Hierarchically assembled helicates as reaction platform – from stoichiometric Diels–Alder reactions to enamine catalysis

• David Van Craen,
• Jenny Begall,
• Johannes Großkurth,
• Leonard Himmel,
• Oliver Linnenberg,
• Elisabeth Isaak and
• Markus Albrecht

Beilstein J. Org. Chem. 2020, 16, 2338–2345, doi:10.3762/bjoc.16.195

• statistical ligand distribution Li[Li3(1)3(L*)3Ti2] (L* = 3–7-H2). The given formula only describes the ratio of the ligands but in fact a statistical mixture of complexes Li[Li3(L*)6Ti2], Li[Li3(1)(L*)5Ti2], Li[Li3(1)2(L*)4Ti2], Li[Li3(1)3(L*)3Ti2], Li[Li3(1)4(L*)2Ti2], Li[Li3(1)5(L*)1Ti2], and Li[Li3(1)6Ti2

• residues were introduced instead of the diene ligands. Again helicates with a statistical distribution of chiral ligands and of the new amine ligands in the complex were investigated as catalysts. The ligands with potential catalytic activity were synthesized in a three-step approach (Scheme 4). Initially

• ][31] stereoselectivity of a Diels–Alder reaction by use of different solvents. The heteroleptic complexes are mixtures with an average ligand distribution as shown [13]. Elucidating the pathway of the stereoinduction of the Diels–Alder reaction. Ten equivalents of chiral ammonium salt are added to the

Formation of an exceptionally stable ketene during phototransformations of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

• Asitanga Ghosh

Beilstein J. Org. Chem. 2020, 16, 2297–2303, doi:10.3762/bjoc.16.190

• distribution of these photoproducts may be wavelength dependent [7]. In order to investigate the photoreaction of such enones, we observed a complete 1,2-acyl shift (1,2-AS) photoproduct formation when 1a–h have been irradiated (Scheme 1) [14][16]. We also observed that such a rearrangement took place very

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• distribution (NNLS analysis). UV–vis titrations of compound 4 (c = 1.0 × 10−6 M), with ct-DNA at pH 7.0 (a) and at pH 5 (b). Insets: dependence of Abs (384 nm) on c(ct-DNA), line – non-linear fit to Scatchard equation [28]. Measurement done in Na cacodylate buffer, I = 0.05 M. a) CD titration of ct-DNA (c

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• a positive impact on the biological absorption and distribution. Moreover, C–H/C–F substitution strongly decreases the basicity of neighboring amines (and lowers the pKa by a similar increment) due to the σ-inductive effect of F. This results in i) a higher oral bioavailability [19], ii) a potential

• most abundant in the solar distribution [78][79], instead absorbing only short wavelengths of UV light, ii) the photoexcitation of simple organic molecules by requisite high-energy UV photons populates higher-order excited states that undergo uncontrolled photodecomposition, such as Norrish-type

• distribution of fluorinated products, with a large preference for fluorination at the penultimate carbon (that would form a secondary radical), consistent with the polarity matching selectivity shown previously (Figure 10) [198][201]. Lectka and co-workers pointed out that the triplet energy of aliphatic

Lipophilicity trends upon fluorination of isopropyl, cyclopropyl and 3-oxetanyl groups

• Benjamin Jeffries,
• Zhong Wang,
• Robert I. Troup,
• Anaïs Goupille,
• Jean-Yves Le Questel,
• Charlene Fallan,
• James S. Scott,
• Elisabetta Chiarparin,
• Jérôme Graton and
• Bruno Linclau

Beilstein J. Org. Chem. 2020, 16, 2141–2150, doi:10.3762/bjoc.16.182

• ]. In this case, the expected lipophilicity reducing effect is offset by the electron-withdrawing effect on the nitrogen (ΔlogP +0.34). The reduction in amine basicity also shifts the distribution of free base and protonated species, resulting in a higher proportion of free base in solution at pH 7.4

• by reversed-phase HPLC). Lipophilicity modulations discussed in this contribution. Distribution of the experimental lipophilicity values of series D, E and F (* denotes an estimated value, see Supporting Information File 1). Comparison of lipophilicities between the linear alkyl, isopropyl

GlypNirO: An automated workflow for quantitative N- and O-linked glycoproteomic data analysis

• Toan K. Phung,
• Cassandra L. Pegg and
• Benjamin L. Schulz

Beilstein J. Org. Chem. 2020, 16, 2127–2135, doi:10.3762/bjoc.16.180

• -specific or peptide-specific. If the user trusts Byonic’s site-specific assignment, then all peptide variants that contain that site are included in calculations of its occupancy and glycoform distribution. If the user prefers to perform a peptide-specific analysis, then each proteolytically unique peptide

• grouping: site-specific analysis, or peptide-specific analysis. For site-specific analysis, the site-specificity of glycosylation assigned by Byonic was trusted, and all peptide variants that contained that site were included in calculations of its occupancy and glycoform distribution. PSMs with identical

Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations

• Ian Walsh,
• Matthew S. F. Choo,
• Sim Lyn Chiin,
• Amelia Mak,
• Shi Jie Tay,
• Pauline M. Rudd,
• Yang Yuansheng,
• Andre Choo,
• Ho Ying Swan and
• Terry Nguyen-Khuong

Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176

• glycans are drawn in SNFG notation [20]. Boxplots showing the quantitation of the 11 different bioreactor conditions. The boxplots show the peak area distribution (expressed as % relative abundance) for each of the 11 bioreactor conditions. Points are averaged relative abundances for three replicates

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• -acyliminium intermediate is provided to explain the addition product distribution. Results and Discussion We began our study by using the iridium catalyst Ir[(ppy)2(dtbbpy)]PF6 (17) and the reaction conditions used in the addition of amine nucleophiles to enamides [48][50]. By exploiting these reaction

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• achieve a better performance a homogeneous distribution of the catalyst and the scavenger within the fixed bed reactor seems to be preferable as it has been observed in multicatalytic systems [42]. In this case, two different fixed bed reactors were prepared with a well-disperse mixture formed by 50 mg of

• PdNPs (Figure 9). However, the images show that for the system 8a + 9c the number of particles and their size distribution are larger than for 8a + 9a. This trend is different to the one observed in batch experiments. Conclusion The results here presented confirm the viability of using polymeric

• images of the polymers after the Negishi reaction between 5 and 6. a) 8a, bar scale 20 nm, PdNP size distribution 4.91 ± 1.26 nm. b) 8a + 9a, bar scale 50 nm, PdNP size distribution 4.23 ± 1.65 nm. c) 8a + 9b, bar scale 50 nm, PdNP size distribution 3.61 ± 1.36 nm. d) 8a + 9c, bar scale 50 nm, PdNP size

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• heating to 473 K until blue spots appeared. Column chromatography was conducted by using silica gel 60 with a particle size distribution of 40–63 μm and 230–400 ASTM, using hexane/EtOAc mixtures as the eluent. High-resolution mass spectrometry (HRMS) analyses were performed using a Bruker microTOF QII

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• hydrogen bonding. The primary site of interaction is the X-COO− group. The geometry of the carboxylate group (and to a large extent also its charge distribution) is the same for all carboxylate anions. Therefore, high affinity towards carboxylates is easily achievable, but selectivity towards a specific

Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio

• Dandan Li,
• Enjuro Harunari,
• Tao Zhou,
• Naoya Oku and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154

• (Figure 3a). Note that the sign distribution of the Δδ(S − R) values in β,β-substituted carboxylic acids is inverted from that observed in the α,α-substituted counterparts (Figure 3b) because the PGME anisotropy group is flipped upside down due to the insertion of an extra methylene group between the

• test compounds. Structures of the compounds 1–5. COSY (bold lines) and selected HMBC correlations (arrows) for 1–4. a) Distribution of positive (red) and negative (blue) Δδ(S − R) values (in ppm) calculated from the 1H NMR chemical shifts of the (S)- and (R)-PGME amides of 1–4. b) Comparison of the

Synthesis, docking study and biological evaluation of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones as potential inhibitors of the mycobacterial galactan synthesis targeting the galactofuranosyltransferase GlfT2

• Marek Baráth,
• Jana Jakubčinová,
• Zuzana Konyariková,
• Stanislav Kozmon,
• Katarína Mikušová and
• Maroš Bella

Beilstein J. Org. Chem. 2020, 16, 1853–1862, doi:10.3762/bjoc.16.152

• complex structure and also mimic its partial charges and charge distribution. Herein, the molecular docking, synthesis and inhibitory activity of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones 1–3 against GlfT2 are discussed. Moreover, we extended the scope of the simultaneous phosphorylation and

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

• size distribution of the deposited nanoparticles [158]. Colmenares and co-workers have reported these methodologies for the synthesis of TiO2 HPCats doped with various transition metals, such as Fe, Pd, Pt, and Au [159][160][161]. For more information, we recommend a recent review published by

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

• reaction intermediates, the ratio of products was calculated from the relative energies of these intermediates using the Boltzmann distribution equation. Establishing the threshold between the two mechanisms Although both, the proton-abstraction and the electrophilic aromatic-substitution, mechanisms are

Synthesis of new fluorescent molecules having an aggregation-induced emission property derived from 4-fluoroisoxazoles

• Kazuyuki Sato,
• Akira Kawasaki,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2020, 16, 1411–1417, doi:10.3762/bjoc.16.117

• distribution of boron ketoiminate scaffold induced by the strong electronegative fluorine atom [39]. The FL intensities were lower than that of the corresponding BKIs, a similar tendency to what was also observed in other F-BKIs 9a and 9c. In summary, we found that the F-BKIs described in this report exhibited

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• -ray data from CSD about the distance of the Cethynyl–H···π interaction [76], an average distance value (ca. 3.0 Å) above the benzene ring centroid can be considered for the statistical distribution of the Cethenyl–H···π interaction [76], which is longer than present calculated value. On the other hand

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin

• Margareta Sohora,
• Leo Mandić and
• Nikola Basarić

Beilstein J. Org. Chem. 2020, 16, 1296–1304, doi:10.3762/bjoc.16.110

• inclusion complexes 2@β-CD and 3@β-CD was investigated, and we found out that β-CD does not affect the decarboxylation efficiency, while it affects the subsequent photochemical H-abstraction, resulting in different product distribution upon irradiation in the presence of β-CD. The formation of ternary

• in the presence and absence of β-CD. However, for the adamantane derivative in the presence of β-CD, the secondary photochemical H-abstraction became more efficient, resulting in a different product distribution. More efficient H-abstraction reaction in the presence of β-CD have been reported [16]. β

Anthelmintic drug discovery: target identification, screening methods and the role of open science

• Frederick A. Partridge,
• Ruth Forman,
• Carole J. R. Bataille,
• Graham M. Wynne,
• Marina Nick,
• Angela J. Russell,
• Kathryn J. Else and
• David B. Sattelle

Beilstein J. Org. Chem. 2020, 16, 1203–1224, doi:10.3762/bjoc.16.105

• schistosomiasis treatment is the effect which climate change may have on aquatic environments (and the intermediate freshwater snail host Biomphalaria glabrata) and therefore on the distribution of water-borne diseases like schistosomiasis [47]. Similarly to the STHs, the WHO 2020 target for schistosomiasis is

• drug development and the approval of tafenoquine (11) and fexinadole (10) [68][69]. With increasing concerns over the potential emergence of resistance to currently deployed anthelmintics, the possibility of climate change altering the distribution of these parasites, coupled with the inability of the

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• basic conditions, the pore size distribution and the chemical properties on the surface can be adjusted (polarity and hydrophobicity) according to the envisaged application. In addition, metal particles can be recovered simply by burning the carbon support [1][2]. Thus, porous carbon materials represent

• ) activation methods for the modification of the porosity of anthracite-based activated carbons. The final pore size distribution (mainly microporous or mainly mesoporous) depends on the choice of the activation agent, the treatment time and temperature and the initial textural properties of anthracite as

• the surface of the treated carbons in form of carboxyl groups, ketones, ether groups and carboxyl-carbonate structures is higher using nitric acid compared to hydrogen peroxide [116]. Nitrogen adsorption–desorption isotherms: The surface area and pore size distribution of solid catalyst materials can

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• (HOMO)→lowest unoccupied molecular orbital (LUMO) transition. Focusing on the orbital distribution, the HOMO lobe of 2a covers the entire molecule, while the LUMO lobe is localized at the tolane moiety. In the case of 3a, the HOMO lobe is localized at the methoxy-substituted benzene ring, while the LUMO

• corresponding bis-oxidized bisbenzil derivatives. Based on theoretical calculations, the selective formation of the fluorinated analogues stemmed from the slight modulation of the charge distribution at the alkyne moiety of the reactant induced by the electron-withdrawing fluorine atoms. Evaluation of the

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• architectures have been discovered, which allow a rigid and uniform distribution of a single well-defined catalytic or precatalytic center within a solid matrix. Of these, metal–organic frameworks (MOFs) [13][14][15][16][17][18] and covalent organic frameworks (COFs) [19][20][21][22] have been the forerunners

• ][31], gas separation and absorption [28][29], enzyme encapsulation [36], and even asymmetric synthesis (albeit with a framework that contained a transition metal ion) [37]. However, for the HOF and CAHOF catalysts to have a similar appeal to other regular active site distribution materials, such as

• . It had a “tangerine wedge” morphology (Figure 3 and Figures S9 and S10, Supporting Information File 1), with evident macropores present on the surface of the particles. The size distribution of the F-1 particles was in the range of 3–5 to 45–50 μm, and most of the particles had a size within a range

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• species demonstrated that the distribution of secondary metabolite biosynthetic genes was not the same even in phylogenetically close species [11]. This finding became our starting point to explore the secondary metabolism in actinomycete genera from which no secondary metabolites were described. “Rare

• minimum energy. The ECD spectra of the 6 structures were simulated by the calculation of 25 states using TD-DFT at the ωB97X-D/Def2-TZVP-PCM(MeCN) level of theory, and then averaged based on their Boltzmann distribution. The calculated ECD spectra were red-shifted by 15 nm. The NMR and ECD spectra of

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• electronic distribution and the spectroscopy of the excited states of benzaldehyde (8) have been examined. These studies illuminate the ways that the various excited states of benzaldehyde (8) decay, either through phosphorescence or through the dissociation to benzene (21) and carbon monoxide (22) or to a

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• peropyrene 1. Furthermore, the observed isotopic distribution was fully consistent with its simulated spectrum (Figure 1). Characterization of the resultant product by single crystal X-ray analysis unambiguously revealed the selective formation of 1 through twofold [3 + 2] pentannulation and sequent twofold

• -fused PAHs in large π-systems. High-resolution MALDI-TOF mass spectrum of 1. Inset: isotopic distribution compared to mass spectrum simulated for C84H50. Single-crystal X-ray structure of 1. (a) Top view and (b) side view of the (P,P) isomer. c) Crystal packing of the enantiomer pairs (P,P and M,M) of 1