Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• unique compounds at a set concentration against T84 human colon cancer cells has provided useful preliminary comparative cytotoxicity data, which can be directly compared to our previous publication showing the effects of crude A. mexicana extracts against this same cell line [9]. However, further

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• bacterial lineages including actinobacteria [4][5][6][7][8][9], myxobacteria [10] and aquatic cyanobacteria [11][12], as well as in liverwort [13] and ascomycete fungi [14]. The odour qualities of 1 may be concentration dependent and range from musty at low concentrations (<1 μg L−1) to camphoraceous at

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• Information File 1). The photoluminescence (PL) characteristics of 4BGIPN have been studied in methylcyclohexane solution (MCH, concentration 3.2 × 10−5 M) and Zeonex polymer films (0.1% concentration by weight) at 298 K and 77 K, which is shown in Figure 5 with data collected in Table 3. Compound 4BGIPN

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• alternative to toluene. The use of chloroform (Table 2, entry 2), as in our previous report [17], showed an improvement on selectivity, however, toluene was chosen as a more benign solvent. After further optimization of the acidic resin, stoichiometry, concentration, temperature, and reaction time (see

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• synthesis of porphyrin 3. Further, the effect of catalyst loading on the rate of reaction was examined by varying the concentration of TCA. The yield of the desired product 3 decreased significantly by lowering the amount of TCA from 20 mol % to 10 mol % (Table 1, entry 11). Whereas no increment in the

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• employ redox mediators can use compounds such as cobalt bipyridine complexes which undergo fast reversible electron transfer reactions [2][4][8]. Z-schemes require a steady state concentration of both oxidized and reduced redox mediator species to allow an efficient shuttling of electrons between

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• deuterated solvents CD3SOCD3 and CD3OD, respectively, were used in 13C NMR spectra calibration. An Anton Paar MCP-150 Polarimeter (Graz, Austria), was used to measure the optical rotations on a 100 mm path length and sodium D line at 589 nm. The sample concentration was 1.0 mg/mL in MeOH. A Shimadzu UV–vis

• 2450 spectrophotometer (Kyoto, Japan) was used to measure the UV–vis spectra at a concentration of 0.02 mg/mL in MeOH. The chemicals and solvents (analytical and HPLC grade) were purchased from Merck KGaA (Darmstadt, Germany), AppliChem GmbH (Darmstadt, Germany), Carl Roth GmbH & Co. KG (Karlsruhe

• brief, 20 µL aliquots of the compounds (1 mg/mL), in methanol were pipetted into the 96-well plates consisting of the respective test microorganisms, with a concentration range between 67 µg/mL and 0.5 µg/mL. Cytotoxicity assays MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test was

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• increase the concentration from 0.06 M to 0.6 M (Table 1, entry 7) maintaining approximately the same reaction time, while further concentration increase resulted in substantially slower kinetics (see Supporting Information File 1, Table S2). When performing the reaction in the dark or under visible light

• negligible depending on the concentration of water. Conclusion A catalyst-free methodology for the selective oxygenation of heteroatoms (S, P, Se) has been developed using only air, water, and light. The protocol allows high conversion and excellent selectivity for a wide scope of substrates, with relative

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• radical anion or radical cation. As a semi-stable, higher energy ground-state entity, this can accumulate in sufficient concentration under the reaction conditions to absorb another photon and thereby generate a super-reducing or super-oxidizing excited state (Figure 2 left). In addition to ‘radical ion

• charge recombination via unproductive back electron transfer (PC•− + D•+ → PC + D), preventing the second excitation. The prevalence of this charge recombination process in conPET effectively regulates a lower steady-state concentration of active photocatalyst compared to PEC where the electrochemical

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• NMR reaction monitoring showed that compound 1d under conditions of excess of KOH in methanol undergoes alkaline hydrolysis along with transesterification of the ester group to give the ring-opened form 6d (Scheme 4), the maximum concentration of which was observed approximately 30 minutes after the

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• unlikely to be detected in ns-TA spectra due to its transient character (the lifetime of this state is short, its concentration is too low to be detected by ns-TA spectroscopy) [67][68]. The monoexponential decay kinetics indicate that the 3LE and 3CS state are in good equilibrium, i.e., the spin–vibronic

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• stoichioimetry and that a number of simple and modified cyclodextrins bind CO2 in water with a Kg of 0.18–1.2 bar−1 (7–35 M−1) with per-O-methyl α-cyclodextrin having the highest CO2 affinity. Keywords: carbon dioxide; crystals; cyclodextrin; gas binding; Introduction The concentration of carbon dioxide (CO2

• Table 1. As CO2 is in large excess high crystal yields can be obtained even though the CD cavity is only partially filled, because more CO2 is bound in solution as crystallization proceeds. When equilibrium is reached as in entries 1–3 (Table 1) the concentration of 1·CO2 is 0.04 M which must be the

• lipophilic cyclodextrin derivative. It suggests that stronger CO2 binders can be found by improving on these two traits. Experimental Crystallization experiments. A cyclodextrin solution was prepared by dissolving 1 in Milli-Q water to the indicated concentration (Table 1) . The solution was then filtered

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• vs high) (Figure 1B). Each AGA experiment was performed at two different reaction scales (15 vs 30 µmol). All AGA runs were performed adjusting the resin amount to the desired reaction scale, while keeping the concentration of all other reagents constant (Figure 1B). The photolabile linkers L1 [22

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• [98]. Reducing the substrate concentration increased efficiency while assisting in avoiding the oligomerization pathways (Table 1, entries 2 and 3). Higher photocatalyst loadings resulted in an increased yield (Table 1, entry 4). Control experiments showed that both the photocatalyst and light were

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• diode array detector over the range from 190 to 650 nm. Subsequently, the relevant metabolites were further purified by isocratic fractionation, by lowering the concentration of acetonitrile by 10% compared to the elution concentration that was achieved with the gradient method. Chrome azurol S assay

• being tested were dissolved in methanol at a concentration of 50 µg/10 µL. Each compound was impregnated onto filter papers at a volume of 10 µL per disc. The inoculated plates were then incubated at 30 °C for 48 hours. The antibacterial activity was evaluated by measuring the zone of inhibition against

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• = 0.9926, and the limit of detection is 4.12 × 10−8 mol·L−1. The fluorescent probe can be used to detect the concentration of Hg2+ ions in aqueous solution, and provides a theoretical basis for the development of new fluorescent probes for detecting heavy metal ions. Keywords: 1,2-bis(4-pyridyl)ethane

• + ions showed that the fluorescence intensity of the probe at 380 nm increased with the increase of Hg2+ ion concentration (Figure 7a). When n(TMeQ[6])/n(G) = 1:1, increasing the concentration of Hg2+ ion will not lead to a significant change in fluorescence intensity, indicating that the guest molecule

• G and TMeQ[6] form an inclusion complex with a molar ratio of 1:1. As shown in Figure 7b, when the concentration range of Hg2+ ions is 0.33 × 10–5–1.65 × 10–5 mol·L−1, the fluorescence enhancement of the system has a good linear relationship with the concentration of Hg2+ ion. The linear regression

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• in higher yields of quinoline 5a. The optimal solvent volume (the concentration of 2a) was chosen considering both reaction yields and practical reasons. Subsequent tuning of temperature and reaction time ensured quantitative NMR yield in the model reaction (Table 1, entry 13). A remarkable advantage

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• compounds 1–5, 7, and 8 was assessed via a cell proliferation assay using Panc02-h7-GP-GFP cells. Unfortunately, none of the compounds did inhibit the proliferation of Panc02-h7-GP-GFP cells at a concentration of 20 μM (Figure S41 in Supporting Information File 1). On the other hand, an enhancement of CD8

• culture, cells were pretreated with compounds at a 20 μM concentration or DMSO for 48 h, with gemcitabine as a positive reference drug. Subsequently, Cell Count Kit-8 (CCK-8, MCE, USA) was added to each well at a 10 μL concentration for 2 h. The absorbance at 450 nm was measured using a microplate reader

• cell line) cells were incubated in high-glucose DMEM (GIBCO, USA) containing 10% fetal bovine serum (FBS, GIBCO, USA), 100 U/mL penicillin, and 100 μg/mL streptomycin. Cells were maintained in an atmosphere of 5% CO2 at 37 °C and subsequently plated in 96-well plates at a concentration of 2 × 104 cells

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

• revealed that this reaction was almost a zero-order reaction as shown by the red line in Figure 2, which did not depend on the concentration of 1a (Figure 2). As shown in entries 3 vs 4 in Table 2, the rate-determining step is considered to be the catalytic cycle A in Scheme 1, which is consistent with the

• for aerobic oxidation, the concentration of the reaction solution was returned to that of batch conditions to maximize the throughput (Scheme 3 and Table 4). When the reaction solution was passed through the honeycomb reactor three times, the reaction was completed in two cycles. The increased

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke–Blackburn–Bienaymé and Ugi reactions

• Oleksandr V. Kolomiiets,
• Alexander V. Tsygankov,
• Maryna N. Kornet,
• Aleksander A. Brazhko,
• Vladimir I. Musatov and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2023, 19, 727–735, doi:10.3762/bjoc.19.53

• microorganisms (see Table 3 for details). Both Gram-positive and Gram-negative bacteria (specifically, strains of E. coli and B. subtilis) were equally inhibited in their growth. Compound 7o, in particular, was able to inhibit the growth of B. subtilis at a concentration of 125 mg/L. Bacteriostatic activity

• the given concentration range. Despite the low level of antibacterial activity observed with the synthesized heterocycles, this could be beneficial for screening these compounds for other types of activity, such as anticancer or antidiabetic effects, since it would minimize any negative impact on the

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

• Information File 1). When the concentration of CS-TPE in aqueous solutions at pH 5.3 was increased from 0 to 80 µg/mL, the optical transmission at 293 nm gradually decreased, suggesting the formation of larger-size aggregates in the solution. As indicated by the inflection points in the curve of optical

• transmittance at 293 nm versus the concentration of CS-TPE, the CACs of CS-TPE with Rf = 2, 10 and 20 mol % were determined to be 32 µg/mL, 34 µg/mL and 35 µg/mL, respectively. Furthermore, CS-TPE solutions with concentrations above the CAC values exhibited a significant Tyndall effect, suggesting the existence

• displayed in Figure S4 (Supporting Information File 1), free TBTQ-C6 (0.10 mM) showed no Tyndall effect in an aqueous solution. However, when mixed with CS-TPE at a concentration of 10 μg/mL, well below their CAC values, clear Tyndall effects were observed, indicating the formation of a large number of

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• (1 to 5 mol % with regards to furfural). The flow rates of pumps A and B being equal, the concentration of furfural in mixture A was ≈0.7 M and that of all furfural derivatives was 0.35 M in the final mixture. Mixture A was passed through a fixed bed reactor 1 filled with magnesium sulfate. The

• lower concentration of the catalyst in the solution, appears to prevent, or at least greatly reduce, the formation of ruthenium aggregates as observed previously, probably by simple dilution effect. As such, the preheating was suppressed for the continuation of our investigations. Extending the scope of

• product was recovered for analysis and purification. The NMR yields were calculated on the alkylated imine before purification (based on a starting concentration of furfural of 0.35 M), and the isolated yields corresponded to the C3-alkylated aldehydes after the hydrolysis step that took place during

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• DABCO provided the best result in terms of reactivity, yielding compound 3a in 77% yield. We also observed that either increasing or decreasing the concentration of the reaction mixture did not bring any improvement (entries 10 and 11, Table 1). Then, the ratio between the reagents was optimized. In

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

• simulations additionally supported the pronounced hypochromic effect (chapter Computational analysis). Fluorescence spectra Fluorescence emission of Phen-Py-1 and Phen-Py-2 measured at pH 5 and pH 7 (cacodylate buffer, Ic = 0.05 mol dm−3) was linearly dependent on the concentration up to 4 × 10−6 mol dm−3

• 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

• complex at the same concentration (Figure 5). The complex of Phen-Py-1–ct-DNA showed a decrease of the CD signal compared to the sum of Phen-Py-1 and ct-DNA spectra, while the complex of Phen-Py-2–ct-DNA showed a small increase of the CD spectra compared to the sum of Phen-Py-2 and ct-DNA. It was