Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• 100 ms. The mass ranges for MS and MS2 scan surveys were 500–800 amu and 30–800 amu, respectively. The curtain gas (nitrogen), nebulizing and heating gas were fixed at 25 psi, 20 psi and 15 psi, respectively. The temperature of the source was 25 °C. MS spectra were acquired and processed using Analyst

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• , and this reactivity pattern was exploited as early as in the 1950s to generate in a controlled way polycyclic aromatic compounds from isolable heteropine precursors. By way of example, the phenanthrene derivative 2 was obtained by heating the dibenzo[b,f]thiepine precursor 1 in the presence of copper

• previously. Importantly, photoirradiation at 254 nm or 365 nm failed to induce any chalcogen extrusion. When thermal activation was tested on solid samples, oxepine 26a, thiepine 28b and thiepine S,S-dioxide 30b were not converted upon heating at 250 °C for 2 hours, thus highlighting their high thermal

• , but it required prolonged heating at higher temperature (250 °C). In this work, seco-HBC 31 was thus successfully obtained via thermally-induced ring contraction of certain heteropines with the concomitant cheletropic elimination of chalcogen fragments. These results nicely illustrate how the nature

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• heating at 90 °C for 4 hours. The crude reaction mass obtained with these conditions was then purified by column chromatography (toluene). After eluting unreacted pristine C70, a dark reddish fraction was isolated and analyzed by HPLC. A major peak was observed at a retention time of 17.5 minutes, which

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• nitrobenzene. For example, quinoquinoline 5 reacts with chloranil upon heating in toluene to give a dark brown, high-melting product, in which, however, the methylene bridge remains unchanged. According to 1H NMR spectroscopy and combustion analysis data, this is complex 9 with a composition close to the ratio

• activator of NBS, as was previously shown by the example of a very successful bromination of 6-methylquinoline at position 5 with a preparative yield of 74% [27]. Indeed, under the new conditions, we obtained dibromo derivative 15 in high yield without heating and subsequent purification (Scheme 7). The

• dibromide 15 closer in chemical properties to the parent compound 5, which also cannot be converted into the corresponding acenaphthylene by direct dehydrogenation (see above). On the other hand, heating dibromide 15 with an excess of pyrrolidine for the purpose of nucleophilic substitution of the bromo

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• significant difference in the values of β-angles, which results in some differences in the densities [10]. The solubility of crystalline indigo is poor even in polar solvents such as aniline, nitrobenzene, phenol, phthalic anhydride, DMSO, and DMF upon heating. The reason for the low solubility and high

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• good yield (this represented a formal synthesis to clozapine [26], if the procedure of Rao [27] is used, which entails heating 4e with 1-methylpiperidine and Ti(IV)Cl4, Scheme 4). Also compound 4a can be transformed to Hügel's 1,2,3-triazole-DBDAP using the methodology described in their report (Scheme

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• glycosylation reactions was distilled under argon over P2O5 and then over CaH2 and stored over molecular sieves (MS) 3 Å. Powdered MS 3 Å (Fluka) were activated before the reactions by heating at ≈220 °C in high vacuum for 6 h. Column chromatography was performed on silica gel 60 (40–63 μm, Merck). Gel

• permeation chromatography was performed in toluene on a column (400 × 20 mm) packed with Bio-Beads S-X3 gel (200–400 mesh, Bio-Rad) using a differential refractive index detector (Knauer). TLC was carried out on Silica Gel 60 F254 plates (Merck), spots were visualized under UV light and by heating plates

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• the DCF molecule [83][84], as shown in Scheme 3. In the reaction between 4-ethynyl-N,N-dimethylaniline (1) and triisopropylsilylethynyl-substituted DCF 2a, heating at 80 °C in acetonitrile selectively yields the corresponding adduct 3a with 64% yield. In 3a, the anilino group forms a covalent linkage

• through the reaction of 1 with 1,1-dicyanoethene (14). They demonstrated that this intermediate was converted into the corresponding TCBD 15 upon further heating, as depicted in Scheme 7. The kinetics of the RE step conformed well to that of a first-order reaction. However, notably, they underscored that

• a derivatized anthracene moiety. Subsequently, to restore the anthracene structure of 18, the retro-DA reaction must occur efficiently. Therefore, through the addition of 1, followed by heating, the generated TCNE is effectively captured by 1. This maneuver concurrently suppresses the progression of

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• with a heating rate of 10 °C min−1. The resulting yellow solid was then finely grounded using an agate mortar. For the photochemical deposition of the Pt co-catalyst, 6 g of the produced PCN were first dispersed in 340 mL of water and subjected to sonication for 90 min. Subsequently, a mixture

Studying specificity in protein–glycosaminoglycan recognition with umbrella sampling

• Mateusz Marcisz,
• Sebastian Anila,
• Margrethe Gaardløs,
• Martin Zacharias and
• Sergey A. Samsonov

Beilstein J. Org. Chem. 2023, 19, 1933–1946, doi:10.3762/bjoc.19.144

• restraints and continued with heating up the system to 300 K for 10 ps with harmonic force restraints of 100 kcal/mol/Å2 on solute atoms. Then, the system was equilibrated for each window at 300 K and 105 Pa in an isothermal, isobaric ensemble for 100 ps. US production runs were performed for all of the

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

• observed during the 1st and 2nd DSC heating and cooling scans. However, glass transitions were detected for all the studied compounds. The glass transition temperatures (Tg) fall in the range between 63 and 93 °C (Figure 5b). A correlation between the glass transition temperature and the molecular weight

• employed to characterize the thermal properties of the samples. The measurements were performed using a TA instrument TGA Q50 apparatus for TGA and a TA instrument DSC Q2000 series thermal analyzer for DSC. During the TGA experiments, the samples were subjected to controlled heating at a rate of 20 °C/min

• ) Phosphorescence was separated from fluorescence using a delay of 0.03 ms after excitation. Excitation wavelengths were 350 and 374 nm, respectively, for recording the PL spectra and PL decay curves. TGA (a) and DSC 2nd heating (b) curves of compounds 6–9. CV curves of compounds 6–9. Photoelectron emission spectra

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• absorption intensity ratio at 330 nm. On the other hand, no consumption of La@C2v-C82 was observed in the reaction of La@ C2v-C82 with 1a (Figure 2b). The reaction of the La@C2v-C82 anion toward 2a–5a requires heating, therefore the reactivity of La@C2vC82 anion is lower than that of the C602− and C60 anion

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

• ]. This approach also supports that the solution-processable OLED application is a perfectly suitable device preparation for DMB-TT-TPA (8). Thermal properties The thermal properties of DMB-TT-TPA (8) were investigated through thermal gravimetric analysis (TGA) at 750 °C at a heating rate of 10 °C min−1

• Horiba, FL3-2IHR fluorescence spectrophotometer. Solid-state and solution-state quantum yields were measured using a Hamamatsu Quantaurus-QY Absolute PL Quantum Yield Spectrometer. Thermal gravimetric analysis (TGA) was performed on a PerkinElmer Diamond TA/TGA with a heating rate of 10 °C min−1 under

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• core [26][36][52][53][54][55]. These methods usually give poor overall yields of the target quinolone products and require rather harsh conditions during the ring-forming step, such as prolonged heating in Ph2O (270 °C) or in dioxane/NaOH (110 °C), respectively. This, along with the importance of the C

• additional decarbamoylative step (Scheme 2). The decarbamoylation of compounds 3a–d was carried out by heating at 60 °C in neat H3PO4 for 90 minutes [62] and gave the corresponding β-enaminoketones 6a–d in good yields (Table 2). The NMR spectra of compounds 6 in DMSO-d6 in all cases indicated a mixture of Z

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• -shifted in the film. These results indicate molecular π-stacking aggregation and excimer formation on the films [2]. The PL in film was obtained as a function of temperature (Figure 4). The observed reduction of the PL intensity on heating is expected for organic semiconductors due to self-quenching

• solution and in spin-coated films for compounds 1 (a) and 2 (b). The PL was excited at the wavelength of maximum absorption. PL as a function of temperature for 1 (a) and 2 (b) casting films on heating. Left: PL spectra; right: intensity of the PL maximum. The PL was excited at the wavelength of maximum

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• under reflux for 23 h. After the reaction had completed (monitored by 1H NMR spectroscopy), the obtained solution was concentrated under water pump vacuum upon heating in a water bath at 65 °C. The product was extracted from the resulting dense brown oil by trituration 4 times with a mixture of ether

• heating rate) [lit [40] mp 269–270 °C (MeOH)]; IR (KBr, cm−1) ν: 3423 (br s), 3365 (s), 3307 (br s), 3182 (br s), 1626 (sh), 1596 (vs), 1555 (s), 1547 (sh), 1242 (s), 1164 (s), 965 (s); 1H NMR (600.13 MHz, DMSO-d6) δ 11.82 (d, 3J = 11.2 Hz, 2Н, two NH), 8.01 (q, 4J = 0.5 Hz, 2Н, H-3 and H-11), 7.47 (d, 3J

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• of the solid samples in spectroscopic grade potassium bromide (KBr). Thermogravimetric analyses were performed using a Pyris 1 TGA thermoanalyzer (Perkin-Elmer), at 10 °C min−1 heating rate, under nitrogen flow (20 mL min−1), from 25 to 350 °C. Melting points were determined in triplicate using a

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• for 6 h to afford the monocycloaddition compounds. Without isolation, the reaction mixtures were then used for the N-propargylation in the presence of K2CO3 under microwave heating at 110 °C for 1 h to give triazolobenzodiazepines 21a–f in 35–65% yields with 2:1 to 7:1 dr (Scheme 13). Other than 2

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• illumination). a) DSC and TGA thermograms measured at a heating rate of 10 °C min−1 under N2 flow. b) Cyclic voltammogram (CV) and differential pulse voltammogram (DPV) analyzed in dry CH2Cl2 at a scan rate of 50 mV s−1 under an argon atmosphere (insert: HOMO/HOMO−1/LUMO orbitals). a) Schematic structure of

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• 1830s, Charles Goodyear invented vulcanized rubber. By heating natural rubber with lead oxide and sulfur, the temperature-sensitive rubber became a more stable material, even at high and low temperatures, while keeping the elasticity, plasticity, insulation, and other excellent characteristics [124

• diazonium salts produces highly reactive aryl radicals (Scheme 18) [153]. The chemical conversion can be initiated by electrochemical reduction [154], a reducing agent [155][156][157], a base [158], heating [159], or photochemically [160]. Aryl radicals may act as a halogen abstractor for alkyl halides and

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

• sulfuric acid before heating. LC–MS chromatograms were recorded with an UltiMate 3000 Series uHPLC (Thermo Fischer Scientific) using a C18 Acquity UPLC BEH column (2.1 × 50 mm, 1.7 µm) connected to an amazon speed ESI-Iontrap-MS (Bruker). Semi-preparative and/or preparative HPLC systems on normal and

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• through the use of additional NaOH and refluxing the crude alkylation mixture. After heating for 3 h, the desired intermediates were recovered in acceptable yields over this two-step one-pot sequence. The amide hydrolysis of 7 and 8 to the desired free naphthylamines 9 and 10 proved challenging, but was

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• traditional heating methods. In the meanwhile, Qiu and Xu et al. reported the coupling reaction between diazo compounds 163 and N-sulfenylsuccinimides 1 under catalyst-, base-, and additive-free conditions (Scheme 71) [101]. The reaction proceeded via a radical pathway, in which a free carbene was generated

• under heating, followed by the formation of ylide, N–S bond cleavage, and C–N bond formation along with the release of N2. In 2019, Sun and co-workers introduced an unprecedented method for the synthesis of isothiourea derivatives via the activation of diaryl/alkyl disulfides 47 with N-halosuccinimides

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• was found that enones 2 were transformed into the corresponding 3-trichloromethylindan-1-ones 3 upon heating in neat TfOH at 80 °C for 2–10 h (Scheme 5). Under the same reaction conditions, hydroxy ketones 1 were cyclized into indanones 3 as well (Scheme 6). The structure of compound 3a was confirmed

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• anionic hybrid NHC, “IMes-acac” consisting of fused diaminocarbene and acetylacetonato units. The latter afforded a series of representative Cu(I) complexes through bidentate coordination (Scheme 16) [30]. 1.2 Deprotonation of NHC-precursors with Cu2O Another important and facile method involves heating

• of the NHC-precursor, i.e. an azolium salt with cuprous oxide using a solvent or under microwave conditions (Scheme 17). Kolychev in 2009 attempted the preparation of NHC–Cu(I) complexes via deprotonation by heating of amidinium salt 53 [(7-Dipp)H][Br] with Cu2O in the presence of sodium acetate in

• , Cazin and co-workers reported the synthesis of Cu(I) complexes 61, 63, and 65 of the so-called ‘abnormal’ NHCs (Scheme 21) [35]. Thus, the conventional heating method as well as microwave irradiation methods were employed. The structures of the synthesized complexes were confirmed by X-ray analysis