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

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• -CD·BES, β-CD·PRO, γ-CD·BES and γ-CD·PRO were prepared via kneading and co-precipitation, and 1H NMR spectroscopic analysis of solutions of their pure complex crystals yielded the host–guest stoichiometries 2:1, 2:1, 1:1 and 3:2, respectively. Both powder X-ray diffraction (PXRD) and single-crystal X-ray

• host–guest stoichiometries and water contents of the four hydrated inclusion complexes enabled accurate assignment of the chemical formulae of these ternary systems. Predicted electron counts for the complexed molecules BES and PRO correlated reasonably well with the complex compositions indicated by

• formation, complex structure, stoichiometry and association constants via the detection and measurement of small deviations in the 1H NMR chemical shifts for both host and guest molecules upon complexation. PXRD studies were generally used to detect the formation of new crystalline phases following attempts

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

• hydrophobic cavity inside the molecule, while all hydrophilic hydroxy groups are arranged outside the cavity. This feature determines the main practical application of CDs as supramolecular hosts for host–guest interaction. Due to their low cost, low toxicity, and good complexation ability, they are

• might be achieved by a supramolecular interaction with a suitable host. Our initial plan was to enhance the solubility of higher acenes by the complexation with CDs. However, linear acenes with more aromatic rings (such as pentacene or heptacene) are, in addition to their poor solubility, also quite

• . Unfortunately, we did not succeed with solvents, such as water or methanol, where an increase in solubility is most desired. But some success we obtained with DMSO. For our experiments, we used the same mass of a host in every experiment, meaning the molar concentration of a CD in the samples was different

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• hydrazone groups. The use of N-TAAD derivatives as potential ligands and receptors was showcased through forming boron chelates and host–guest complexes with water and simple alcohols. Keywords: azaadamantanes; cyclotrimerization; hydrazones; inclusion complexes; molecular recognition; Introduction

• as synthetic receptors to form host–guest complexes based on H-bond interactions with amide/carbamoyl groups [31][32]. In addition, N-TAADs can be viewed as analogs of hexahydrazide ligands, which were reported to stabilize high-valent metal complexes [33][34]. Since N-amino groups can be easily

• of the obtained TAAD derivatives were performed, and the formation of boron chelates and host–guest complexes having an unusual intramolecular H-bonded network was showcased in this work. Results and Discussion Synthesis of 3N-TAADs, 2N,1O-TAADs and 1N,2O-TAADs Our strategy to construct TAAD

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme

• Jia-Hua Huang,
• Jian-Ming Lv,
• Liang-Yan Xiao,
• Qian Xu,
• Fu-Long Lin,
• Gao-Qian Wang,
• Guo-Dong Chen,
• Sheng-Ying Qin,
• Dan Hu and
• Hao Gao

Beilstein J. Org. Chem. 2022, 18, 1396–1402, doi:10.3762/bjoc.18.144

• analyze the function of TadA, we introduced tadA into the quadruple auxotrophic host Aspergillus oryzae NSAR1 (niaD−, sC−, ∆argB, adeA−) (Supporting Information 1, Tables S1 and S2) [26], which has been widely used for biosynthesis of fungi-derived natural products due to its genetic tractability [27

• whether 2 was generated by A. oryzae NSAR1. The result showed that the heterologous host indeed converts 1 to talaro-7,13-dien-19-ol (2, Scheme 1A; Supporting Information File 1, Figure S18). Mechanistic characterization of TadA So far, cyclization mechanisms of FC-type diterpenes afforded by PaFS [18

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• with an ionic liquid (EQEmax = 0.12%, Bmax = 10 cd m−2), which was incorporated to increase charge mobility within the emissive layer. We later showed that this emitter could act as host material in combination with a cyanine dye emitter [18]. The EQEmax for this host–guest device was higher than for

• the non-doped device, at 2.0% demonstrated 100% exciton utilization efficiency in the device and efficient energy transfer from the host to the guest cyanine emitter. Deep blue emission in LEECs is challenging. We also reported a blue-emitting LEEC employing a cationic sulfone-based donor–acceptor

• suggests that the conformation of the emitter in the solid state is slightly more conjugated than that in solution or that there are specific host–guest interactions with the DPA unit that perturbs the energy of the excited state. The emission is broader than that of a structurally similar emitter, QAD

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• host against oxidative radicals generated by UV irradiation [25][32]. To verify the antioxidative effect of the isoflavone dimers, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)-based antioxidant activity was performed [33]. The results showed that while 2 and 3 had an activity roughly

• potential host–microbial interaction in the rhizosphere. Flavones and isoflavones are common molecules in plant roots and can be secreted in soil, playing a role in allelopathic interference [35][36]. To our knowledge, this is the first bacterial P450 that can dimerize plant flavonoids. Since dimerization

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• in the Refseq database. Nodes are colored according to the host organism’s order. Enzymes with known biosynthetic products are colored red. N2H4-detecting colorimetric assay. Proposed biosynthetic pathway of azodyrecin. 1H (500 MHz) and 13C (125 MHz) NMR data for azodyrecin D (7), azodyrecin E (8

Efficient production of clerodane and ent-kaurane diterpenes through truncated artificial pathways in Escherichia coli

• Fang-Ru Li,
• Xiaoxu Lin,
• Qian Yang,
• Ning-Hua Tan and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2022, 18, 881–888, doi:10.3762/bjoc.18.89

• producing terpentetriene and ent-kaurene from ISO and DMAA (Figure 3). To decrease the burden on the host cell [38], the six genes (phoN, ipk, idi, ggdps, tdps, and ttes) leading to the production of terpentetriene, each with a strong and inducible T7 promoter, were cloned into pETDuet-1 plasmid to form

• Information File 1) [31]. These results demonstrated that the two-step artificial pathway coupled with downstream genes for the terpentetriene and ent-kaurene biosynthesis was successful and efficient. Though a single plasmid expression system might lower the host cell burden, our results showed that the two

• % (v/v)) was added, suggesting that higher glycerol concentrations might be harmful for the host cell, which was also supported by the less cell pellets harvested. We next explored optimal IPTG concentrations (0, 0.05, 0.1, 0.25, 0.5, and 1 mM) on the production of terpentetriene and ent-kaurene. As