Refine
Has Fulltext
- no (106)
Year of publication
Document Type
- Article (106) (remove)
Language
- English (106)
Is part of the Bibliography
- yes (106)
Keywords
- Conformational analysis (6)
- Cytotoxicity (5)
- Leguminosae (5)
- Antiplasmodial (4)
- DFT calculations (4)
- NMR (4)
- NMR spectroscopy (4)
- antiplasmodial (4)
- cytotoxicity (4)
- conformational analysis (3)
- Antiplasmodial activity (2)
- Asteraceae (2)
- Dynamic NMR (2)
- Flavone (2)
- Isoflavone (2)
- Mycobacterium tuberculosis (2)
- Plasmodium falciparum (2)
- Surface exudates (2)
- Tephrosia purpurea (2)
- Theoretical calculations (2)
- modified Mannich reaction (2)
- (+)-Tephrodin (1)
- 1-Methylthio-1-phenyl-1-silacyclohexane (1)
- 10-Methoxy-10,7 '-(chrysophanol anthrone)-chrysophanol (1)
- 3,4-Dihydroisoquinoline (1)
- 3-Hydroxyisoflavanone (1)
- 3-Oxo-14 alpha, 15 alpha-epoxyschizozygine (1)
- 4-Substituted cyclohexanones (1)
- 4-methylene-cyclohexyl pivalate (1)
- 6 alpha-Hydroxy-alpha-toxicarol (1)
- 8-oxohobartine (1)
- ALTONA equation (1)
- Alkenyl cyclohexanone (1)
- Alkenyl cyclohexenone (1)
- Aminonaphthol (1)
- Aminonaphthols (1)
- Anthraquinone (1)
- Anti-Plasmodial activity (1)
- Anti-inflammatory (1)
- Anticancer (1)
- Antileishmanial (1)
- Antimalarial plants (1)
- Antimicrobial (1)
- Antimicrobial activities (1)
- Apoptosis (1)
- Aristotelia chilensis (1)
- Asphodelaceae (1)
- Azadironolide (1)
- Benzazepine (1)
- Benzylbenzofuran (1)
- Biflavonoid (1)
- Block copolymer (1)
- Bulbine frutescens (1)
- C-13 (1)
- C. bonducella (1)
- Cancer (1)
- Carvotacetones (1)
- Cassiamin A (1)
- Cassiamin B (1)
- Celastraceae (1)
- Chalcone (1)
- Charge transfer (1)
- Chelates (1)
- Chemotaxonomy (1)
- Conformational equilibrium (1)
- Coumaronochromone (1)
- Coumestan (1)
- D. melleri (1)
- DFT and MP2 calculations (1)
- DFT structural study (1)
- DSC (1)
- Dalbergia melanoxylon (1)
- Dianellin (1)
- Dimeric anthraquinone (1)
- Diterpenoid (1)
- Docking (1)
- Dodonaea angustifolia (1)
- Dorstenia kameruniana (1)
- Dynamic NMR spectroscopy (1)
- E. schliebenii (1)
- Escherichia coli (1)
- F-19 (1)
- Flavanone (1)
- Furanocoumarin (1)
- Fusarium proliferatum (1)
- Fusicoccane diterpenes (1)
- GWD (1)
- Gas phase electron diffraction (1)
- H-1 (1)
- H. pubescens (1)
- Halogenation (1)
- Hammett-Brown plots (1)
- Hypoestes verticillaris (1)
- Isoflavanones (1)
- Isolations (1)
- Kenusanone F 7-methyl ether (1)
- Kniphofia foliosa (1)
- Knipholone cyclooxanthrone (1)
- LCST (1)
- Lannea rivae (1)
- Lannea schweinfurthii (1)
- Ligand design (1)
- Lignans (1)
- Limonoid (1)
- Lobelia tupa (1)
- Lonchocarpus bussei (1)
- Lonchocarpus eriocalyx (1)
- Low-temperature C-13 and Si-29 NMR (1)
- Malaria (1)
- Mammea usambarensis (1)
- Mammea-type coumarins (1)
- Maytenus boaria (1)
- Maytenus disticha (1)
- Maytenus spp. (1)
- Millettia dura (1)
- Millettia dura; (1)
- Millettia lasiantha (1)
- Millettia leucantha (1)
- Millettia micans (1)
- Millettia oblata ssp teitensis (1)
- Mitochondrial ROS (1)
- Modified Mannich reaction (1)
- Moraceae (1)
- Multi-drug resistance (1)
- Mundulea sericea (1)
- Naphthoxazines (1)
- Naphthoxazinoquinazolines (1)
- Naphthoxazinoquinazolinones (1)
- Ormocarpum kirkii (1)
- Oxidation (1)
- P-31 NMR (1)
- PWD (1)
- Palladium (1)
- Penicillium digitatum (1)
- Pentylsedinine (1)
- Phenylanthraquinone (1)
- Piperidine alkaloid (1)
- Platycelphium voense (1)
- Platyisoflavanone (1)
- Pleurotus ostreatus (1)
- Pterocarpan (1)
- Quantum chemical calculations (1)
- Quinazolines (1)
- RAFT polymerization (1)
- Reaction products (1)
- Reagents (1)
- Renewable resources (1)
- Responsive polymer (1)
- Ring current effect (1)
- Roots (1)
- S li-gands (1)
- Schizophrenic self-assembly (1)
- Schizozygane indoline alkaloid (1)
- Schizozygia coffaeoides (1)
- Senecio roseiflorus (1)
- Simulation of H-1 NMR spectra (1)
- Sophoronol-7-methyl ether (1)
- Sphaeranthus bullatus (1)
- Staphylococcus aureus (1)
- Stem (1)
- Stem bark (1)
- Stereochemistry (1)
- Structure revision (1)
- Sulfobetaine methacrylate (1)
- Tephrosia aequilata (1)
- Tephrosia subtriflora (1)
- Tephrosia villosa (1)
- Terpurinflavone (1)
- Thienopyridine (1)
- Toonacilin (1)
- Toonapubesins F (1)
- Turraea nilotica (1)
- Turraea robusta (1)
- UCST (1)
- Xanthone (1)
- Zanthoxylum holstzianum (1)
- Zanthoxylum leprieurii (1)
- [4+2] cycloaddition (1)
- activity (1)
- aequichalcone A (1)
- aequichalcone B (1)
- aequichalcone C (1)
- alkaloid (1)
- antileishmanial (1)
- antimycobacterial activity (1)
- benzophenanthridine alkaloid (1)
- beta-dihydroagarofuran-type sesquiterpene (1)
- chalcone (1)
- crystal structure (1)
- cyclic imines (1)
- cycloaddition (1)
- cytotoxic (1)
- dihydro-beta-agarofuran (1)
- dihydromyricetin (1)
- dihydromyricetin-3-O-beta-glucoside (1)
- dynamic NMR spectroscopy (1)
- exo-methylene conformational effect at cyclohexane (1)
- flavanonol (1)
- flavonol (1)
- holstzianoquinoline; (1)
- indole alkaloids (1)
- isoflavone (1)
- leguminosae (1)
- marker compound (1)
- medicinal mushrooms (1)
- nAChR (1)
- norcaesalpin D (1)
- ortho-quinone methide (o-QMs) (1)
- phytomedicine (1)
- prenylated flavanonol (1)
- pristimerin (1)
- pterocarpan (1)
- pterocarpene (1)
- quantum chemical calculations (1)
- restricted N-S rotation (1)
- retrochalcone (1)
- rutaceae (1)
- seco-Anthraquinone (1)
- sesquiterpene (1)
- spectroscopy (1)
- starch phosphorylation (1)
- subtriflavanonol (1)
- trans-fagaramide (1)
- tuberculosis (1)
Institute
The manuscript describes the phytochemical investigation of the roots, leaves and stem bark of Millettia lasiantha resulting in the isolation of twelve compounds including two new isomeric isoflavones lascoumestan and las-coumaronochromone. The structures of the new compounds were determined using different spectroscopic techniques.
Through the reactions of 1- or 2-naphthol and 4,5-dihydro-3H-benz[c]azepine or 6,7-dihydrothieno[3,2-c]pyridine, new aminonaphthol derivatives were prepared. The syntheses were extended by using N-containing naphthol analogues such as 5-hydroxyisoquinoline and 6-hydroxyquinoline. The ring closures of the novel bifunctional compounds were also achieved, resulting in new naphth[2,1-e][1,3]oxazines, naphth[1,2-e][1,3]oxazines, isoquinolino[5,6-e][1,3]oxazines and quinolino[5,6-e][1,3]oxazines. H-1 NMR spectra of the target heterocycles 16, 20 and 21 were sufficiently resolved to indentify the present stereochemistry; therefore, beside computed structures, spatial experimental (dipolar coupling-NOE) and computed (ring current effect of the naphthyl moiety-TSNMRS) NMR studies were employed. The studied heterocycles exist exclusively as S(14b),R(N), R(14b),S(N), and S(16b)S(N) isomers, respectively. The flexible moieties of the studied compounds prefer. (C) 2016 Elsevier Ltd. All rights reserved.
The conformational equilibrium of the axial/equatorial conformers of 4-methylene-cyclohexyl pivalate is studied by dynamic NMR spectroscopy in a methylene chloride/freon mixture. At 153K, the ring interconversion gets slow on the nuclear magnetic resonance timescale, the conformational equilibrium (-G degrees) can be examined, and the barrier to ring interconversion (G(#)) can be determined. The structural influence of sp(2) hybridization on both G degrees and G(#) of the cyclohexyl moiety can be quantified.
To synthesize functionalized Mannich bases that can serve two different types of ortho-quinone methide (o-QM) intermediates, 2-naphthol and 6-hydroxyquinoline were reacted with salicylic aldehyde in the presence of morpholine. The Mannich bases that can form o-QM and aza-o-QM were also synthesized by mixing 2-naphthol, 2-nitrobenzaldehyde, and morpholine followed by reduction of the nitro group. The highly functionalized aminonaphthol derivatives were then tested in [4+2] cycloaddition with different cyclic imines. The reaction proved to be both regio- and diastereoselective. In all cases, only one reaction product was obtained. Detailed structural analyses of the new polyheterocycles as well as conformational studies including DFT modelling were performed. The relative stability of o-QMs/aza-o-QM were also calculated, and the regioselectivity of the reactions could be explained only when the cycloaddition started from aminodiol 4. It was summarized that starting from diaminonaphthol 25, the regioselectivity of the reaction is driven by the higher nucleophilicity of the amino group compared with the hydroxy group. 12H-benzo[a]xanthen-12-one (11), formed via o-QM formation, was isolated as a side product. The proton NMR spectrum of 11 proved to be very unique from NMR point of view. The reason for the extreme low-field position of proton H-1 could be accounted for by theoretical calculation of structure and spatial magnetic properties of the compound in combination of ring current effects of the aromatic moieties and steric compression within the heavily hindered H(1)-C(1)-C(12b)-C(12a)-C(12)=O structural fragment.
1-Methylthio-1-phenyl-1-silacyclohexane 1, the first silacyclohexane with the sulfur atom at silicon, was synthesized and its molecular structure and conformational preferences studied by gas-phase electron diffraction (GED) and low temperature C-13 and Si-29 NMR spectroscopy (LT NMR). Quantum-chemical calculations were carried out both for the isolated species and solvate complexes in gas and in polar medium. The predominance of the 1-MeSaxPheq conformer in gas phase (1-Ph-eq :1-Ph-ax = 55:45, Delta G degrees = 0.13 kcal/mol) determined from GED is consistent with that measured in the freon solution by LT NMR (1-Ph-eq:1-Ph-ax = 65:35, Delta G degrees = 0.12 kcal/mol), the experimentally measured ratios being close to that estimated by quantum chemical calculations at both the DFT and MP2 levels of theory. (C) 2019 Elsevier Ltd. All rights reserved.
The low temperature (95 K) NMR study of 1-Ph-1-t-Bu-silacyclohexane (1) showed the conformational equilibrium to be extremely one-sided toward thePh(ax),t-Bueq conformer. The barrier to interconversion has been measured (4.2-4.6 kcal/mol) and the conformational equilibrium [Delta nu = 1990.64 ppm (Si-29), 618.9 ppm (C-13), 1-Ph-ax:1-Pheq = (95.6-96.6%):(3.4-4.4%), K = 25 +/- 3, Delta G degrees = -RT ln K = 0.58-0.63 kcal/mol] analyzed. The assignment and quantification of the NMR signals is supported by MP2 and DFT calculations.