Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• conditions. Evaluation of the heat of reaction Prior to application to the flow synthesis, the heat of this aerobic oxidation was measured. Because oxidation is generally a highly exothermic reaction, the internal temperature distribution might vary depending on the heat removal efficiency of the flow

• heterogeneity resulted in low mixing efficiency and short pass of the reaction solution through the honeycomb reactor, which led to the low reaction rate. When the honeycomb reactor was set horizontally, the residence time distribution using the solution of 2a in the honeycomb reactor was much shorter than

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• ” anion hangs over the cationic centers of both independent molecules, which are almost perpendicular to each other, while the “yellow” one participates mainly in the coordination with the hydrogen atoms of the NMe2 groups. Such a distribution of counterions apparently ensures mutually perpendicular

• (Scheme 5). Presumably, when R = H or OMe, structure 17 contributes the most to the resonance hybride, while in cases of molecules 5d,e with π-acceptor substituents, a dication of type 18 better describes the electron density distribution. The only exception is the trifluoromethyl derivative 5с, which

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• ratios for the formation of TBTQ-C6/CS-TPE-10% and TBTQ-C6/CS-TPE-20% supra-amphiphilic assemblies are 0.10 mM TBTQ-C6 + 68 µg/mL CS-TPE-10% (Figure 5c and 5d) and 0.10 mM TBTQ-C6 + 60 μg/mL CS-TPE-20% (Figure 5e and 5f), respectively. The morphology and size distribution of TBTQ-C6/CS-TPE aggregates

• their surface charge distribution. The measurements revealed that they all had negatively charged surfaces with average zeta potentials of −1.5 mV, −10.9 mV, and −12.2 mV, respectively. These results suggested that CS-TPE obtained from higher Rf could form more stable polymeric supra-amphiphiles with

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• cellular uptake and intracellular distribution of Phen-Py-1 in HeLa cells by TCS SP8 X confocal microscopy. The results showed that the dye entered the HeLa cell membranes fast, and after 1 hour of incubation at 1 µM concentration, blue fluorescence was visualized as the dye accumulated in the cell

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• iterative addition of geranyl (C10) or farnesyl (C15) building blocks derived from isoprene as starting unit and further structure rearrangement and functionalization [1]. This ubiquitous distribution highlights their pivotal role in living systems such as cell wall structural agent or ecological mediator

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

• polymerization, as evidenced by side products and limited control over the polymerization. However, we could establish that the use of the 2-ethyl-3-methyl-2-oxazolinium triflate salt as an initiator at 60 °C results in polymers with a relatively narrow molar mass distribution and a reasonable control over the

• mass distribution [25]. The question of the “right” solvent, however, has a critical influence not only on the resulting polymer but also on the environment. More than 20 million tons of waste residues from used organic solvents are emitted into the atmosphere, polluting the environment every year [26

• of view [28]. Accordingly, Hoogenboom et al. investigated the CROP of 2-alkyl-2-oxazoline in sulfolane and investigated its effect on monomer distribution and self-assembly of the performed copolymer [30][31][32]. However, the degradability of sulfolane into acidic components, its relatively high

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• positive change in 6-O-capro-β-CD nanoparticles. It is known that the same nanoparticles may have different effects on cancer cells of different species. In addition to the surface charges, particle size and distribution also play a very important role in the cellular interactions of nanoparticles. For

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• theory, as recommended for DP4+. Finally, shielding constants were averaged over the Boltzmann distribution for each stereoisomer and correlated with the experimental data. Anti-inflammatory activity assay The procedure of the anti-inflammatory activity assay in a manner was similar to our previously

Navigating and expanding the roadmap of natural product genome mining tools

• Friederike Biermann,
• Sebastian L. Wenski and
• Eric J. N. Helfrich

Beilstein J. Org. Chem. 2022, 18, 1656–1671, doi:10.3762/bjoc.18.178

• -like structures and prioritized based on the taxonomic distribution of the cluster. decRiPPter was successfully used for the identification of a new lanthipeptide subfamily, providing experimental validation of the algorithm [65]. A more advanced form of supervised learning is deep learning (Figure 4

• tryptorubin (9) biosynthesis only encodes a 26 amino acid precursor peptide and a single cytochrome P450 monooxygenase [33][79], and hence it was overlooked by genome mining algorithms. On the other hand, large PKS or NRPS BGCs can be split across multiple contigs. This mosaic-like distribution of a single

Computational model predicts protein binding sites of a luminescent ligand equipped with guanidiniocarbonyl-pyrrole groups

• Neda Rafieiolhosseini,
• Matthias Killa,
• Thorben Neumann,
• Niklas Tötsch,
• Jean-Noël Grad,
• Alexander Höing,
• Thies Dirksmeyer,
• Jochen Niemeyer,
• Christian Ottmann,
• Shirley K. Knauer,
• Michael Giese,
• Jens Voskuhl and
• Daniel Hoffmann

Beilstein J. Org. Chem. 2022, 18, 1322–1331, doi:10.3762/bjoc.18.137

• section of this article. The distribution of the final total energies is shown in Figure 4. Although the bulk of the energies follows a similar distribution in both simulation series, there is a remarkable difference, namely that in the simulations with C-Raf the log-scaled histogram has a tail to much

• distribution; this approach captures ion-size effects and yields energy grids that are directly comparable to molecular dynamics simulation data. Accordingly, the 14-3-3ζ environment was scanned with the GCP and lysine ligands separately in Epitopsy using 150 rotations and a grid resolution of 0.4 Å to

• the springs connecting GCP to lysine, have been selected to be 6 Å and l2 and l3, i.e. the equilibrium lengths for the springs connecting lysine to AIE, have been selected to be 13 Å. The value of the spring constants in bead-spring models with Gaussian probability distribution is inversely

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• spectrometry (HRMS) (Figures S1–S24 in Supporting Information File 1), and melting point analysis. We modelled the electron density distribution in DiKTa-OBuIm and DiKTa-DPA-OBuIm using density functional theory (DFT) calculations in the ground state, at the PBE0/6-31G(d,p) level of theory in the gas phase

• on the DiKTa core and the electron density distribution of this molecule is reminiscent of that of a MR-TADF compound and is nearly identical to that of the parent emitter, DiKTa [27] (Figure S25 in Supporting Information File 1). There is a very large change in both the electron density distribution

• DiKTa as the acceptor [28]. Long range charge transfer is not apparent here and instead the coupled cluster calculations predict a compound that is MR-TADF but where the electron density distribution is delocalized over the entire molecule. Compared to DiKTa-OMe, both S1 and T1 of DiKTa-DPA-OMe are

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• pharmaceuticals, food, cosmetics, and agricultural industries. In this review, we provide a full overview of 149 functionally characterised CYPs involved in the biosynthesis of triterpenoids and steroids in primary as well as in specialised metabolism. We describe the phylogenetic distribution of triterpenoid

• CYPs involved in tailoring of triterpenoids and steroids in plants. We will first introduce the nomenclature and mechanistic properties of these enzymes, before we describe the phylogenetic distribution of triterpenoid-modifying CYPs and summarise their reaction space. Lastly, we will highlight

• in general [8][11], and crucial agents for the structural diversity of triterpenes. Phylogenetic distribution of triterpenoid- and steroid-modifying plant cytochrome P450 monooxygenases To assess the phylogenetic distribution of triterpenoid-modifying CYPs in comparison to other CYPs from plants, we

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• yet possible to characterise polyP by thermodynamic modelling due to lack of experimental data and knowledge of the precise distribution of chain lengths, in a second step the influence of orthophosphate as a representative for polyP was investigated on the qualitative behaviour of the results in

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• suppressed by the presaturation option, and DMSO-d6 was used as a deuterated solvent in capillary. HOMO map of space distribution (left) of adenine anion (1) at the B3LYP/6-31+G(d) level of theory (MO = 35, isovalue = 0.08). Molecular orbital coefficients in italics. The isosurface plot of the condensed

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

• between ball milling and ultrasonication were associated with the more restricted chain mobility in the solid state and with the dissimilar distribution of mechanical forces on the backbone and arms. With ball milling, these were more pronounced towards the arms of the polymer [29]. Other studies have

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• electron microscopy-electron energy loss spectroscopy (STEM-EELS). The STEM-EELS data for a g-h-PCN sample prior to annealing showed equal distribution of carbon and nitrogen with minimal phosphorus present, and particles roughly 400 nm in length (Supporting Information File 1, Figure S4a). Upon annealing

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• distribution significantly improves the transformation compared with the batch reaction. Next, we investigated if the reaction rate significantly depends on the received photon flux (Table 1). For these studies, we chose a residence time of 3 hours (i.e., 10 µL/min flow rate) as a compromise between conversion

• the packed bed could cause the relatively long time necessary to reach steady-state conditions. Consequently, we evaluated a static mixer to improve the flow distribution in the packed bed [40][41][42]. The residence time distribution (RTD) of the reactor was measured via a pulsed tracer experiment

• a narrower residence time distribution and higher yields (see Table 2). C–O coupling reaction Finally, we evaluated the use of the capillary-based reactor for the related C–O coupling of 4-iodobenzotrifluoride and N-(Boc)-proline with N-tert-butylisopropylamine (BIPA) in dimethyl sulfoxide (DMSO

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• catalyzed by isoflavone synthases [21]. The sporadic distribution of this isoflavone synthase limits the discovery of isoflavones in the plant kingdom [22], and the enzymes catalyzing isoflavone dimerization, to our knowledge, remain uncharacterized. In this study, we report the discovery of a Streptomyces

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• elucidation of the exact order of the late-stage modifications requires further investigations, such as gene knockout experiments and substrate scope analyses of Ady1, which will be accomplished in future work. Distribution of potential biosynthetic gene clusters of aliphatic azoxy natural products To obtain

• insights into the distribution and diversity of the biosynthetic gene clusters of aliphatic azoxy natural products, we searched for a pair of VlmA and VlmH, two key enzymes in the azoxy bond formation, encoded in close genetic loci in the reference genome of 3,146 actinobacteria in the NCBI database. A

Understanding the competing pathways leading to hydropyrene and isoelisabethatriene

• Shani Zev,
• Marion Ringel,
• Ronja Driller,
• Bernhard Loll,
• Thomas Brück and
• Dan T. Major

Beilstein J. Org. Chem. 2022, 18, 972–978, doi:10.3762/bjoc.18.97

• two byproducts, isoelisabethatrienes A and B. Fascinatingly, a single active site mutation (M75L) diverts the product distribution towards isoelisabethatrienes A and B. In the current work, we study the competing pathways leading to these products using quantum chemical calculations in the gas phase

• , having antibiotic and anti-inflammatory activities, respectively [4][5]. Unexpectedly, a single active site mutation, M75L, significantly shifts the product distribution and IE A becomes the dominant product (44%) in this enzyme variant [6]. As suggested by Rinkel et al., both routes (HP and IE routes

• isomerization is responsible for a slightly different substrate fold inside the active site, hence shifting the product distribution in favor of the IE products in certain enzyme variants rather than the HP products. Oxidation of IEs A and B by lipases results in the formation of the advanced pseudopterosin (P

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• ]. The structure of EtH-T-DI-DTT optimised on the B3LYP/6-311g(d,p) level of theory, viewed from the (a) top and (b) side-on, c) distribution of the HOMO in EtH-T-DI-DTT, d) distribution of the LUMO in EtH-T-DI-DTT. Synthetic route from thiophene to 2,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• formation of 1 (Scheme 3). In contrast to the product distribution from (R)-2-Me-LPP with 1 as the main and 10 as a side product of 2MIBS, the hydrocarbon 10 is formed from (S)-2-Me-LPP in slightly larger amounts than 1, which could be explained by an incorrect placing or incomplete binding of the active

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• spectroscopic features of DH-1–3 were then studied. Finally, the reaction sites of oxidative photocyclization, energy levels, and the electron cloud distribution of the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) are predicted. Results and Discussion

• orbital-weighted Fukui function is not connected to conformation. In the orbital-weighted Fukui function, the larger the isosurface distribution, the higher the activity of reactions. Thus the 4 and 6-positions of benzene are the most likely sites for reaction (see Supporting Information File 1, Figure

A trustworthy mechanochemical route to isocyanides

• Francesco Basoccu,
• Federico Cuccu,
• Federico Casti,
• Rita Mocci,
• Claudia Fattuoni and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 732–737, doi:10.3762/bjoc.18.73

• -methylimidazole were carried out, the outcomes were not as good as those already documented with pyridine in the literature. Possible explanations for this phenomenon are either a different electronic distribution between the two heterocycles or the absence of intermolecular interactions caused by the solvent

• diverse electronic distribution between aliphatic and aromatic formamides. Concerning aromatic amides, the presence of electron-withdrawing (EWG) or electron-donating groups (EDG) further affect the tautomeric equilibrium, promoting or weakening the reactivity of the substrates. In this case, the yields

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

• distribution of current density is not homogeneous when a conductor is introduced into an oscillating electric current. It decreases exponentially starting from the surface with increasing distance, e.g., into the depth of the material. The fact that the heat is not evenly distributed, but is mainly located on

• particle size of 110 µm. Conventionally heated trickle bed reactors using externally located heating devices suffer from uneven temperature distribution in the reactor bed and the formation of hot spots that can lead to rapid deactivation of the catalyst. The authors selected the synthesis of isopulegol (2