Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• monitoring and in situ speciation. In addition, phosphine ligands have found various applications as auxiliary ligands in organometallic transition-metal complexes. A great number have exhibited potential application in organic light-emitting devices (OLEDs) [3], medicine [4][5][6] and catalysis [1][7][8

Oligomeric ricinoleic acid preparation promoted by an efficient and recoverable Brønsted acidic ionic liquid

• Fei You,
• Xing He,
• Song Gao,
• Hong-Ru Li and
• Liang-Nian He

Beilstein J. Org. Chem. 2020, 16, 351–361, doi:10.3762/bjoc.16.34

• IL settled well after the reaction and was absent in the product. Monitoring oligomerization process by 1H NMR (400 MHz, CDCl3). Reusability of the IL catalyst. Reaction conditions: 10 g (30 mmol) ricinoleic acid, 190 °C, 6 h, 50 kPa. 1H NMR (400 MHz, DMSO-d6) spectra of [HSO3-BDBU]H2PO4: a) Fresh

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• collected, i.e., DNA-viscosity measurements [70]. Thus, the monitoring of the DNA viscosity changes when compounds 11 and 12 are present, may be elucidating in regard to their binding mode to DNA. As known, the changes of the relative DNA viscosity (η/ηo)1/3 are proportionally related to changes of the

Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

• Sarah Kölsch,
• Heiko Ihmels,
• Jochen Mattay,
• Norbert Sewald and
• Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

• of the initially formed Z-isomers Z-3a and Z-3b, with both processes generally being possible starting from 3b and 3c (Scheme 2). On the one hand, the photometric monitoring as well as the 1H NMR spectroscopic studies of the photoreaction of 3b indicated a preceding E-to-Z isomerization (cf

• base pairs). Spectrophotometric monitoring of the irradiation of styrylquinolizinium derivatives 3a (A), 3b (B), 3c (C), and 3d (D) in acetonitrile [cL = 10 µM (A), cL = 20 µM (B, C, D)]. The arrows indicate the changes of absorption upon irradiation. Absorption of the monomers (c = 20 µM, red) 3b (A

• ) and 3c (B) and their dimers (black) 4b and 4c in H2O after 1.5 h and 4 h, respectively, at ca. 450 nm. Photometric monitoring of the photoreaction of 3b (c = 20 µM) to the dimer 4b by irradiation at ca. 450 nm in H2O (A) and of the photoinduced cycloreversion of 4b (c = 20 µM) to the monomer 3b at 315

Microwave-assisted synthesis of 2-substituted 4,5,6,7-tetrahydro-1,3-thiazepines from 4-aminobutanol

• María C. Mollo,
• Natalia B. Kilimciler,
• Juan A. Bisceglia and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2020, 16, 32–38, doi:10.3762/bjoc.16.5

• experimental conditions, several novel 2-aryl-1,4,5,6-tetrahydro-1,3-thiazepines were synthesized in good to high yields (Table 2). Due to the different reactivity of each substrate, irradiation times and temperatures were individually adjusted by monitoring the disappearance of substrate (TLC). Derivatives 4f

A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones

• Daniel P. Pienaar,
• Kamogelo R. Butsi,
• Amanda L. Rousseau and
• Dean Brady

Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287

• monitoring. Due to the persistent presence of unreacted starting materials in all examples given, it was decided to dose with second equivalents of base (KOt-Bu) and CH3CN after 1 h of reaction, as seen in most examples in Table 1. Disappointingly, we were unable to further significantly increase product

Preparation of anthracene-based tetraperimidine hexafluorophosphate and selective recognition of chromium(III) ions

• Qing-Xiang Liu,
• Feng Yang,
• Zhi-Xiang Zhao,
• Shao-Cong Yu and
• Yue Ding

Beilstein J. Org. Chem. 2019, 15, 2847–2855, doi:10.3762/bjoc.15.278

• monitoring. In recent years, some fluorescent chemosensors for the detection of chromium(III) have been developed [15][16][17][18][19][20][21][22][23]. Generally, chemosensors with fluorescence enhancement are more efficient than fluorescence turn-off chemosensors [24][25][26][27][28][29] because the

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• (Figure S3, Supporting Information File 1). On repeating this cycle, slow decomposition was observed, estimated at 14% after 3 cycles. Calcium binding by hosts 1E and 1Z was investigated by spectrophotometry, specifically monitoring aromatic ring chromophores which give rise to absorption bands observed

A photochemical determination of luminescence efficiency of upconverting nanoparticles

• Baptiste Amouroux,
• Clément Roux,
• Jean-Claude Micheau,
• Fabienne Gauffre and
• Christophe Coudret

Beilstein J. Org. Chem. 2019, 15, 2671–2677, doi:10.3762/bjoc.15.260

• solution. Compared to physical radiometry, actinometry is directly transposable to the monitoring of photochemical transformations as it originates from the very same concept and can be performed in the same experimental conditions. It is also adapted to turbid mixtures and can be extended to polychromatic

• green light escapes the photoreactor. Under these conditions the actinometric equation becomes so the flux in photon per second emitted by the source is: where V is the total volume of the DAE solution and the monitoring optical path is 1 cm. Finally, the average upconversion-QY, ΦUC can be estimated by

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

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• transduction, apoptosis and even necrosis [8][9][10]. The monitoring of plasma membranes, their biophysical properties, endocytosis/exocytosis of several types of molecules, as well as their dynamic changes, may be performed by using fluorogenic organic dyes or derivatives thereof [11][12][13][14][15]. The

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

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