A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• containing 3.7 mL p-anisaldehyde, 135 mL ethanol, 5 mL sulfuric acid, and 1.5 mL glacial acetic acid. Light pink spots were observed following heating at 105 °C. Kinetics assays were carried out by varying concentrations of substrate (myo-inositol or scyllo-inositol) from 1 mM to 60 mM with 1 μM Hyg17 and 10

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

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

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

• also in the alpha position of the furanone ring. Reactions with allenic acids 11 were carried out according to a similar scheme, in the one-pot mode, without isolation of OH-insertion intermediates 12 (Scheme 4). In order to accelerate the cyclization step in this case, moderate heating was used after

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• . The reverse reaction 3a–c→2a–c with full restoration of the initial absorption and fluorescence properties was characterized by a high activation barrier and could be accomplished by heating a solution of 3a–c in o-dichlorobenzene at 423 K or by passing dry hydrogen chloride through a solution of 3a–c

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

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

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

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

• aldehyde 9, elimination of MgBrF results in the formation of allene 11. To confirm our hypothesis, we studied the reaction of haloolefins 3 and 7 with iPrMgCl and BuLi. Thus, olefin 3a in Et2O reacted with iPrMgCl solution in THF at −80 °C to form Grignard reagent 12 and by heating the reaction mixture to

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• associated with low catalyst loading, extremely high efficiency and broad substrate scope and the possibility of use of both organic solvents or water, with the drawback however, of the employment of conventional heating [92]. In 2019, Toy et al. proposed an alternative approach for the Friedel–Crafts

• need for conventional heating (70 °C), while also requiring longer reaction times of up to 72 h for sterically hindered substrates [93][94]. A novel approach for the formation of BIMs was described, in 2020, by Herrera and co-workers, who utilized iodoalkynes as a simple halogen bond-based

• yields of 85% after 20 minutes of stirring. The nano-TiO2 catalyst was easily recovered by centrifugation, where it could be reused up to four times, without any reductions in product conversion. What holds back the efficiency of this nanocatalytic protocol is the application of conventional heating, as

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• short-term heating of the melted reactants at 220–250 °C is described, and the compounds were characterized by means of single-crystal X-ray crystallography, NMR, UV–vis, and IR spectroscopy, as well as cyclic voltammetry. The reaction with o-amino-, o-hydroxy-, and o-mercapto-substituted arylamines

• . Results and Discussion We found that a convenient way toward 6,8-di-tert-butyl-2-(arylamino)-3H-phenoxazin-3-ones 4 involves the short-term heating (30 min) of a molten mixture of 1 and an arylamine at 250 °C, followed by purification of the products by column chromatography. No preliminary grinding of

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