The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

• Moisés Alejandro Alejo Hernandez,
• Katia Pamela Villavicencio Sánchez,
• Rosendo Sánchez Morales,
• Karla Georgina Hernández-Magro Gil,
• David Silverio Moreno-Gutiérrez,
• Eddie Guillermo Sanchez-Rueda,
• Yanet Teresa-Cruz,
• Brian Choi,
• Armando Hernández Garcia,
• Alba Romero-Rodríguez,
• Oscar Juárez,
• Siseth Martínez-Caballero,
• Mario Figueroa and
• Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

• catalyze the formation of Dha-Cys or Dhb-Cys [21]. Moreover, lanPt encodes a membrane protein with two ABC transporter domains and a C39 peptidase domain. The protein cleaves the leader peptide to generate mature lanthipeptides and exports them to the extracellular environment [22]. The diversity of

• in more pronounced morphological changes after 5 hours of treatment. The changes included the loss of the characteristic cocci structure, with the formation of blebs that increased the membrane's rugosity. Besides, cytosolic leakage and remnants of the outer membrane were identified (see Figure 6B, C

• , G, and H). The treatment with the mature peptides led to numerous blebs visible after 1 hour. Interestingly, no cocci structures were detected after 5 hours of treatment (see Figure 6). The precursor peptides, especially cellulosin, appear to elicit some effects on the membrane of S. epidermidis

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• oxidation of phenols on A- and E-rings, yield bisquinone 94. The membrane-bound peptidase SfmE excises the long-chain fatty acid moiety on the N-terminus of the C1 side chain. Secretion through the efflux pump SfmG, and extracellular oxidative deamination catalyzed by the berberine bridge enzyme (BBE)-like

• fatty acid moiety on the C1 side chain (Scheme 9). Although the enzymatic deacylation of 94 can be catalyzed by the membrane-bound peptidase SfmE, similar chemical transformations require harsh conditions and are difficult to perform in the presence of highly reactive functional groups. To circumvent

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• perform oxygen-directed methylation [59]. A range of natural products are known to undergo O-methylation [61], improving membrane permeability, absorption, and oral bioavailability [61][62]. The most extensively studied O-MTs are those that methylate catecholic hydroxy groups [63]. Several O-methylation

• proteusin family of RiPPs. They are produced by the tunicate symbiont Candidatus Entotheonella factor and exhibit membrane activity against Gram-positive bacteria and are highly cytotoxic. Cytotoxicity was tested with murine leukaemia cells; polytheonamide A, B, and C showed IC50 values between 68 and 78 pg

• towards the C-terminus, named "axial amphipathicity". Thus, this methylation is thought to play an important role in correct target membrane insertion and the associated cytotoxic effect [125]. TsrM is another cob(II)alamin-dependent C-MT (Figure 10). This enzyme is involved in the biosynthesis of

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• applications and performances depend on key components such as their separators/ion-exchange membranes. The most studied and already commercialized Nafion membrane shows great chemical stability, but its water content limits its high proton conduction to a limited range of operating temperatures. Here, we

• -triazinephosphonate (TPs) derivatives. The evaluation of the proton conduction properties of the new membranes and relative humidity (RH) conditions and at 60 °C, showed that they present higher proton conductivities than the prepared Nafion membrane and similar or better proton conductivities than commercial Nafion

• N115, in the same experimental conditions. The Nafion-doped membrane with compound TP2 with a 1.0 wt % loading showed the highest proton conductivity with 84 mS·cm−1. Keywords: electrolyser; fuel cells; Nafion-modified membranes; phosphonates; proton exchange membranes; triazine; Introduction

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• found in nature in order to enable different biological functions in a precise manner, e.g., actin in biological molecular motors, the cytoskeleton, and cell membrane [5][6][7][8]. Mimicking natural supramolecular assemblies in aqueous medium, the intrinsic supramolecular dynamicity, stimuli

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• cyanoarenes, nitroarenes, quinolines, and pyridines using a proton-exchange membrane (PEM) reactor was developed. Cyanoarenes were then reduced to the corresponding benzylamines at room temperature in the presence of ethyl phosphate. The reduction of nitroarenes proceeded at room temperature, and a variety of

• hydrogen [13][14][15][16][17][18]. Meanwhile, electrochemical systems using solid polymer electrolytes (SPEs) have recently attracted significant attention [19]. Among these, proton-exchange membrane (PEM) reactors are powerful tools for hydrogenation [20][21][22][23][24][25][26][27][28][29][30][31][32][33

• ][34][35][36][37][38][39][40][41][42][43]. The PEM reactor included a membrane electrode assembly (MEA) consisting of a PEM and an electro-catalyst supported on carbon (Figure 1). Humidified hydrogen gas (H2) or H2O was injected into the anodic chamber and the substrate passed through the cathodic

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• obtained by centrifugation at 50400g for 16 h and subjected to UV−vis−NIR measurements (Figure 3a). After concentrating the extract obtained above, the residue (e-SWNTs) was suspended in dichloromethane by sonication and filtered through a PTFE membrane (pore size 0.1 μm). This washing process was repeated

• PTFE membrane. This process to remove host molecules was repeated three times, until no absorption bands from the host molecules were observed in the UV−vis spectra of washings. After the resulting p-SWNTs were washed with dichloromethane several times to thoroughly remove all the organic molecules

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

• several significant processes, terpenoids play an indispensable role in cell-wall and membrane biosynthesis, sensing, plant defense, electron transport, or conversion of light into chemical energy [1][2]. Based on the number of hydrocarbon units, terpenes are classified into various families like

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• living organisms produce and use such metabolites as biocatalysts in nature. Therefore, it is thought that the production of HSMs has some physiological significance. For example, other microbial species reportedly activate energy metabolism and strengthen the cell membrane or walls in high-temperature

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• brevis [27], can penetrate the lipid phase of a Gram-positive inner cell membrane [28][29]. Despite exhibiting high antimicrobial activity, this compound also disrupts the membranes of higher mammalian cells, as evidenced by their pronounced hemolytic activity [30]. Establishing a concise and diverse

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• transporters to form the siderophore Fe(III) complex extracellularly [2][3]. Subsequently, the stable and water soluble siderophore Fe(III) complex is transported across the cell membrane into the cytoplasm, where the iron is released from the complex by reduction, generating free Fe(II) ions that are

• ) resembles those of other amphiphilic marine siderophores such as marinobactins and aquachelins exhibiting the membrane affinity [21] as well as the self-assembling ability to form iron-containing vesicles [22]. This study presents another suite of amphiphilic peptidic siderophores originating in the

• hydrolysates were dissolved in water (160 µL), and treated with saturated NaHCO3 (200 µL) and 1% ʟ-FDLA in acetone (160 µL). The mixtures were heated at 40 °C for 30 minutes, quenched with 1 M HCl (200 µL), and concentrated in vacuo. The residue was dissolved in DMSO (400 µL) and passed through a membrane

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• cyclizations and post-cyclization modifications are especially important in fungal meroterpenoid biosynthesis, contributing to the structural diversity of this class of compounds. Fungal meroterpenoid cyclases (CYCs) are seven-membrane-spanning transporter-like enzymes that regulate the conformations of

• chair–chair stereocontrol, the structure basis of InsA7 should be unique. A structural comparison of InsB2 and InsA7 will help to clarify the differences in their structural bases. Recent advances in artifical intelligence (AI) have even made the structural modeling of membrane-bound proteins possible

• have also expanded the variety of meroterpenoids [41][42]. These untapped membrane enzymes will be applicable for engineered biosynthesis, with structural models providing useful information for mutagenesis, as in the engineering of meroterpenoid cyclases [11] and fungal P450 oxygenases catalyzing

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

• represents prototypes of molecular machines in which guest binding is regulated by stimuli-induced conformational changes between open and closed states (Figure 1). This feature holds significant promise for applications in sensing, drug delivery, or membrane transport within biological systems. Moreover

• release of siRNA or miRNA encapsulated within them into the solution in vitro and in vivo [21]. The closed conformation of 2 with parallel alkyl chains acts as a building block of the bilayer membrane and is packed together with other lipids. When the surrounding medium becomes acidic, the tweezers adopt

• their open conformation. This causes fluctuations and local defects in the packing of a bilayer (Figure 3), leading to membrane disruption and release of active components from within the vesicles [22]. Such concept makes these tweezers good candidates for controlled drug delivery. The group of F. Wang

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• is synthesized on the inner leaflet of the cytoplasmic membrane, before translocation to the outer leaflet, where it is then used as the monomeric building block of peptidoglycan biosynthesis. Lipid II is a validated antibiotic target for clinically prescribed antibiotics including vancomycin and

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• and at the same time improved cell membrane permeability. Therefore, it became a commonly used strategy to modify medicine candidates [22][23][24]. Based on these advantages, we envisioned a one-step synthesis of dihydropyrido[1,2-a]indolone skeletons utilizing an indole substrate and a

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

• 200 mL of water, the DWCNT-glycerol mixture was filtered through a 1.0 μm pore size polytetrafluoroethylene (PTFE) membrane (Merck, Omnipore 47mm). To ensure complete removal of glycerol from the DWCNTs, we repeated the washing process until 2 L of water had passed through the membrane, resulting in

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

• H2O (2.7 mL), the suspension was sonicated with a probe sonicator (40 kHz, 150 W, 10 min), centrifuged (16,000g, 10 min), and then filtrated (200 nm pore-size membrane filter) to yield a clear brown solution containing host–guest composite (PA-OCH3)n·(C60)m. The UV–visible analysis clearly showed new

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

• recent studies [9][10][11][12][13][14]. Most of them belong to the adenylate-forming enzyme superfamily (ANL superfamily) and utilize ATP to activate nitrous acid by AMPylation, with the only exception being AzpL in alazopeptin biosynthesis, which is a membrane protein that catalyzes diazotization

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• achieved, for example, by immobilizing the catalysts to a solid support [15], e.g., silica gel [16][17][18], organic polymers [19][20][21], magnetic nanoparticles [22][23], or by membrane separation, e.g., using organic solvent nanofiltration (OSN) [24][25][26], which methods can be easily implemented in

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

• cell membrane integrity [21]. In the context of cancer therapy development, metal complexes of N-acylhydrazones stand out. For example, Firmino et al. demonstrated that gallium(III) complexes of isoniazid-derived hydrazones exhibit strong cytotoxicity against HL-60 and HCT-116 cancer cell lines [22

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• synthetic and biological membranes and therefore to induce an increase of membrane permeability. However, the effect of cholesterol (CHOL) content in the membrane on the CD permeabilizing effect was not considered yet. Given that an increase in CHOL content reduces the membrane permeability, the aim of this

• work was to reveal how CHOL would modulate the CDs effect on the membrane. Hence, liposomes made of dipalmitoyl phosphatidylcholine (DPPC) and various CHOL contents (DPPC/CHOL 100:10, 100:25, 100:50, and 100:100) encapsulating the hydrophilic fluorophore, sulforhodamine B (SRB), were prepared and

• exposed to the native CDs (α-CD, β-CD, γ-CD) and four β-CD derivatives: the randomly methylated-β-CD (RAMEB), the low methylated-β-CD (CRYSMEB), the hydroxypropyl-β-CD (HP-β-CD) and the sulfobutyl ether-β-CD (SBE-β-CD) at different CD/DPPC molar ratios (1:1, 10:1, and 100:1). The membrane permeability was

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

• often attributed to high binding affinity to DNA, interference with protein biosynthesis, induction of membrane leakage, and affecting GTPase activity in bacteria cell division [12][13][14][15]. Recent reports have also pointed to inhibition of the ‘filamenting temperature-sensitive mutant Z’ (FtsZ

• ]. Similar to berberine, results have demonstrated that the antibacterial activity of chelerythrine can be tied to DNA intercalation and disruption to cell membrane permeability [11][24]. One particular mechanism of action noted for chelerythrine’s antitumor bioactivity is through the inhibition of protein

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

• ) that exhibit promising anticancer properties renew the interest in this class of compounds. Indeed, ether lipid represent a new and promising class of compounds featuring the capacity to modulate selectively the activity of some membrane proteins or, for other compounds, feature antiproliferative

• the endoplasmic reticulum (ER). Then, ELs are spread off in the cell, to the plasma membranes but also in other biomembranes (membrane of mitochondria, ER, nucleus). The occurrence of ELs in tissues was first assessed by Snyder and Woods who reported that neutral ELs and phosphoglycero ELs were

• functions of ether lipids offer an interesting overview of the current knowledge of the effect of plasmalogen and ELs on membrane properties at a molecular scale. Shortly, according to molecular dynamics simulation, PE-plasmalogens form thicker, compressed and rigid bilayers when compared to PE-diacyl

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

• . Carpenter and co-workers also proposed, but did not test, recycling their amine with electrochemistry and light [32]. They cited a work by Itoh et al. who modified a proton exchange membrane electrolyzer with a Rh–Pt catalyst to generate hydrogen from water to hydrogenate benzene to cyclohexane in one

• of artificial photosynthesis research investigating the compartmentalization of different reactions using liposomes and membranes [38]. Another alternative could be to use redox-active polymers as recyclable donors which would allow microporous membrane separation. Redox-active polymers are a very

• active area of research for aqueous and non-aqueous RFBs [59][60]. This is because often the most expensive component of an RFB is the ion-exchange membrane used to prevent the mixing of charged species and recombination. Microporous membranes are much less expensive, and the particulate size of redox