Acid-catalyzed rearrangements in arenes: interconversions in the quaterphenyl series

• Sarah L. Skraba-Joiner,
• Carter J. Holt and
• Richard P. Johnson

Beilstein J. Org. Chem. 2019, 15, 2655–2663, doi:10.3762/bjoc.15.258

• 10 mL vessels with temperature monitoring by an external sensor. General procedure for rearrangement in the microwave (MW) reactor. In a similar manner as described in [28], under a nitrogen atmosphere, the substrate (ca. 4 – 50 mg) and 1,2-dichloroethane (DCE, 4 mL) were added to a 10 mL reaction

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• to the pyrenyl moiety. Most interesting are the fluorescence properties of the dyes (see spectra in Figure 2), which revealed a dual emission phenomenon (see ratio ILW/ISW of the intensities I of the long-wavelength (LW) and short-wavelength (SW) emission band; Table 1). The monitoring of the

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• stained with NR [19]. Recently, the phase of the microcapsules and their energy release were analyzed by monitoring the color of NR fluorescence in an energy storage microsystem [22]. Although NR solvent effects are a useful tool in biology and technology, an adequate description and characterization of

Indium-mediated C-allylation of melibiose

• Christian Denner,
• Manuel Gintner,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2019, 15, 2458–2464, doi:10.3762/bjoc.15.238

• with NaOMe (pH 9) until a pH around 9 was reached. The solution was stirred at rt for 2 h, until reaction monitoring via TLC analysis (1-butanol/acetone/H2O 5:4:1, v/v/v) showed complete conversion of the starting material. The reaction mixture was diluted with dichloromethane (dichloromethane/MeOH, 1

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• reaction was followed by monitoring the recovery of absorbance at 336 nm, which corresponds to the maximal absorbance (λmax) of the E isomer. The orange circles in Figure 8a show the recovery profile of E-1 in the presence of 0.5 equiv of 2, following the reaction equation, (Z-1)2 + Z-1 → (E-1)22. The

• (0.8 equiv), 0.187 mM (1.0 equiv); 0.249 mM (1.33 equiv)). The rate of back-isomerization was followed by monitoring the increase in absorbance at λmax (336 nm). In control experiments, we followed the back-isomerization of Z-1 (0.187 mM) in the absence of 2 and in the presence of [Pd(NO3)2(tmeda

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

• at different time points after spinal cord injury. This dendrimer has potential uses as a drug/siRNA carrier and phenotype-specific cell tracer, i.e., for enhanced cell therapies combined with monitoring of cell fate and function [61]. Dendrimers with pyridine imine terminal functions and their

• deciphering the mechanism of action of these dendrimers, in particular for monitoring the intracellular penetration. This fluorescent dendrimer avidly binds to the cell membrane during the first 10 min of exposure and after 24 h, it has penetrated the cell, probably by endocytosis, and went in the

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• -30ADSF for liquid CO2 and two LC-20ADXR for modifier and make-up delivery), an on-line supercritical fluid extraction module (SFE-30A auto extractor equipped with 0.2 mL extraction vessels) for reaction monitoring, an autosampler (SIL-30AC) for purified compounds, a column thermostat (CTO-20AC) equipped

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• dimethylamine in dry THF (6.0 mL, 12.07 mmol). The reaction mixture was stirred for 7 days at rt (reaction monitoring by TLC – dichloromethane/petroleum ether 5:2). The reaction mixture was washed successively with aq citric acid and water, dried over Na2SO4, filtered and evaporated under vacuum. The crude

Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• oxaphospholium ion E1 (Table 1) through an intermediate formation of allyl cation E (Scheme 1). Ion E1 is transformed very fast into another species; after one minute new signals appear in the NMR spectra (see 31P NMR monitoring of this process in Figure 2), and after 12 hours it is completely converted to this

• the same transformations of 1a followed by hydrolysis of the reaction mixture affording a mixture of alcohol Z-9 and diene E-10a (Table 2, entries 1 and 2). The formation of compound 14 in an NMR monitoring experiment may also indicate that alcohol Z-9 is formed upon hydrolysis of allene 8 (Table 2

• achieved. This reaction gave rise to phosphoryl-substituted alkenes and indanes. The intermediates of these reactions were investigated by means of NMR and DFT calculations, that shed light on the reaction mechanisms. Allenes 1a–j used in this study. 31P NMR monitoring of the progress of transformation of

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• visually inspect reaction progress. The low boiling point of propylene oxide means that the reaction-mixture temperature inside the jar cannot be monitored, but as our previous experiments have shown that monitoring the jar temperature, between certain limits, can give information about the energetics of

Efficiency Eff_syn of complex syntheses as multicomponent reactions, its algorithm and calculations based on concrete criteria

• Heiner Eckert

Beilstein J. Org. Chem. 2019, 15, 1425–1433, doi:10.3762/bjoc.15.142

• , deriving from direct costs such as fixed employee and laboratory costs, laboratory rental and maintenance costs, operating costs, i.e., power, water, (gas), inert gas and disposal costs. Standard laboratory activities that are repetitive, such as reactor configuration, filling, reaction monitoring

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• course of an enzymatic reaction. Thus, the progress of the reaction can be signaled by a luminescence increase or decrease with time, which enables a highly sensitive real-time luminescence monitoring of the enzymatic activity [6]. STA has been applied to screening enzyme inhibitors or activators

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• acylation reagent with aluminium trichloride. In situ Raman monitoring of reaction of phthalic anhydride with p-xylene. FCR of pyrene and phthalic anhydride. Scope of acylation reagents in FCR under mechanochemical activation conditions and comparison with other reaction conditions (isolated yields

Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• lies outside of the milling chamber where sample can pass in and out for continuous monitoring [48]. This allows for varying milling media with the benefit of in situ measurements. For some processes like reactive aging with enzymes [22], polytetrafluoroethylene (PTFE) jars were preferred over

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

• Sebastian Haferkamp,
• Andrea Paul,
• Adam A. L. Michalchuk and
• Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

• monitoring multi-phase reactions during ball milling. Keywords: ball milling; C–C coupling; in situ; mechanochemistry; multivariate data analysis; Introduction Mechanochemistry offers a wide array of applications. It is used widely for synthesis of inorganic, metal-organic, and organic molecules and

• ] in understanding reaction kinetics of these processes. Early insight into formation pathways was provided ex situ, in which the mechanical treatment was stopped, and powder removed for analysis [10][11]. More recently, further detail has been gained by monitoring mechanochemical transformations in

• is of great interest. The characteristic bands are usually well separated, and the course of the reaction can be followed easily. The advantage of Raman spectroscopy was recently demonstrated [19], where its combination with XRPD allowed monitoring of the mechanochemically catalyzed Knoevenagel

Design of a double-decker coordination cage revisited to make new cages and exemplify ligand isomerism

• Sagarika Samantray,
• Sreenivasulu Bandi and
• Dillip K. Chand

Beilstein J. Org. Chem. 2019, 15, 1129–1140, doi:10.3762/bjoc.15.109

• with the ligand L1 at two different metal-to-ligand ratios (1:1 and 3:2). We also carried out the complexation of bare palladium(II) with the ligand L1 at two different metal-to-ligand ratios (1:2 and 3:4). The complexation reactions performed in DMSO-d6 allowed the monitoring of complex formation and

Precious metal-free molecular machines for solar thermal energy storage

• Meglena I. Kandinska,
• Snejana M. Kitova,
• Vladimira S. Videva,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• Stanislav B. Baluschev,
• Silvia E. Angelova and
• Aleksey A. Vasilev

Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106

• excess of crown ether 3 was easily removed. In general the zwitterionic salts 2a–d reacted to complete depletion in ethanol and in the presence of piperidine as catalyst with the crown ether benzaldehyde 3 (TLC monitoring, ethyl acetate/ethanol 4.5:0.5). After the addition of ethyl acetate the

Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• 100% acetonitrile. Monitoring and collection based on UV–vis absorbance at 210 nm and 254 nm, respectively. Purity analysis was performed using UPLC–MS with UV–vis detection on a Waters Acquity UPLC + Waters XEVO-G2 system using a Waters Acquity CSH C18, 1.7 µm, 2.1 × 100 mm column. Samples were run

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• by others [24][25], then the myristoyl group (C14:0) was added using myristoyl chloride in the presence of DMAP (Scheme 1) [26]. NMR monitoring Following the formation of thioglycosides by 1H NMR analysis A test reaction, based on 10 mg of 1a, was performed in deuterated methanol (MeOD) and the

• were kept as significant. Pictures were prepared using PyMOL (version 0.99rc6, DeLano Scientific, San Carlos, CA, 700). Structure of the β-thiols 1a and 1b and of the commercial alkenes 2a and 2b. Periodic monitoring by 1H NMR (300 MHz, DMF-d7) of the formation of product 8 from a mixture compounds 1b

Azologization of serotonin 5-HT₃ receptor antagonists

• Karin Rustler,
• Galyna Maleeva,
• Piotr Bregestovski and
• Burkhard König

Beilstein J. Org. Chem. 2019, 15, 780–788, doi:10.3762/bjoc.15.74

• thermal half-lives (THL) of the cis-isomers of compounds 5a, 5b, 12a, 16a–d, 23, and 28 was accomplished by monitoring the increase in absorbance which corresponds to the evolution of the trans-isomer after irradiation and exposure to dark. In contrast to the heterocyclic compounds 5a, 5b, 12a, and 16a–d

New sesquiterpenoids from the South China Sea soft corals Clavularia viridis and Lemnalia flava

• Qihao Wu,
• Yuan Gao,
• Meng-Meng Zhang,
• Li Sheng,
• Jia Li,
• Xu-Wen Li,
• Hong Wang and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2019, 15, 695–702, doi:10.3762/bjoc.15.64

• , 220.1825). PTP1B inhibitory activity assay The recombinant PTP1B catalytic domain was expressed and purified according to a previous report [24]. The enzymatic activities of the PTP1B catalytic domain were determined at 30 °C by monitoring the hydrolysis of pNPP. Dephosphorylation of pNPP generated the

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of Leishmania major infection

• Chelsea L. Rintelmann,
• Tara Grinnage-Pulley,
• Kathleen Ross,
• Daniel E. K. Kabotso,
• Angela Toepp,
• Anne Cowell,
• Christine Petersen,
• Balaji Narasimhan and
• Nicola Pohl

Beilstein J. Org. Chem. 2019, 15, 623–632, doi:10.3762/bjoc.15.58

• intracellular monitoring and validation of T cell antigen presentation. This new probe would also be linked to the surface of a polyanhydride copolymer microparticle based on 1,6-bis(p-carboxyphenoxy)hexane (CPH) and sebacic anhydride (SA) to allow for enhanced internalization and uptake of the immunogenic

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• Stuart SMP30 apparatus with automatic temperature monitoring. Starting materials: Adamantyloxyamine (4) was prepared following a modified published procedure [20]. For the first step, the O-adamantylation of N-hydroxyphthalimide, the recommended diethyl ether as a solvent was replaced by 1,2

Thiol-free chemoenzymatic synthesis of β-ketosulfides

• Adrián A. Heredia,
• Martín G. López-Vidal,
• Marcela Kurina-Sanz,
• Fabricio R. Bisogno and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2019, 15, 378–387, doi:10.3762/bjoc.15.34

• CAL-B. It is worth noting that this amount represents a ≈8 fold decrease of used enzyme as compared to the corresponding small scale reaction (Table 2, entry 8). After 24 h, we were delighted to find that no enolester was detected by TLC monitoring, and after extraction and silica gel column

Synthesis of C₃-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step

• Sambasivarao Kotha and
• Saidulu Todeti

Beilstein J. Org. Chem. 2019, 15, 371–377, doi:10.3762/bjoc.15.33

• stirred at room temperature for 1 h. At the conclusion of the reaction (TLC monitoring), the reaction mixture was concentrated at reduced pressure and dried under vacuum. The crude product was purified by silica gel column chromatography (2% MeOH/CHCl3) to obtain the Boc-deprotection product 14 (68 mg, 95