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Synthesis and characterization of polymers incorporating N-alkyl urea-peptoid sequencesChen, Xiaoping January 2013 (has links)
No description available.
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Understanding the Solvent-free Nucleophilic Substitution Reaction Performed in the High Speed Ball Mill (HSBM): Reactions of Secondary Alkyl Halides and Alkali Metal-Halogen SaltsMachover, Sarah B. 20 September 2011 (has links)
No description available.
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FRIEDEL-CRAFTS ACYLATION STUDIES ON 3-ALKYL-1-(PHENYLSULFONYL)INDOLES USING ALUMINUM CHLORIDE AND BISMUTH TRIFLATEKarrepu, Venkateswara Reddy 11 April 2012 (has links)
No description available.
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An Evaluation of Biodegradation Rates and Pathways of High Volume Surfactants in the Sewer SystemMenzies, Jennifer Z. 16 October 2015 (has links)
No description available.
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Stereoselective Radical Cyclopropanation by Co(II)-Based Metalloradical Catalysis:Ke, Jing January 2022 (has links)
Thesis advisor: X. Peter Zhang / Thesis advisor: James P. Morken / Chapter 1. Stereoselective Cyclopropanation of Alkenes with Alkynyl- and Vinyl-Substituted Diazo Compounds Alkynyl- and vinyl-substituted cyclopropanes are ubiquitous structural motifs in drug molecules and bioactive compounds. In addition, alkynyl- and vinyl-substituted cyclopropanes may serve as useful intermediates for stereoselective organic synthesis. Metal-catalyzed cyclopropanation of alkenes with alkynyl- and vinyl-substituted diazo compounds offers a potentially general approach for stereoselective construction of these valuable three-membered ring structures. This chapter summarizes the development of stereoselective olefin cyclopropanation with alkynyl- and vinyl-substituted diazo compounds.
Chapter 2. Metalloradical Activation of In Situ-Generated α-Alkynyldiazomethanes for Asymmetric Radical Cyclopropanation of Alkenes
We have developed a Co(II)-based metalloradical system that is highly effective for asymmetric radical cyclopropanation of alkenes with in situ-generated α-alkynyldiazomethanes. Through fine-tuning the cavity-like environments of D₂-symmetric chiral amidoporphyrins as the supporting ligand, the optimized Co(II)-based metalloradical system is broadly applicable to different alkynyldiazomethanes for asymmetric cyclopropanation of a broad range of alkenes, providing general access to valuable chiral alkynyl cyclopropanes in high yields with excellent diastereoselectivities and enantioselectivities.
Chapter 3. Asymmetric Radical Process for Cyclopropanation of Alkenes with In Situ-Generated α-Vinyldiazomethanes
We have demonstrated the feasibility of using vinyl aldehyde-derived sulfonylhydrazones as new metalloradicophiles for the generation of allylic radicals. Through fine-tuning the cavity-like environments of D₂-symmetric chiral amidoporphyrins as supporting ligands, the key α-Co(III)-allylic radical intermediates are exclusively engaged in the highly asymmetric cyclopropanation with wide-ranging alkenes in the optimized Co(II)-based metalloradical system, as shown broadly applicable to activate different α-vinyldiazomethanes.
Chapter 4. Asymmetric Synthesis of Vinyl-Substituted Cyclopropanes by Radical C-H Alkylation from Alkynes and In Situ-Generated Alkyldiazomethanes via Co(II)-Based Metalloradical Catalysis
We have successfully expanded the application of Co(II)-based MRC by applying in-situ generated alkyldiazomethanes as new radical precursors for stereoselective synthesis of vinyl-substituted cyclopropanes by radical cascade C-H alkylation of alkynes. Through fine-tuning of D₂-symmetric chiral amidoporphyrins as the supporting ligands, the Co(II)-catalyzed radical cascade process, which proceeds in a single operation under mild conditions, enables asymmetric construction of vinyl-substituted cyclopropanes in high yields with excellent diastereoselectivities and good enantioselectivities. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
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Development of chemical tools for covalent protein modification using metal-chelation assisted short peptide tag / 短鎖ぺプチドタグへの金属配位を利用したタンパク質化学修飾ツールの開発Vikram, Thimaradka 23 May 2023 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第24818号 / 工博第5161号 / 新制||工||1986(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 浜地 格, 教授 森 泰生, 教授 生越 友樹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Analýza a izolace intermediátů biosyntetické dráhy alkylprolinových derivátů / Analysis and isolation of intermediates involved in the biosynthetic pathway of alkylproline derivativesCudlman, Lukáš January 2019 (has links)
(EN) This work aims at preparation, analysis and isolation of intermediates of biosynthetic pathways of 4-alkyl-L-proline derivatives for their structural elucidation. Compounds with incorporated 4-alkyl-L-proline derivatives include clinically used lincosamide antibiotic, lincomycin A, antitumor pyrrolobenzodiazepines and bacterial hormone hormaomycin. Detailed knowledge of biosynthetic pathways of these biological active substances can be used to prepare new, more efficient derivatives. The first part of this work focuses on yellow-coloured dicarboxylic intermediates 1 and 2 of the biosynthetic pathway of 4-propyl-L-proline - the precursor of lincomycin A. In the presence of the methylation agent, S-adenosyl-L-methionine, and LmbW C- -methyltransferase, 1 was partially converted into intermediate 2. Using ultra-high performance liquid chromatography, both intermediates were identified from absorption and mass spectrometry spectra. A semi-preparative chromatographic method for isolation of both intermediates was developed. Surprisingly, a significantly lower stability of 2 compared to intermediate 1 was observed in an in vitro enzymatic reaction mixture. The second part of the work focuses on 4-ethylidene-L-proline - the precursor of tomaymycin belonging to pyrrolobenzodiazepines. After...
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The Mizoroki-Heck Reaction in Tunable Aryl Alkyl Ionic LiquidsLerch, Swantje, Fritsch, Stefan, Strassner, Thomas 19 March 2024 (has links)
We report the use of imidazolium based tunable aryl alkyl ionic liquids (TAAILs) as solvents in the Mizoroki–Heck reaction. Different commercially available palladium sources, inorganic bases, TAAILs and reaction conditions were tested for the synthesis of trans-stilbene using bromobenzene and styrene. A variety of different stilbene derivatives were synthesized with exclusive formation of the (E)-isomers and isolated yields up to 97%. We were able to optimize the reaction conditions using only 0.25 mol% of Pd(OAc)2 as the catalyst and a reaction time of 4 hours. No additional ligands or additives are used in the reaction. The catalytic system using TAAILs achieved higher yields than commercially available imidazolium and phosphonium ionic liquids, demonstrating the potential of tailored ionic liquids as a reaction medium for the Mizoroki– Heck reaction.
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POLYCYCLIC AROMATIC HYDROCARBONS IN SELECTED FISHES FROM THE ATHABASCA AND SLAVE RIVERS, CANADA2016 March 1900 (has links)
Human activities over the years, especially the unconventional exploitation of oil sands deposits, downstream on the Athabasca River (AR), might have affected the water quality and ecological integrity of the river basin, thereby presenting a threat to the environment and human health. There have been concerns that the oil sands process-affected waters stored in tailing ponds may be percolating to surface waters as well as underground waters, contaminating neighboring watersheds with a cocktail of chemicals including Polycyclic aromatic hydrocarbons (PAHs). PAHs are present both naturally and from human activities as pollutants in the environment. Forest fires, geologic activities, and oil seeps are examples of natural sources of PAHs in the environment. The major sources of PAHs in the Athabasca region are leaching of oil sands deposits and contamination from oil sands production. On occasions, forest fires contribute PAHs in the area. There has been no comparative data on the exposure of PAHs to fish along the AR and Slave River. I used an integrative monitoring of selected fishes as an indicator to achieve four objectives: i) describe the spatial and seasonal distribution of measurable concentrations of products of biotransformation of polycyclic aromatic hydrocarbons (PBPAH) in bile of fish; ii) determine the levels of parent PAHs in the muscle of fish, and extrapolate the data to estimate potential risk to human consumers, and to identify which species and geographic regions, if any, pose the greatest risk to humans; iii) use patterns of contamination to provide a scientific basis for elucidating the source of contamination; and iv) perform fish health investigation by collecting morphometric health measures and perform a systematic assessment of the occurrence of lesions in the fishes. I sampled whitefish (Coregonus clupeaformis), jackfish/northern pike (Esox luscius), walleye (Sander vitreus), goldeye (Hiodon alosoides) and burbot (Lota lota) from Fort McMurray, Fort McKay, and Fort Chipewyan in Alberta, and from Fort Smith and Fort Resolution on the Slave River in the Northwest Territories. The rationale for selecting fishes included: their abundance along the basin (some have short ranges, e.g., northern pike); their dietary/nutritional and cultural significance to communities in the area; their feeding strategy, such as benthic, supra-benthic, or pelagic, trophic status, and patterns of migration and habits of spawning. I addressed the first objective in Chapter 2, where the total PBPAHs were determined. Concentrations of products of biotransformation of 2 and 3-ringed, 4-ringed, and 5-ringed PAHs were measured using synchronous fluorescence spectroscopy. Spatial and seasonal differences were observed with greater concentrations of PBPAHs in samples of bile of fish collected from Fort McKay as well as greater concentrations of PBPAHs in bile of fish collected during summer compared to those collected in other seasons. Overall, PBPAHs were greater in fishes of lower trophic levels and fishes more closely associated with sediments. In particular, goldeye (Hiodon alosoides), consistently contained greater concentrations of all the PBPAHs studied. In Chapter 3, I achieved the second objective by measuring levels of parent PAHs in muscle of selected fishes and extrapolated the results to determine potential human health risks due to fish consumption. Dorsal muscle of fishes from upstream reaches of the AR close to oil sands extraction and upgrading activities, contained greater concentrations of individual PAHs than concentrations in muscle of fishes from further downstream in the Slave River. Risks posed by PAHs to humans were assessed using a B[a]P equivalents approach. According to the risk assessment results, the average lifetime risk of additional cancers for humans who consumed fish was less than 10-6. In Chapter 4, alkylated PAHs were also measured in fish muscle to achieve the third objective. The general presence of naphthalenes and phenanthrenes and the evaluation of molecular ratios (i.e., LMW/HMW alkyl-PAHs) allowed me to conclude that the major source of pollution is petrogenic, probably due to increases in oil sand activities around Fort McMurray and Fort McKay. I achieved the fourth objective in Chapter 5 by studying the health status and potential effects of industrial development on individuals of economically and culturally significant fishes. A resurgence in condition factor of all species after a low in 2011 was observed. Annual variation was also observed in condition factor and the incidence of anomalies or lesions. Morphometric data demonstrated relatively consistent health among fishes in both the Athabasca and Slave rivers. Analysis of condition factor and somatic indices did not demonstrate consistent differences along the river system. Overall, the health of fish as determined by the metrics employed in this study, does not appear to be adversely affected by the current level of development in the Alberta oil sands region. The data presented in this dissertation make invaluable contribution to the much needed monitoring program in the Athabasca and Slave Rivers. Overall, my findings provide baseline data on fish health, concentrations of parent and alkylated PAHs, and products of biotransformation of PAH in five species of large-bodied fishes consumed by humans in communities in the Lower Athabasca and Slave River basin. These results will be useful for establishing the status and trends and spatial distribution of PAHs during monitoring of the lower Athabasca basin and most importantly, as a valuable reference point before any potential permitted discharges of wastewaters from processing of oil sands to the AR.
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Percutaneous delivery of thalidomide and its N-alkyl analogues for treatment of rheumatoid arthritis / Colleen GoosenGoosen, Colleen January 1998 (has links)
Rheumatoid arthritis (RA) is a chronic inflammatory joint disease associated with high levels of
tumour necrosis factor-alpha (TNF-a) in synovial fluid and synovial tissue (Saxne et al., 1989).
Thalidomide is a proven inhibitor of the biological synthesis of TNF-a (Sampaio et al., 1991)
and is believed to rely on this action for its suppression of the wasting of tissue which
accompanies RA. Oral administration of thalidomide has proven to be effective in RA, but
unacceptable side effects are easily provoked (Gutierrez-Rodriguez, 1984). Administration of
thalidomide via the dermal route can down-regulate TNF-a production in and around the
affected joint, and this without raising the systemic blood level to a problematical level.
Based on thalidomide's physicochemical properties, it is unlikely that it can be delivered
percutaneously at a dose required for RA. Therefore, we have embraced the idea of using
N-alkyl analogues of thalidomide. The most important feature that an analogue of this
compound might contribute is decreased crystallinity and increased lipophilicity. Ordinarily both
these parameters should favour percutaneous delivery. The current study was primarily aimed
at exploring the feasibility of percutaneous delivery of thalidomide and subsequently, three of its
odd chain IV-alkyl analogues (methyl, propyl and pentyl) via physicochemical characterization
and assessment of their innate abilities to diffuse through skin as an initial step towards
developing a topical dosage form for the best compound. The biological activities, more
specifically their potential to inhibit the production of TNF-a was determined for thalidomide and
its N-alkyl analogues.
In order to achieve the objectives, the study was undertaken by synthesizing and determining
the physicochemical parameters of thalidomide and its N-alkyl analogues. A high level of
crystallinity is expressed in the form of a high melting point and heat of fusion.
This limits solubility itself, and thus also sets a limit on mass transfer across the skin. Generally,
the greater a drug's innate tendency to dissolve, the more likely it is that the drug can be
delivered at an appropriate rate across the skin (Ostrenga et al., 1971). Therefore, the melting
points and heats of fusion were determined by differential scanning calorimetry. Aqueous
solubility and the partition coefficient (relative solubility) are major determinants of a drug's
dissolution, distribution and availability. N-octanollwater partition coefficients were determined
at pH 6.4. Solubilities in water, a series of n-alcohols and mixed solvents were obtained, as well
as the solubility parameters of the compounds in study. Secondly, in vitro permeation studies
were performed from these solvents and vehicles using vertical Franz diffusion cells with human
epidermal membranes. Thirdly, tumour necrosis factor-alpha (TNF-a) inhibition activities were
assessed for thalidomide and its N-alkyl analogues.
By adding a methyl group to the thalidomide structure, the melting point drops by over 100°C
and, in this particular instance upon increasing the alkyl chain length to five -CH2- units the
melting points decrease linearly. Heats of fusion decreased dramatically upon thalidomide's
alkylation as well. Methylation of the thalidomide molecule enhanced the aqueous solubility
6-fold, but as the alkyl chain length is further extended from methyl to pentyl, the aqueous
solubility decreased exponentially. The destabilization of the crystalline structure with
increasing alkyl chain length led to an increase in lipophilicity and consequently an increase in
solubility in nonpolar media. Log partition coefficients increased linearly with increasing alkyl
chain length. Solubilities in a series of n-alcohols, methanol through dodecanol, were found to
be in the order of pentyl > propyl > methyl > thalidomide. The N-alkyl analogues have more
favourable physicochemical properties than thalidomide to be delivered percutaneously. The in
vitro skin permeation data proved that the analogues can be delivered far easier than
thalidomide itself. N-methyl thalidomide showed the highest steady-state flux through human
skin from water, n-alcohols and combination vehicles. Thalidomide and its N-alkyl analogues
were all active as TNF-a inhibitors.
Finally, active as a TNF-a inhibitor, N-methyl thalidomide is the most promising candidate to be
delivered percutaneously for treatment of rheumatoid arthritis, of those studied. / Thesis (PhD (Pharmaceutics))--PU for CHE, 1999.
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