A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• pursuit are equally significant. One of the efficient approaches for finding new secondary metabolites from microorganisms is physicochemical (PC) screening. This approach involves the screening of the physicochemical properties of potential compounds, such as UV spectroscopy, mass spectrometry, and color

Incorporation of a metal-mediated base pair into an ATP aptamer – using silver(I) ions to modulate aptamer function

• Marius H. Heddinga and
• Jens Müller

Beilstein J. Org. Chem. 2020, 16, 2870–2879, doi:10.3762/bjoc.16.236

• oligonucleotide has to be performed by using UV spectroscopy. Hence, only the amount of DNA eluted during the initial five washing steps can be quantified. It is impossible to determine the amount of the oligonucleotide eluted by the AMP solution, as AMP absorbs in the same wavelength range as DNA. It is, however

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• . Further, the separated isomers of 3–7 were irradiated and the reaction course followed by UV spectroscopy. In all cases, the longest wavelength absorption band gradually disappeared upon irradiation. Based on previous research, it was assumed, that the preliminary process could be a photoisomerization

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

• selective compounds with DNA was good to excellent, as verified with extensive CT DNA-affinity studies. A deeper insight in the photochemical behaviour of the nitro (11) and the chloro (12) derivatives using UV spectroscopy in the absence of DNA was indicative of the disruption of 11 whereas 12 showed a

α-Photooxygenation of chiral aldehydes with singlet oxygen

• Dominika J. Walaszek,
• Magdalena Jawiczuk,
• Jakub Durka,
• Olga Drapała and
• Dorota Gryko

Beilstein J. Org. Chem. 2019, 15, 2076–2084, doi:10.3762/bjoc.15.205

• temperature in acetonitrile (for UV spectroscopy, Fluka) on a Jasco J-715 spectropolarimeter at 0.2 nm/step with an integration time of 0.5 s over the range 180–400 nm with 100 nm/min scan speed, 5 scans. For the in situ ECD standard measurements the chiral vic-diol (1–8 mg, ca. 0.003 M/L) was dissolved in a

• stock solution of the [Mo2(O2CCH3)4] (4–6 mg, ca. 0.002 M/L) in DMSO (5 mL) (for UV spectroscopy, Fluka) so that the molar ratio of the stock complex to ligand was about 1.5:1, in general. The measurements were performed on a Jasco J-715 spectropolarimeter with parameters: 0.5 nm/step with an

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• techniques. For our multi-spectroscopic studies, we utilize FTIR spectroscopy, mass- and isomer-selective IR/UV techniques (IR/R2PI, for methodical developments, cf., e.g., [8][26][27][28][29] and UV/IR/UV spectroscopy, cf., e.g., [30][31][32][33][34][35][36][37][38][39][40][41][42][43]) and chirped-pulse

• investigation on the isolated phenyl vinyl ether–methanol complex is presented. From the FTIR spectra, the existence of one isomer is concluded, which is confirmed by IR/UV spectroscopy in the electronic ground state (S0). The combined vibrational and electronic spectroscopic investigations, including a

Microfluidic radiosynthesis of [¹⁸F]FEMPT, a high affinity PET radiotracer for imaging serotonin receptors

• Thomas Lee Collier,
• Steven H. Liang,
• J. John Mann,
• Neil Vasdev and
• J. S. Dileep Kumar

Beilstein J. Org. Chem. 2017, 13, 2922–2927, doi:10.3762/bjoc.13.285

• day. The molar activity of the final product was determined to be >148 GBq/µmol (>4 Ci/µmol) by both UV spectroscopy and mass spectrometry methods and both methods were found to be in agreement. The chemical purity was determined using both UV spectroscopy and mass spectrometry and little chlorinated

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

• Alena A. Vavilova and
• Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

• -diethylacetamide groups in cone and partial cone conformations have been synthesized. Their complexation ability towards a number of tetrabutylammonium salts n-Bu4NX (X = F−, Cl−, Br−, I−, CH3CO2−, H2PO4−, NO3−) was studied by UV spectroscopy. The effective receptor for the anions studied as well as selective

• ; UV spectroscopy; Introduction Anions play a key role in many biochemical processes [1] as substrates and/or cofactors in enzymatic reactions [2], in the environment (phosphate and nitrate in the ponds provoking their eutrophication) [2][3][4], and in phase-transfer catalysis [5][6]. The dysfunction

• complex formed. Thus, the binding efficiency should decrease in the range from the F− ion to the larger I− ion. The receptor properties of the synthesized compounds 3, 5, 6 toward the tetrabutylammonium salts n-Bu4NX (X = F−, Cl−, Br−, I−, CH3CO2−, H2PO4−, NO3−) were studied by UV spectroscopy for

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• mixture was incubated for 10 min. Subsequently, a sufficient quantity of 4-OD/E106QVPH (from P. putida mt-2) was added so that the reaction was complete within 20 min (monitored by UV spectroscopy). For the preparation of 5d, an aliquot of 4-OT was added to the diacid mixture (which already contained 4-OD

Thiazol-4-one derivatives from the reaction of monosubstituted thioureas with maleimides: structures and factors determining the selectivity and tautomeric equilibrium in solution

• Alena S. Pankova,
• Pavel R. Golubev,
• Alexander F. Khlebnikov,
• Alexander Yu. Ivanov and
• Mikhail A. Kuznetsov

Beilstein J. Org. Chem. 2016, 12, 2563–2569, doi:10.3762/bjoc.12.251

• the nature of the dynamic process observed in solutions of 2-aminothiazolidines. This phenomenon was first detected by UV spectroscopy [19] and believed to be caused by a proton transfer between nitrogen atoms (amino–imino tautomerism), however, contradictory information on the equilibrium ratio of

Synthesis and characterization of pH responsive D-glucosamine based molecular gelators

• Navneet Goyal,
• Hari P. R. Mangunuru,
• Bargav Parikh,
• Sonu Shrestha and
• Guijun Wang

Beilstein J. Org. Chem. 2014, 10, 3111–3121, doi:10.3762/bjoc.10.328

• the trapped drug in the gel matrix, naproxen sodium was incorporated into the gels and the release kinetics of naproxen was monitored with UV spectroscopy. The gel formed by compound 16 in DMSO/water was selected for the study, the release profiles of naproxen from the gel in the presence of water and

Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

• Lisa Markenstein,
• Antje Appelt-Menzel,
• Marco Metzger and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325

• (shown in Scheme 4) by the methylated CDs and CD polymers was quantified by the phase solubility method [53][54]. Solubility of midazolam was measured by UV spectroscopy as the function of the concentration of the CD derivative. The resulting occupancies are listed in Table 2. The value for native β-CD

• membrane cellulose filter, suitably diluted and analyzed using UV spectroscopy. The concentration of midazolam in each solution was determined by measuring its absorbance at 240 nm (ε = 21,240 M−1cm−1). The intrinsic absorption of each CD polymer was taken into account. Cell viability was determined using

• . Acknowledgements This work was funded by the Federal Ministry of Research and Technology (BMBF), Project No. 13N11804. Thanks to Devid Hero and Jessica Hilschmann for their synthetic work, Annegret Engelke and Blandine Boßmann for UV spectroscopy and GC headspace measurements.

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

• Amjid Iqbal,
• El-Habib Sahraoui and
• Finian J. Leeper

Beilstein J. Org. Chem. 2014, 10, 2580–2585, doi:10.3762/bjoc.10.270

• to NAD+ is monitored by UV spectroscopy at 340 nm. In order to follow the time-course of binding of furan 17, various concentrations (1–8 µM) were incubated with apo-PDC in a Mg2+-containing buffer and aliquots were taken out at timed intervals (1–30 min) and added to the assay solution containing

Autonomous assembly of synthetic oligonucleotides built from an expanded DNA alphabet. Total synthesis of a gene encoding kanamycin resistance

• Kristen K. Merritt,
• Kevin M. Bradley,
• Daniel Hutter,
• Mariko F. Matsuura,
• Diane J. Rowold and
• Steven A. Benner

Beilstein J. Org. Chem. 2014, 10, 2348–2360, doi:10.3762/bjoc.10.245

• , each holding 10 µM of DNA (by UV spectroscopy at 260 nm prior to dilution). For the annealing step, aliquots (1 µL, containing each 10 pmol, ca. 125–250 ng of DNA) were combined from each of the stock solutions with 5× ISO buffer (8 μL, 25% PEG-6000, 500 mM Tris-HCl, pH 7.5, 50 mM MgCl2, 50 mM DTT, 5

Reversibly locked thionucleobase pairs in DNA to study base flipping enzymes

• Christine Beuck and
• Elmar Weinhold

Beilstein J. Org. Chem. 2014, 10, 2293–2306, doi:10.3762/bjoc.10.239

• duplexes dissociate and elute as their respective single strands, while the covalently linked duplexes elute significantly later. HPLC-purified cross-linked duplexes were desalted using a NAP-5 gel filtration column as described below. UV spectroscopy UV spectroscopy was performed using a Varian CARY 3E UV

• and allowed to enter the gel bed. The DNA was eluted with H2O (1 mL), and the concentration of the eluate was determined by UV spectroscopy. The integrity of the cross-linked duplexes was confirmed by analytical denaturing anion exchange HPLC. The desalted duplexes were aliquoted (1 nmol), immediately

Second generation silver(I)-mediated imidazole base pairs

• Susanne Hensel,
• Nicole Megger,
• Kristina Schweizer and
• Jens Müller

Beilstein J. Org. Chem. 2014, 10, 2139–2144, doi:10.3762/bjoc.10.221

• effect. Figure 2 shows the melting curves of two of the double helices, determined by temperature-dependent UV spectroscopy (for the other two duplexes, see Supporting Information File 1). As can clearly be seen, the addition of one equivalent [39] of Ag(I) leads to a significant increase in the melting

Synthesis of a sucrose dimer with enone tether; a study on its functionalization

• Zbigniew Pakulski,
• Norbert Gajda,
• Magdalena Jawiczuk,
• Jadwiga Frelek,
• Piotr Cmoch and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2014, 10, 1246–1254, doi:10.3762/bjoc.10.124

• separations were performed on silica gel (Merck, 230–400 mesh). Progress of the reactions was monitored by thin-layer chromatography (TLC) performed on aluminum plates covered with silica gel (60 F254, Merck). The ECD spectra were acquired at room temperature in DMSO (for UV-spectroscopy, Fluka) on a Jasco J

Toward unidirectional switches: 2-(2-Hydroxyphenyl)pyridine and 2-(2-methoxyphenyl)pyridine derivatives as pH-triggered pivots

• Christina Tepper and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2012, 8, 977–985, doi:10.3762/bjoc.8.110

• was investigated with the help of UV spectroscopy. Quantum chemical calculations at the B3LYP/6-31G* level of theory were performed to show that in the case of 2-(2-methoxyphenyl)-3-methylpyridine and 2-(2-hydroxyphenyl)-3-methylpyridine the rotation during the switching process proceeds

• ., clockwise) and the minority will rotate in the other direction (e.g., counterclockwise), the whole process will now exhibit net unidirectionally (e.g., clockwise). Proof of the switching process The switching process can easily be observed by UV spectroscopy. The protonation was accomplished by the addition

meta-Oligoazobiphenyls – synthesis via site-selective Mills reaction and photochemical properties

• Raphael Reuter and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2012, 8, 877–883, doi:10.3762/bjoc.8.99

• . Isomerization studies Compounds 13, 15, 16 and 2 were analyzed by UV spectroscopy. All of them exhibit the typical behavior of azobenzenes, with a strong absorption at 330 nm for the π–π* transition and a weak absorption at 430 nm for the n–π* transition (Figure 3). For compounds 16 and 2 an increased

Evaluation of a commercial packed bed flow hydrogenator for reaction screening, optimization, and synthesis

• Marian C. Bryan,
• David Wernick,
• Christopher D. Hein,
• James V. Petersen,
• John W. Eschelbach and
• Elizabeth M. Doherty

Beilstein J. Org. Chem. 2011, 7, 1141–1149, doi:10.3762/bjoc.7.132

• , over sequential runs, and with commercial catalyst cartridges. In addition, the consistency of the hydrogen flow was indirectly measured by in-line UV spectroscopy. Finally, system contamination due to catalyst leaching, and the resolution of this issue, is described. The impact of these factors on the

• by UV spectroscopy (Figure 2). UV traces from runs 3 and 5 represent uninterrupted, full conversion to ethylbenzene, with short spikes in the curve corresponding to bubbles passing through the flow cell. In four out of six of the reactions (runs 1, 2, 4, and 6), peaks corresponding to unreacted

Intramolecular hydroxycarbene C–H-insertion: The curious case of (o-methoxyphenyl)hydroxycarbene

• Dennis Gerbig,
• David Ley,
• Hans Peter Reisenauer and
• Peter R. Schreiner

Beilstein J. Org. Chem. 2010, 6, 1061–1069, doi:10.3762/bjoc.6.121

• , VII, VIII, and X elements [2][3][4][5][6][7][8][9][10][11][12] it was only very recently that free hydroxycarbenes were generated by high vacuum flash pyrolysis (HVFP) followed by immediate matrix isolation and thoroughly characterized by means of IR- and UV-spectroscopy [13][14][15]. Very

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• properties and mesomorphism, we prepared compounds with BF4− (1b), PF6− (1c), CF3SO3− (1d) and (CF3SO2)2N− (1e) anions in excellent yield by anion metathesis in water/CH2Cl2 as solvent (Scheme 4). All these compounds were fully characterized by 1H NMR, 13C NMR {1H}, FT-IR and UV spectroscopy, as well as