Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• 10.3762/bjoc.20.205 Abstract Nitration of O-methylisouronium sulfate under mixed acid conditions gives O-methyl-N-nitroisourea, a key intermediate of neonicotinoid insecticides with high application value. The reaction is a fast and highly exothermic process with a high mass transfer resistance, making

• its control difficult and risky. In this paper, a homogeneous continuous flow microreactor system was developed for the nitration of O-methylisouronium sulfate under high concentrations of mixed acids, with a homemade static mixer eliminating the mass transfer resistance. In addition, the kinetic

• reaction system. Therefore, it is feasible to model homogeneous nitrification and optimize the reaction in a continuous flow system based on NO2+. An important prerequisite for kinetic modeling is the elimination of issues related to mass and heat transfer. The effect of mass transfer resistance is greater

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• due to heat generation by electric resistance. With these results in hand, the substrate scope was investigated. First, the applicability of halogen-containing diphenylmethanol compounds 1b and 1c to the electrochemical carboxylation under the reaction conditions shown in Table 1, entry 8 was

• /cm2) under atmospheric pressure of bubbling carbon dioxide at room temperature. The temperature of the reaction mixture increased to 40–50 °C at the end of the electrolysis in every case due to generation of heat by electric resistance during the electrolysis. After 8 F/mol of electricity had been

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• proceeded smoothly yielding 4j in quantitative yield. However, obtaining compound 4r presented some challenges due to the resistance of ester 2r towards conventional oxidation methods (see Table S5 in Supporting Information File 1). Consequently, a multi-step process involving ester hydrolysis and

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

• Moisés Alejandro Alejo Hernandez,
• Katia Pamela Villavicencio Sánchez,
• Rosendo Sánchez Morales,
• Karla Georgina Hernández-Magro Gil,
• David Silverio Moreno-Gutiérrez,
• Eddie Guillermo Sanchez-Rueda,
• Yanet Teresa-Cruz,
• Brian Choi,
• Armando Hernández Garcia,
• Alba Romero-Rodríguez,
• Oscar Juárez,
• Siseth Martínez-Caballero,
• Mario Figueroa and
• Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

• Institute of Technology, Chicago, Illinois 60616 Institute of Chemistry, National Autonomous University of Mexico, Mexico City, 04510, Mexico Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, 04510, México 10.3762/bjoc.20.159 Abstract Antimicrobial resistance presents a

• associated bioactive peptides. Keywords: antimicrobials; genome mining; lantibiotics; lanthipeptides; multi-drug resistant bacteria; natural products; Introduction Antimicrobial resistance (AMR) is a significant public health challenge. Only in 2019, there were 4.95 million deaths associated with AMR [1

• ], a number expected to increase exponentially. One fundamental objective of the Global Action Plan on Antimicrobial Resistance by the World Health Organization (WHO) is the investment in developing new drugs, diagnostic tools, vaccines, and other interventions [2]. In this context, many antibiotics

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

• alternative to classical synthesis [25][26][27][28]. Electrochemical oxidation reactions are further used to emulate enzymatic oxidations of drugs and explore potential metabolites [29][30][31]. Electrochemical flow systems provide fast electrosynthesis with low cell resistance, large electrode area, and good

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• section. N-Methyltransferases N-Methylations of peptides offer several advantages for peptide therapeutics, including conformational modulation, influence on receptor subtype specificity, increased proteolytic resistance, and improved oral bioavailability and cell permeability [82][83]. N-Methylation can

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• 10 mV, over a frequency range of 65 kHz to 5 Hz. The bulk resistance (Rb) of the membranes were calculated using the ZView software (Version 2.6b, Scribner Associates). A Binder KBF 115 climatic chamber was used to perform the measurements at a temperature of 60 °C and different relative humidity (RH

• ) conditions (40, 60 and 80%). The measurements were performed directly from the temperature-controlled humidity chamber, after a 2 h equilibration period. The proton conductivity (σ) was calculated using Equation 1 where L – distance between the two electrodes (cm), Rb – bulk resistance (Ω), and A - cross

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• cycle (Figure S1a and S1b, Supporting Information File 1). In contrast, the previously studied reversibility of the photoswitching of DA10 had revealed 10% absorbance decreases per cycle [37], indicating a mild improvement to the fatigue resistance of DA11. To further investigate the photostability and

• , possibly due to the reduced stabilization and improved fatigue resistance of the cyclized-isomer in a polar environment. Photochemical properties of DAn in aqueous medium Delighted by the good photoswitchability performance of DAn in organic solvent, the photochemical properties and supramolecular assembly

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• formation is one of main causes of bacterial antimicrobial resistance infections. It is known that the soluble lectins LecA and LecB, produced by Pseudomonas aeruginosa, play a key role in biofilm formation and lung infection. Bacterial lectins are therefore attractive targets for the development of new

• ; lectin A; photoswitchable ligands; Introduction Bacterial infection is a growing health problem due to antimicrobial resistance (AMR) among others. AMR causes approximately 33,000 deaths per annum in Europe only [1], and costs between €1.5 and €9 billion in healthcare and associated activities. Many

• the leading cause of morbidity and mortality in cystic fibrosis and immunocompromised patients and as one of the leading causes of nosocomial infections [1]. Due to the existence of numerous molecular mechanisms conferring resistance to multiple classes of antibiotics, therapeutic options are

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• -substituent as compared to their ortho- or meta-substituted counterparts. It might be explained by the less obvious steric resistance of the former in the process of Schiff base formation. In addition, an alkylidenyl-equipped 3-cyclohexanone was found to be incompatible with the current reaction system, only

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• . We previously studied substituent effects in acenes and reported that several substituents promote photooxidative resistance in pentacenes [5] and larger acenes including heptacene [6] and nonacene [7]. One or more substituents that promote photooxidative resistance by quenching singlet oxygen could

• photooxidative resistance, especially along the acene-like segment, plus a strong measure of kinetic stabilization at the 1,3-carbons of the furan ring. As described here, there are compelling reasons to contemplate the synthesis of large, persistent isoacenofurans with unusually small HOMO–LUMO gaps. In this

• resistance to the most reactive 1,3-carbons of the furan ring. A combination of experimental and computational studies clarifies the impacts of these sterically congesting substituents on each molecule’s electronic structure. We further studied the reaction rates of 1,3-diarylisobenzofurans with the strong

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• , biochemical and structural studies support a model in which this A3-mediated mutagenesis promotes tumour evolution and strongly influences disease trajectories, including the development of drug resistance and metastasis [18][19][20][21][22][23]. Of the seven A3 enzymes, three (A3A, A3B and A3H) are at least

• with reduced tamoxifen sensitivity of tumours in those patients [19] and poor survival rates for estrogen receptor-positive (ER+) breast cancer patients [21][29]. In line with these observations, A3B overexpression accelerates the development of tamoxifen resistance in murine xenograft with ER+ breast

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• transport. On the other hand, unipolar electron transport could be facilitated in the case of DCPQs 1a–6a given their extremely deep HOMO energy levels. Deep HOMO levels are important for optimal device performance and resistance to oxidation [34]. Compounds with deep LUMO energy levels are essential for

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

• inducing resistance, and this approach has contributed to the isolation of many new compounds [47]. The ribosome engineering method is based on the principle that a mutation in the ribosomal S12 protein, which is associated with the acquisition of antibiotic resistance, activates secondary metabolism. The

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• organism shares the same habitat with the predator Myxococcus xanthus that feeds on other bacteria including B. subtilis, and bacillaene is the primary factor conferring B. subtilis cells resistance to predation by M. xanthus [8]. The identification of its biosynthetic gene cluster (bae) revealed that the

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• vancomycin-resistant S. aureus (VRSA). However, the recent discovery of daptomycin-resistant Enterococcus and S. aureus provided the impetus to develop novel derivatives that enable more comprehensive structure–activity relationship (SAR) and resistance mechanism studies. Multiple approaches have been

• exhibit a potent ability to induce tubulin depolymerization [77], originally isolated from the cyanobacteria Nostoc sp. ATCC 53789 [78]. Notably, the cryptophycins cannot serve as substrates for P-glycoprotein and multiple drug resistance-associated proteins, making them attractive as chemotherapeutic

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• in Supporting Information File 1). To investigate whether the identified var biosynthetic gene cluster is responsible for variochelin production, we substituted varG encoding the polyketide synthase (PKS) module with a chloramphenicol resistance (cmR) gene cassette, using homologous recombination

• amplified by PCR, using Variovorax sp. H002 genomic DNA as the template. The chloramphenicol-resistance gene (cmR) and a linearized recipient plasmid pRED were amplified by PCR, using pRED as the template. The primer sets used to amplify the above-mentioned four fragments are listed in Table S2 (Supporting

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

• presence of a resistance gene within a biosynthetic gene cluster can indicate that it produces an antimicrobial compound [27]. We searched for annotated resistance genes in the surrounding genomic neighborhood of PF01408 sequences. We found 1,166 PF01408 sequences were associated with nearby glyoxalase

• /bleomycin resistance protein/dioxygenase superfamily (PF00903) sequences, 81 associated with CrcB-like protein, camphor resistance (PF02537) sequences, 22 associated with aminoglycoside antibiotic resistance kinase (PF04655) sequences, and 2 associated with putative multidrug resistance efflux protein

• pathways. Genome neighborhood analysis shows that many PF01408 sequences can be found near known biosynthetic enzymes, aminotransferases, and resistance genes suggesting that these enzymes may be promising candidates for targeted gene mining strategies to discover novel natural products. Experimental

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• (Figure 2). Furthermore, 7b, 7c, and 13b provided full control of ELEIN, one of the most difficult turfgrass weeds to control in the tropics and warmer temperate zones, emphasizing the potential of novel FAT inhibitors to contribute to integrated weed and resistance management. Conclusion The agrochemical

• (ALOMY_R, also known as slender foxtail or black twitch) and ryegrass (LOLSS_R). Remarkably, 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine 7b turned out to be superior to market standards (i.e., 1 and 2 in wheat) in terms of overall efficacy and resistance breaking potential. Halogen-free target compound 7c also

• structural scope of modern agrochemical research and to address sustainability goals, e.g., overcoming herbicide resistance and meeting demanding environmental safety goals. Experimental Synthesis Representative procedure for the synthesis of 6-bromo-5-(2-fluorophenyl)-2,3-dihydro[1,3]thiazolo[4,5-b]pyridine

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

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

• clinical trials as neuroprotective agents, presenting an attractive alternative to traditional anti-inflammatory and anti-Parkinson’s disease drugs [7]. With the increased drug resistance of bacteria to modern medicine, BIMs have emerged as an interesting alternative, due to their antibacterial and

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

• allowed precise control of the incident photon wavelength. To measure the photocurrent flowing in the circuit under illumination, a Keithley 6517B electrometer/high resistance meter was utilized, providing accurate and sensitive readings. An energy scan of the incident photons was performed by

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

• the analysis procedure. AFM measurements of the organic films were performed using a Nanosurf EasyScan2 apparatus in tapping mode with a scanning rate of 1.0 Hz covering 512 × 512 lines. Hole-only devices were fabricated using indium tin oxide (ITO) coated glass plates (sheet resistance of about 15 Ω

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• limitations, as demonstrated by Elavarasan and colleagues. Their team synthesized TQT-C60 and anchored it to fullerene molecules (Figure 3) to prevent aggregation during thermal aging. The researchers found that TQT-C60 demonstrated enhanced morphological stability and thermal resistance compared to the

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

• substrate with a sheet resistance of 12 Ω sq−1 was pre-cleaned carefully and cured with UV/O3 for 20 min. The OLED with an active diode area of 0.04 cm−2 was fabricated using a Kurt J. Lasker mini SPECTROS 100 thin film deposition system under vacuum conditions with a base pressure lower than 1 × 10−5 bar