2 edition of Application of carbamoylimidazolium salts in small molecule and combinatorial synthesis. found in the catalog.
Application of carbamoylimidazolium salts in small molecule and combinatorial synthesis.
Written in English
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.
|Contributions||University of Toronto. Dept. of Chemistry.|
|The Physical Object|
|Pagination||xv, 305 leaves :|
|Number of Pages||305|
Synthesis is a common term in the field of chemistry. Learn all about the process of this key reaction alongside examples. So far, the reactions you have seen have only one product molecule on the right-hand side of the chemical equation. Let's take a look at more complex reactions with multiple products. Binary salts combined with. Through a comparison between targeted synthesis and combinatorial approach in the study of fluorescent organic compounds, we can conclude that the targeted synthesis with rational design and systematic modification using combinatorial approach are complementary to each other for the discovery of novel, small molecules with desired photophysical.
The tRNA molecule forms a tight complex with the GTP-bound form of EF-Tu (Figure ). In this complex, the amino acid attached to the tRNA is masked. Unmasking is required for the tRNA to transfer its amino acid in protein synthesis, and it occurs on the ribosome when the GTP bound to EF-Tu is hydrolyzed, allowing the tRNA to dissociate. Nonenzymatic Template Directed RNA Synthesis DNAse I Footprinting of Small Molecule Binding Sites on DNA Gene Targeting Using Peptide Nucleic Acid Nucleic Acid Library Construction Using Synthetic DNA Constructs In Vitro Selection From Combinatorial Nucleic Acid Libraries
The invention discloses a new natural antipodal kaurane derivative and a preparation method and application thereof. The natural antipodal kaurane derivative can be a compound, a combination, an optical isomer, a medicinal salt and a solvate which are shown in the formula (I). The preparation method of the compounds comprises the steps of: extracting with a solvent and separating and purifying. This presentation will focus on the development of practical chemical methods and their application to the high-throughput organic synthesis of thematic libraries for drug discovery. The Synthesis of Heterocyle Libraries Using Solid-Phase Rhodium Carbenoid Reactions Dr. Bruce Clapham, Department of Chemistry, The Scripps Research Institute.
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Carbamoylimidazolium salts 1 are versatile electrophiles in organic synthesis, reacting with a variety of nucleophiles (). 1., 2. Treatment of the salts 1 with thiols results in the formation of thiocarbamates 2, 2 whereas reaction with secondary or primary amines generates tetra- or trisubstituted ureas 3.
1 Reaction of 1 with phenols or the alkoxides of aliphatic alcohols generates Cited by: Carbamoylimidazolium salts 3a–d were chosen as representative examples for the purpose of library synthesis, and were synthesized using the previously reported protocol ().Thus, refluxing the secondary amines 1 with N,N′-carbonyldiimidazole (CDI) ( equiv) in THF afforded carbamoylimidazoles 2, which were isolated in excellent yields and purity after only an aqueous by: These salts are readily prepared by the sequential treatment of secondary amines with N,N′-carbonyldiimidazole (CDI) and iodomethane (Scheme 9).
Authors envisaged that the carbamoylimidazolium salts, while relatively unreactive with alcohols, would react with nucleophlic alkoxides to produce the corresponding carbamates (Table 12).Cited by: see article for more examples.
Abstract. Readily prepared carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents, as a result of the ‘imidazolium' salts react with amines, thiols, phenols/alcohols, and carboxylic acids in high yields, without the need for subsequent chromatographic purification of the products, producing ureas, thiocarbamates.
His current research involves the development of small molecule combinatorial libraries. Richard A. Houghten was born in Illinois in He received his B.S. in chemistry from California State University, Fresno, inand his M.S. in organic chemistry from UC Berkeley in "Carbamoylimidazolium Salts as Diversification Reagents: An Application to the Synthesis of Tertiary Amides from Carboxylic Acids." Grzyb, Justyna A.; Batey, Robert A.
Tetrahedron Lett.44, DOI: / "Copper(II)-Catalyzed Ether Synthesis from Aliphatic Alcohols and Potassium Organotrifluoroborate Salts.". Introduction. Combinatorial techniques are now well-established in many scientific endeavors [1 ••].The application of these ideas to chemical problems has resulted in many complementary techniques for the rapid synthesis of chemical libraries 2, 3, 4, the heart of these techniques is a way to quickly synthesize and separate a desired compound or compounds from.
This book is a practical guide for those engaged in small-molecule combinatorial chemistry as well as those wishing to learn the field. Aimed at nonspecialists, the chapters are written in a tutorial style by internationally recognized experts.
Application of Automated Parallel Synthesis. Combinatorial chemistry has deeply impacted the drug discovery process by accelerating the synthesis and screening of large numbers of compounds having therapeutic and/or diagnostic potential.
These techniques offer unique enhancement in the potential identification of new and/or therapeutic candidates. Our efforts over the past 10 years in the design and diversity-oriented synthesis of low. Onium Salt Supported Organic Synthesis in Water: Application to Ugi’s 4Components Reaction Article in Heterocycles 73(1) December with 32 Reads How we measure 'reads'.
The design, synthesis, and structure−activity relationship development of naphthalene-derived human CCR8 antagonists is described. In vitro binding assay results of these investigations are reported, critical interactions of the antagonists with CCR8 are defined, and preliminary physicochemical and pharmacokinetic data for the naphthalene scaffold are presented.
Combinatorial library design attempts to choose the best set of substituents for a combinatorial synthetic scheme to maximize the chances of finding a useful compound, such as a drug lead. Initial efforts were focused primarily on maximizing diversity, perhaps allowing some bias by the inclusion of a small, fixed set of pharmacophoric substituents.
Readily prepared carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents, as a result of the ‘imidazolium’ effect.
The salts react with amines, thiols, phenols/alcohols, and carboxylic acids in high yields, without the need for subsequent chromatographic purification of the products, producing ureas. Achieving functional group diversity in parallel synthesis: solution-phase synthesis of a library of ureas, carbamates, thiocarbamates, and amides using carbamoylimidazolium salts.
Tetrahedron Letters49 (36), Combinatorial biosynthesis is an attractive method to synthesize potential seeds for clinical drugs, or to synthesize a series of candidate compounds for high-throughput screening. – Successful examples are the production of flavonoids by recombinant E. coli and yeast cells.
– Coincubation of yeast cells carrying isoflavone synthase (IFS) and recombinant E. coli cells carrying. Relatively early yet significant examples of small molecule combinatorial synthesis are the 1,4-benzodiazepine libraries, synthesized on a solid phase in the early s.Benzodiazepines are known to have a wide range of biological activities.
The 1,4-benzodiazepine scaffold represents a versatile pharmacophore (or core structure. This book traces the latest advances in rational drug discovery and combinatorial library design, covering basic principles, design strategies, methodologies, software tools and algorithms, and applications. knowledge- based approaches for the design of small-molecule libraries for drug discovery, relative and absolute diversity analysis of.
The synthesis of nine new carbohydrate-based quaternary ammonium salts and two new triazolium salts starting from d-glucose has been synthesis utilized the regio- and stereoselective ring opening reaction of 2,3-anhydro sugars by.
A convenient protocol for the parallel solution-phase synthesis of a library of thiocarbamates, ureas, carbamates, and amides from carbamoylimidazolium salts has been developed.
Co-crystallization is the supramolecular phenomenon of aggregation of two or more different chemical entities in a crystalline lattice through non-covalent interactions. It encompasses the study of the manifestation of multi-component crystalline solids as well as their design.
The chemistry community and th. Carbamoylimidazolium and Thiocarbamoylimidazolium Salts: Novel Reagents for the Synthesis of Ureas, Thioureas, Carbamates, Thiocarbamates and Amides.
Article Nov Our approach employs the one-bead-one-compound (OBOC) approach to library des which capitalizes on split-pool combinatorial synthesis .In this book chapter, selected applications of bismuth(III) salts in the construction and/or functionalization of important molecular structures, valuable from the medicinal chemistry point of.