Notice bibliographique
Résumé
Due to the growth number of infectious diseases, a huge demand of new antimicrobial agents are required.In this regard, Thiobarbituric acid (TBA) moieties were explored.As its name indicates, TBA is the sulfur version of the barbituric acid.The work in barbituric moieties dated long ago in 1864 by Baeyer, when it was reported that these barbituric derivatives can be used as anesthetics, sedative or anticonvulsive agents.In the present work and taking advantage that TBA structure shows several points where diversity can be introduced, therefore several functionalities were introduced in the TBA analogues and their antimicrobial properties were studied in Gram-positive and Gram-negative bacteria.(Chapter 1) These are the chemical modifications explored: i) N-substitution, where this site can be substituted with a symmetrical substituents; ii) reaction at C-5 position owing to the high acidity of the protons which includes acylation, acetylation, Schiff bases, Knoevenagel condensation thioamide and enamine formation.The antimicrobial activity screening for the synthesized compounds were against Gram-positive (S. aureus and B. subtilus) and Gram negative (E. coli and P. aeruginosa) bacteria.Among all thiobabituric derivatives synthesized, Boc-Phe-TBA showed a promising activity, which confirms that TBA could be an excellent scaffold when combined with N-protected amino acids for developing antimicrobial compounds.(Chapter 2)The characterization of 20 thiobarbituric derivatives was carried out in different spectroscopy techniques such as: Nuclear Magnetic Resonance (NMR), Ultra violet spectroscopy, Infra-Red spectroscopy and single X-ray crystallography.In NMR characterization the acetylation of TBA was the most interesting due to the fact that this type of compound have the tendency of forming Enol and Keto tautomerism.This was proved by NMR and also by theoretical calculation, and the results confirm that the 1 H NMR for this compound (A01) showed resonance at 17.72 ppm (singlet) for OH.This indicate that the enol form is more stable than the keto form.In UV characterization due to the fact TBA derivatives are not known aromatic and yet they are UV active.Therefore the absorption of few TBA derivatives were study in different solvents hence these showed absorption iv at maximum wavelength (max) in the range of 322 -285 nm respectively.For IR characterization, these derivatives (A01, A02, A03, A04, A06, A10, A12, A13, A14 and A17) were evaluated, and showed absorption stretching frequency of thiocarbonyl (C=S) in three different ranges, 1395-1570 cm -1 , 1260-11420 cm -1 and 940 -1140 cm -1 .For X-ray crystallography, crystals of A01, A02, A06, A13, A17 and A18 were obtained by hot recrystallization from ethanol and the intramolecular H-Bonding formation was observed in all cases, intermolecular H-bonding was observed for A17.(Chapter 3) v DECLARATION I Plagiarism declaration I, Sikabwe Noki declare that 1.The research work reported in this thesis, except where otherwise indicated,
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,006 | 0,002 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».