Application of carbamoylimidazolium salts in small molecule and combinatorial synthesis
Notice bibliographique
Résumé
This thesis is a summary of research conducted since February 2000 in the laboratories of Professor Robert A. Batey at the University of Toronto and is continuation of work performed here on carbamoylimidazolium salts. Chapter A covers the synthesis of the imidazolium salts, as well as their application in small molecule preparation. The salts are prepared in two steps with minimal purification, and have been successfully applied to the generation of amides from carboxylic acids. The amides are generated under mild conditions in excellent yields and are pure after aqueous work-up. Previous work in our laboratory has shown that derivatized anilines are unreactive towards the salts. Here the conditions were optimized for the reaction of salts with derivatized anilines to generate substituted ureas. Since imidazolium salts are capable of reacting with various nucleophiles a comparative study was carried out to determine the order of reactivity of the nucleophiles towards the salts. It was shown that sulfur based nucleophiles react significantly faster than any other nucleophile, while aliphatic alcohols and anilines do not react to any significant amount under weakly basic conditions. Synthetically useful selectivity levels between alkyl amines, phenols and carboxylic acids were not obtained. Chapter C covers the application of carbamoylimidazolium salts in the generation of heterocyclic alkaloids. Very poor reactivity of anilines under mild basic conditions allowed for a 4-component Povarov reaction of unprotected p-aminophenol with carbamoylimidazolium salt, aldehyde and 2,3-dihydrofuran. Lastly, the imidazolium salts were used in a short synthesis of fused bicyclic lactams. Chapter B focuses on combinatorial synthesis. Firstly, a semicarbazide library was generated. Hydrazides were reacted with N, N '-carbonyldiimidazole to generate 1,3,4-oxadiazol-2-ones, which were ring opened with amines to generate semicarbazides. Secondly, N, N'-diacylated imidazolidines exhibit herbicidal activity. Thus, we attempted to create a combinatorially friendly method for their synthesis. A common imidazolium salt intermediate was generated from monoacylated imidazolidine, which was then reacted with various amines. Lastly, a small library of ureas, carbamates, thiocarbamates and amides was synthesized to demonstrate the utility of the salts as a common precursor to various functionalities, which can be synthesized in parallel and under same conditions with minimal purification.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
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 tête enseignante, 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 ».