Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• Naziha Tarannam Prashant Kumar Gupta Shani Zev Dan Thomas Major Department of Chemistry and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel 10.3762/bjoc.20.101 Abstract In the current work, we analyzed the origin of difference in stabilities among

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

• Luca Julianna Tóth,
• Kateřina Krejčová,
• Milan Dejmek,
• Eva Žilecká,
• Blanka Klepetářová,
• Lenka Poštová Slavětínská,
• Evžen Bouřa and
• Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

• the beginning of the pandemic, a variety of heterocyclic small molecules – either of natural or synthetic origin – was reported as promising inhibitors of the SARS-CoV-2 RdRp [13][14][15]. However, compounds with a sufficient combination of high potency and suitable pharmacokinetic properties are

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• deuterium incorporation. However, when D2O-saturated nitromethane was used >95% D-incorporation took place. Hence the small (500–2000 ppm) content of water in commercially available nitromethane was at the origin of the hydrochlorination reaction (Scheme 16). As a result, the reaction of 104 with water

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• pathway on the adiabatic potential energy surface that connects these conformations caused by the deformation of the PASE linker. The reaction pathway for the conformational change of the PASE itself was found to have a reaction activation barrier [9]. First, we identify that the origin of the barrier is

• , where conformation 1 corresponds to a 0 rotation, conformation 2 a 2π/3 rotation, and the conformation at the activation barrier top a π/3 rotation, respectively. To confirm the origin of the activation barrier that appears between conformation 1 and 2, we discuss the structural features of the

• how an activation barrier appears on the potential energy surface in PASE adsorbed on graphene. The conformational change between two bi-stable PASE structures can be regarded as rotational motion around a C–C bond in the alkyl chain. An origin of an activation barrier is the steric hindrance coming

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

• seeds per pot depending on the plant species (10 seeds for corn and wheat spectrum). The harmful plants and crops used in greenhouse tests were the following species: Alopecurus myosuroides (ALOMY), resistant Alopecurus myosuroides (ALOMY_R, origin: Germany), Apera spica-venti (APESV), Brachiaria

• platyphylla (BRAPP), Bromus tectorum (BROTE), Echinochloa crus-galli (ECHCG), Digitaria sanguinalis (DIGSA), Eleusine indica (ELEIN), Glycine max (GLXMA), Lolium rigidum (LOLRI), Lolium sp. (LOLSS), resistant Lolium sp. (LOLSS_R, origin: France), Poa annua (POAAN), Setaria viridis (SETVI), Sorghum halepense

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

• Eiichi Kayahara,
• Yoshiyuki Mizuhata and
• Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

• suggested the partial electron transfer from [10]CPP to [5]CPP2+ in the complex, and this charge-transfer (CT) interaction is most likely the origin of the higher association constant of the dicationic complex than the neutral one. Keywords: charge-transfer; cycloparaphenylene; dication; host–guest

• photophysical and electrochemical analyses and DFT calculations. Therefore, this CT is most likely the origin of the increased Ka value. We also discuss the charged double-layer structure, as determined by X-ray crystallographic analysis. Results and Discussion The size-complementary interaction between CPP2

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

• radical acceptor moieties. Therefore, we investigated the origin of this selectivity under electrochemical conditions. Results and Discussion Anodic oxidation of uridine derivative 1 was performed in a CH2Cl2/Bu4NPF6 (0.1 M) electrolyte system using a carbon felt (CF) anode and a Pt cathode in the

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

Studying specificity in protein–glycosaminoglycan recognition with umbrella sampling

• Mateusz Marcisz,
• Sebastian Anila,
• Margrethe Gaardløs,
• Martin Zacharias and
• Sergey A. Samsonov

Beilstein J. Org. Chem. 2023, 19, 1933–1946, doi:10.3762/bjoc.19.144

• , respectively), while on the way back, the still high correlation with the H-bond number (0.58) and an essentially decreased one with the native contact number (0.36) mean that hydrogen binding dominates the binding energetics of the system and is an origin of multipose binding. When correlating the values for

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• (Figure 1C). Elongation of the tether in fullerenes 10 and 11 reduced product ratios to still significant A/D10/9 ~ A/D11/9 = 2.1. The origin of this decrease in anion–π catalysis is likely to include increasing entropy losses in pseudo-macrocyclic transition states. Normalized against the fullerene-free

• . The origin of autocatalysis on π-acidic surfaces was clarified only this year because the involvement of two molecules of water in the decisive transition state XI complicated the situation [70]. This reaction was intriguing for reasons beyond autocatalysis. It is the only example so far where

• graphite might be relevant with regard to early steps in the origin of life [124][125]. Conclusion Anion–π catalysis on carbon allotropes originates from the observation that access to strong anion–π interactions by increasing the intrinsic π acidity of aromatic surfaces is not realistic. Any permanent

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• natural products of microbial origin such as HHQ and its C5-congener. Two compounds with high activity against S. aureus have been identified among the newly obtained quinolones, with MICs ≤ 3.12 and ≤ 6.25 µg/mL, respectively. Keywords: antibacterial; β-keto amides; enaminones; 4-quinolones; quorum

• most prominent examples in this regard are the fluoroquinolone antimicrobials [3] – a remarkably successful drug class, used to treat bacterial infections caused by both Gram-positive and Gram-negative bacteria [4]. Other notable 4-quinolones of synthetic origin are ivacaftor [5] and elvitegravir [6

• avicennae [18]. Inhibition of hepatitis C virus replication by 2-nonyl-4-quinolone, isolated from Ruta angustifolia leaves, has also been reported [19]. Another significant group of natural 4-quinolones are those of microbial origin. The function of these compounds in the microbial world is a matter of

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• /HEPES mixture (pH 7.4). Experimental conditions: l = 1.0 cm and T = (25.0 ± 0.1) °C. (A) Gaussian fitting of the bands in the spectrum at t0, along with the spectra of precursors TMP (dotted gray curve) and MBA (dotted purple). Deconvolution performed with Origin software. (B) Spectra measured at t0 and

• 10% DMSO/buffer mixtures (pH ranging from 3.8 to 8.2). Inset: A440 versus pH with sigmoidal fitting. Gaussian fitting of the bands in a solution of the hydrazone in (B) 10% DMSO/acetate buffer (pH 3.8) and (C) 10% DMSO/Tris-HCl buffer (pH 8.2). Deconvolution performed with Origin software. Spectra of

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• ), suggesting that breynin formation may involve the attachment of a mercaptoacetamide to 5, followed by cyclization. However, to the best of our knowledge, the origin of mercaptoacetamide has not been reported and further biosynthetic exploration is needed. We also isolated two new sulfur-containing

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• considered to have two mechanisms, degenerative transfer and reversible termination, which are comparable to RAFT and NMP, respectively (Scheme 7) [70]. Iodine transfer polymerization (ITP) is also a commonly used degenerate chain-transfer method. Its origin can be traced back to the 1970s [71] and it is

• gaseous [195]. While the depolymerization in both systems has a thermodynamic origin [196], the mechanism of poly(olefin sulfone) depolymerization is much more complex. Bowmer et al. proposed a simultaneous radical/cationic process (Scheme 20b) [197]. Meanwhile, an anionic process is also possible in the

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

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• groups into the aromatic ring. This reaction has a great scope of forming aza-stereocenters which can be tuned by different asymmetric catalysts. This review assembles recent advances in asymmetric aza-Friedel–Crafts reactions mediated by organocatalysts. The mechanistic interpretation with the origin of

• mechanistic approaches with explanation about the origin of stereoselectivities has also been elaborated. This reaction has been successfully utilized as the key step in the syntheses of different important natural products which have been included in this article as well. On searching the literature, it has

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

• structures of compounds 1–6 isolated in this study and of the structurally related siderophores massiliachelin (7) and (S)-dihydroaeruginoic acid (8). 1H,1H-COSY and selected 1H,13C-HMBC correlations in 1. Proposed origin of the isolated compounds 1–6 as well as massiliachelin (7). Domain notation of the

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• with the bicyclic substrate to produce 123. A 5-exo-trig ring closure of 123 produces 124 followed by a rapid protodemetalation with water releasing the final indane product 119a and regenerating the active Rh(I) species. The authors proposed that the origin of the diastereoselectivity is due to

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

• Manuel Pedrón,
• Jana Sendra,
• Irene Ginés,
• Tomás Tejero,
• Jose L. Vicario and
• Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

• alkenes under chiral BINOL-derived Brønsted acid catalysis has been studied by Houk and Rueping in 2014 [33]. These authors established the origin of the enantioselectivity and the differences between the catalyzed and uncatalyzed reactions, suggesting that the catalyzed reaction is, actually, a so-called

• the reaction. To investigate further the origin of the observed lack of reactivity for medium- and long-size tethers we applied the Houk’s distortion model [30] to our substrates using the modified model [9] that allows the analysis of intramolecular reactions. According to that modified model, the

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

• Robert N. Goldberg,
• Robert T. Giessmann,
• Peter J. Halling,
• Carsten Kettner and
• Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

• study should be clearly identified, e.g., by giving the UniProtKB [15] and/or Protein Data Bank [16] identifier(s) and origin (e.g., species, tissue). If the enzyme has not been registered, one should provide as much information as possible, i.e., the source and the amino acid sequence. Reporting an

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

• -loaded polycationic-β-cyclodextrin nanoparticles caused reduced cell viability in CT26 and HT29 colon carcinoma spheroid tumors of mice and human origin, respectively. In addition, the release profile, which is one of the critical quality parameters in new drug delivery systems, was investigated

• -parenteral route. In this context, release kinetic modeling studies and 3D cell culture studies of colon carcinoma cells of mice and human origin were carried out for the first time for CPT-loaded positively charged β-CD nanoparticles with different formulations. A positive surface charge was achieved

• . According to the results of the study performed with colon cancer cell lines of two different origin (murine and human), it was observed that the blank nanoparticles caused a decrease in cell viability (to <70%). Similar results were obtained in cell culture studies performed on different cancer cells by

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

• biosynthesis → polyketide biosynthesis). As such, NP biosynthetic pathways utilize members of existing enzyme families that have evolved to perform new metabolic functions. Consequently, NP BGCs “borrow” genes encoding paralogs of enzymes that have their origin in primary metabolism and that have diverged into

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• of CD solution. The blank titrations of CDs to the solvent were performed similarly, and the heat of dilution was subtracted from the corresponding isotherms. The isotherms were fitted with ITC 200 1.25.5 (Malvern Panalytical Ltd, UK) software, based on Origin 7SR4 v 7.0552 (OriginLab Corporation, MA

On drug discovery against infectious diseases and academic medicinal chemistry contributions

• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 1355–1378, doi:10.3762/bjoc.18.141

• pharmaceutical industry which certainly owe some of its origin to the academic world [34][35][36][37]. This perspective will not describe the true chemical challenges as well as the many environmental issues surrounding this last problem. All these are actually well described in books [38][39][40][41][42][43

• experiments following the screening of a library [51][52]. However, many of these compounds, often of natural origin [53]; polyphenols and curcumin being emblematic [54], are the bread and butter of quack medicine. Indeed, these will be found active on many biochemical or cellular assays [46] and will thus

• new drugs to treat tuberculosis is also of interest. The starting point was probably CGI-17341 (20), a mutagenic compound reported by Ciba-Geigy in 1989 for its effect on mycobacteria [150]. And this substance owes its origin to the many nitroimidazole derivatives known for their anti-infective

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• nonlinear regression method (Levenberg–Marquardt algorithm) using both mono- and double-exponential functions (Microcal Origin software). In most cases, the double-exponentials described the observed behavior much better (see Supporting Information File 1, Figures S1–S11). Experimental data were fitted with