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Search for "monitoring" in Full Text gives 386 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril
Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171
- dye are regenerated. This principle has enabled, for example, real-time monitoring of enzymatic activity [18][19][20], the detection of membrane-transport activity [21] and membrane fusion [22], and even cellular imaging appears to be a potential future prospect [23][24]. However, most combinations of
An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change
Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167
- also exhibits LCST behavior. Compound 3 is soluble in aqueous media at 20 °C, the solution becomes turbid at 40 °C, and turns back to a clear solution upon cooling. The clouding point of 3 was determined by monitoring the transmittance change (Figure 3). The clouding point of 3, determined by
- monitoring the transmittance change, was 24 °C (2 mM in aqueous solution, Figure 3a, black line) which is 18 °C lower than the clouding point of 1 (42 °C, Figure 3b, black line) [5]. This is due to the fact that the benzene units carrying the hydrophobic alkyl chain ring in 3 are more hydrophobic than the
Assessing the possibilities of designing a unified multistep continuous flow synthesis platform
Beilstein J. Org. Chem. 2018, 14, 1917–1936, doi:10.3762/bjoc.14.166
- 411008, India 10.3762/bjoc.14.166 Abstract The multistep flow synthesis of complex molecules has gained momentum over the last few years. A wide range of reaction types and conditions have been integrated seamlessly on a single platform including in-line separation as well as monitoring. Beyond merely
- important drug molecules and discussed challenges involved in developing such a control process [60]. Monitoring: Utilization of in-line analysis techniques and constant monitoring of the product also requires specialized equipment to be used and relative ‘analysis time’ in the whole process sequence is
- monitoring a given reaction/purification) but that can be added at the specific steps wherever needed. 6. Utility: At this point of time it is assumed that for each reaction step the heating or cooling arrangement (also referred as ‘utility’ in the chemical process engineering and plant operation) is
Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium
Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160
- comparatively poorer yields (Table 2, entries 10–12). Monitoring of the reaction at different time intervals under otherwise identical conditions showed slightly progressive increase in the yield of the product formed (Table 2, entries 13–15) with a maximum yield of 93% after 4 hours (Table 2, entry 9). However
Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant
Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159
- under Ishihara's conditions [13] in water at 70 °C (Scheme 2). NMR monitoring indicated 95% conversion of the starting sodium salt 5 to the iodine(V) product 6 after about 3 h stirring at 70 °C (Figure S1 in Supporting Information File 1). After cooling the aqueous solution to room temperature, the
- from the literature that sodium periodate can oxidize various ArI to ArIO2 in boiling water or aqueous acetic acid [19][20]. We have found that according to NMR monitoring (Figure S2 in Supporting Information File 1), the reaction of sodium 2-iodobenzenesulfonate (5) with sodium periodate in water
Strong binding and fluorescence sensing of bisphosphonates by guanidinium-modified calix[5]arene
Beilstein J. Org. Chem. 2018, 14, 1840–1845, doi:10.3762/bjoc.14.157
- quality of pharmaceutical formulations, as well as monitoring drug plasma concentrations, analyzing drug biodistribution in bone tissue, and detecting drug excretion in urine. For example, BPs are of poor bioavailability if orally administered (generally with absorption less than 1%) and about 50% of the
- ]arene (GC5A, Scheme 1b). Such label-free sensing strategy exhibits potential application in real-time monitoring concentrations of BPs in urine and pharmacokinetic studies. Results and Discussion The main skeleton of BPs possesses two phosphate groups which are potential binding sites and therefore GC5A
First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones
Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156
- spectra were registered with a FTIR NEXUS spectrometer (as film or KBr pellets). UV–vis spectra were recorded using a UV–vis JASCO V-630 spectrophotometer. Melting points were determined in capillaries with a Stuart SMP30 apparatus with automatic temperature monitoring. Starting materials: 1,4
Synthesis and photophysical studies of a multivalent photoreactive RuII-calix[4]arene complex bearing RGD-containing cyclopentapeptides
Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150
- hour. The use of CuNPs greatly facilitated the monitoring of the reaction and the work-up, as these nanomaterials being easily removed from the crude mixture by simple centrifugation. To our delight, [Ru(TAP)2phen]2+-calix[4]arene-[c-(RGDfK)]4 conjugate 9 was isolated in 31% yield after purification by
Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit
Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145
- disappointment, the attempted O,O’-bis-alkylation of 1 with 1-iodooctane (Williamson etherification, Table 1, entry 1), afforded a multicomponent reaction mixture (TLC monitoring, 100% conversion of 1), from which we succeeded in isolating only G-0 chloro-dendron 2a and the O,O’,N-tris-alkylated side product 2b
- K2CO3 as proton scavenger) resulted in no dendrimer formation; decomposition of D-N
NH was observed instead (as determined by additional NMR monitoring). Nevertheless, the desired G-2 dendrimer 5 could be obtained through an alternative route, namely, by amination of G-1 chloro-dendron D-Cl with
- )alkanoic acid-based tripodal melamines into the corresponding tri acid chlorides (not depicted in Scheme 4) followed typical procedures (in refluxing thionyl chloride with SO2 and HCl generation), a long reaction time (up to 24 h, as determined by HRMS monitoring) was mandatory for this transformation to
Drug targeting to decrease cardiotoxicity – determination of the cytotoxic effect of GnRH-based conjugates containing doxorubicin, daunorubicin and methotrexate on human cardiomyocytes and endothelial cells
Beilstein J. Org. Chem. 2018, 14, 1583–1594, doi:10.3762/bjoc.14.136
- for real-time monitoring of cells to distinguish short-term (0–2 hours) and long-term (0–72 hours) effects elicited by the drug or carrier–drug conjugates. The basic theory of impedimetry is that proliferation/viability of cells is well detectable by monitoring of the electric impedance (Z) in an AC
Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions
Beilstein J. Org. Chem. 2018, 14, 1529–1536, doi:10.3762/bjoc.14.129
- laboratories because of its ease of use, safety and control [3][4][5][6]. Continuous flow technologies are generally more effective than traditional batch processes with key advantages including intensified heat and mass transfer, inline reaction monitoring, higher mass throughput, safer control of hazardous
Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles
Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120
- control of selectivity. Moreover, additional parameters such as pH value, the nature of the ions and the concentration of glycerol in the liquid phase can be tuned in liquid-phase processes [4]. Monitoring of electrocatalytic reactions is challenging as all products are dissolved in the electrolyte. High
Hypervalent iodine(III)-mediated decarboxylative acetoxylation at tertiary and benzylic carbon centers
Beilstein J. Org. Chem. 2018, 14, 1046–1050, doi:10.3762/bjoc.14.92
- , followed by hydrolysis, offers an efficient and practical method for the synthesis of tertiary and benzylic alcohols. The following experiments were performed in attempts to gain insights into the reaction pathway. Monitoring the reaction by 1H NMR spectroscopy showed for the reaction of a mixture of 1a
Hypervalent iodine-guided electrophilic substitution: para-selective substitution across aryl iodonium compounds with benzyl groups
Beilstein J. Org. Chem. 2018, 14, 1039–1045, doi:10.3762/bjoc.14.91
- monitoring the progress by TLC. The products were purified through PREP-TLC (hexane/ethyl acetate 90:10). Examples of the reductive iodonio-Claisen rearrangement compared to new reactivity seen with benzyl metalloids. Crossover reaction experiments. Suggested mechanism based on product formation and
Polysubstituted ferrocenes as tunable redox mediators
Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86
- (E1/2 = 1140 mV in MeCN vs FcH/FcH+) in CD2Cl2 under NMR monitoring shows that the Cp proton resonances broaden upon oxidation and shift to lower field, while the methyl proton resonances of the ester substituents shift to higher field and remain much sharper (Figure 8, Table 2, Figures S36–S38
- chemical shifts of the Cp or ester methyl protons. Ongoing investigations focus on the spectroscopic monitoring of 1–4 as redox mediators in selected electrosynthetic transformations. Experimental Dichloromethane, CD2Cl2 and CD3CN were distilled from calcium hydride. Electrochemical experiments were
Mechanochemistry of nucleosides, nucleotides and related materials
Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81
- observations at a molecular scale [97] and from in situ monitoring of bulk-scale reactions [98]. The limited work relating to the chemical transformation of nucleoside and nucleotide substrates has been mainly focussed upon exploiting the (lack of) solvent requirements. This can allow access to unprecedented
Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies
Beilstein J. Org. Chem. 2018, 14, 838–848, doi:10.3762/bjoc.14.69
- simulation time frame and calculate the host–guest binding affinity in each case. By monitoring the frames during the time interval of the simulations, we observed that the sterol group of the guest cholesterol molecule remains encapsulated inside the hydrophobic β-CD dimeric cavity while its aliphatic tail
Stepwise radical cation Diels–Alder reaction via multiple pathways
Beilstein J. Org. Chem. 2018, 14, 704–708, doi:10.3762/bjoc.14.59
- development in our laboratory. GC–MS Monitoring of the oxidative SET-triggered reaction of aryl vinyl ether 1c. Radical cation Diels–Alder reaction of trans-anethole [17]. Radical cation Diels–Alder reactions of aryl vinyl ether and sulfides [17][25]. Radical cation Diels–Alder reaction of aryl vinyl ether (1
Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry
Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52
- investigated using phenylboronic acid (3) in combination with different ortho- and para-substituted bromoarenes in aqueous ethanolic mixtures employing K2CO3 as base [38]. Monitoring of the reaction progress via inline UV–vis spectroscopy as well as offline HPLC analysis [38] led to the result that after an
- ). The stability of emulsions to gravity-induced creaming or coalescence was assessed by monitoring the position of the water–emulsion or oil–emulsion interfaces respectively. Microscopy images of the emulsions were recorded using an Olympus BX53 microscope with GXCAM-U318 camera attached and GXCapture-T
Investigating radical cation chain processes in the electrocatalytic Diels–Alder reaction
Beilstein J. Org. Chem. 2018, 14, 642–647, doi:10.3762/bjoc.14.51
- efficiency of up to 8000%. The reaction monitoring profiles showed sigmoidal curves with induction periods, suggesting the involvement of intermediate(s) in the rate determining step. Keywords: chain process; Diels–Alder reaction; electrocatalytic; radical cation; single electron transfer; Introduction
- electrochemical synthesis in that one electron can run the radical cation chain process up to 65 times. GC–MS monitoring showed a sigmoidal curve with an induction period. The monitoring was carried out in the presence of a large excess (10 equivalents) of isoprene (2), which might follow pseudo-first order
- ) and the aromatic radical cation (3·+) would impact the overall reaction rate. Indeed, when the monitoring was carried out with a lower concentration of trans-anethole (1), no induction period was observed and the reaction required nearly a stoichiometric amount of electricity to complete (Figure 3
Continuous multistep synthesis of 2-(azidomethyl)oxazoles
Beilstein J. Org. Chem. 2018, 14, 506–514, doi:10.3762/bjoc.14.36
- ). HPLC monitoring of the formation of 2-(azidomethyl)oxazole 7a. Continuous sequential thermolysis of vinyl azides 1 and ring expansion of azirines 2 with bromoacetyl bromide to give 2-(bromomethyl)oxazoles 6. Continuous-flow three-step sequential synthesis of 2-(azidomethyl)oxazoles 7a–c from vinyl
Carbohydrate inhibitors of cholera toxin
Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34
- lactose-2-aminothiazoline conjugate as a CT antagonist. Its affinity for CTB was determined by monitoring the change in fluorescence of tryptophan-88, located in the GM1 binding site, upon titration of the protein with the inhibitor. Compound 6 showed excellent binding with a Kd value of 23 µM [41
The selective electrochemical fluorination of S-alkyl benzothioate and its derivatives
Beilstein J. Org. Chem. 2018, 14, 389–396, doi:10.3762/bjoc.14.27
- current power supply model 5944 by monitoring electricity with a Hokutodenko Coulomb/Ampere-hour meter HF-201. Cyclic voltammetry measurements Cyclic voltammetry was carried out in 0.1 M Bu4NBF4/MeCN using a glass cell. A platinum disk electrode ( = 0.8 mm) was used as a working electrode. A platinum
Fluorogenic PNA probes
Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17
- into a measurable signal. Among several available modes of detection, fluorescence detection offers a number of distinct advantages, but mainly that it is relatively simple, selective, highly sensitive and can be used for real-time monitoring of the biological targets and even their interactions in
- unbound probes, which is most commonly achieved by solid phase hybridization followed by washing to eliminate the unbound probes before performing the fluorescence readout. These assays require multiple steps, and so are time-consuming making them unsuitable for real-time monitoring, such as nucleic acid
- amplification, monitoring of enzyme activities and localization and quantitation of nucleic acids in living cells. Therefore, it is highly desirable to develop a “smart” fluorogenic oligonucleotide probe that can directly report the presence of the target by a simple fluorescence readout in homogeneous and wash
Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications
Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7
- straightforward applications is merely for monitoring whether a certain process involves a conformational change or not. A few examples of such applications are described below. In a collaborative investigation with Falkenberg and Gustafsson, we investigated the role of the transcription factor A (TFAM) in the
- structure resolution and monitoring of a different distance range with high accuracy. With the recent advent of new base–base FRET pairs, the coming years offer great prospects for increased use of such methodology. The combination of base–base FRET and single-molecule-based FRET on nucleic acids with
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