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Search for "NMR" in Full Text gives 2993 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

  • Eiichi Kayahara,
  • Yoshiyuki Mizuhata and
  • Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

Graphical Abstract
  • state of the corresponding host–guest complex. Here, we report on the size complementary formation of the host–guest complex between [10]CPP and the dication of [5]CPP, [10]CPP⊃[5]CPP2+ (Figure 1c). The association constant, Ka, determined by 1H NMR titration, was about 20 times higher than that of the
  • host–guest complex consisting of neutral [10]CPP and [5]CPP, [10]CPP⊃[5]CPP [31]. While the 1H NMR analysis also supported the closed-shell electronic structure of both the host and the guest, neutral [10]CPP and [5]CPP2+, respectively, a partial CT from the host to the guest was suggested by the
  • + and neutral CPP was first examined by adding a solution of [5]CPP2+[B(C6F5)4−]2 in CD2Cl2 to a mixture of [8]-, [9]-, [10]-, [11]-, and [12]CPPs in CD2Cl2 at 25 °C (Figure 2a). In the 1H NMR spectrum of the resulting mixture, only the signals of [10]CPP and [5]CPP2+ shifted downfield by about 0.44 ppm
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Published 23 Feb 2024

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

  • Nahed Ketata,
  • Linhao Liu,
  • Ridha Ben Salem and
  • Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

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  • from Acros. KOPiv (95%) was purchased from Doug Discovery. These compounds were not purified before use. All reagents were weighed and handled in air. All reactions were carried out under an inert atmosphere with standard Schlenk techniques. 1H, 19F and 13C NMR spectra were recorded on Bruker Avance
  • data of synthesized compounds. Supporting Information File 44: Copies of 1H, 19F, and 13C NMR spectra. Acknowledgements We are grateful to Dr. Elsa Caytan for NMR experiments. Part of this work has been performed using the PRISM core facility (Biogenouest, Univ Rennes, Univ Angers, INRAE, CNRS, FRANCE
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Published 23 Feb 2024

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

  • Carlos R. Azpilcueta-Nicolas and
  • Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

Graphical Abstract
  • ). Importantly, electron paramagnetic resonance (EPR) spectroscopy at 25 °C supported the formation of species 107. However, NMR measurements at −40 °C showed the accumulation of BiIII complex 131, which can be prepared separately in a stoichiometric experiment. As such, two different pathways may lead to the C
  • , accompanied by the formation of cyano-B(pin) 142. Importantly, in the absence of ZnCl2, intermediate 140 could be detected by HRMS and 11B NMR, highlighting the pivotal role of ZnCl2 in promoting rearomatization. N-Heterocyclic carbene (NHC) catalysis In 2019, Nagao and Ohmiya reported the decarboxylative
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Perspective
Published 21 Feb 2024

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

  • Eugeny Ivakhnenko,
  • Vasily Malay,
  • Pavel Knyazev,
  • Nikita Merezhko,
  • Nadezhda Makarova,
  • Oleg Demidov,
  • Gennady Borodkin,
  • Andrey Starikov and
  • Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

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  • short-term heating of the melted reactants at 220–250 °C is described, and the compounds were characterized by means of single-crystal X-ray crystallography, NMR, UV–vis, and IR spectroscopy, as well as cyclic voltammetry. The reaction with o-amino-, o-hydroxy-, and o-mercapto-substituted arylamines
  • unambiguously established based on COSY, HSQC, and HMBC NMR-spectroscopic data. Further, the 15N NMR spectrum of 5a confirmed the typical pyrrole-like character of the N(12) atom as well as the pyridine-like character of the N(7) and N(14) atoms (Figure S31, Supporting Information File 1) [21][22]. The
  • reaction products as 12H-quinoxaline[2,3-b]phenoxazines was confirmed through DFT calculations, X-ray crystallography, and NMR spectroscopy. Electronic absorption spectra (Table 2 and Figures 5–7) and electrochemical properties (Table 3) of the heteropentacyclic compounds 4a–h, 5a–c, 6a,b, and 10c revealed
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Published 21 Feb 2024

Spatial arrangements of cyclodextrin host–guest complexes in solution studied by 13C NMR and molecular modelling

  • Konstantin Lebedinskiy,
  • Ivan Barvík,
  • Zdeněk Tošner,
  • Ivana Císařová,
  • Jindřich Jindřich and
  • Radim Hrdina

Beilstein J. Org. Chem. 2024, 20, 331–335, doi:10.3762/bjoc.20.33

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  • 2026/5, 121 16 Praha, Czech Republic Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 43 Praha, Czech Republic 10.3762/bjoc.20.33 Abstract 13C NMR spectroscopic analyses of Cs symmetric guest molecules in the cyclodextrin host cavity, combined with molecular
  • signals in 13C NMR spectra. This signal split can be correlated to the distance of the guest atoms from the wall of the host cavity and to the spatial separation of binding sites preferred by pairs of prochiral carbon atoms. These measurements complement traditional solid-state analyses, which rely on the
  • crystallization of host–guest complexes and their crystallographic analysis. Keywords: anisotropy; 13C NMR; cyclodextrin; host–guest complexes; Introduction Complexation of organic and inorganic compounds with α-, β-, or γ-cyclodextrins and their derivatives [1] is an established tool used in medicine for drug
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Published 20 Feb 2024

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

  • Sharmila Neupane,
  • Marcelo Rodrigues de Amorim and
  • Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

Graphical Abstract
  • – unguisin J (1) – along with known unguisin B (2) were isolated from a solid culture of Aspergillus heteromorphus CBS 117.55. The structure of compound 1 was elucidated by extensive 1D and 2D NMR spectroscopic analysis including HSQC, HMBC, COSY, and 2D NOESY as well as HRESIMS. The stereochemistry of 1 and
  • compound 1 was elucidated by 1D and 2D NMR and HRESIMS/MS. Unguisin B was identified by the 1H and 13C NMR data with the reported data [1][5]. Compound 1 was obtained as a white amorphous solid optically active, with +23.4 (c 0.1, MeOH). Its molecular formula was established as C41H56N8O7 by HRMS ([M + H
  • ]+ at m/z 773.4338, calculated for C41H57N8O7+, m/z 773.4345, Δ 0.9 ppm; [M + Na]+ at m/z 795.4162, calculated for C41H56N8O7Na+, m/z 795.4164, Δ 0.3 ppm) and NMR data analysis, corresponding to eighteen indices of hydrogen deficiency. Its UV spectrum exhibited absorption maxima at λmax 219 and 279 nm
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Published 19 Feb 2024

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

  • Aissam Okba,
  • Pablo Simón Marqués,
  • Kyohei Matsuo,
  • Naoki Aratani,
  • Hiroko Yamada,
  • Gwénaël Rapenne and
  • Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

Graphical Abstract
  • using a high-pressure mercury lamp equipped with a sharp cut filter (λ > 380 nm), which resulted in a smooth conversion into the PBI product 6a within 20 min. Interestingly, the sulfoxide derivative exhibited enhanced kinetics, as confirmed by UV–vis spectroscopy and NMR experiments. The latter was also
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Published 15 Feb 2024

Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes

  • Wenqing Hao,
  • Long Wang,
  • Jinlei Zhang,
  • Dawei Teng and
  • Guorui Cao

Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29

Graphical Abstract
  • investigated the performance of other organic and inorganic bases, but they did not improve the yield (Table 1, entries 8–12). The structure of spiropyridazine-benzosultam 3aa was determined by 1H NMR, 13C NMR, HRMS analysis and single-crystal X-ray crystallography [33]. Further experiments conducted with
  • reaction from 3aa to 4aa. The effects of solvents, bases, reaction time and temperature on the [4 + 2] annulation reactiona. Supporting Information Supporting Information File 28: Experimental part, NMR and HRMS spectra.
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Published 14 Feb 2024

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C70 production

  • Cristina Castanyer,
  • Anna Pla-Quintana,
  • Anna Roglans,
  • Albert Artigas and
  • Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

Graphical Abstract
  • , leading to β-site isomers as minor products. Taking this into account, we carefully analyzed the NMR spectra of compound 2a. Analysis of 1H NMR spectra of 2a provided valuable information that confirmed the generation of two regioisomers in a 71:29 ratio (Figure 2). Comparable proportions of reactions at
  • column chromatography, giving an inseparable mixture of different isomers. The oxygenation process was confirmed by HRMS, which gave a single peak at m/z = 1170.0756 corresponding to [3a + Na]+. On analyzing carefully the mixture by 1H NMR spectroscopy, we observed three different sets of three methyl
  • protons marked in red and the ones marked in green might be those of the β-isomer (29%). Unfortunately, NMR experiments did not allow to differentiate between α- and β-3a derivatives. The reaction was carried out also with bis(fulleroid) derivative 2b, exhibiting the same behavior. Conclusion In this
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Published 13 Feb 2024

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

  • Kazuhiro Okamoto,
  • Naoki Shida and
  • Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

Graphical Abstract
  • current (Figure 2B, blue line). We considered that the inter- and intramolecular chemoselectivities were derived from the pKa of the proton sources. The pre-organization of the amide substrate and phosphate bases is an important process in PCET [13]. Recently, Gschwind et al. published a detailed NMR
  • in vacuo and the resulting residue was subjected to 1H NMR spectroscopy or column chromatography. A divided-cell experiment was performed using an H-type cell (4G glass filter). Compound 1 (0.2 mmol), Bu4NPF6 (387 mg, 1 mmol), phosphate base (90 mg, 0.2 mmol), CH2Cl2 (10 mL), and methyl vinyl ketone
  • was removed by filtration through a short silica gel pad under reduced pressure. The filtrate was concentrated in vacuo and the resulting residue was subjected to 1H NMR spectroscopy or column chromatography. Application of amidyl radical species generated by PCET. (A) Effect of phosphate base on the
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Published 12 Feb 2024

Nucleophilic functionalization of thianthrenium salts under basic conditions

  • Xinting Fan,
  • Duo Zhang,
  • Xiangchuan Xiu,
  • Bin Xu,
  • Yu Yuan,
  • Feng Chen and
  • Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

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  • )thianthrenium salt.a Supporting Information Supporting Information File 16: Experimental procedures, characterization data for all new compounds, and NMR spectra of products. Funding We are grateful for the financial support from the National Natural Science Foundation of China (22001227), the China
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Published 08 Feb 2024

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

  • Ekaterina V. Kolupaeva,
  • Narek A. Dzhangiryan,
  • Alexander F. Pozharskii,
  • Oleg P. Demidov and
  • Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

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  • nitrobenzene. For example, quinoquinoline 5 reacts with chloranil upon heating in toluene to give a dark brown, high-melting product, in which, however, the methylene bridge remains unchanged. According to 1H NMR spectroscopy and combustion analysis data, this is complex 9 with a composition close to the ratio
  • 1:1 (Scheme 2). Complex 9 is insoluble in most organic solvents, but it turned out to be unstable in DMSO-d6 solution, as evidenced by monitoring its 1Н NMR spectra (Supporting Information File 1, Figure S1). Figure S1a shows the spectrum of the starting quinoline 5, Figure S1b represents complex 9
  • results of 1H NMR spectra and TLC analysis, the second component was still present. This “permanent impurity” cannot be separated by chromatography or recrystallization, but it can be eliminated to some extent by washing the nitration products with hot chloroform, in which the impurity is slightly better
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Published 08 Feb 2024

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

  • Milandip Karak,
  • Cian R. Cloonan,
  • Brad R. Baker,
  • Rachel V. K. Cochrane and
  • Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

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  • Supporting Information Supporting Information File 12: Experimental procedures, characterization data, and selected copies of 1H, 13C, and 31P NMR spectra. Acknowledgements We extend our gratitude to Professor Alethea Tabor and Professor Stefan Howorka from University College London for their valuable
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Published 06 Feb 2024

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

  • Yumei Wang,
  • Guangzhu Wang,
  • Yanping Zhu and
  • Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

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  • and the reaction mixture was stirred at room temperature for 3 h. After concentrating the mixture, the residue was purified by column chromatography on silica gel using a mixture of petroleum ether/ethyl acetate 30:1 (v/v) as the eluent to afford products 2. The yields were determined by 19F NMR
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Published 01 Feb 2024

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

  • Amina Moutayakine and
  • Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

Graphical Abstract
  • then evaporated under reduced pressure and the crude was purified by flash chromatography (hexane/AcOEt 9:1), to yield o-(2-bromophenyl)aminoaniline (3a) as a purple oil (0.07 g, 59% yield).1H NMR (CDCl3, 400 MHz) δ 4.00 (s, NH2, 2H), 5.76 (s, NH, 1H), 6.59–6.61 (d, J = 8 Hz, Ar, 1H), 6.65–6.69 (t, J
  • = 8 Hz, Ar, 1H), 6.79–6.83 (t, J = 8 Hz, Ar, 1H), 6.85–6.87 (d, J = 8 Hz, Ar, 1H), 7.09–7.13 (m, Ar, 3H), 7.49–7.51 (d, J = 8 Hz, Ar, 1H); 13C NMR (CDCl3, 100 MHz) δ 110.42, 114.41, 116.47, 119.48, 119.70, 127.00, 127.04, 128.39, 132.62, 142.45, 143.03; HRESIMS (m/z): [M + H+] calcd for C12H11BrN2
  • °C; 1H NMR (DMSO-d6, 400 MHz) δ 6.87–7.00 (m, Ar, 6H), 7.31–7.35 (t, J = 8 Hz, Ar, 1H), 7.66–7.68 (d, J = 8 Hz, Ar,1H), 7.84 (s, Ar, 1H), 9.85 (s, Ar, 1H); 13C NMR (CDCl3, 100 MHz) δ 119.52, 120.23, 121.17, 121.73, 123.24, 123.40, 124.95, 130.29, 132.56, 133.67, 140.43, 150.92, 168.40; ESIMS (m/z
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Published 31 Jan 2024

Comparison of glycosyl donors: a supramer approach

  • Anna V. Orlova,
  • Nelly N. Malysheva,
  • Maria V. Panova,
  • Nikita M. Podvalnyy,
  • Michael G. Medvedev and
  • Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

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  • treated with 90% aq trifluoroacetic acid in CH2Cl2 to give diol 7 (70% yield) that was formed due to migration of a chloroacetyl group from O-7 to O-9. The structure of diol 7 was established by NMR spectroscopy, high-resolution mass spectrometry and X-ray diffraction analysis (see the Experimental
  • during purification by silica gel chromatography. On the other hand, NMR analysis of the crude reaction mixtures may be misleading due to possible overlap of the signals of H-3eq belonging both to disaccharide and monosaccharide derivatives sometimes present in such glycosylation mixtures. At low
  • after immersion in a 1:10 (v/v) mixture of 85% aq H3PO4 and 95% aq EtOH. 1H, 13C, and 19F NMR spectra of solutions in CDCl3 and acetone-d6 were recorded on a Bruker AVANCE-600 instrument at 600 MHz for 1H and 151 MHz for 13C or on a Bruker AM-300 instrument at 300 MHz for 1H, 75 MHz for 13C, and 282 MHz
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Published 31 Jan 2024

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N3 linker for glycodendrimersomes preparation to study lectin binding

  • Mark Reihill,
  • Hanyue Ma,
  • Dennis Bengtsson and
  • Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

Graphical Abstract
  • 4.95 ppm with a J value of 3.6 Hz in the 1H NMR spectrum proving the anomeric α-configuration. The presence of Troc-rotamers was also apparent, with a ratio of 19:6 being observed by 1H NMR in CDCl3 at 25 °C. Catalytic amounts of NaOMe (0.005 M) in MeOH were used to remove the acetate from compound 4
  • choice [12], surprisingly better than a benzoylated donor [19], why this donor was the first one tested also with the quite different acceptor 5. An NIS/AgOTf-promoted glycosylation with donor 6 [20] yielded 79% of disaccharide 7. Due to the presence of rotamers, NMR spectra of 7 proved to be difficult
  • to analyse when data were recorded in CDCl3. Changing the NMR solvent to CD3OD greatly reduced the complexity of the spectra [21][22][23]. Since 7 possessed an azido group as part of the linker, removal of the Troc group under reductive conditions was ruled out due to probable chemoselectivity issues
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Published 30 Jan 2024

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

  • Viktoria A. Ikonnikova,
  • Cristina Cheibas,
  • Oscar Gayraud,
  • Alexandra E. Bosnidou,
  • Nicolas Casaretto,
  • Gilles Frison and
  • Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

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  • methide intermediate 9 upon elimination of the hydroxy group. This highly electrophilic species could trigger a second intramolecular Friedel–Crafts reaction leading to 6. The cyclic connectivity of 6 was determined by bidimensional NMR experiments, incidentally showing a broadening of the signals of
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Published 25 Jan 2024

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

  • Changdong Shao,
  • Chen Ma,
  • Li Li,
  • Jingyi Liu,
  • Yanan Shen,
  • Chen Chen,
  • Qionglin Yang,
  • Tianyi Xu,
  • Zhengsong Hu,
  • Yuhe Kan and
  • Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

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  • conditions for the copper-promoted C5-brominationa. Supporting Information Supporting Information File 38: General information, experimental procedures for all the products, characterization data, and NMR spectra. Funding This work was supported by the National Natural Science Foundation of China (21801088
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Published 23 Jan 2024
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  • 1H nuclear magnetic resonance (NMR) spectroscopy. Their investigation revealed that the product plays a pivotal role as an autocatalyst in the kinetics, as illustrated in Scheme 8 [104][105][106]. The traditional model posits that an alkyne (A) and TCNE (designated as B in Scheme 8) initially form a
  • manner, ultimately affording 27 with 90% yield. The formation of intermediates 24, 25, and 26 was elucidated through 1H NMR analysis, of which 24 and 26 were successfully isolated and characterized. A comprehensive analysis of the [2 + 2] CA–RE reaction activation parameters via 1H NMR spectroscopy
  • yield for the ring-formation process was modest at 5% (see Scheme 16) [121][122]. The macrocycle in 46 was observed to engage with the peptide segment in low-polarity solvents. In contrast, 1H NMR analysis suggested that the macrocycle disengaged from the peptide segment and relocated along the alkyl
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Published 22 Jan 2024

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

  • Chuan Yang,
  • Wei Shi,
  • Jian Tian,
  • Lin Guo,
  • Yating Zhao and
  • Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

Graphical Abstract
  • NMR (Figure S3 in Supporting Information File 1) [30] and high-resolution mass spectrometry. You and co-workers proposed a reaction pathway involving the combination of the indole substrate and Umemoto’s reagent to form an electron donor–acceptor (EDA) complex [31]. We excluded the possibility of an
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Published 19 Jan 2024

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

  • Julika Schlosser,
  • Olga Fedorova,
  • Yuri Fedorov and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

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  • the amine 2b gave the corresponding amide 2g in 28% yield. The chloro-substituted derivative 2e was synthesized in a Sandmeyer-reaction from 2b in 20% yield. The products 2a–g were identified and fully characterized by NMR spectroscopy (1H, 13C, COSY, HSQC, and HMBC), elemental analyses, and mass
  • chemicals (Alfa, Merck, Fluorochem or BLDpharm) were of reagent grade and used without further purification. 1H NMR spectra were recorded with a JEOL ECZ 500 (1H: 500 MHz and 13C: 125 MHz) and a Varian VNMR S600 (1H: 600 MHz and 13C: 150 MHz) at T = 25 °C. The 1H NMR and 13C{1H} NMR spectra were referenced
  • µmol) in MeCN/H2O (6:1, 400 mL) was irradiated for 49 min. The crude product was washed with n-hexane (2 × 3 mL) and EtOAc (3 × 5 mL) and recrystallized from MeOH with addition of HClO4 to give the product as brown amorphous solid (14 mg, 35 µmol, 10%); mp > 200 °C (decomp.); 1H NMR (600 MHz, CD3CN) δ
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Published 18 Jan 2024

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

  • Christina Schøttler,
  • Kasper Lund-Rasmussen,
  • Line Broløs,
  • Philip Vinterberg,
  • Ema Bazikova,
  • Viktor B. R. Pedersen and
  • Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

Graphical Abstract
  • synthesis of compound 23 (Scheme 4). A compound that may tentatively be assigned to 28 was observed by MALDI–MS analysis of the reaction mixture, but less than needed for an NMR sample was isolated. Furthermore, the isolated compound proved quite insoluble in all investigated deuterated solvents, and
  • Systems X10/X50: 40–63 μm). TLC was performed using aluminum sheets covered with silica gel coated with fluorescent indicator. NMR spectra were recorded on a Bruker instrument at 500 MHz and 126 MHz for 1H and 13C NMR, respectively. Deuterated chloroform (CDCl3, 1H = 7.26 ppm, 13C = 77.16 ppm), deuterated
  • by flash column chromatography (SiO2, 20% EtOAc/heptane), and recrystallization from CH2Cl2/MeOH followed by centrifugation yielded 9 (136 mg, 57%) as an orange solid. Rf = 0.18 (70% CH2Cl2/heptane); mp 178–181 °C; 1H NMR (500 MHz, CDCl3) δ 7.99 (s, 1H), 7.80 (d, J = 8.4 Hz, 2H), 7.76 (s, 1H), 7.72
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Published 15 Jan 2024

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

  • Matthias R. Steiner,
  • Max Schmallegger,
  • Larissa Donner,
  • Johann A. Hlina,
  • Christoph Marschner,
  • Judith Baumgartner and
  • Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

Graphical Abstract
  • molecules were determined by single-crystal X-ray crystallography. The bonding situation in the solid state together with NMR data suggests an important contribution of an ylidic resonance structure in these molecules. The phosphonium phenolates are characterized by UV–vis absorptions peaking around 360 nm
  • toward the desired product 3-(allyloxy)propanenitrile was observed after stirring the reaction mixture for 24 h at room temperature. Analyzing the reaction mixture with 1H NMR spectroscopy revealed the formation of a minor amount of a novel compound characterized by two multiplets centered at 3.31 and
  • product of interest 2a. Compound 2a was identified by a combination of NMR spectroscopic methods and single-crystal X-ray structure analysis (vide infra) as the zwitterionic phospha-Michael adduct of 1 and acrylonitrile, formally stabilized by proton transfer from the phenol group to the initially formed
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Published 10 Jan 2024

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

  • Lorenzo Catti,
  • Shinji Aoyama and
  • Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

Graphical Abstract
  • , and graphene nanoplatelets) are achieved through noncovalent encircling with the bent amphiphiles. The resultant imidazole-modified nanocarbons display a pH-responsive surface charge, as evidenced by NMR and zeta-potential measurements. In addition, solubilization of a nitrogen-doped nanocarbon (i.e
  • pyridinium-based amphiphiles (Figure 1c). The noncovalent modification of C60 with multiple imidazole side-chains is found to yield a pH-responsive surface charge, as evidenced by NMR and zeta-potential measurements. A nitrogen-doped nanocarbon, i.e., graphitic carbon nitride (g-C3N4), is likewise
  • and structure of aromatic micelles Aromatic micelle (PA-CH3)n was facilely generated via dissolution of PA-CH3 (2.1 mg, 4.3 μmol) in water (8.6 mL). The 1H NMR spectrum of PA-CH3 in D2O showed significantly upfield-shifted signals (Δδ = −2.73 ppm for Hb) compared to the spectrum in CD3OD, in a manner
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Published 08 Jan 2024
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