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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Synthesis of 5- (2-Thienyl) Barbituric Acid

Truitt, Benjamen Price January 1942 (has links)
A study of the synthesis of 5- (2-Thienyl) barbituric acid.
2

Elaboration de librairies de molécules structurellement diversifiées à partir du squelette de l'acide kojique par des méthodes de synthèse micro-ondes et de flux continu / Elaboration of molecules' libraries structurelly diversified from kojic acid skeleton by microwave and continuous flow synthesis methodologies

Leleu, Ludovic 03 November 2017 (has links)
La structure de l’acide kojique et sa réactivité permet d’effectuer des transformations conduisant à la synthèse de composés polycycliques différents et structurellement très diversifiés. Ces hétérocycles sont obtenus en plusieurs étapes en s’appuyant sur des réactions typiques telles que des cycloadditions [5+2], Diels-Alder, [5+2]/[4+2] tandem, des réactions à 3 composantes ou encore l’utilisation de lithiens. L’utilisation d’appareillages spécifique tels que un réacteur micro-ondes et un synthétiseur en flux continue permettent l’obtention des molécules ciblées d’une façon plus spécifique et efficace. Les chimiothèques de molécules obtenues peuvent dès lors être testé pour une éventuelle activité biologique envers diverses structures. / The structure of kojic acid and its reactivity give the opportunity to make tranformations leading to the synthesis of different polycyclic compounds and structurally diversified. These heterocycles are obtained in several steps by typical reactions like [5+2] cycloaddtions, Diels-Alder reactions, tandem [5+2]/[4+2] cycloadditions, 3 compounds reactions or the use of lithiens. The use of specific equipments like microwave equipment and continuous-flow equipment give the opportunnity to obtain target molecules. Compounds libraries will be test for a biological activity.
3

The Synthesis of 5-Alkyl-5-(2-Thienylmethyl)-Barbituric Acids

Scarbrough, Martha Nell January 1947 (has links)
This thesis describes the synthesis of a series of 5-alkyl-5-(2-thienylmethyl)-barbituric acids.
4

Attempted Synthesis of 5-Allyl-5-(2-Thienyl)-Barbituric Acid

Skinner, Charles Gordon January 1947 (has links)
This thesis describes attempts to synthesize 5-allyl-5-(2-thienyl)-barbituric acid as an improved anticonvulsant.
5

Hydantoins as Anticonvulsants. III. 5-Alkoxy- and Aryloxymethyl-5-(2-Thienyl) Hydantoins

Sadler, Jack W. January 1950 (has links)
It has been shown in the case of a compound synthesized in this laboratory that substitution of the thienyl group for one of the phenyl groups in diphenyl hydantoin produces a compound with less toxicity and somewhat greater activity. It was considered of interest to carry out an analogous substitution in the series of 5-phenyl-5-alkoxymethylhydantions.
6

Hydantoins as Anticonvulsants. IV. The Synthesis of 5-Substituted-5-(2-Tetrahydropyranyl) Hydantoins

Toothaker, Wallis Lee January 1950 (has links)
The project discussed in the paper consists of the substitution of another type of heterocycle, 2-tetrahydropyranyl, in position 5 of the hydantoin nucleus.
7

"Du dör inte av att vara hungrig en stund" : Människors erfarenheter kring intermittent fasta och drivkrafterna bakom denna kosthållning / "You don’t die from being hungry for a while" : People’s experiences of intermittent fasting and the motives behind this diet

Olesen, Pauline, West, Camilla January 2013 (has links)
Bakgrund Intermittent fasta är ett aktuellt ämne som fått stort genomslag i Sverige. Forskningen har konstaterat att intermittent fasta kan påverka kroppsvikten och den mentala hälsan. Det har även observerats ett samband mellan intermittent fasta och förlängt liv. Syfte Syftet med studien var att utforska vilka upplevelser och erfarenheter människor har som går eller har gått på en intermittent fasta, samt ta reda på vilka motiv och drivkrafter som influerar människor till att utöva denna kosthållning. Metod Åtta kvalitativa intervjuer med semistrukturerad frågeguide genomfördes. Intervjuerna spelades in och transkriberades ordagrant. Datainsamlingen analyserades med kvalitativ innehållsanalys. Resultat Deltagarna ansåg att fasta bara handlade om att ta en paus från att äta. Drivkrafterna som låg bakom utövandet av intermittent fasta var framför allt viktnedgång, förändrad kroppssammansättning samt förbättrad mental och fysisk prestation. Det fanns en allmän uppfattning om att hungern var påtaglig under fastan men att den var hanterbar. Många var överens om att det kunde vara svårt att fasta vid sociala sammanhang men att det var viktigt att vara flexibel med fastan och inte bli fundamental. Slutsats Viktnedgång var den största drivkraften till varför deltagarna utövade intermittent fasta. Dieten var något deltagarna kunde vara flexibla med, dels för att inte låta dieten styra ens liv men också för att inte avvika från de sociala normerna. Hungern sågs som en liten uppoffring för att få en kropp som stämmer överens med samhällets kroppsideal. / Background Intermittent fasting is a current topic that has had great impact in Sweden. Research has found that intermittent fasting can affect body weight and mental health. It has also been observed a correlation between intermittent fasting and a longer life. Objective The aim of the study was to explore the experiences of people who follow or has followed an intermittent fasting, as well the motives and driving forces that influence people to practice this diet.M ethod Eight qualitative interviews with a semi-structured interview guide were conducted. The interviews were recorded and transcribed word for word. The data collection was analyzed using a qualitative content analysis. Results Participants believed that fasting just is about taking a break from eating. The motives behind the practice of intermittent fasting were particularly weight loss, changes in body composition and improved mental and physical performance. There was a general perception that the hunger could be apparent during the period of fasting but it was manageable. Several agreed that it could be difficult to fast in social contexts but it was important to be flexible with the fast and not to be fundamental. Conclusion Weight loss was the major motivator as to why participants began practicing intermittent fasting. The diet was something participants could be flexible with, partly because they did not want to let the diet control their life, but also because they did not want to deviate from social norms. The hunger was considered as a small sacrifice to get a body that lived up to society's ideals.
8

Varför väljer vuxna i Sverige att följa olika former av dieter? : En studie om orsak till samt val av diet / Why do adults in Sweden choose to follow some kind of diet? : A study about reasons for and choice of a diet

Carlsson, Jenny, Lundberg, Erika January 2014 (has links)
Bakgrund: Dieter får allt större utrymme i media samtidigt som allt fler följer någon diet. Syfte: Syftet var att undersöka varför vuxna personer i Sverige valt att följa någon form av diet. Vidare undersöktes bland annat socioekonomiska faktorers inverkan på valet av diet. Metod: En webbaserad enkät distribuerades via Facebook där 235 personer deltog genom ett bekvämlighetsurval. Enkäten bestod av 23 slutna frågor. Svaren sammanställdes och analyserades i IBM SPSS Statistics 21.0. Resultaten analyserades med hjälp av Chi-2 test, Mann Whitney U test samt boxplots. Signifikansnivån sattes till p<0,05. Resultat: Studien visade att fler kvinnor än män, fler överviktiga än normalviktiga samt fler deltagare bosatt i samhällen än städer följt någon diet (p=0,001, p=0,002 respektive p=0,047). Vanligaste förekommande diet var LCHF och den vanligaste orsaken att följa en diet var för att må bra följt av utseendemässiga skäl. Främsta anledningen till att följa sin dåvarande eller senaste diet var för att deltagaren ansåg den hållbar. Deltagarna angav att de kom i kontakt med sin dåvarande eller senaste diet via vän, familj eller bekant, detta angavs även som vanligaste sättet att få vidare kunskap om dieten. Slutsats: En diet är inte per automatik hälsosam och en definition skulle underlätta framtida arbete inom området. För att förändra befolkningens kostvanor kan de sociala faktorerna vara av stor betydelse. / Background: Diets receive increasing media attention while more and more follow some kind of a diet. Objective: The aim was to investigate if and why adults in Sweden have chosen to follow any kind of diet. The impact of socioeconomics factors, on the choice of following a diet, were further analysed. Method: A web-based survey was distributed via Facebook where 235 people participated through a convenience sample. The questionnaire consisted of 23 closed questions. Responses were compiled and analyzed in IBM SPSS Statistics 21.0. The results were analyzed using the Chi-2 test, Mann Whitney U test and boxplots. The significance level was set at p <0.05. Results: The study showed that more women than men, more obese than normal-weight and more participants living in smaller municipalities than cities followed some kind of diet (p = 0.001, p = 0.002 and p = 0.047). Most common diet was LCHF and the most common reason to follow a diet was to feel good followed by reasons of appearance, which was the same for both sexes. Most common reason to choose their, for the time ongoing or latest diet, was that it was considered sustainable. Participants indicated that they came in contact with that same diet by friend, family or acquaintance who also were indicated as the most common way to gain further knowledge about the diet. Conclusion: A diet is not automatically healthy and a definition would facilitate future work in the field. In order to change people's eating habits social factors can play an important role.
9

DIASTEREOSELECTIVE OXIDOPYRYLIUM-OLEFIN [5+2]- CYCLOADDITION, DESIGN AND SYNTHESIS OF A NOVEL CLASS OF SARS-COV-2 3CL PROTEASE INHIBITORS, AND SYNTHETIC APPROACH TO (-)-RASFONIN, AN ANTITUMOR AGENT

Monika Yadav (13123668) 20 July 2022 (has links)
<p>  </p> <p>Seven-membered ring structures are one of the most important structural motifs found widely in natural products and bioactive molecules. Although several [5+2]-cycloaddition reactions have been developed to construct these seven membered cores, asymmetric cycloaddition reactions are less explored. Described in Chapter-1 is a base mediated intramolecular diastereoselective [5+2]-cycloaddition reaction that afforded highly functionalized seven membered rings in good yields and excellent diastereoselectivities. The high diastereoselectivity is controlled by the alkyl stereocenter and the chain length of the alkene tether. The existing chirality of the substrate can direct the stereochemical outcome of the [5+2]-cycloaddition reaction. Furthermore, this methodology has been applied to synthesize various potent HIV-1 protease inhibitors. </p> <p>COVID-19 pandemic has profoundly affected life around the globe and costed us 6 million lives. Therefore, there is an urgent need for rational design of new drug candidates to specifically target different SARS-CoV-2 proteins. Recently, Pfizer developed an FDA-approved antiviral therapeutic agent, Paxlovid, targeting SARS-CoV-2 3CLpro. Chapter-2 discusses a concise synthetic route to synthesize active component of Paxlovid, Nirmatrelvir, in 6-steps without any epimerization. We have also developed a series of potent covalent inhibitors targeting SARS-CoV-2 3CLprotease and compared the antiviral activities of these inhibitors with that of Nirmatrelvir. </p> <p>In the final chapter, a concise partial synthesis of the segment A of (-)-Rafonin is discussed. (-)-Rasfonin is an antitumor agent that induces apoptosis in <em>ras</em>-dependent cells. We have proposed an asymmetric chiron approach to install the α-pyranone ring of rasfonin. Our goal is to perform SAR studies on this natural product by designing various analogues. </p>
10

\"Fotoluminescência excitada no ultravioleta em polímeros conjugados\" / Photoluminescence excited in the ultraviolet in conjugated polymers

Marcelo Meira Faleiros 13 February 2007 (has links)
Os polímeros conjugados luminescentes são materiais com grande potencial tecnológico, mas apesar de estudados desde a década de 80, algumas de suas propriedades óticas ainda não foram totalmente entendidas. Por exemplo, ainda persistem dúvidas quanto à natureza das suas excitações primárias. Nesse sentido foi feito um estudo da fotoluminescência do poli[2-metoxy-5-(2-etil-hexiloxi)-1,4-fenileno vinileno] (MEH-PPV), polímero semicondutor luminescente cujas propriedades ópticas já foram muito investigadas. Além da banda de absorção principal na região visível do espectro, ele possui três bandas no ultravioleta. O objetivo deste trabalho é investigar a fotoluminescência do MEH-PPV quando excitado na região do ultravioleta. Após fotoexcitação no ultravioleta, observou-se apenas a fotoluminescência usual no visível. A intensidade da emissão depende fortemente da energia de excitação, da temperatura e da estrutura morfológica do sistema polimérico, determinada pelo método de preparação das amostras. Os resultados indicam que os estados excitados no ultravioleta relaxam rapidamente de forma não-radiativa até os estados de menor energia, de onde então ocorre a luminescência. Entretanto, a eficiência da fotoluminescência excitada no ultravioleta é consideravelmente reduzida, indicando que a excitação a altas energias abre novos canais de relaxação não-radiativos. / Luminescent semiconducting polymers are technological promising materials, but although studied since the 80’s some of their optical properties have not yet been fully understood. For instance, the nature of their primary excitations is still on debate. Therefore we proposed to study the photoluminescence following photoexcitation in the ultraviolet of the polymer poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV). It is a semiconducting luminescent polymer with a main absorption band in the visible part of the spectrum, but with three other absorption bands in the ultraviolet. After ultraviolet photoexcitation it was observed only the usual visible photoluminescence. The intensity of photoluminescence depends strongly on temperature, excitation wavelength and morphological structure of the polymer, determined by the method of sample preparation. The results show that by ultraviolet excitation the excited states relax rapidly non-radiatively to the lower energy states, from where luminescence results. However, the photoluminescence efficiency with ultraviolet photoexcitation is considerably reduced, implying that the highly excited states in the polymer have more non-radiative relaxation channels available.

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