Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• , and polynucleotide binding affinity has been investigated by UV–vis, fluorescence and CD spectroscopy and molecular modeling. Further, binding of Phen-Py-1 to human dipeptidyl peptidase III enzyme was investigated by fluorescence spectroscopy and microcalorimetric measurements. Results and Discussion

• % yield, respectively. Compounds are stable in the refrigerator for more than six months; however, after one year partial decomposition of sample Phen-Py-2 was observed. Spectroscopic characterization of Phen-Py-1 and Phen-Py-2 in aqueous solution UV–vis spectra Studied compounds Phen-Py-1 and Phen-Py-2

• decrease of UV–vis spectra upon heating up to 90 °C and a baseline increase indicated intermolecular stacking and aggregation of compounds, which was more pronounced for Phen-Py-2. Spectroscopic characterization data are given in the Table 1 and Supporting Information File 1, Figure S1. A linker between

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

• ascorbate in DMSO (Scheme 9). According to UV–vis and circular dichroism (CD) spectrum measurements, the authors state that the formation of the dimer of porphyrin 50 can be attributed to DNA hybridization and through-space electronic interactions. In this investigation, it was found that the DNA serves as

• 45–50% yields. This click reaction was performed between 3-azido-BODIPY 77 and zinc porphyrin 35a or 21,23-dithiaporphyrin 79 in the presence of CuI/DIPEA in THF/CH3CN (Scheme 16). UV–vis absorption and electrochemical studies revealed the presence and interaction of both the moieties in the

• the synthesis of the novel 1,3,5-benzene-centered and triazole-bridged porphyrin star trimer 129 (Scheme 25) in 30% yield via CuAAC click reaction. In the UV–vis absorption spectrum, the absorption bands of product trimer 129 and starting compound 127 were almost coincided with each other, which

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• samples using a Shimadzu IRAffinity-1S instrument coupled with a Golden Gate™ attenuated total reflectance (ATR) accessory device (Specac). Sorption experiments: The absorption of phenolphthalein and 1-naphthol was analysed using an Agilent Technologies Cary 8454 UV–vis device, equipped with an Agilent

• paths, additional SEM micrographs, infrared spectra of the samples in the fingerprint region, table with compositions of the reacting mixtures. Acknowledgements The authors wish to thank M. Domeño for his help with UV–vis and HPLC measurements. Funding The authors also thank the University of Navarra

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• chromatography system which utilizes multiple columns in parallel with a series of valves to stagger the injection of crude material to each of the column lines. The columns are filled with a diethylaminopropyl-functionalized polymer, followed by an UV–vis detector to identify and separate the different peaks

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

• success in the increase of tetracene solubility, we struggled to evaluate the supramolecular interaction. Unfortunately, it seems that the complexation does not change the position of the chemical shifts on the NMR spectra and the shape or intensity of the UV–vis spectrum. The decrease in the guest's

• or TOF. The drying and nebulizer gas was nitrogen. High-resolution mass spectra were measured with an Agilent Technologies 6530 Accurate-Mass Q-TOF LC/MS spectrometer. Samples were ionized by electrospray technique (ESI) and detected by quadrupole or TOF. UV–vis spectroscopy spectra were measured

• binding calculated from ITC experiments. Supporting Information Supporting Information File 326: Synthetic procedures, characterization, 1H, 13C DEPT, 2D NMR, IR, UV–vis spectra of synthesized compounds; UV–vis spectra of tetracene solutions in DMSO; ITC thermograms. Funding This work has been supported

Using UHPLC–MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library

• Sasha Hayes,
• Aya C. Taki,
• Kah Yean Lum,
• Joseph J. Byrne,
• Merrick G. Ekins,
• Robin B. Gasser and
• Rohan A. Davis

Beilstein J. Org. Chem. 2022, 18, 1544–1552, doi:10.3762/bjoc.18.164

• a PerkinElmer spectrometer. UV data was recorded on a JASCO V-650 UV–vis spectrophotometer. NMR spectra were recorded at 25 °C on a Bruker AVANCE III HD 500 or 800 MHz NMR spectrometer equipped with a cryoprobe. The 1H and 13C chemical shifts were referenced to the solvent peak for DMSO-d6 at δH

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• . The synthesis of the dyads is based on the ordinary derivatization of the NI and PTZ chromophores [20]. The molecular structures were confirmed by 1H NMR, 13C NMR, and HRMS methods (Experimental section). UV–vis absorption and fluorescence emission spectra The UV–vis absorption spectra of the

• linker is non-negligible, which results in a CT absorption in which the phenyl moiety acts as the donor. This analysis is supported by the UV–vis absorption spectrum of the 3-phenyl NI [43]. A careful examination of the UV–vis absorption spectra indicates that the PTZ moiety in NI-Ph-PTZ induces a slight

• processes of these dyads upon photoexcitation. Experimental General methods All the chemicals used in synthesis are analytical pure and were used as received without purification. UV–vis absorption spectra were measured on a UV-2550 spectrophotometer (Shimadzu Ltd., Japan). Fluorescence emission spectra

Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes

• Almaz A. Zagidullin,
• Farida F. Akhmatkhanova,
• Mikhail N. Khrizanforov,
• Robert R. Fayzullin,
• Tatiana P. Gerasimova,
• Ilya A. Bezkishko and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139

• oriented towards the Fe atom. According to the computations, 8b-I is also slightly more advantageous compared to 8c with the same energy difference. The experimental UV–vis spectra of 8b and 8c in CH2Cl2 were similar and contained bands at about 280, 320, and 380 nm. The bands at 280 and 320 nm were more

• -chlorophenyl)-1,2-diphosphaferrocene (8b) from sodium bis(diglyme) 3,4,5-tris(3-chlorophenyl)-1,2-diphosphacyclopentadienide (7b) and [FeCp(η6-C6H5CH3)][PF6] is described. The structure of 8b was studied using experimental NMR, UV–vis, and electrochemical analyses as well as theoretical studies. The meta- and

• ), P1–C1 1.837(3) for 6c. Deposition numbers 2176393 for 5c and 2176394 for 6c contain the supplementary crystallographic data for this paper [41]. Considered conformations of 8b-I and 8b-II. Top: experimental UV–vis spectra of 8с (black) and 8b (red). Bottom: broadened calculated UV–vis spectra of 8c

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• Supporting Information File 1. Both compounds were further purified by temperature-gradient vacuum sublimation and characterized by 1H and 13C NMR spectroscopy (Figures S9–S12, Supporting Information File 1) as well as high-resolution mass spectrometry. Photophysical studies and DFT calculations The UV–vis

• aggregates. Supporting Information Supporting Information File 204: General information, synthesis and characterization data including NMR spectra, computational details, UV–vis data, Lippert–Mataga plot, and acid–base switching. Funding A. K. M. is grateful to the Prime Minister's Research Fellowship

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• solution. The color of the solution was gradually changed from deep red to dark violet, typically for the anionic complexes. The solutions obtained were ESR-silent, indicating formation of the closed-shell species. The UV–vis study showed an intensive absorption at 546 nm for 3 and at 519 nm for 4. The

• using the UV–vis method (see Supporting Information File 1 for the details) is 5.1, indicating high stability of the anion. Synthesis of dehydroalanine derivatives 6 The reaction products were isolated by column chromatography and analyzed using spectral methods. Both alkene and hydrogenated complexes

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• and one bromine atom (see Scheme 8). UV–vis absorption spectra of all obtained rhenium complexes (Figure 1) and those of the free ligands (Figure S4, Supporting Information File 1) were measured in acetonitrile. The molar extinction coefficients ε of the complexes were calculated from the obtained

• -diisopropylethylamine; OLED, organic-light emitting diode; SCE, saturated calomel electrode; TADF, thermally activated delayed fluorescence; TEMPO, 2,2,6,6-tetramethylpiperidinyloxyl; TIQ, triazoloimidazoquinoxaline. UV–vis absorption spectra of the obtained metal complexes (18 µM solutions) in acetonitrile at 20 °C

• tetrazole precursors. We thank André Jung for the deciding hint regarding the imidazole structure and the Soft Matter Synthesis Laboratory for the opportunity to use their UV–vis spectrophotometer. Funding L.H. acknowledges funding by the Landesgraduiertenförderung Baden-Württemberg. C.L. acknowledges

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• the higher Φfl value of OTT-2 is mainly attributed to the smaller knr value compared with that of OTK-2. The solid-state optical properties of OTK-2 and OTT-2 were investigated by solid-state UV–vis diffuse reflection–photoabsorption and fluorescence spectral measurements, and time-resolved

• [33] and OTT-2 in toluene. (c) Solid-state UV–vis diffuse reflection–absorption and (b) and (d) fluorescence spectra (λex = 484 nm for OTK-2 [33] and 512 nm for OTT-2) of OTK-2 and OTT-2 in the solid state. Insets in (a) and (b): color and fluorescence images of OTK-2 (left) and OTT-2 (right) in

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• V (ΔEp = 0.06 V), respectively. UV–vis absorption spectroelectrochemistry (see Figures S20 and S21 in Supporting Information File 1) shows the evolution of the dication and dianion states with the longest wavelength absorption band extending into the near-IR with broad features, characteristic of

• two sequential reversible oxidations and two sequential reversible reduction waves. UV–vis spectroelectrochemistry reveals the absorption profiles of the dications and dianions as highly delocalised intermediate charged states. EtH-T-DI-DTT is readily soluble in organic solvents due to the ethylhexyl

• ], in combination with donor polymer 15, both fused thiophene systems, achieved a PCE of 18%, as published in 2019, the highest value up to then [31]. With a three component system of PBQx-TF, eC9-2Cl, and F-BTA3, a PCE of 19% was achieved [32]. Normalised UV–vis spectra of EtH-T-DI-DTT in 10−5 M CH2Cl2

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• , respectively [43]. As displayed in Figure 13c and 13d, the UV–vis–NIR absorption spectra manifested that the larger steric hindrance interrupted the binding of BCF more effectively than that of BBr3. Conclusion For fluorescent materials containing nitrogen atoms with Lewis basic nature, it is easily found that

• ) Cyclic voltammetry curves of the four compounds and HOMO/LUMO energy level diagram and (d) estimated from the CV tests. Figure 11a–d were reproduced from [45] with permission from The Royal Society of Chemistry. This content is not subject to CC BY 4.0. (a) UV–vis absorbance and (b) PL spectra (excited

• theory. UV–vis–NIR absorption spectra of (c) compound 21 and (d) compound 22 before and after adding the Lewis acids B(C6F5)3 and BBr3 in o-DCB solution, respectively. Figure 13b–d were reprinted with permission from [43], Copyright 2011 American Chemical Society. This content is not subject to CC BY 4.0

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• channels (Figures S4 and S8 in Supporting Information File 2), which is a suitable characteristic for helicene compounds used as supramolecular self-assembly units [34][35][36][37][38][39][40][41]. Spectroscopic features of DH-1–3 The UV–vis absorption spectra of DH-1–3 in dichloromethane are shown in

• Figure 4. In general, the UV–vis absorption spectra of DH-1–3 are generally similar in shape and exhibit three major absorption bands within 230–280 nm (band-I), 280–330 nm (band-II), and 304–414 nm (band-III) (Figure 4). Progressive red-shifts in the absorption spectra of band-I, band-II, and band-III

• omitted for clarity. UV–vis absorption spectra of DH-1–3 in CH2Cl2 ([c] = 1 × 10−5 M). Synthetic route to S-shaped double helicenes DH-1–3. Crystal parameters of helicenes DH-1 and DH-2. Supporting Information Supporting Information File 193: Spectral and computational data. Supporting Information File

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• . Using 1,3,5-trimethoxybenzene (TMB, 9) as a model substrate, we optimized the perfluoroalkylation reaction under irradiation of a 300 W Xenon arc lamp (Table 2). Based on the UV–vis absorption of our reagents 1, we used long-pass filters at either 280 nm or 295 nm to avoid side reactions caused by

• perfluoroalkylsulfinates 2 and halogenated electrophilic partners. Left: isolated yields of synthesized perfluoroalkylating reagents: perfluorobutyl (1a), perfluorohexyl (1b), and perfluorooctyl (1c) analogues (after conversion of byproduct); middle: gram amounts of perfluorooctyl product 1c; right: UV–vis absorption of

• this work, especially Robin Stein and Tara Sprules on the NMR data, Hatem Titi on SCXRD interpretation, Nadim Saadé and Alexander Wahba on HRMS, and Petr Fiurasek and Ehsan Hamzehpoor on UV–vis spectroscopy. Funding The authors acknowledge the Canada Research Chair (Tier I) foundation, the E.B. Eddy

Structural basis for endoperoxide-forming oxygenases

• Takahiro Mori and
• Ikuro Abe

Beilstein J. Org. Chem. 2022, 18, 707–721, doi:10.3762/bjoc.18.71

• substituted with Ala or Phe generates an N-1 dealkylated product, which is non-enzymatically created from C21 hydroxylated products, as a major product. Based on these structural analyses, as well as an EPR analysis of the enzyme reaction of FtmOx1 and a transient ultraviolet–visible (UV–vis) absorption

• , including kinetic, UV–vis absorption, and EPR analyses of FtmOx1 wild type and its Y68F, Y74F, Y140F, and Y224F variants [70]. Their results revealed that the Y68F variant did not accumulate the initial tyrosyl radical and the formation of verruculogen was significantly decreased, while the Y224F variant

• these tyrosine residues [75]. The transient-kinetic, UV–vis absorption, and EPR analyses of FtmOx1 variants containing non-canonical Tyr analogs also indicated that Tyr68, rather than Tyr224, acts as the catalytic residue in the FtmOx1 reaction, supporting the CarC-like mechanism. NvfI: Nonheme iron

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• of the guest molecule was proven by UV–vis and IR spectroscopy. The multicomponent prism (Figure 3) was finally utilized as a heterogeneous catalyst for Michael and Diels–Alder (DA) reactions in water, representing an uncommon hydrogen-bond donating heterogeneous catalyst [59]. Intrigued by the

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• S20 in Supporting Information File 1). The UV–vis spectra of all compounds in H2O are shown in Figure S17 (Supporting Information File 1). The fluorescence intensities of the ring-fused compounds 3a,b gradually decreased with increasing water fractions, and the ratio of water to ethanol Φ values (ΦH2O

• for compounds 3a, 4a, and 4e using the TD-B3LYP/6-311+G(d,p)//B3LYP/6-31G(d,p) level of theory. Supporting Information Supporting Information File 34: General information, synthesis of 3a,b, and 4a–e, experimental procedure of fluorescence, theoretical computation method measurements, NMR, UV–vis

• introduction of pyridine rings has not been examined. Our simple one-pot method easily enables the introduction of a pyridine group to maleimide under mild conditions, affording the A–D–A-type molecules that are expected to be novel low-molecular-weight fluorescent materials in moderately good yields. The UV

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• by a Lambda 950 UV–vis–NIR spectrometer (Perkin Elmer). The fluorescence quantum yields (ΦF) in ambient air were estimated by the integrating sphere method [49] in integrating sphere (Sphere Optics) coupled to a CCD spectrometer PMA-12 (Hamamatsu) via optical fibers excited with a CW xenon lamp. ΦPF

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• using a Shimadzu UV-2600 UV–vis spectrophotometer in MeOH. ECD spectra were recorded on a JASCO J-815 polarimeter. 1H and 13C nuclear magnetic resonance (1H and 13C NMR) spectra were recorded on 300 and 500 MHz Bruker FTNMR Ultra ShieldTM spectrometers. Specific rotations were measured with a JASCO P

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• compound 1 was fully characterized by 1H and 13C NMR and IR spectroscopy, MS spectrometry as well as elemental analysis (for the detailed data, see Supporting Information File 1). Steady-state PL spectra To reveal the photophysical properties of diluted solutions of compound 1, UV–vis absorption and steady

• structures of 1 and POZ-DBPHZ. Steady-state UV–vis absorption (Abs) and photoluminescence (PL) spectra of dilute solutions (c ≈ 10−5 M) of compound 1. The PL spectra were acquired with λex = 340 nm for the cyclohexane solution and λex = 360 nm for solutions in the other solvents. Time-resolved PL decay

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• corresponds to a 1:1 binding stoichiometric ratio between G and m-TPEWP5 in the aqueous solution. Furthermore, the association constant (Ka) [36] was calculated to be 8.62 × 104 M−1 based on the UV–vis titration experiment (Figure S4, Supporting Information File 1). This result further confirmed that the

• , respectively. Initially, we compared the overlapping efficiencies of both donor and acceptor systems by using UV–vis and fluorescence spectroscopy. The absorption band of the EsY acceptor shows good overlapping with the emission band of m-TPEWP5G donor (Figure 4a). We therefore speculated, that there may be an

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• hydrogen of TMeQ[6] on its outer surface. In addition, when using UV–vis spectroscopy (Figure S5 and Supporting Information File 1, Figure S6) to investigate their interaction, it’s found that the presence of TMeQ[6] does not affect the absorbance of TBT, indicating that TMeQ[6] prefers to interact with

• with strong host–guest interaction. In addition, we also used the UV–vis spectrum to verify the above inference and to further investigate their molar ratio in detail. Q[7] has a larger cavity than TMeQ[6], giving it the ability to bind TBT. Therefore, the absorbance of TBT gradually decreases and

• addition, the UV–vis spectrum in Figure 4a shows that the absorbance of TBT keeps on the decrease (ΔA = 0.623) without red shift or blue shift in the presence of Q[8]. Both of the above phenomena show that Q[8] interacted with the “arm” of TBT and produced precipitation due to aggregation, which is also

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• [35]. Further chemical exploration on the genus Couchioplanes will disclose its actual biosynthetic capacity in secondary metabolism. Experimental General experimental procedures Optical rotations were measured using a JASCO P-1030 polarimeter. UV spectra were recorded on a Shimadzu UV-1800 UV–vis