Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to (−)-sandaracopimaradiene in the fungus Arthrinium sacchari

• Fumito Sato,
• Terutaka Sonohara,
• Shunta Fujiki,
• Akihiro Sugawara,
• Yohei Morishita,
• Taro Ozaki and
• Teigo Asai

Beilstein J. Org. Chem. 2024, 20, 714–720, doi:10.3762/bjoc.20.65

• GC–MS conditions. Based on these results, we proposed that AsCPS synthesizes CPP and that AsPS subsequently converted it to compound 1. Notably, Ar. sacchari MPU169 is known as a producer of myrocins (Figure 1A), which are known to exhibit antiangiogenic activity [33]. Based on the chemical structure

• peaks were not related to diterpenoids and were likely derived from the host strain. B) Chemical structure of (−)-sandaracopimaradiene (1)). GC–MS analysis of the enzymatic reactions. A) Extracted ion chromatograms (EICs) at m/z 272 of the extracts from the reaction mixture of AsPS and AsCPS; AsPS and

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

• structure – a linear hexapeptide with β-hydroxyaspartate and hydroxamate functional groups, serving in iron-binding coordination. Three new variochelins C–E (3–5) were characterized by varied fatty acyl groups at their N-termini; notably, 4 and 5 represent the first variochelins with N-terminal unsaturated

• , including soil-isolated plant pathogens. Results and Discussion Isolation and structure elucidation In this study, we explored the secondary metabolite potential of the soil-isolated Variovorax sp. H002, domesticated from the Medicinal Plant Garden of the Faculty of Pharmaceutical Sciences, Hokkaido

• showed a molecular weight of m/z 535.7912 for the [M − 2H]2− ion, inferring a chemical formula of C47H83O17N11 (calcd 535.7911 for the double-negative ion). A combination of 1H NMR and COSY analyses revealed a peptidic structure comprising two Nδ-acetyl-Nδ-hydroxyornithine residues, a proline (Pro), a

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• to synthesise ligands featuring two chiral imidazolidin-4-one units linked to the pyridine ring at the 2- and 6- positions (Figure 1 – ligands I and II). These newly designed ligands represent tridentate entities. Such structure modification provides the ligands structurally conformable to well-known

• donor ability to pyridine. This change reduces the ring size within the ligand structure, potentially increasing the space available for coordinating reacting species, thereby possibly enhancing catalytic activity and enantioselectivity. We also aimed to assess the impact of alkyl groups at the 5

• -position of the imidazolidine ring on the enantioselectivity of the reaction. Hence, we developed a ligand incorporating an unsubstituted pyrrolidine ring instead of the imidazolidine unit (Figure 1 – ligand IV). This structure characterises a 'proline-type' derivative, enabling its use not only in a

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• : aromatic nucleophilic substitution; azide–tetrazole equilibrium; 4-azido-2-sulfonylquinazolines; quinazolines; sulfonyl group dance; Introduction The quinazoline core is a privileged structure with a wide range of applications. Quinazoline derivatives exhibit a broad spectrum of biological activities

• out also with quinazoline derivatives 1b and 1c (Scheme 2), the structure features of which may slow-down the fast SNAr processes due to the substituents’ character. The desired products 4b and 4c were obtained in MeOH and isolated in 44 and 40% yields, respectively. Methanol is known to decrease

• hours without compromising selectivity. Although tetrabutylammonium azide (TBAA) is better soluble in DMSO than NaN3, practical challenges associated with its use led to the preference for NaN3. Confirmation of regioselectivity for the sulfonyl group dance products The regioselectivity and the structure

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• react with acceptors to produce reducing radical species, capable of reducing organic electron transport materials with a low electron affinity [4][5]. It is not only in modifying the molecular structure to improve the electron accepting ability that there is innovation in new organic electron transport

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• member of the emerging ion-endohedral fullerene family, have attracted significant attention owing to the distinctive ionic properties originating from the ion pair structure consisting of a cationic endohedral fullerene core and an external counter anion. Despite being a relatively recent addition, Li

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

• analog of polycavernosides [1][3][4][5]. A detailed analysis of the NMR data revealed the planar structure of 1, as shown in Figure 2. COSY and HMQC spectral analyses revealed several partial structures, indicated by the bold bonds in Figure 2. Four HMBC were observed from singlet methyl signals: δH 0.85

• HMBC δH 1.62 (H-23)/δC 84.6 (C-25), δH 2.18 (H-24)/δC 84.6 (C-25), and δH 2.18 (H-24)/δC 68.6 (C-26) revealed a terminal alkyne structure. Additionally, COSY correlations shown in Figure 2 revealed the side chain structure of 1 containing a terminal alkyne and a conjugated trans triene (C-15 to C-26

• ). We then focused on the macrolide structure of 1. Six HMBC, δH 0.94 (H-30)/δC 82.0 (C-3), δH 0.94 (H-30)/δC 38.3 (C-4), δH 0.94 (H-30)/δC 85.3 (C-5), δH 0.90 (H-31)/δC 82.0 (C-3), δH 0.90 (H-31)/δC 38.3 (C-4), and δH 0.90 (H-31)/δC 85.3 (C-5), along with COSY correlations shown in Figure 2, revealed a

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

• the complete structural determination of 3. To overcome this challenge in structural determination, we obtained a single crystal of 3 and performed X-ray diffraction analysis, which unambiguously established the structure of 3 as 5′-desmethylpreterretonin A (Figure 2C and Figure S1 in Supporting

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• existing ones. Keywords: GBB-3CR; imidazo[1,2-a]pyridine; microwave; phosphotungstic acid; Introduction Imidazo[1,2-a]pyridine is a privileged structure that plays an important role in organic synthesis and in the pharmaceutical industry. This scaffold is present in drugs with several biological

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• the C(oxazole)–N(sulfonamide) bond. No coalescence is observed at up to 110 °C indicating that these motifs might be useful as a robust atropisomeric system. The molecular structure of 13 and 14 have been unambiguously determined by single crystal X-ray diffraction (Scheme 2) [28]. The N–metal

• interatomic distances are between 3.53 and 3.66 Å leaving insufficient space for bond rotation about the C–N axis with the sulfonamide substituents being approximately perpendicular to the fused aromatic unit. A percentage buried volume of 44.6% was calculated from the crystal structure of 13 using Cavallo’s

• , with a major one accounting for approximately 80% of the total, were observed in the 1H NMR spectra of 15 likely due to restricted rotation around the metal carbene bond combining with the locked rotation around the oxazole C4–N bond. Elemental analysis was consistent with the proposed structure and

Introduction of a human- and keyboard-friendly N-glycan nomenclature

• Friedrich Altmann,
• Johannes Helm,
• Martin Pabst and
• Johannes Stadlmann

Beilstein J. Org. Chem. 2024, 20, 607–620, doi:10.3762/bjoc.20.53

• supplanted by highly simplified terms for N-glycans that count the number of antennae or certain components such as galactoses, sialic acids and fucoses and give only limited room for exact structure description. The highly illustrative – and fortunately now standardized – cartoon depictions gained much

• the chemical peculiarities deliberately introduced by their sorcery. Biochemists and medical chemists, however, rather focus on the native glycan structure as grafted on the protein substrate by the biosynthetic machinery. Thus, biochemists could do with the much simpler IUPAC code [1] (Figure 1

• ), which has the invaluable advantage of being an alphanumeric code and which nowadays mostly dispenses use of Greek letters for annotating anomericity. Look – as an example – at entry G75903TQ in the relevant database GlyTouCan (glytoucan.org) [7] for the structure that we will herein baptize Na6-4(AF)F6

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• terpene alkaloid; natural products; Penicillium; structure elucidation; Introduction Penicillium, a genus within the Ascomycota phylum, is a type of critical saprophytic fungus with over 400 strains identified in diverse environments such as mountains, oceans, and the human gut [1]. After the first

• , given the application of suitable activation techniques. Results and Discussion Compound isolation and structure elucidation To activate the silent BGCs in Penicillium shentong XL-F41, we conducted small-scale fermentations using various media. Analysis revealed that HPLC peaks, which correspond to

• substructure at C-14 with a methine at C-16, indicated by the methoxy group. The position of the methoxy substituent was established by HMBC correlations, and the 13C NMR data suggested that compound 1 includes a 4-oxo-2,3-dihydro-(1H)-quinolin-3-yl fragment. The planar structure was established from HMBC

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

• analyses of these enzymes and the invention of AlphaFold2 have facilitated access to their structures. Structure-based mutagenesis combined with applications of unnatural substrates has further diversified the catalytic repertoire of these enzymes. The information in this review provides useful knowledge

• cationic intermediates, leading to the terpenoid structure of each product [6][7]. Particular attention has been paid to the biosynthesis of the compounds derived from farnesyl-DMOA (5) composed of 3,5-dimethylorsellinic acid (DMOA, 4) and the C15 terpenoid moiety due to their structural diversity (Figure

• resulting cation intermediate at C-4' to induce an acyl shift, forming the steroid-like structure of 7 with a 6-6-6-5 ring (Figure 2). Swapping terpenoid cyclases in heterologous expression systems A search of the genome database for Trt1-homolog CYCs revealed the enzyme AusL (41% identity with Trt1) in

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

• effect remains if the local structure of the linker consisting of an alkyl group and a pyrene group is maintained. Therefore, it is likely that the kinetic behavior of a protein immobilized with a single PASE linker exhibits an activation barrier-type energy surface between the bi-stable conformations on

• reported. The adsorption of PASE has been considered to mainly come from the pyrene fragment, which forms π–π stacking on these graphitic carbon materials [6][7][8]. The sensitivity of the oscillator-based sensor depends on the structure of the linker molecule. Therefore, understanding the adsorption

• mechanism of the PASE linker on graphene and identifying characteristic conformations of the adsorbed molecules are of great importance. Recently, a research group including two of the present authors theoretically investigated the adsorption structure of PASE [9], revealing that PASE on graphene has a

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• the reaction in the presence of DIPEA proceeded selectively, albeit more slowly. By increasing the DIPEA loading to 50 mol %, the product 2a was isolated in 75% yield after incubation for 7 days at room temperature. The structure of the obtained spirobutenolide was confirmed by single crystal X-ray

• structure of product 3b has been confirmed by crystallographic data. An approach to the construction of the THF cycle using a diazo reagent and 3-bromopropan-1-ol (13) [41] or similar halogenated OH substrates [42] has already been demonstrated in the literature using selected examples. We first validate

• presented in Scheme 5. As can be seen, the yields of the target compounds 4 vary from good to moderate per two steps of synthesis. The introduction of acceptor substituents in both the aniline and arylidene moieties of the DAS molecule leads to a decrease in the yield of the final spirocycle. The structure

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

• ], the signals of methine protons of E-isomers should be in the region of approximately 5.90 ppm [14]. Other IR, 1Н and 13С NMR spectroscopy and HRMS data confirming the structure of the synthesized compounds 1 and 2a–c are presented in Supporting Information File 2. Nonacylated compound 1 showed long

• products 3a–c were comprehensively characterized by IR, 1Н and 13C NMR spectroscopy, HRMS (Supporting Information File 2) as well as by X-ray diffraction analysis. The molecular structure of 3b is shown in Figure 3. The crystal data, details of the data collection and refinements for 3b as well as complete

• lists of bond lengths and bond angles are given in Tables S1–S4, Supporting Information File 3. Compound 3b had the structure of an O-acylated isomer and possessed an E-s-cis(S,N) conformation relative to the C(l)–C(9) bond (Figure 3). The benzo[b]thiophene fragment was planar, whereas the propionyl

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

• the release of fatty acids from the plastids to the endoplasmic reticulum, where they are utilized for the synthesis of acyl lipids that are essential components for various physiological and defensive processes [3][4][5][6]. As this enzyme target does not exist in other kingdoms, structure–activity

• lead structure with ample space for structural variations. By formally replacing one pyridine moiety of 1,8-naphthyridine 4 by a five-membered thiazole unit, we have identified thiazolo[4,5-b]pyridine 5 as a strong inhibitor of acyl-ACP thioesterase, which has further been confirmed via an X-ray co

• -crystal structure [12]. Additionally, greenhouse trials have shown that thiazolopyridine 5 and a large number of closely related analogues display excellent control of grass weed species in preemergence applications [13][14]. Independently, researchers at Syngenta have shown that the pyridine unit in the

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

• ). The crystallographic structure of the closed form revealed a helicoidal folding of tweezers resulting in a stacking of the Pt–salphen moieties with a Pt–Pt distance of 3.75 Å slightly above the limit for Pt–Pt interactions. In order to enable better interactions in the closed form, modified Pt–salphen

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• the presence of a new compound designated KR21-0001A (1). The structure was elucidated by NMR, and the absolute stereochemistry was determined by advanced Marfey’s method. The results indicated that 1 is a new analog of dihydroxybenzoic acid. 1 has no antimicrobial activity against bacteria and fungi

• 129.4) and C-10 through a sulfur atom. Based on these results, the structure of 1 was elucidated as 4-((2-acetamido-2-carboxyethyl)thio)-2,3-dihydroxybenzoic acid. The absolute configuration of 1 was determined by advanced Marfey’s analysis. 1 was de-sulfurized with skeletal Ni and then hydrolyzed with

• of 0.5 mL·min−1 and gradient elution with MeOH/H2O with 0.1% FA. Structure elucidation Spectra from 1H NMR at 500 MHz and 13C NMR at 125 MHz were measured in CD3OD using a JNM-ECA500 (JEOL Ltd., Tokyo Japan). Chemical shifts were referenced to CD3OD (3.31 ppm) in the 1H NMR spectra and CD3OD (49.0

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

• gold and HOTf, however, they are not easily explained by simple either/or mechanisms [14][32][33]. Due in part to optimization challenges and in part to remaining gaps in characterizing structure–activity relationships for alkene hydroamination, we sought to obtain additional understanding by

• independently prepare it. The structure ended up being unique and puzzling. When [LAu(NCCH3)]SbF6 was treated with an equivalent of free ligand, a complicated 31P NMR spectrum was acquired which we at first believed to be a result of erroneous choice of free ligand! Three signals were observed, a set of

• Lewis bases as additive to the bulk CH2Cl2 solvent (Figure 6) and compared them to the baseline rate in the absence of additive. The rates of formation of 3a are mildly sensitive to alcohol structure with MeOH outperforming EtOH and propanol. For the set of linear alcohols, the shorter the chain, the

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

• and mass spectrometric data. X-ray crystallographic analysis confirmed and established the structures and absolute configurations of compounds 1–3, thus providing the first characterized crystal structure of an ovalicin-type sesquiterpenoid. In the antimicrobial assays, compounds 1–3 showed broad

• sesquiterpenoids (1, 2), together with three known related analogs (3–5) [10][11][12][13] have been isolated and identified from the bioactive fraction of P. boydii CS-793. Details of the isolation and purification, structure elucidation, and biological evaluation of compounds 1–5 are described herein. Results and

• LH-20, and semi-preparative HPLC, yielded compounds 1–5 (Figure 1). Structure elucidations Pseudallene A (1), initially obtained as colorless amorphous powder, was assigned a molecular formula of C16H28O5S with three indices of hydrogen deficiency according to the HRESIMS data. The 1H NMR spectrum

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• % isolated yield (Scheme 2) and the structure was confirmed by NMR spectroscopy and X-ray crystallography (Figure 1). To expand the substrate scope of this difluorination method, a range of DBM derivatives 1b–n was synthesized from para-substituted acetophenones, para-substituted benzoyl chlorides and

• ); ref codes IZICEA [47], XOPZEK and XOPZIO [48]) are known. Interestingly, in contrast to the previously described acyclic structures no OH···O(H) hydrogen bonds are present in structure 5e – the molecules are linked by OH···O(NO2) interactions. Discussion Keto–enol tautomer studies have shown that DBM

• -generated N-fluoroammonium ion 7 to form 2-fluoro- and 2,2-difluoro-1,3-dicarbonyl products. Molecular structure of 2,2-difluoro-1,3-diphenylpropane-1,3-dione (3a). Crystal packing structure of 3f as determined by SXRC. Molecular structure and crystal packing of 5e as determined by SXRC. Monofluorination of

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• ]. However, until now there was no information about the structure and spectral characteristics of the obtained compounds. We have now synthesized these compounds, fully characterized them, and studied some of their transformations. We found that not only (E)-butene 1a but also (Z)-butene 1b reacted with

• 11 had an allene structure. It was also important to note that the reaction proceeded more selectively in ether, which significantly reduced the amount of byproducts. Pure final alcohol 10 was isolated by column chromatography on SiO2 in 46% yield and 1H, 19F and 13C NMR spectra were in full

• higher-boiling heptane. In this case, the desired product was isolated by double distillation at 7 °C in 50% yield and >90% purity and was fully characterized by 1H, 19F, 13C NMR and IR spectra. The presence of a characteristic band at 2038 cm−1 in the IR spectrum confirmed the allene structure of

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• ]. Moreover, the intracellular concentrations of a series of AMS derivatives in Escherichia coli, Bacillus subtilis, and Mycobacterium smegmatis have been investigated by Tan et al., demonstrating non-obvious correlations between the chemical structure and permeability among various bacteria, owing to the

• previously described an activity-based protein profiling (ABPP) strategy for NRPSs using ABPs that target A-domains (Figure 2b) [13][14][15]. The probes comprise an aminoacyl-AMS ligand and a photoaffinity group with clickable alkyne functionality appended to the 2′-OH group of adenosine. A complex structure

• benzophenone moiety in probe 3. The samples were then reacted with TAMRA-N3 (structure shown in Figure S4, Supporting Information File 1) under copper(I)-catalyzed azide–alkyne cycloaddition conditions [21] and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis coupled with in-gel

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

• new CPP analogs [4][5][6][7][8] and unveiling their unique physical properties, such as size-dependent photophysical [9][10][11][12][13][14][15] and redox properties [16][17][18][19][20][21]. The other, and one of the most exciting, functions of CPPs derived from the ring structure is their host

• up new possibilities for the fabrication of supramolecular structures based on the non-covalent interactions using carbon nanorings [37][38]. Despite the unique structure of the host–guest complexes, however, their electronic structures are not very attractive. This is because the complex formation

• reported that two-electron oxidation of [n]CPPs yields dications, [n]CPPs2+ [17][21][43], which are unusually stable due to the presence of in-plane aromaticity derived from the ring structure [19]. Therefore, we speculated that the CPP dication could be used as a host or a guest to alter the electronic