Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 83 for “"Structure elucidation"”.
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Genomics as a tool for natural product structure elucidation
… novelty determination (dereplication), structure elucidation, three principal bottlenecks in the discovery process, as reviewed in Chapter 1. We report here progress in the use of genomics to facilitate the discovery and contextualization of new chemical matter. In Chapter 2, we report …
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AI-assisted reaction impurity prediction and inverse structure elucidation
… and performing impurity propagation, inverse structure elucidation – that is, identifying unknown impurities post hoc from analytical data, such as mass spectrometry data – presents a significant challenge. In this work, impurity prediction was established by developing an AI-based reaction …
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Structure elucidation of sweet and bitter principles of Polypodium glycyrrhiza.
Structure elucidation of sweet and bitter principles of Polypodium glycyrrhiza.
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Isolation and Structure Elucidation of Anticancer and Antimalarial Natural Products
… and twenty-four known compounds, and their structures were elucidated by using a combination of 1D (1H and 13C) and 2D NMR spectroscopy including COSY, HASQC, HMQC, HMBC, and NOESY sequences, mass spectrometry, UV, IR, ECD, optical rotation, and chemical conversions. In addition, ten known …
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Approaches to intermolecular structure elucidation utilizing NMR and DNP parameters
… The first part involves the study of molecular structure utilizing Ianthanide induced shift (LIS) and lanthanide induced relaxation (LIR) nuclear magnetic resonance (NMR). It the course of these studies, it was found that the trifluoroethoxy group is a good deactivating group towards lanthanide …
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Isolation and Structure Elucidation of Anticancer and Antimalarial Natural Products
… acid (4.2), and twenty-six known compounds. The structures of these compounds were elucidated by using a combination of 1D (1H and 13C) and 2D NMR spectroscopy, mass spectrometry, UV, IR, CD, optical rotation, and chemical modifications. Compounds 5.1 and 5.2 showed moderate antiproliferative …
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Isolation and Structure Elucidation of Antiproliferative Natural Products from Madagascar
… following dissertation discusses the isolation, structure elucidation, and bioactivity studies of these isolates. The following compounds from plants of Madagascar's rainforest are discussed in the order they were studied: flavonoids and long-chain compounds from Schizolaena hystrix, a …
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Isolation and Structure Elucidation of Antiproliferative Agents From Madagascar Rainforests
… compounds were isolated from these extracts. The structure elucidation and characterization of these compounds was carried out using mass spectrometry and 1D and 2D NMR techniques. The bioassay-guided fractionation of Roupellina (Strophanthus) boivinii yielded three new and one known cardenolide …
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Isolation, Structure Elucidation, and Synthesis of Natural Products from Marine Cyanobacteria
<p>This thesis describes the isolation, structure elucidation, and synthesis of natural products from marine cyanobacteria. A crude extract from a cyanobacterium collected in Curacao showed selective affinity for the dopamine D<sub>5</sub> receptor in a screen against a panel of CNS receptors. Due …
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Structure elucidation and studies relating to the synthesis of plasmalopentaene-12
… and chromatographic techniques enabled the structure of the precursor to be elucidated. Based on the structure of the precursor, the name plasmalopentaene-12 was coined. Synthetic methodology was developed for obtaining synthetic plasmalopentaene12. This was necessary in order to confirm the …
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Aspects of natural product chemistry: Biosynthesis, structure elucidation and HSCCC/MBI/FABMS
The structure and biosynthesis of cremeomycin, a novel cytotoxic antibiotic from Streptomyces cremeus NRRL 3241, were established. Cremeomycin was found to be 3-diazo-4-methoxycyclohexa-4,6-dien-2-one carboxylic acid by X-ray crystallography. Through the intermediacy of 4-methoxysalicylic acid, …
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Geometric representation learning for chemical property prediction, structure elucidation, and molecular design
… from datasets of (potentially labeled) molecular structures via deep neural networks. In predictive chemistry, deep learning is increasingly being used to replace expensive physics-based simulations and even experimental measurements of chemical properties. In generative chemistry, deep generative …
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Isolation and Structure Elucidation of Antiproliferative and Antiplasmodial Natural Products from Plants
… from Hohenbergia antillana (Bromeliaceae). The structures of these compounds were elucidated by using 1D (1H and 13C), 2D (HMBC, HSQC, COSY, NOESY) NMR spectroscopy and mass spectrometry. The structures of the compounds were also confirmed by comparing them with reported values from the …
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Isolation and Structure Elucidation of Cytotoxic Natural Products from Suriname and Madagascar
… fractionated to yield four compounds. The structures of these compounds were elucidated with mass spectrometry and 1-D and 2-D NMR spectroscopy. The ethyl acetate extract of the twigs of Garcinia macrophylla from Suriname was weakly cytotoxic in the A2780 human ovarian cancer cell bioassay. …
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Isolation, Structure Elucidation and Biological Evaluation of Natural Products From Plants and Fungi
… were isolated by using this technique. The structure of the isolated compounds was elucidated through various spectroscopic methods, including high-resolution mass spectrometry, one and two-dimensional nuclear magnetic resonance spectroscopy. Finally, the isolated compound was submitted for …
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Isolation, structure elucidation and approaches to the partial synthesis of new taxol analogs
… on the chemistry of paclitaxel and on its structure-reactivity relationships, we have investigated T. brevifolia extracts and have isolated two new taxoids. These are the A-nortaxol analog 7,13-deacetyl-9,10-debenzoyltaxchinin C 2.1 and 9-deacetyl-9-benzoyl-10-debenzoylbrevifoliol 2.4. The …
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Isolation, Structure Elucidation, and Total Synthesis of Biologically Active Natural Products from Plants
… addition total synthesis was used to confirm the structure of one new compound (4.5) and two other new natural-product like compounds (4.6 and 4.7) were also synthesized and investigated for antiplasmodial activity.
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Total synthetic efforts and structure elucidation in route to brocazine and cahuitamycin natural products
… emphasis on E and F, as well as the structural elucidation of the cahuitamycin family, with emphasis on C. The brocazine family of natural products were isolated by Meng et al. in 2014 and 2016 from an endophytic fungus derived from the marine mangrove plant Avicennia marina named Penicillium …
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Structure Elucidation of Bioactive Compounds Isolated from Endophytes of Alstonia scholaris and Acmena graveolens
Alstonia scholaris is an evergreen tree native to Southeast Asia and Australia. It is commonly used as a medicinal plant throughout these regions. In the present study, an endophyte of the genus Xylaria was isolated from a stem of Alstonia scholaris, its mycelia and exudate extracted, and the …
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Structure Elucidation and Biosynthesis of Selected Bioactive Marine Natural Products (Bromophenols, Aplysina, Fistularis, Kelletia)
The biosynthesis of bromophenols in Aplysina fistularis has been reinvestigated, making use of liposome-encapsulated precursors. The incorporation of both phenylalanine and tyrosine into two antimicrobial sponge metabolites, 2,6-dibromo-4-hydroxy-2,5-cyclohexadienone-4-acetamide and …
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