Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• selective sesqui-TSs failed to transform 104–112. After further modification with cytochrome P450 CYP720B1 in the yeast host, 28 noncanonical terpenoids were generated, 10 of them are shown in Figure 8c (113–122) [58]. Notably, the widespread biosynthesis of C16 terpenoids was reported in a recent study in

Monitoring carbohydrate 3D structure quality with the Privateer database

• Jordan S. Dialpuri,
• Haroldas Bagdonas,
• Lucy C. Schofield,
• Phuong Thao Pham,
• Lou Holland and
• Jon Agirre

Beilstein J. Org. Chem. 2024, 20, 931–939, doi:10.3762/bjoc.20.83

• a whole host of other interesting pieces of information. In an analogous way to looking at glycosylation over time, the type and validity of carbohydrates in the PDB can also be observed over time. The statistics page available alongside the Privateer Web App contains up-to-date plots of validation

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• alteration of stereochemical assignment of spiroviolene would have consequences for a different mechanistic proposal. We herein report the production of spiroviolene (1) in a heterologous host by taking advantage of an artificial isopentenol utilization pathway [21][22][23][24][25][26], and confirm its

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• either 1) covalent functionalization of the fullerene surface with polar moieties or 2) complexation with water-soluble host molecules or polymers. Related to the former approach, the Nakamura group [11], Wudl group [12], and Hirsch group [13] reported initial work in the early 1990s on water-soluble C60

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

• -acyltransferase polyketide synthase biosynthetic gene cluster sdl (80 kb) from Streptomyces sp. B59 was cloned and transferred into a heterologous host, Streptomyces albus J1074, resulting in the production of a class of polycyclic macrolide shuangdaolides A (1), B, and D and dumulmycin (2) [29]. Furthermore

• , genome mining of the marine actinomycete Streptomyces seoulensis A01 enabled the identification of a giant type I polyketide synthase gene cluster (asm) [30]. Heterologous expression of the cryptic asm cluster using a bacterial artificial chromosome vector in a heterologous host led to the production of

• HSMs from Streptomyces sp. CA40. Palmu et al. discovered gaudimycins by heterologous expression of the biosynthetic gene clusters pga or cab, which were silent in the producing strain Streptomyces sp. PGA64 or Streptomyces sp. H021 relative to another host, Streptomyces lividans TK24 [73]. Resistomycin

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

• and AsCPS as described below. First, we examined the heterologous expression of AsPS and AsCPS in the heterologous host Aspergillus oryzae NSAR1. These two genes along with AsGGS were amplified and integrated into the pUARA2 vector, yielding the plasmid pUARA2-AsGGS/AsCPS/AsPS (Table S1 in Supporting

• Supporting Information File 1). We also examined the expression of several oxidoreductases in the flanking region in the same host strain, but the possible products other than 1 were not clearly observed (data not shown). Further characterization of oxidative modifications is in progress and will be reported

• 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

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

• four enzymes in the Aspergillus oryzae NSARU1 strain [19]. Consequently, the A. oryzae transformant yielded two metabolites 1 and 2, which were absent in the host strain (Figure 2B, traces i and ii). Although we were unable to isolate compounds 1 and 2 because of their instability, high-resolution mass

• keto–enol tautomerization to form 8 (Figure S2, Supporting Information File 1). Incubation of 7 with the host A. oryzae strain indeed resulted in the formation of 8 (Figure S3, Supporting Information File 1), confirming that InsA7 is not involved in the enoylreduction. Our findings revealed that four

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

• will be discussed as examples of engineering biosynthetic pathways and key enzymes involved in fungal meroterpenoid biosynthesis. Furthermore, a construction of the artificial biosynthetic pathway composed of the fungal meroterpenoids pathway and the pathway from other species, in fungal host

•  2). In 2012, the biosynthesis of terretonin, a meroterpenoid derived from compound 5 and produced by the filamentous fungus Aspergillus terreus, was investigated [8][9] using the heterologous expression host Aspergillus oryzae strain NSAR1, a filamentous fungus developed by multiple mutations of

• , the combinatorial biosynthesis of diterpene pyrones, derived from a pyrone skeleton and a C20 terpenoid skeleton, has been achieved by combining multiple biosynthetic pathways in a fungal heterologous expression host [16]. First, subA (PKS), subC (PT), subD (GGPP synthase), subE (FMO), and subB (CYC

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

• using a similar principle [24]. The protection from the solvent of the intercalated Pt guest enables its fluorescence emission and is accompanied by the induction of chirality in the resulting host–guest complex. A significant enhancement of the circular dichroism response of the chiral guest is

• observed confirming the formation of the host–guest complex. Again, protonation of the pyridine results in a guest release and a loss of the CD signal. Thus, this system provides a peculiar example of the control of chirality by a pH stimulus. A similar moiety employed for acid–base-triggered

• can abduct it from the terpyridine. The luminescence properties in the closed state can also be modulated by the formation of host–guest complexes. This happens with ligands complexing the metal center only, such as terpyridines and phenanthrolines. In fact, the counterions of the zinc2+ cation and

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

• , [10]CPP⊃[5]CPP2+. While the same host–guest complex consisted of neutral CPPs, [10]CPP⊃[5]CPP, was already reported, the cationic complex showed an about 20 times higher association constant in (CDCl2)2 at 25 °C (103 mol L−1). Electrochemical and photophysical analyses and theoretical calculations

• 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

• 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

Spatial arrangements of cyclodextrin host–guest complexes in solution studied by ¹³C NMR and molecular modelling

• Konstantin Lebedinskiy,
• Ivan Barvík,
• Zdeněk Tošner,
• Ivana Císařová,
• Jindřich Jindřich and
• Radim Hrdina

Beilstein J. Org. Chem. 2024, 20, 331–335, doi:10.3762/bjoc.20.33

• 2026/5, 121 16 Praha, Czech Republic Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 43 Praha, Czech Republic 10.3762/bjoc.20.33 Abstract 13C NMR spectroscopic analyses of Cs symmetric guest molecules in the cyclodextrin host cavity, combined with molecular

• modelling and solid-state X-ray analysis, provides a detailed description of the spatial arrangement of cyclodextrin host–guest complexes in solution. The chiral cavity of the cyclodextrin molecule creates an anisotropic environment for the guest molecule resulting in a splitting of its prochiral carbon

• signals in 13C NMR spectra. This signal split can be correlated to the distance of the guest atoms from the wall of the host cavity and to the spatial separation of binding sites preferred by pairs of prochiral carbon atoms. These measurements complement traditional solid-state analyses, which rely on the

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

• ramoplanin [2]. It is also the target for a host of other antimicrobials (mostly non-ribosomal peptides), including the tridecaptins [3], nisin [4], teixobactin [5], clovibactin [6], malacidin [7], and cilagicin [8]. Despite significant progress in the chemical synthesis of lipid II and its analogues, the

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

• present amphiphile is originated from bent aromatic amphiphile AA [12][13], composed of two anthracene panels linked by a m-phenylene spacer with two cationic side-chains, which assembles into an aqueous ≈2 nm-sized aromatic micelle with broad host functions [14][15][16][17][18][19][20][21]. Replacement

• 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

• guest-derived absorption bands around 340 nm and 420–650 nm, confirming the solubilization of C60 in water (Figure 4b). Similar host–guest composites were also obtained using PA-CH3, PA-OH, and PA-Im under the same conditions. It is noteworthy that the C60-solubilization efficiency varied depending on

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

• small singlet–triplet splitting and a fair photoluminescence quantum yield (PLQY). The optimized organic light-emitting diode (OLED) based on 13 wt % CPC doped in 1,3-bis(9H-carbazol-9-yl)benzene (mCP) as host exhibited maximum current efficiency, power efficiency, and external quantum efficiency (EQE

• . Similarly, the strongest TADF intensity was obtained for the neat films of compound 9 and of compound 9 molecularly dispersed in the host 1,3-bis(N-carbazolyl)benzene (mCP; Figure 3c,d and Figure S3a in Supporting Information File 1). Low-energy absorption bands of molecular mixtures of compounds 6–9 and

• film of compound 8 showed a more than twice lower PLQY which was enhanced using the mCP host. The other compounds showed similar PLQY trends (Table 1). Thermal properties The thermal stability and phase transitions of the synthesized derivatives 6–9 were investigated utilizing thermogravimetric

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• conventional device architecture of ITO/PEDOT:PSS/TFB/TAPC:TCTA:emitter (DMB-TT-TPA (8))/TPBi/LiF/Ca/Ag, where TFB, TCTA/TAPC, and TPBi acted as hole transport, hole transporting host, and electron transport materials, respectively (Figure S2 in Supporting Information File 1). The current efficiency–luminance

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• synthesis of three-dimensional cryptands by Lehn [5], and spherands by Cram [6]. Later on, various classes of macrocyclic compounds were designed, demonstrating remarkable features in areas spreading from simple coordination chemistry [7], through host–guest chemistry, sensing [8], biomedicine [9], and

• date back to 1982 when Krishnan and Thanabal reported synthesising a new host molecule with multiple cavities capable of encompassing several guest molecules/ions [39]. The molecule demonstrated an exciting feature of binding Na+, Mg2+, Ca2+, K+, NH4+, and Ba2+ cations. The incorporation of cations

• complex was created, where both ions were held in close proximity. It was further reported that 5 could adapt its binding behaviour depending on the counteranion in the caesium salt. Later Sessler and co-workers used naphthocrown-strapped calix[4]pyrrole 6 as a host to entrap CsF or CsCl ion pairs [103

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• ; endophytic fungi; hemiketal polyketide; Introduction Endophytic fungi are organisms that reside almost ubiquitously inside the fresh healthy tissue of plants, and they may increase the resistance of the host tropical trees to survive in extreme conditions [1]. As the global diversity of endophytic fungi is

• those exclusive to their host plants, is not only important from a biomolecular standpoint but also from an ecological perspective. In continuation of our interest to explore secondary metabolites of rare and hitherto unexplored fungi hosted in Cameroonian medicinal plants [5][6], we investigated the

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• affinity and selectivity of the R[4]A–amine complexes depend on several factors, including the size, shape, and functional groups of both the host and the guest molecules. For example, R[4]A derivatives with different substituents on the aromatic rings [12] have been synthesized to enhance the binding

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• pattern shown in Figure 1, where R is the host atom or functional group to which the halogen is covalently bound, where X is the halogen atom possessing the σ-hole (halogen bond donor), and where Y is the Lewis base (halogen bond acceptor) [31]. σ-Holes arise from anisotropic covalent bonds between the

• halogen and its host, where polarization of the halogen’s electronic charge is directed towards the covalent bond [24]. This results in a phenomenon called polar flattening, resulting in a non-spherical distribution of electron density on the halogen’s surface, with a positive electrostatic potential

• strength of a σ-hole typically increases with polarizability within the same group (I > Br > Cl >> F) [41][46][47]; however, the electron attracting abilities of the host [31][46], the electronegativity of the halogen atom [41] and, the degree of spn-hybridization in the covalent σR–X bond can also

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

• temperature dependence on solubility in water [16]. Therefore, binding of the unipolar CO2 molecule is expected to cause less water H-bond disruption in this host. Conclusion This work shows that CO2 is bound 1:1 by α-cyclodextrins and that the affinity can be improved with a smaller cavity and more

Cyclodextrins as building blocks for new materials

• Miriana Kfoury and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2023, 19, 889–891, doi:10.3762/bjoc.19.66

• . CDs are the most studied supramolecular hosts. They provide the most extensive database on molecular recognition in the literature, with more than 100,000 publications [2]. CDs owe their success not only to the unique molecular structure [3], which allows them to act as host compounds, but also to

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

• cucurbit[6]uril (TMeQ[6]) and 1,2-bis(4-pyridyl)ethene (G) were used to construct a supramolecular fluorescent probe G@TMeQ[6]. The host–guest interaction between TMeQ[6] and G was investigated using 1H NMR spectroscopy, single-crystal X-ray diffraction and various experimental techniques. The results show

• that TMeQ[6] and G form an inclusion complex with a host–guest ratio of 1:1 and the equilibrium association constant (Ka) was 2.494 × 104 M−1. The G@TMeQ[6] fluorescent probe can sensitively recognize Hg2+ ions by fluorescence enhancement. The linear range is 0.33 × 10−5–1.65 × 10−5 mol·L−1, R2

• ; fluorescent probe; Hg2+ ion recognition; host–guest chemistry; tetramethyl cucurbit[6]uril; Introduction Mercury, as one of the most toxic heavy metal pollutants, not only seriously pollutes the ecological environment but also causes great harm to human health. Mercury and inorganic mercury ions (Hg2+) in

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

• -soluble bowl-shaped six-fold carboxylated tribenzotriquinacene derivative TBTQ-C6 via host–guest binding. The spherical nanoparticles formed by CS-TPE amphiphiles or TBTQ-C6/CS-TPE supra-amphiphiles disintegrated under alkaline stimulation at pH 10.4 and the dispersion of the aggregates after the collapse

• supramolecular systems derived from water-soluble macrocycles, including cyclodextrins (CDs), calix[n]arenes (CXs), cucurbiturils (CBs), and pillararenes have been widely studied [2][6][7][8]. Similar to those macrocyclic acceptors, tribenzotriquinacene (TBTQ) derivatives, a class of versatile host molecules

• -methyltribenzotriquinacene-2,3,6,7,10,11-hexayl)hexakis(oxy))hexaacetate (TBTQ-C6) and 2,2',2'',2''',2'''',2'''''-((((12d-methyltribenzotriquinacene-2,3,6,7,10,11-hexayl)hexakis(oxy))hexakis(methylene))hexakis(1H-1,2,3-triazole-4,1-diyl))hexaacetate (TBTQ-CB6), which act as host molecules to bind to guest molecules to

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• , partial least square (PLS) modeling was used for the determination of the composition of solutions containing tryptophan methyl ester, phenylalanine, norephedrine, N,N’-bis-(α-methylbenzyl)sulfamide, sulfaguanidine or sulfamethoxazole using the spectral data of the corresponding CD host–guest complexes

• above-mentioned host and guest components. However, FTIR bands that appear in specific regions where no interference occurs can also be relevant for the presence of individual compounds in the complex. This is the case for the weak band corresponding to the symmetric stretching vibrations of =CH groups

• complexes and is assigned to flavonoids is found at 807–821 cm−1, and corresponds to the out-of-plane bending vibrations of the C–H groups. This band appears at significantly lower values in rutin and rutin-related complexes. β-CD was selected as the host for the formation of ternary complexes with the

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• triplet quenching pathways. The construction of water-soluble porphyrin nanospheres was reported by Zhang et al. in 2014 [54] by intramolecular host–guest interactions using porphyrin 126 containing two permethyl-β-cyclodextrin (PM-β-CD) and two dicarboxylatophenyl arms at meso-positions. The synthesis of

• excellent yields using Zn(OAc)2 in a CHCl3/MeOH mixture. Their UV–vis titration study revealed that these host systems exhibit strong anion-binding affinities. Furthermore, with the help of kinetic studies, the absorption efficiency of malachite green dye was investigated by using free-base porphyrins 171a

• interaction was observed. In 2010, the same group also reported the construction of a well-defined porphyrin nanowire [70] in water using Zn(II) porphyrin-CD conjugate 174 and free-base porphyrin-adamantane conjugate 176b through a robust 1:1 β-CD/adamantane host–guest interaction. First, porphyrin 176b was