selectin binders; multivalency; self-assembly in water; supramolecular polymers; Introduction Deciphering the interaction of artificial molecular building blocks with biological components is a key element on the way to understanding and selectively manipulating biological systems. Throughout nature

• self-assembly turns out to be crucial in obtaining supramolecular polymers suitable for interactions with biological targets [16]. Peptide amphiphiles provide access to supramolecular structures in this competitive environment by taking advantage of nature’s versatile toolbox of noncovalent

Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies

• Cheng Qian,
• Yuan Chen,
• Qian Zhao,
• Ming Cheng,
• Chen Lin,
• Juli Jiang and
• Leyong Wang

Beilstein J. Org. Chem. 2021, 17, 52–57, doi:10.3762/bjoc.17.6

• luminescence with glum values of +0.0021, and −0.0025, respectively. The second way to fabricate the rac-TBPP-based CPL-active material is to co-gel the fluorescent rac-TBPP with a chiral ᴅ-glutamic acid gelator DGG by co-assembly strategy. At the molar ratio of rac-TBPP/DGG = 1:80, the glum value of the co

• the TB unit the fluorescence intensity of these co-assembly co-gels enhanced sharply (Figure 2a). More interestingly, at the molar ratio of rac-TBPP/DGG = 1:16, the CPL spectra of the co-gel shows a negative signal, while at the molar ratio of rac-TBPP/DGG = 1:32 or higher, positive signals exhibiting

• the co-assembly strategy. The cogels show significant CPL emission and stoichiometry-controlled inversion of chirality due to the hydrogen bonding interactions and packing modes in the supramolecular co-assemblies. Owing to TB special V-shaped structure, rigid conformation, and nitrogen stereogenic

Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• for Nanoscale Science and Nanotechnology, Ben-Gurion University, Beer Sheva 84105, Israel 10.3762/bjoc.17.5 Abstract The facile fabrication of free-floating organic nanocrystals (ONCs) was achieved via the kinetically controlled self-assembly of simple perylene diimide building blocks in aqueous

• ). Convenient control over the structure and function of organic nanocrystals can enhance their utility in new and developed technologies. Keywords: aromatic amphiphiles; exciton diffusion; organic nanocrystals; perylene diimides; self-assembly; Introduction Semiconductor and metal nanoparticles exhibit size

• the assembly. In general, gaining control over the crystal formation represents a long-standing challenge [29][30][31][32]. In this respect, understanding and controlling the crystallization process is key to fabricating organic nanocrystals with a predesigned morphology and properties [33][34][35