Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• -isomers and of products of the photoinduced rearrangement completed by 1,5-H shift reaction, 3a,4-dihydronaphtho[2,3-c]furans(pyrroles) C, were established based on the data of 1H and 13C NMR spectroscopy and X-ray diffraction studies. Keywords: benzo[b]thiophene; fulgide; fulgimide; photorearrangement

• afford exclusively fulgimides 3Z and 7E, respectively, as the single products (Scheme 2 and Scheme 3). According to IR, 1H and 13C NMR spectroscopy data Z- and E-isomers of fulgide 3 exist in the form of the open isomers O. This was also confirmed by X-ray diffraction study. The molecular structures of

• -, Z-isomers and closed forms C were identified with the use of 1H and 13C NMR spectroscopy and their molecular structures confirmed by X-ray diffraction studies. Experimental General: The 1H and 13C NMR spectra in CDCl3 were obtained on an integrated analytical LC-SPE-NMR-MS AVANCE-600 system from

Fluorohydration of alkynes via I(I)/I(III) catalysis

• Jessica Neufeld,
• Constantin G. Daniliuc and
• Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

• organocatalyst, Selectfluor® was employed as the terminal oxidant, and an amine/HF complex enlisted as the fluoride source (please see Supporting Information File 1 for full details). The reaction was performed in CHCl3 at ambient temperature and the crude reaction mixtures were analysed by 19F NMR spectroscopy

• , carbonyl and alkynyl group are optimally preorganised with a C5 linker. With this in mind, the amide derivatives 12 and 13 were exposed to the standard reaction conditions. Curiously, the reactions were extremely ineffective yielding the respective α-fluoroketones in only 15% yield as determined by 19F NMR

• spectroscopy. This contrasts sharply with the phthalimide derivative 7 (64%). Doping a representative reaction (14 → 9) with methyl benzoate (15) (Figure 3B) to explore for potential activator effects also proved unsuccessful. Finally, a stoichiometric reaction of alkynyl phthalimide 16 with freshly prepared p

Facile synthesis of 7-alkyl-1,2,3,4-tetrahydro-1,8-naphthyridines as arginine mimetics using a Horner–Wadsworth–Emmons-based approach

• Rhys A. Lippa,
• John A. Murphy and
• Tim N. Barrett

Beilstein J. Org. Chem. 2020, 16, 1617–1626, doi:10.3762/bjoc.16.134

• T3P® [17], yielded olefin 15 in 93% yield as a 94:5 mixture of stereoisomers – presumably E/Z, although this is not conclusive from the 1H NMR spectrum. Based on LC–MS and 1H NMR spectroscopy observations, it is believed that aldehyde 5 exists predominantly as the corresponding hydrate and an excess

• with CD3OD by 1H and 13C NMR spectroscopy indicated the formation of the monolabelled compound 17 as the major product, demonstrating that lithiation only occurs at a single position of compound 13 (Scheme 6). When performed on a multigram scale, phosphonate 7 was isolated in 68% yield after

• aldehydes.a Supporting Information Supporting Information File 94: Detailed experimental procedures, and product characterisation data, along with 1H and 13C NMR spectra. Acknowledgements Thanks to Sean M. Lynn for assistance with NMR spectroscopy analysis and the GSK UK Discovery Analytical team for

A dynamic combinatorial library for biomimetic recognition of dipeptides in water

• Florian Klepel and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131

• function yields a smaller increase in binding affinity than adding a second one, pointing towards a cooperative contribution of both phenyl rings. Pure F is the weakest tested binder, which hints at the selectivity towards dipeptides. Next we used NMR spectroscopy to further characterize the binding

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• analyzed by 19F NMR spectroscopy. A series of typical photocatalysts (for example, iridium catalysts) were ineffective in promoting the reaction. Rewardingly, a gold catalyst, [AuCl(μ-dppm)]2 [25][26][27], provided reasonable yields of 3a after one day of irradiation along with a full conversion of the

• . Yield determined by 19F NMR spectroscopy using an internal standard. Proposed mechanism of the fluoroalkylation reaction. Supporting Information Supporting Information File 332: Full experimental details, compound characterization, and copies of NMR spectra.

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• ), the 1-ethyl derivative 20 did not react at all with the anhydrides 5–7. The structures of compounds 25 and 26 were confirmed by 2D NMR spectroscopy and singe-crystal X-ray analysis (Figure 3). The piperidine moiety is planar to a significant extent due to the combined influence of the aromatic ring

• , respectively, were formed as single diastereomers (Scheme 6). The 1-ethyldihydroisoquinoline 20 showed a pronounced lower reactivity to anhydride 8, with a 30% yield of 29 as compared to 28 (71%), probably due to a steric hindrance. The relative configuration of 28 and 29 was established using 2D ROESY NMR

• spectroscopy. The spectra showed cross peaks between the protons from the cis-oriented alkyl-C-11b and H-1, which unequivocally proved the trans relative configuration of the substituents at C-1 and C-11b (Figure 4). 1-Alkyl-3,4-dihydroisoquinolines have been reported to react as C-nucleophiles or 1,3-C,N

The McKenna reaction – avoiding side reactions in phosphonate deprotection

• Katarzyna Justyna,
• Joanna Małolepsza,
• Damian Kusy,
• Waldemar Maniukiewicz and
• Katarzyna M. Błażewska

Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119

• esters that indicated a more efficient transesterification reaction at this temperature. Depending on the experiment, the progress of the reaction was monitored by 1H and 31P NMR spectroscopy in short intervals. The complete deprotection of the phosphonate ester group in compound 8 and 9 was observed. In

• storage and/or use of BTMS, which exposes it to traces of water. As mentioned in the previous section, compounds having multiple bonds could undergo an addition reaction upon exposure to HBr [42]. We studied this problem using 1H NMR spectroscopy with the model acrylamide 11 (Scheme 3), representing a

• susceptibility of 2-chloro-N-phenethylacetamide (13), towards halogen exchange mediated by BTMS (Scheme 6). The reaction progress was monitored by 1H NMR spectroscopy monitoring the signals of the methylene groups C(O)CH2Cl in 13 vs C(O)CH2Br in the product 22 (see Figure S16 in Supporting Information File 1

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

• oxime 1g (Scheme 5). Oxime radical 16 is a pale blue crystalline compound that is stable at room temperature [35][62], whereas liquid neat di-tert-butyliminoxyl radical (8) decomposed within a week [59]. The di(1-adamantyl)iminoxyl radical (16) was characterized by IR, UV–vis, EPR, and NMR spectroscopy

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• resonance (NMR) spectroscopy, infrared spectroscopy, and high-resolution mass spectrometry) successfully identified the more polar product as the half-oxidized benzil 2a and the less polar one as the fully oxidized bisbenzil 3a. Fluorinated bistolane 1b, bearing a hexyloxy chain, also underwent PdCl2

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• , elemental analysis, and 1H NMR spectroscopy. The framework was supported by hydrogen bonds between the sulfonate anions and the ammonium cations of NDS and protonated TAPM moieties, respectively. The CAHOF material functioned as a new type of catalytically active Brønsted acid in a series of reactions

• organic framework F-1. The structure of F-1 was established by single crystal and powder X-ray diffraction, NMR spectroscopy, and elemental analysis. The morphology of F-1 was assessed by SEM, and its stability was determined by TGA. We report the use of F-1 as a heterogeneous, robust, and recoverable

• after several hours, the catalyst was removed by centrifugation or filtration through a dense paper filter. The filtrates were evaporated, and the residue was weighed and analyzed by 1H NMR spectroscopy. The experimental results are summarized in Table 1. Uncrystallized F-1 promoted the ring opening of

Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

• Valeria Nori,
• Antonio Arcadi,
• Armando Carlone,
• Fabio Marinelli and
• Marco Chiarini

Beilstein J. Org. Chem. 2020, 16, 1084–1091, doi:10.3762/bjoc.16.95

• 4 and 6 was unambiguously confirmed by NMR spectroscopy [43]. Conclusion In conclusion, we have demonstrated that cascade cyclocarbopalladations of the readily available aryl/alkyl-substituted N-propargyl-2-iodobenzamides 2 followed by Suzuki–Miyaura coupling reactions with arylboronic acids, in the

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• , Turkey WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, G128QQ Glasgow, UK 10.3762/bjoc.16.93 Abstract Two novel carbazole-based compounds 7a and 7b were synthesised as potential candidates for application in organic electronics. The materials were fully characterised by NMR

• spectroscopy, mass spectrometry, FTIR, thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, and absorption and emission spectroscopy. Compounds 7a and 7b, both of which were amorphous solids, were stable up to 291 °C and 307 °C, respectively. Compounds 7a and 7b show three

Suzuki–Miyaura cross coupling is not an informative reaction to demonstrate the performance of new solvents

• James Sherwood

Beilstein J. Org. Chem. 2020, 16, 1001–1005, doi:10.3762/bjoc.16.89

• investigated (see Supporting Information File 1). In each case study, conversion to the desired product was measured by 1H NMR spectroscopy (see Supporting Information File 1, Figure S4). The results are summarised in Table 1. No evidence of significant hydrodehalogenation or other unintended reactions was

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• presence of a palladium catalyst, with yields ranging from 27 to 50%. The chemical structures of 3–6 were confirmed by 1H and 13C NMR spectroscopy, elemental analysis and mass spectrometry. Transparent thin films of these compounds could be prepared by vacuum evaporation or by spin coating from solutions

Fabclavine diversity in Xenorhabdus bacteria

• Sebastian L. Wenski,
• Harun Cimen,
• Natalie Berghaus,
• Sebastian W. Fuchs,
• Selcuk Hazir and
• Helge B. Bode

Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84

• fabclavine Ia (1) could be determined by NMR spectroscopy [20]. Furthermore, bioinformatic analysis of Xenorhabdus and Photorhabdus genomes revealed that the ability to produce fabclavines or related compounds might be widespread in these strains [22][26]. In order to analyze the associated fabclavine

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• compounds 3a and 3b were confirmed by NMR spectroscopy (1H, 13C, COSY, HSQC, HMBC), mass spectrometry (ESIMS), and elemental analysis. Photophysical and photochemical properties The absorption spectra of 3a and 3b exhibit the characteristic long-wavelength absorption bands of the styryl-substituted

• coumarin 307 [71], Figure S1A, Supporting Information File 1 and Table 1), but the shift and intensity of the emission band did not change upon the addition of Cu2+. The reaction of 3a upon the addition of Cu2+ was also investigated by 1H NMR spectroscopy in order to obtain more insight into the mechanism

• [17], we still presume that it was formed after the Cu2+-induced ring-opening reaction, but the following processes were too fast so that the intermediate B could not be detected by NMR spectroscopy (Scheme 4). Additionally, the development of the absorption spectra in the presence of Fe3+ revealed a

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• using NMR spectroscopy and DFT calculations [33]. In particular, the unprecedented double α-oxygenation of bipyrroles was shown to occur through stepwise acetoxylation, which we found to compete with α–α oligomerization. These new bipyrrole boomerangs exhibited enhanced fluorescence with Φfl values of

Preparation of 2-phospholene oxides by the isomerization of 3-phospholene oxides

• Péter Bagi,
• Réka Herbay,
• Nikolett Péczka,
• Zoltán Mucsi,
• István Timári and
• György Keglevich

Beilstein J. Org. Chem. 2020, 16, 818–832, doi:10.3762/bjoc.16.75

• -diastereomers (cis- and trans-10) were separated by column chromatography, and they were identified by nuclear Overhauser effect (NOE) NMR spectroscopy. In the ROESY spectrum of the cis-diastereomer (cis-10), the phenyl 1H resonances give NOE/ROE crosspeaks with the C(4)H and one of the C(5)H2 1H resonances. By

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• 2,5,10,13-tetramesitylterrylene (TM4) in 58% yield. TM4 was successfully isolated through a silica gel pad and by reprecipitation. The structure of TM4 was characterized by mass spectrometry and 1H and 13C NMR spectroscopy. High-resolution MALDI mass spectrometry detected the parent ion peak at m/z

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• of TIPS-ethynyl-substituted BODIPY derivatives 3–6 were characterized by 1H and 19F NMR spectroscopy, high-resolution mass spectrometry, and X-ray crystallographic analysis. The solid-state structures of the diethynyl-substituted BODIPYs were unambiguously elucidated by X-ray diffraction analysis (3a

Efficient synthesis of 3,6,13,16-tetrasubstituted-tetrabenzo[a,d,j,m]coronenes by selective C–H/C–O arylations of anthraquinone derivatives

• Seiya Terai,
• Yuki Sato,
• Takuya Kochi and
• Fumitoshi Kakiuchi

Beilstein J. Org. Chem. 2020, 16, 544–550, doi:10.3762/bjoc.16.51

• ,j,m]coronene 7aa was also examined (Figure 2), as Wu and co-workers have studied the self-assembling property of the tetrabenzo[a,d,j,m]coronene derivative possessing n-octyl groups at the 2, 7, 12, and 17-positions by 1H NMR spectroscopy and suggested its intermolecular π–π interaction in solution

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• compounds was examined. Because the separation of the product from silicon-based byproducts was troublesome, the isolated yields were lower than the yields determined by NMR spectroscopy (2a, 52%, Table 2, entry 1). When (E)-1a was used as the substrate, the opposite enantiomer (S)-2a was obtained in >99

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• suggested that the reaction proceeds via an intermediate six-membered selenocyanate 5, which could be observed at a lower temperature. Indeed, monitoring the reaction by 1H NMR spectroscopy using the same conditions as in the synthesis of the selenocyanate 4, but at 0 °C confirmed this assumption (Scheme 6

• chemistry. Monitoring the reaction of thiaselenole 1 with KSeCN by 1H NMR spectroscopy (in accordance with the data of Table 1). Reaction conditions: compound 1 (0.5 mmol), KSeCN (0.5 mmol), MeCN (2.5 mL), 0 °C. Possible formation of reaction products starting from 1 via seleniranium 2 or thiiranium cations

• alkyl propiolates (77Se NMR data are included). One-pot synthesis of diselenide 8 from thiaselenole 1 (77Se NMR data are included). Synthesis of compounds 6a–j from diselenide 8. Results the reaction of thiaselenole 1 with KSeCN based on 1H NMR spectroscopy monitoring (Figure 1).a Supporting

Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

• Anna R. Bockman and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

• the relative reactivity of the various amines, a pseudo-first order kinetics of the amidation reaction was probed. The reaction was followed by 1H NMR spectroscopy at room temperature, following the disappearance of 7-CMP and appearance of the amide product (Figure 3). By monitoring the reaction