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Search for "structure elucidation" in Full Text gives 116 result(s) in Beilstein Journal of Organic Chemistry.
Icilio Guareschi and his amazing “1897 reaction”
Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93
- posthumously in 1919 [35]. In 1894, Guareschi reported the first high-yield synthesis and the structure elucidation of triacetonamine (6, Scheme 3) [35][36][37], the sterically hindered amine that is the starting material for the synthesis of the popular oxidant TEMPO [38]. Triacetonamine had first been
Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols
Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80
- enantioselective transformations, while the 2-phenyliminooxazolidines could be interesting in the field of antiproliferative or antioxidants studies based on our former studies on 2-imino-1,3-heterocycles [42][43]. Biologically active 2-amino-1,3-diols. NOESY experiments and X-ray structure elucidation of
Unexpected rearrangements and a novel synthesis of 1,1-dichloro-1-alkenones from 1,1,1-trifluoroalkanones with aluminium trichloride
Beilstein J. Org. Chem. 2021, 17, 404–409, doi:10.3762/bjoc.17.36
- Supporting Information File 58: Detailed experimental procedures and NMR spectra for all compounds referenced. Acknowledgements We thank Mr Martin Annau for his valuable assistance in NMR interpretation and structure elucidation, Mrs Susanne Ries for performing the mass spectrometry measurements and Dr
Chemical constituents of Chaenomeles sinensis twigs and their biological activity
Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257
- which the results were expressed as a percentage of the control group (untreated cells). Chemical structures of compounds 1–13. Structure elucidation of compound 1. (A) Key COSY (blue bold) and HMBC (red arrows) correlations of 1. (B) Key NOESY (black dashed) correlations of 1. The 3D structure of 1 was
Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio
Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154
- describe the isolation, structure elucidation, including the absolute configuration, and bioactivity of 1–4. Results and Discussion The producing strain was cultured in a sea water-based medium and then extracted with n-BuOH. The extract was successively fractionated by silica gel chromatography using a
Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study
Beilstein J. Org. Chem. 2020, 16, 1636–1648, doi:10.3762/bjoc.16.136
- )benzaldehydes under acidic conditions resulted in the formation of the regioisomeric aldehydes and/or dimer-like products. Detailed NMR studies and single-crystal X-ray measurements supported the structure elucidation of the compounds. DFT calculations were also carried out to clarify the reaction mechanism
- →22a = 89.1 kJ·mol−1, while the reaction leading to the minor (RR) isomer had a larger activation barrier (ΔG#4e→22b = 101.9 kJ·mol−1). Moreover, the formation of the latter intermediate was significantly more endergonic (ΔG4e→22b = 69.2 kJ·mol−1) than ΔG4e→22a (37.9 kJ·mol−1). The structure
- elucidation of compounds 3a [1], 3b, 8a,b, and 23a,b was based on the molecular formula obtained from HRMS, comprehensive 1H and 13C NMR study and on the single-crystal X-ray structure of compounds 3a [1], 3b, 8b, 23a, and 23b (for spectra and detailed interpretation, see Supporting Information File 1
Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)
Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132
- , Demospongiae). We describe the structure elucidation of the new scalarane sesterterpene 12-deacetoxy-4-demethyl-11,24-diacetoxy-3,4-methylenedeoxoscalarin (Figure 2), isolated from all our Doriprismatica stellata nudibranch, egg ribbon and Spongia cf. agaricina samples (Figure 3). It is the first scalarane
One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation
Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72
- annulation was favorable for the formation of six-membered rings. Nevertheless, the existence of several rotamers of 1 derived from the restricted rotation of the peripheral phenyl ring substituents and its nonplanar geometry prevented the structure elucidation by proton NMR analysis [35]. Single crystals of
Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines
Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27
- under different conditions (ultrasonic activation and conventional heating) were unsuccessful, and only dihydropyrimidine 7 was obtained. Structure elucidation The purity and structures of the synthesized heterocycles were determined using elemental analysis, mass spectrometry, NMR spectroscopy (1D and
Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica
Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293
- -forming S. aureus. The structure elucidation and determination of the absolute configuration were accomplished using a combination of spectroscopy, including 1D and 2D NMR, HRMS, Mosher ester analysis, and comparison of calculated/experimental ECD spectra. A chemotaxonomic investigation of the secondary
- bioactive secondary metabolites. Herein, we report on the isolation, structure elucidation, and biological activities of six compounds from Gibellula sp. and Cordyceps javanica. Furthermore, the species-specific patterns of secondary metabolite production were studied. Results and Discussion Structure
- purification conditions. Isolation and structure elucidation of compounds 1–6 The fractionation of the EtOAc extract of Gibellula sp. BCC39707 (dissolved in MeOH) was carried out on an Agilent 1100 series HPLC system (Agilent Technologies). The compounds were separated through a reversed-phase C18 column
Terpenes
Beilstein J. Org. Chem. 2019, 15, 2966–2967, doi:10.3762/bjoc.15.292
- taxol from Taxus brevifolia that is used to treat breast and other types of solid cancers, while artemisinin from Artemisia annua is used as a cure against malaria [4]. This thematic issue covers all different aspects of terpene chemistry and biochemistry, including compound isolation and structure
- elucidation, total synthesis, biosynthetic studies, bioactivity and functionalisation for mode of action studies, and other applications of terpenes, e.g. as fragrances. I thank all colleagues who have participated in this issue for their contributions and the whole Beilstein team for the professional support
Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering
Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283
- the number of screens that can be done. Though genetic construction, culturing bacteria, terpenoid extraction, and chromatographic analysis can be carried out (semi-)automatedly, terpenoid structure elucidation constitutes another major bottleneck of these endeavors. At this end, the development of
Facile regiodivergent synthesis of spiro pyrrole-substituted pseudothiohydantoins and thiohydantoins via reaction of [e]-fused 1H-pyrrole-2,3-diones with thiourea
Beilstein J. Org. Chem. 2019, 15, 2864–2871, doi:10.3762/bjoc.15.280
- out that earlier, we have communicated initial data on this transformation [30][31]. However, taking into account more advanced structure elucidation methods employed in the present work (e.g., NMR, single crystal X-ray diffraction), we concluded that the structures of the products were identified
Preparation of anthracene-based tetraperimidine hexafluorophosphate and selective recognition of chromium(III) ions
Beilstein J. Org. Chem. 2019, 15, 2847–2855, doi:10.3762/bjoc.15.278
- signal corresponding to the NCHN motif in perimidine was present at δ = 8.69 ppm [42]. Structure elucidation of compound 3 As can be seen in the crystal structure of 3 in Figure 1, the cationic moiety of the complex contained two (N-ethylperimidinyl–C2H4)2NCH2– arms attached to the 9- and 10-positions of
Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa
Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270
- ; polyporaceae; secondary metabolites; structure elucidation; Introduction Over the past years, we have been studying the secondary metabolites of African Basidiomycota that were collected in rainforests and mountainous areas of Western Kenya. These species were new to science, and proved to be a prolific
Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis
Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256
- characterisation of A. nanangensis will be reported elsewhere in due course. Herein, we report the isolation, structure elucidation and bioassay of a family of drimane sesquiterpenoids from A. nanangensis, which we named the nanangenines. Notably, A. nanangensis distinguishes itself within the genus by the
Isolation of fungi using the diffusion chamber device FIND technology
Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216
- growth of M. violaceum with an inhibition zone of 3 mm in diameter (miconazole, half concentrated, was used as positive control with an inhibition zone of 10 mm; see Supporting Information File 1, Table S3 for full experimental data). Detailed chemical investigation of H. cf. alpina including structure
- elucidation of the new metabolites 1 and 2 On the basis of its preferred growth on saline media, the H. cf. alpina (strain No. 824), isolated during this study, was selected for further chemical investigations. To the best of our knowledge this is the first chemical investigation of a member of the Heydenia
Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana
Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198
- strain BRIP10943 (CS10) [14] and their phytotoxicity. This led to the isolation of four new sativene-type sesquiterpenoid natural products along with seven related known analogues and one sesterterpenoid. Herein, the isolation, structure elucidation and phytotoxic activities of these compounds are
Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.
Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196
- lower than those of 4ß-hydroxywithanolide E. Our work establishes androwithanolides as a new subclass of withanolides. Keywords: androstanes; Physalis peruviana; steroids; structure elucidation; withanolides; Introduction Traditional medicine has long been a source of inspiration for modern drug
Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions
Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145
- and structure elucidation are both in progress and will aid the development of an, at least, kilolab-scale procedure for standardised quality products. Experimental The details of the reactions are described in Supporting Information File 1. All reagents and organic solvents were used without further
New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita
Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98
- clusters. Keywords: bioinformatics; gene cluster analysis; natural products; secondary metabolites; structure elucidation; terpenes; Introduction The basidiomycete Agrocybe aegerita (synonym: A. cylindracea) was traditionally accommodated in the genus Agrocybe (family Bolbitiaceae) until a recent
Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry
Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66
- extra synthetic steps that make the atom economy of this approach very low and the entire synthetic procedure time consuming. Structure elucidation of difunctionalized CDs is a challenging task, irrespective of the strategy used. In the direct difunctionalization approach, the disulfonyl-capped CD has
- scalable, amenable to chromatographic separation and reproducible difunctionalization methods. Moreover, the direct NMR spectroscopic analysis would provide structure elucidation without any reference material, time-consuming chemical conversions or enzymatic degradation. Hetero-difunctionalized CDs are
New sesquiterpenoids from the South China Sea soft corals Clavularia viridis and Lemnalia flava
Beilstein J. Org. Chem. 2019, 15, 695–702, doi:10.3762/bjoc.15.64
- investigation of two title animals led to the isolation of four new halogenated laurane-type sesquiterpenoids 1–4, one new aromadendrane-type sesquiterpenoid 6) together with three related known compounds 5, 7 and 8 (Figure 1). Herein, the isolation, structure elucidation and bioactivity evaluation of these
Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines
Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41
- intermediates 2 and 3 in hand, we proceeded with the synthesis and structure elucidation of the designed structures G and H (Figure 1) which are represented by compounds 7–11 in Scheme 1. Firstly, we prepared a regioisomeric compound 5 by repeating the previously elaborated sequence of double CuAAC reaction (2
Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum
Beilstein J. Org. Chem. 2018, 14, 2974–2990, doi:10.3762/bjoc.14.277
- , and therefore it is mandatory for unambiguous structure elucidation to compare analytes that fall into this class to all the possible isomers. A similar problem can apply to the structural assignment of compounds with multiple stereocentres based on GC–MS data, because the various possible
- patterns are sufficiently different for a confident structural assignment. Also biosynthetic considerations can help in the structure elucidation, because some aromatic substitution patterns are in line with a polyketide biosynthesis mechanism, while other substitution patterns may be difficult to
- (10), trimethylpyrazine (11) and 2-ethyl-3,6-dimethylpyrazine (12) were also observed. These compounds were previously reported from the actinobacterium Corynebacterium glutamicum in which pyrazines are biosynthetically derived from acetoin and its higher homologs [24]. For unambiguous structure
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