Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• obtained and investigated by IR spectroscopy. The IR spectra show the absence of the line of stretching vibrations of the O–H bond, characteristic of the parent oximes, as well as the appearance of a new intense band corresponding to the asymmetric vibrations of the C=N–O• fragment (1550 сm−1 for the

• solution at room temperature without decomposition according to EPR and IR spectroscopy. Compound 20 represents a very rare example of sterically unhindered, but nonetheless extremely persistent oxime radical. Other long-living oxime radicals with electron-withdrawing substituents are also known, for

Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment

• Jan Geldsetzer and
• Markus Kalesse

Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64

• of the molecule was elucidated by a combination of NMR, UV and IR spectroscopy and molecular dynamics calculations (MD, MM2) [12]. However, its (Z)-enamide motif and the polyoxygenated middle segment are synthetically challenging. Results and Discussion Synthesis of amide 3 Here we report our

Visible-light-induced addition of carboxymethanide to styrene from monochloroacetic acid

• Kaj M. van Vliet,
• Nicole S. van Leeuwen,
• Albert M. Brouwer and
• Bas de Bruin

Beilstein J. Org. Chem. 2020, 16, 398–408, doi:10.3762/bjoc.16.38

• discussions regarding the IR spectroscopy measurements. Funding This research was supported by The Netherlands Organization for Scientific Research (NWO), the Holland Research School of Molecular Chemistry (HRSMC), the UvA Research Priority Area “Sustainable Chemistry” and the Advanced Research Center

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• . The ruthenium:oxygen ratio was found to be 3:1 from the XPS elemental ratio (Figure S8, Supporting Information File 1). Further confirmation of the presence of surface oxides was obtained through IR spectroscopy, which showed a Ru–O stretching peak at 462 cm−1 (Figure S9, Supporting Information File 1

• ). IR spectroscopy also revealed that the surface of the catalyst contained a negligible amount of organic compounds and was therefore appropriately clean. Thus, the RuNC that we used in this study can be characterised as Ru@RuOx where the bulk of the Ru nanocatalyst is zerovalent state and contained

• using a significantly higher loading of RuCl3 (10 mol %) under the optimised conditions for 48 h. Analysis of the product after the experiment by IR spectroscopy indicated the presence of an additional peak at 1610 cm−1 for a C=O moiety. For further confirmation of the alkenylation reaction, the solid

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• solution using 1H NMR, UV–vis and IR spectroscopy, and DTA. The properties of the BALE–Q[8] inclusion complex, such as stability, solubility, in vitro antioxidant activity and release performance were studied by means of UV–vis spectroscopy. Results and Discussion Host–guest interactions Q[8] and BALE in

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• , 22 °C, 1 h) with 88–77% yield after silica gel column chromatography (Scheme 1). The structures of nucleosides 4 and 5 were confirmed by NMR and IR spectroscopy (for the synthesis of a related unprotected nucleoside, see [31]). The MS spectra of 4 and 5 exhibited appropriate high resolution molecular

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

• 10-positions of anthracene. In addition, compound 3 was used as a chemosensor to research the ability to recognize Cr3+ through fluorescence and UV titrations, HRMS, as well as 1H NMR and IR spectroscopy. The results indicate that 3 is an effective chemosensor for Cr3+. Keywords: chemosensor

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

• studied by in situ Raman and ex situ IR spectroscopy. Keywords: ball milling; Friedel–Crafts reaction; mechanochemistry; Introduction The Friedel–Crafts reaction (FCR) is a very powerful tool in organic chemistry for the synthesis of aromatic ketones. It is of great industrial importance and widely used

• ion intermediate could not be unequivocally verified. Similar conclusions could be drawn from ex situ IR spectroscopy [62] which indicates rapid complexation and disappearance of phthalic anhydride (Supporting Information File 1, Figures S43 and S44). A further study was carried on complexation of

• of in situ IR spectroscopy in solution [63]. Conclusion In conclusion, the experimental results demonstrate that Friedel–Crafts acylations could be effectively carried out under solid state ball-milling conditions. The reaction takes place by the initial complexation of the carbonyl group of the

Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

• Qichao Zhang,
• Jian Lv and
• Sanzhong Luo

Beilstein J. Org. Chem. 2019, 15, 1304–1312, doi:10.3762/bjoc.15.129

• cation. Also, FeBr3, a chiral Fe(III) monophosphate (M = FeBr2) 1c or even the bulky Fe(III) bisphosphate 2a promoted the dissociation of trityl bromide. In the latter case, the dissociation was estimated to be 54% by in-situ IR spectroscopy (UV–vis spectra were not applicable due to absorption overlap

Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors

• Sven Grätz,
• Sebastian Zink,
• Hanna Kraffczyk,
• Marcus Rose and
• Lars Borchardt

Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112

• validating the complete insolubility in common organic solvents (like DCM, ethanol, DMF, chlorofrom, n-hexane), the nature of the polymer was investigated via IR spectroscopy. In the past the C–Cl vibration at 680 cm−1 has commonly been used to establish whether the desired crosslinking via the

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

• photoisomerization and a longer life time of the higher energy forms in comparison with the known analogs. The chemical structures of all dyes in the series were characterized by NMR, UV–vis, IR spectroscopy and elemental analysis. The steady-state photophysical properties of the dyes were elucidated. The stability

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

• Iveta Chena Tichá,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2019, 15, 830–839, doi:10.3762/bjoc.15.80

• subsequently applied as catalysts in enantioselective reactions. We fully characterized the series of new 16 cinchona–CD derivatives including non-methylated and permethylated CDs by 2D NMR, MS, IR spectroscopy and we optimized their preparation (less than 3 h and up to 95% isolated yield). We applied them in

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

• Vaida Milišiūnaitė,
• Rūta Paulavičiūtė,
• Eglė Arbačiauskienė,
• Vytas Martynaitis,
• Wolfgang Holzer and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62

• ]pyrazoles was explored (Scheme 2). For substrates 3b–j, the reactions were complete after 14 hours at 120 °C, and products 4b–j were generated in fair to excellent yields. The structural assignments of 4a–j were based on multinuclear NMR and IR spectroscopy as well as high-resolution mass spectrometry (HRMS

Mn-mediated sequential three-component domino Knoevenagel/cyclization/Michael addition/oxidative cyclization reaction towards annulated imidazo[1,2-a]pyridines

• Olga A. Storozhenko,
• Alexey A. Festa,
• Delphine R. Bella Ndoutoume,
• Alexander V. Aksenov,
• Alexey V. Varlamov and
• Leonid G. Voskressensky

Beilstein J. Org. Chem. 2018, 14, 3078–3087, doi:10.3762/bjoc.14.287

• produced in a sequential three-component manner (Scheme 5). The structures of the synthesized compounds 5a–h, 6a–k, 7–14, 17–20 were confirmed by 1H, 13C NMR, IR spectroscopy and HRMS spectra (see Supporting Information File 1 for details). The structure of the compound 7b was unambiguously determined by a

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• interaction between manganese(II) chloride and cellobiose generates the co-catalytic effect. The interactions of MnCl2 with -OH groups and other oxygen atoms of cellobiose were confirmed by IR spectroscopy [53]. In another study, 1-(3-sulfopropyl)-3-methyl-1H-imidazolium chloride (63) and 1-(4-sulfobutyl)-3

• . The α,α′-dibromo-p-xylene (112) was chosen as a linker because of containing the benzene rings for post-synthetic functionalization. HMP-1 (113) and HMP-1-SO3H (114) were confirmed by IR spectroscopy. The peak corresponding to the C–Br bond was not detected in the FTIR spectrum of HMP-1. The peaks at

Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis

• Tobias Fiedler,
• Michał Barbasiewicz,
• Michael Stollenz and
• John A. Gladysz

Beilstein J. Org. Chem. 2018, 14, 2354–2365, doi:10.3762/bjoc.14.211

• NMR (1H, 31P{1H}, 13C{1H}; always CDCl3) and IR spectroscopy, mass spectrometry, and microanalysis, as summarized in the experimental section. The 13C{1H} NMR spectra proved to be most diagnostic of structure, and were analyzed in detail. The 31P{1H} NMR spectra were all very similar (broad apparent

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• higher (25% on average) than that of N-hydroxysuccinimide (2b). Structures of the iodo-oxyimides 3aa–ka, 3ab–db, 3fb, 3hb and 3kb were confirmed by 1D and 2D NMR spectroscopy, IR spectroscopy, high-resolution mass spectrometry and elemental analysis. An additional confirmation of the structure of 3ca was

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• reaction between p-phenylenediamine and graphene oxide with no additive (heating at 80 °C for 24 h), should be directly observed using IR spectroscopy. In this case, benzene rings were claimed to be introduced to GO via the presence of a strong absorption band located at ca. 1500 cm−1 (C=C stretching

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• established by 1H and 13C NMR spectroscopy as well as by IR spectroscopy and MALDI–TOF mass spectrometry. Their compositions were determined by elementary analysis. A standard set of signals typical for distal disubstituted calixarenes was found in the 1H NMR spectra of 4a and b (Supporting Information File 1

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• problems, IBS was previously characterized by 1H and 13C NMR, IR spectroscopy, high-resolution mass spectrometry, and elemental analysis. However, all previously reported attempts to grow single crystals of IBS from methanol or acetonitrile resulted in reduction with the formation of 2

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• accommodation of 12 n-octyloxy chains, the occurrence of a starburst effect [18][58][59] during the covalent m-trimerisations (Scheme 3), was also presumed (see section 3.2.1). 3.2 Assignments by means of NMR and IR spectroscopy The 1H NMR data deserving of comment are listed in Table 3. 3.2.1 Rotational

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

• electronically excited (S1) state is analyzed, in which a destabilization of the OH∙∙∙O structure compared to the S0 state is observed experimentally and theoretically. Keywords: dispersion interactions; IR spectroscopy; quantum-chemical calculations; rotational spectroscopy; structure determination; weak

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• surface, Pd/NCNT achieved an approximately three-times higher current density in NaOH than in KOH. In situ electrochemistry/IR spectroscopy was applied to unravel the product distribution as a function of the applied potential in NaOH and KOH. The IR spectra exhibited strongly changing band patterns upon

• oxidation. Keywords: cation effect; electrocatalysis; glycerol oxidation; in situ electrochemistry/IR spectroscopy; Introduction The conversion of biomass to biofuels is a promising process for carbon-neutral energy conversion [1]. First-generation biofuels such as bioethanol or biodiesel are produced

• -performance liquid or ion chromatography and differential electrochemical mass spectrometry provide information about the nature of dissolved and chemically stable products [10][11]. A rather direct view on the reaction is provided by infrared (IR) spectroscopy. Specifically designed experimental cells focus

Synthesis of pyrazolopyrimidinones using a “one-pot” approach under microwave irradiation

• Mark Kelada,
• John M. D. Walsh,
• Robert W. Devine,
• Patrick McArdle and
• John C. Stephens

Beilstein J. Org. Chem. 2018, 14, 1222–1228, doi:10.3762/bjoc.14.104

• using 1H and 13C NMR spectral data, HRMS, and IR spectroscopy. In addition, an X-ray crystal structure was obtained for pyrazolo[1,5-a]pyrimidinone 3m and is shown in Figure 2. Conclusion In conclusion, we have developed a new facile method for the one-pot microwave-assisted synthesis of substituted

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• . The formation of complex G was demonstrated through IR spectroscopy. Indeed, the frequency of the NH and OH groups in this complex was higher than that in the single ligand 51. On the other hand, the frequency of the carbonyl group was the same as that of pure ligand 51, showing that this ligand