Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• , 174.5; IR (ATR, KBr, cm−1): ν 3400, 3359, 3255, 1625, 1602, 1563, 1554, 1508, 1495, 1483, 1455, 1436, 1425, 1402, 1385, 1356, 1332, 1319, 1303, 1283, 1257, 1215, 1151, 1095, 1067, 1053, 1035, 1011; HRMS–ESI-TOF (m/z): [M + H]+ calcd for C13H14N7S+, 300.1026; found, 300.1031. X-ray structure

• determination 3g: Crystal data for C15H22N8O2 (M = 346.40 g/mol): monoclinic, space group P21/c (no. 14), a = 14.734(3) Å, b = 9.000(2) Å, c = 13.125(4) Å, β = 104.29°, V = 1686.6(8)Å3, Z = 4, T = 295(2) K, μ(Mo Kα) = 0.097 mm−1, Dcalc = 1.364 g/cm3, 6415 reflections measured (5.4° ≤ 2Θ ≤ 59°), 6415 unique (R

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• group in the neighboring oxindole scaffold. Therefore, it can be concluded that the obtained dispiro compounds 3a–m have this kind of relative configuration on the basis of 1H NMR spectra and crystal structure determination. It should be pointed out that ammonium acetate was employed as nitrogen source

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• -(substituted)phenylsulfonyl-4-thiocarbamoylpyrazoles in moderate to high yields. It was concluded that in 2-cyanothioacetamides, cyano and enamino groups are more active in the reaction with hydrazines than the thiocarbamoyl function. Experimental X-ray structure determination of 5b, 6a, 7a 5b: Crystal data

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• . Acknowledgements Crystal structure determination was performed in the Department of Structural Studies of the N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences.

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• structure of the inclusion complex formed by TMeQ[6] and G was obtained using X-ray single-crystal diffraction analysis. The crystal data and parameters are shown in Table 2. The single-crystal structure determination shows that the inclusion complex crystallizes in the triclinic crystal system, with the

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• different mesh numbers. Single crystals of both were obtained by slow evaporation from diethyl ether. The less polar, minor material gave ice-white needles, and an X-ray single crystal structure determination revealed the product to be cholesta-3,5-diene (9, Figure 3). The 1H NMR data of 9 are in full

• assignment of 4 was unequivocally confirmed by X-ray crystal structure determination. Compound 4 was erroneously reported to have the α-configuration at C3 [10]. Now, the NMR chemical shift data of 4 are in full agreement with those reported earlier [12]. The reaction of 3-bromocholest-5-ene with NaN3 in DMF

• the azido substituent on the β-face of the steroid (compound 6). Conclusion For each product 4, 5 and 9 the stereochemical assignment has now been confirmed by X-ray single crystal structure determination, and the NMR data are in agreement with those of previous reports. Former structural

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• ; stereoisomers; Introduction Calculation of 1H and 13C NMR chemical shifts and coupling constants using density functional theory (DFT) has increasingly become an adjunct to structure determination [1][2][3][4][5][6][7][8]. In particular for complex organic compounds, determination of relative stereochemistry

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• (2{2}) gave unprecedented yields of the hydroxypyrazines 3{3,2}, 3{4,2}, or 3{5,2} along with only traces of the corresponding isomers in the latter two cases. Experimental X-ray-based structure determination. As further detailed in Supporting Information File 1, the structural elucidation of

Structural basis for endoperoxide-forming oxygenases

• Takahiro Mori and
• Ikuro Abe

Beilstein J. Org. Chem. 2022, 18, 707–721, doi:10.3762/bjoc.18.71

• from Chenopodium ambrosioides, the sequence, structural, and mechanistic analyses have not been vigorously pursued [24]. While many review articles on the structure determination, biological analysis, and synthesis of endoperoxide-containing natural products have been reported [1][2][3][4][5][6][7][11

Organocatalytic asymmetric nitroso aldol reaction of α-substituted malonamates

• Ekta Gupta,
• Narendra Kumar Vaishanv,
• Sandeep Kumar,
• Raja Krishnan Purshottam,
• Ruchir Kant and
• Kishor Mohanan

Beilstein J. Org. Chem. 2022, 18, 217–224, doi:10.3762/bjoc.18.25

• , single-crystal X-ray data of 4a, copies of NMR spectra, and HPLC chromatograms. Acknowledgements We thank Dr. Tejender S. Thakur, MSB division, CSIR-CDRI for supervising the X-ray data collection and structure determination. The SAIF division is acknowledged for the analytical support. CDRI

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

• Alla I. Vaskevych,
• Nataliia O. Savinchuk,
• Ruslan I. Vaskevych,
• Eduard B. Rusanov,
• Oleksandr O. Grygorenko and
• Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

• of 2-(buten-3-yl)quinazolin-4(3H)-ones 7. Optimization of the reaction conditionsa. Synthesis of 1-(hydroxymethyl)-2,3-dihydropyrroloquinazolin-5(1H)-ones 6. Supporting Information Supporting Information File 376: Detailed experimental procedures for all compounds and precursors, X-ray structure

• determination, 1H/13C/19F NMR spectra for all compounds.

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• actinomycete of the genus Actinomadura. We herein describe the isolation, structure determination, and biological activities of 1‒3. Results and Discussion The producing strain Actinomadura sp. AKA43 was isolated from DSW collected at a depth of −800 m in Sagami Bay, Japan. Strain AKA43 was cultured in A16

A straightforward conversion of 1,4-quinones into polycyclic pyrazoles via [3 + 2]-cycloaddition with fluorinated nitrile imines

• Greta Utecht-Jarzyńska,
• Karolina Nagła,
• Grzegorz Mlostoń,
• Heinz Heimgartner,
• Marcin Palusiak and
• Marcin Jasiński

Beilstein J. Org. Chem. 2021, 17, 1509–1517, doi:10.3762/bjoc.17.108

• nitrile imine 7a generated from 8a. Supporting Information Supporting Information File 246: General information and experimental data of all isolated products, details of the crystal structure determination, and copies of 1H and 13C NMR spectra for all products. Funding Financial support by the

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines

• Alexei N. Izmest’ev,
• Dmitry B. Vinogradov,
• Natalya G. Kolotyrkina,
• Angelina N. Kravchenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2021, 17, 1141–1148, doi:10.3762/bjoc.17.87

• conditionsa. Supporting Information Supporting Information File 167: Experimental and analytical data. Supporting Information File 168: CIF file for compound 5i. Acknowledgements Crystal structure determination was performed in the Department of Structural Studies of the N. D. Zelinsky Institute of Organic

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• ribonucleotide had a high resemblance to the unmodified uridine, allowing it to be used as a probe for RNA structure determination through 19F NMR [211]. This modification led to RNA which was stable and predominantly in the C3'-endo (north) conformation [211], similar to the 2',4'-diF-RNA previously reported by

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• ) level of theory [42]. X-ray structure determination Single crystal X-ray diffraction data of the mesoionic compounds 8a, 10, 11a, and salt 9 were collected on a SMART Apex II diffractometer using graphite monochromatic Mo Kα radiation (λ = 0.71073 Å) at a temperature of 100 K. The structures were solved

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• agreement to those predicted for modelled MTSL-TFET pairs in adjacent subunits in the X-ray structure, showing only small discrepancies. Overall, the results of this work clearly demonstrated the value of solution 19F NMR for quaternary structure determination and as an alternative approach for generating

Molecular basis for protein–protein interactions

• Brandon Charles Seychell and
• Tobias Beck

Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1

• methods. These methods are summarised in Figure 1. Atomic resolution methods focus on the structure determination of protein complexes and elucidating the PPIs at a near-atomic resolution. Such methods include X-ray crystallography [12], nuclear magnetic resonance (NMR) [13], and cryogenic electron

Synthesis of tetrafluorinated piperidines from nitrones via a visible-light-promoted annelation reaction

• Vyacheslav I. Supranovich,
• Igor A. Dmitriev and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 3104–3108, doi:10.3762/bjoc.16.260

• experimental details, compound characterization, X-ray data, and copies of NMR spectra. Supporting Information File 507: Crystallographic information file for compound 3f. Supporting Information File 508: Crystallographic information file for compound 3h. Acknowledgements The crystal structure determination

Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

• Md. Rokon Ul Karim,
• Enjuro Harunari,
• Amit Raj Sharma,
• Naoya Oku,
• Kazuaki Akasaka,
• Daisuke Urabe,
• Mada Triandala Sibero and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

• rare class of natural products, first described in 2015 by Fenical et al. from marine Nocardiopsis [21] and were recently found from a marine obligate bacterium Microbulbifer by our group [22]. We herein report the isolation, structure determination, and biological activities of two new

Leveraging glycomics data in glycoprotein 3D structure validation with Privateer

• Haroldas Bagdonas,
• Daniel Ungar and
• Jon Agirre

Beilstein J. Org. Chem. 2020, 16, 2523–2533, doi:10.3762/bjoc.16.204

• in the compositions of the glycans added to specific glycosylation sites – microheterogeneity. This variation in the microheterogeneous composition patterns arises due to the competition of glycan-processing enzymes in biosynthesis pathways [23]. Implications for the structure determination of

• monosaccharide minimal-energy conformation. While these features were recognised to address some long-standing needs in carbohydrate structure determination [39][40], significant challenges remain, particularly in the scenario where the glycan composition cannot be ascertained solely from the three-dimensional

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

• Thomas Schneider,
• Michael Keim,
• Bianca Seitz and
• Gerhard Maas

Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173

• cyclization required extended heating in refluxing toluene and finally furnished the neutral polycycle 11 in good yield. The paddlewheel-shaped structure of 11 was established by an XRD structure determination and is shown in Figure 1. The reactivity of 1a in the Diels–Alder reaction with anthracene may be

• NOESY NMR experiments and confirmed by an X-ray structure determination (see Figure 3). A mechanistic scheme for the formation of indenes 12 and benzo[a]fluorenes 13 is proposed in Scheme 5. The electrophilic propyn-1-iminium ion 1a adds chemoselectively (by conjugate addition) and regioselectively