Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• . Finally, we evaluated the antibacterial activities of the compounds obtained in this study. As a result, only compound 3 exhibited weak activity against Staphylococcus aureus ATCC 6538 and Bacillus cereus with the minimum inhibitory concentration (MIC) of 500 µg/mL, respectively. Preterretonin A, the DMOA

• -derived counterpart of 3, displayed weaker activity against the two bacterial strains and was not active at the concentration of 500 µg/mL. Thus, the lack of the C-5′ methyl group somehow contributes to the biological activity of 3. Conclusion We employed a pathway engineering approach to create a series

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• using the same protocol as described above for Hyg17 except that a HiLoad 26/600 Superdex 200 pg size-exclusion chromatography column (Cytiva) equilibrated in 50 mM NaCl, 20 mM Tris pH 8.0 was used. Protein concentration was determined by UV absorbance at 280 nm using the calculated extinction

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• ) were used. 1 mL of a 2a–c solution and 1 mL of a perchlorate solution were mixed directly in the cuvette and thoroughly stirred. Hence, the working concentration of the compounds 2–c and the cations was 5.0 × 10–5 mol⋅L−1 and 1.0 × 10−5 mol⋅L−1. HRMS analysis was performed on a Bruker UHR-TOF Maxis

• after the addition of metal perchlorates (с2a 5 × 10−5 mol·L−1, сM2+ 1.0 × 10−4 mol·L−1). Job’s plot at the wavelength 429 nm, reflecting the interaction of compound 2a with Fe2+ in acetonitrile. The total concentration c2a + cFe2+ was 1.5 × 10−4 mol·L−1. Fluorescence intensity of compound 2a upon

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• pI50 values were calculated from plots of inhibition values vs test compound concentration using Model 205 of the ID Business Solutions Ltd Xlfit software suite. The FAT A binding fluorescent tracer was synthesized from (2S,4S)-4-[(2,6-difluorophenyl)methoxymethyl]-4-ethyl-2-methyl-N-(prop-2

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• faster with more Lewis basic urea substrates, (3) mixed solvents are uniquely able to enhance rates, with protic methanol and DCM identified as the best combination, and (4) kinetic isotope effects are variable depending on the concentration of protons in solution with small deuterium KIE’s at low

• concentration of deuterated species and large solvent KIE’s when performed in pure CH3OH versus CD3OD. Connections between catalyst activity and decomposition were made and a structurally interesting new bisphosphine–gold complex was isolated. Although our results do not provide conclusive evidence for or

• , Table 2, entry 4). We were not able to determine the maximum impact of added MeOH, because the rate of cyclization became too fast to be detectable by 1H NMR kinetics (t < 5 minutes). A LN-LN plot of MeOH concentration versus observed rate gives a slope of 0.7, indicating less than first order

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• , the bacteria were cultivated in the LB broth medium at 37 °C for the human pathogenic bacteria, while the temperature was 28 °C for the aquatic pathogens, and they were prepared at a concentration of 1.5 × 108 CFU/mL. Tested compounds and positive control (chloramphenicol) were dissolved in DMSO to

• give a stock solution with DMSO as a negative control. Then, 95 μL of thus prepared bacteria and 5 μL of the above tested compounds or chloramphenicol (with the final concentration of 0.5, 1, 2, 4, 8, 16, 32, 64 μg/mL) were added into the 96-well plates and cultivated at 37 °C or 28 °C for 24 h

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

• reduction in the concentration of these cytokines, as well as, increased intestinal permeability and improved expression of tight junction proteins that control the polarity of cells when using DIM in Caco-2 human cells [3]. BIMs have also been linked with the therapy of various cancers with one of their

• -effects that it can cause in the more sensitive subgroups of patients. Specifically, when DIM was used in tandem with tamoxifen, the ratio between 2OHE1/16αOHE1 increased up to 229%, as well as the concentration of the sex hormone binding globulin (SHBG) that inhibits the growth of breast cancer cells [4

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• resulting concentration of radicals. In such instances, opting for a stronger catalytic reductant or utilizing a stoichiometric electron donor can greatly improve the efficiency of radical generation. On the other hand, additional factors such as the ability of Brønsted and Lewis acid additives to promote

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

• kinetics allowed us to derive an IC50 of 1.4 µM (Figure S2a,b; Supporting Information File 2). No inhibition was observed with chondroitin 6-sulfate tetrasaccharide (CSC), and only very weak inhibition for BGHT2 but no IC50 could be determined as we could not increase the concentration to reach the plateau

• crystallography. We obtained several hits for the full-length protein after sparse screening using a crystallization robot at the HTX platform, EMBL, Grenoble. Pill-shaped crystals obtained under conditions of a high salt concentration, in particular ammonium sulfate (Figure S3, Supporting Information File 2

• reference (streptavidin only) and subtracting a blank injection (running buffer – zero analyte concentration). Data evaluation and curve fitting was performed using the provided BIACORE X100 evaluation software (version 2.0). Measurements were at least done in duplicate. Then, to perform competition

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• were run using other solvents such as toluene and chlorobenzene, increasing the C70 concentration from 1.2 M to 2.4 M, and decreasing the catalytic load to 5 mol % (Table S1 in Supporting Information File 1). However, none of these trials improved the yield of bis(fulleroid) 2a. The same reaction was

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• cyclic voltammogram of 1. (B) Cyclic voltammograms of 1 in the presence of additives (AcOH or HFIP). (C) Comparison of oxidation potentials of 1 using Bu4NOAc or Bu4NCl. (D) Cyclic voltammograms for the cathodic side. All cyclic voltammograms were recorded in CH2Cl2/Bu4NPF6 (0.1 M). Sample concentration

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• and straightforward as it is usually considered. Keywords: concentration; glycosylation; protecting groups; reactivity; sialic acids; stereoselectivity; Introduction Glycoconjugates containing sialic acid occur on the surface of all cell types in a variety of organisms. They participate in a broad

• ]. As in other glycosylation reactions [22][23][24][25][26][27][28][29], the result of sialylation is affected by a variety of variables [30][31][32][33][34][35][36][37][38][39] including the nature of protective groups on either partner [26][38][40][41][42][43][44][45] and concentration of reagents [31

• affect the outcome of glycosylation [31][33][34][37][39][43][44][46][56][57], one must choose a concentration at which to perform the test glycosylation. This can be done either by analogy with similar reactions or by utilizing some rationalization, the second approach is more attractive. For the

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• large excess of HF·Py (40 equiv) proved to be necessary to remove the bulky silyl group. After concentration, the crude product was acetylated (Ac2O/Py, 1:2, v/v), furnishing per-acetylated compound 8 in a 53% yield over the 3 steps. Deacetylation of 8 with freshly prepared 1 M NaOMe/MeOH in MeOH at pH

• cell. Samples were prepared at the concentration (g/100 mL) in the solvent indicated. Deprotected glycans were lyophilised using a freeze-dryer Alpha 1-2 LDplus (Christ Ltd): pressure: 0.055 mbar; ice-condenser temperature: −55 °C. 2-[2-(2-Azidoethoxy)ethoxy]ethyl 3-O-acetyl-2-deoxy-4,6-O-di-tert

• hours. Filtration followed by concentration and lyophilisation of the filtrate yielded 2 as a pale-yellow foam (972 mg, 66%). Rf = 0.3 (EtOAc/MeOH, 3:2); [α]D +76 (c 1.0, H2O); 1H NMR (500 MHz, D2O) δ 4.95 (d, J = 3.8 Hz, 1H, H-1GalNAc), 4.62 (d, J = 7.9 Hz, 1H, H-1Gal), 4.41–4.31 (m, 4H, H-2GalNAc, H

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• results in the formation of a 6,6-dicyano-heteropentafulvene derivative 37 as an additional byproduct along with the typical TCBD adduct 4 (Scheme 14) [117]. The yields and formation ratios of 4 and 37 depend on the type and concentration of the surfactant employed. For instance, when the nonionic

• surfactant, Brij 30, was used as the reaction solvent at a concentration of 20 mM, exceeding the critical micelle concentration, 4 and 37 were obtained in a ratio of 53:47, with 64% yield. Notably, 37 exhibits instability in silica gel and polar solvents. In particular, when 37 is kept in ethyl acetate or

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• comparison with control experiments without photosensitizer. In general, a photoinduced DNA damage by the quinolizinium 3f was observed, whose extent increased with increasing irradiation time and with increasing concentration of 3f. Thus, after 2 min of irradiation with fixed concentration (c = 2.5 × 10−5 M

• ) 38% of the supercoiled DNA were transformed to the open-circular form, whereas after 5 min, 73% of the DNA were damaged by strand cleavage (Table 2A). At the same time, experiments with varying ligand concentration revealed 81% of damaged DNA after 2 min of irradiation with c = 5.0 × 10−5 M, which

• -electrophoretic analysis of photoinduced DNA-strand cleavage in the presence of 3f depending on the irradiation time (A), on the concentration (B), and in the presence of 3c,e–g (C). Lanes 1, 10 and 11 (A) and lane 11 (B): control experiment without 3f. Lanes 1 and 2 (B): control experiment without 3f, irradiated

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• coefficient, c is the concentration of a light-absorbing solute, and d is the optical path length. Figure 8 shows the measured absorbance as function of the photocatalyst loadings in the methanol/water solution using different optical path lengths. The absorbance depends linearly on the photocatalyst

• concentration for low concentrations, which agrees with the Beer–Lambert law [33][34]. An extinction coefficient of 3.5 L g−1 cm−1 was determined by fitting the experimental data. The deviation of the absorbance from the linear relation is attributed to increased scattering at high loadings and/or long optical

• photon flux density, c0 is the photocatalyst concentration, and kr is the recombination rate. The linear correlation between reaction rate and photon flux visible in Figure 12b indicates that the system is still in regime 1 and the hydrogen generation rate is limited by the available photon flux, even

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• dispersion is likely composed mostly of isolated DWCNTs. To investigate the liquid crystal behavior, the DWCNT dispersion was concentrated by ultra-filtration (Figure 2a). As the concentration of DWCNTs increased, the isotropic phases (Figure 2d, the DWCNT concentration = 0.078 vol %) changed to the nematic

• phase (Figure 2b, the DWCNT concentration = 0.41 vol %). At intermediate concentrations, biphasic states appeared where the nematic droplets, tactoid, coexisted in the isotropic phase (Figure 2c, the DWCNT concentration = 0.16 vol %) [15][17][22][23][29][30]. The nematic phase shows disturbed textures

• obtained values for the SWCNT-SC dispersions (L/D = 1088 and = 665, black symbols) [22][23]. The Onsager theory predicts that the phase transition concentration for rod-like particles with aspect ratio L/D is ϕiso~bip = 3.34 D/L and ϕbip~nem = 4.49 D/L [24]. The L/D dependence of each phase transition

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• study was performed by monitoring the appearance of the zwitterion absorption by means of UV–vis spectroscopy in chloroform or in methanol as the solvent. The concentration of the respective Michael acceptor was varied ([Michael acceptor] = 2.5 mmol/L to 10 mmol/L) and was at least ten-fold higher than

• the concentration of the phosphine 1 ([1] = 0.25 mmol/L) to obtain pseudo first-order kinetics. Figure 4 shows typical time vs conversion plots for an initial Michael acceptor concentration of 7.5 mmol/L. Time conversion plots were then evaluated using COPASI [47]. To obtain second-order rate

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• tighter and more adaptable aromatic–aromatic stacking interactions. The aliphatic amphiphile sodium dodecyl sulfate (SDS) showed a 10-times lower efficiency compared to PA-Im under the same conditions (Figure S38 in Supporting Information File 1). The concentration of C60 in the solution of (PA-Im)n·(C60

• showed broad, featureless absorption bands, with a characteristic small peak at ≈580 nm for the E22 transition only in the case of the s-CNT host–guest composite (Figure 4f,g) [24]. The concentration of GN in the aqueous solution of (PA-OCH3)n·(GN)m was estimated to be ≈0.03 mg mL−1. Amphiphile PA-OCH3

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• cells within the concentration range. This indicates the low cytotoxicity of these compounds. Meanwhile, compounds 3m,l are characterized by a borderline inhibition of cell culture viability. Attention is drawn to the increased toxic effect of 3m on cells of tumor origin, in comparison with normal human

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• OD600 reached 0.8. After the culture was cooled on ice for 30 min, isopropyl β-ᴅ-thiogalactopyranoside (IPTG) was added to the culture (for CmaA1 and CmaA3 expression, final concentration was 100 µM; for CmaA6 expression, IPTG was not added) and incubated with shaking (150 rpm) at 15 °C for 20 h. Cells

• µL of 4.0 µM AvaA7 (final concentration: 0.2 µM) and 5.0 µM of different concentrations of NADPH or NADH (final concentration: 25–800 µM) were added to the reaction mixture (final reaction volume: 100 µL). The initial velocity of the reaction catalyzed by AvaA7 was estimated by monitoring the

• decrease in absorbance at 435 nm for 3-DAA using a SpectraMax M2 microplate reader (Molecular Devices, San Jose, CA, USA). The kinetic parameters (Vmax, kcat, and Km) were calculated by fitting the substrate concentration [S]–initial velocity (v) plot using the equation v = Vmax × [S] / (Km + [S]). To

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• many radicals [28][29][30][31]. The reaction is substantially accelerated by UV excitation at 365 nm; quantitative conversion of benzyl bromide at low initial concentration (3 mM) can be achieved within 1 h using both (N-DMBI)2 or (Cyc-DMBI)2 and UV (Table 1, entries 3 and 6), while even at higher

• -normalized initial reaction rate (d([RX]/dt)0/[D2]0) as a function of the initial benzyl bromide concentration ([RX]0) obtained from several experiments of the type shown in part (a) for different [D2] and [RX] for both D2 = (Cyc-DMBI)2 and (N-DMBI)2. For these slow reactions, the “initial” rates were

• estimated from the change of substrate concentration over the first 30 min reaction time. Top: UV–vis absorption spectra for the two dimeric reductants in THF emphasizing (a) the different positions of the relatively strong absorption peaks and (b) the presence of a low-energy shoulder in the spectrum of (N

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• . By using these solvents, we aimed to investigate and visualize the charge transfer nature of the organic compounds under study through their spectra. To prepare the films, we used a spin-coating method by using a high-concentration THF solution (2 mg/mL). To study the phosphorescence spectra of Me

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• @C2v-C82 anion with 1a. 110 °C, 2 h. (b) La@C2v-C82 with 1a. 110 °C, 2 h. (c) La@C2v-C82 anion with 1a. hv > 350 nm, 1 h. (d) La@C2v-C82 with 1a. hv > 350 nm, 1 h. Black line is the HPLC profiles of La@C2V-C82 at the same concentration as the reaction. Reaction mixtures with La@C2v-C82 anions were