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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"Acyl transfer"”.
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Acyl transfer to lysine : an investigation acyl transfer across large rings
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.
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Part I. Anionic Acyl Transfer Catalysis;Part II. Enantioselective alcoholysis of Acyl Donors;Part III. Enantioselective N-acylation
… and N-methylimidazole, are widely used as acyl transfer catalysts. In contrast, anionic nucleophiles have been little explored in acyl transfer catalysis, although their high nucleophilicity may enable unique applications. In the course of my studies, 1,2,4-triazole anion was found to be an …
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Synthesis and conformation of peptides : I. stability of short templated alpha-helical peptides ; II. new templates for intramolecular acyl transfer
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997.
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Methods for Directed C–O Bond Functionalization of Esters and Acyl Equivalents
… the mechanisms of new transition metal-catalyzed acyl transfer reactions using substrates at the ester oxidation state. New methods discussed include steric-controlled arene acylation via sequential C–O/C–H bond activation and a Suzuki-Miyaura cross coupling using N-pyridylimidates as acyl …
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Diastereoselective acylation of trans-2-substituted-cyclohexanols and glycosidase inhibition studies
<p>Part I. The reaction between chiral acyl chlorides and trans -2-substituted-cyclohexanols proceeds diastereoselectively, i.e. produces mixtures of unequal amounts of diastereomers. We found for the first time that addition of pyridine or diisopropylethylamine accelerates the acylation, and …
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Expanding the Spiroligomers Toolbox as Protein-Protein Interaction Inhibitors
… interactions. After the discovery of an acyl-transfer coupling reaction by Dr. Zachary Brown, a previous graduate student of Schafmeister group, the synthesis of highly functionalized spiroligomers that mimic the helical domain of p53 was undertaken before each molecule was tested for …
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Synthesis of enantio-pure amides by reversal of the Geobacillus pallidus RAPc8 amidase hydrolysis reaction in non-aqueous media
… towards synthesis. For synthesis to occur, an acyl donor and an acyl acceptor are required, in which the acyl acceptor acts as a nucleophile. The applicability of amidases in non-aqueous media opens new possibilities for processes in which the enzyme can be used for the industrial synthesis of …
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Characterization and Synthesis of Cyclodextrin Inclusion Complexes and their Applications as Fluorescent Probes for Sensing Biomacromolecules
… amine of 1. The technique relies on an S to N acyl transfer from a guest molecule to a CD host resulting in the mono-acylation of the host. The importance of the linker between the guest and the reactive acylating agent was fully explored. Furthermore, two CD probes are synthesized and are …
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Novel nitrogen containing polymers via Reissert chemistry
… benzothiazole, isoquinoline and quinoline. Acylated linear polyamine derivatives were obtained by the step growth condensation polymerization of open chain bis(Reissert compound)s with suitable dihaloalkanes; intrinsic viscosities of up to 0.48 dl/g were obtained in unoptimized runs. The …
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Structural Basis for Protein Recognition, Acyl-substrate Delivery, and Product Release by ACP in the Biosynthesis of Lipid A
<p>Acyl-carrier-protein (ACP) is the principal transporter of fatty acids, coordinating acyl-transfer among a vast network of diverse enzymes and biochemical processes. ACP association with protein partners is thought to be exceedingly transient. This paradigm has posed challenges for understanding …
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Halo Enol Lactones as Enzyme-Activated Irreversible Inhibitors of Chymotrypsin: Their Synthesis, Kinetics, and Mechanism of Inactivation (Suicide Substrates)
… or suicide substrates for (alpha)-chymotrypsin. Acyl transfer to the active site serine generates a halo methyl ketone that remains tethered in the catalytic site during the lifetime of the acyl enzyme, available for reaction with an enzymatic nucleophile. To investigate the structural …
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Studies on the use of peptide auxiliaries in the meso-desymmetrization of epoxides, and the kinetic resolution of secondary alcohols
… on the existing classes of asymmetric DMAP-type acyl-transfer catalysis as the major topic of the thesis. Chapter 2 describes the synthesis and evaluation of four peptide ligands used in combination with scandium(III) triflate for the meso-desymmetrization of cyclohexene oxide. …
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Trehalose Monomycolate Biosynthesis and Utilization in Mycobacterium tuberculosis
… Antigen 85 (Ag85) family of enzymes catalyze the transfer of mycolic acids from a single donor, trehalose monomycolate (TMM), to different acceptors located within the cell wall. Although there are three different pathways in M. tb to produce trehalose, only one, the otsAB pathway, leads to the …
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Enzymology of DHHC-mediated Protein S-Acylation
Protein <italic>S</italic>-acylation is the post-translational modification of proteins with long-chain fatty acids at cysteine residues via a thioester linkage. The most commonly attached lipid is 16-carbon palmitate, thus the process is often called palmitoylation. Unlike other lipid …
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Kinetic Resolution of N-Acyl-b-Lactams, b-Lactams, and N-Acyl-Thiolactams using Amidine-Based Catalysts
… the context of enantioselective nucleophilic acyl substitution, there are 3 types of processes depending where chirality is present: Type I, where the nucleophile: alcohol or amine) gets resolved, Type II, where chirality resides in the leaving group, and Type III, where a chiral acyl donor is …
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The crystal structure of an aliphatic amidase from Geobacillus pallidus RAPc8
… It shows both amide hydrolysis and acyl transfer activities, and also exhibits stereo selectivity for some enantiomeric substrates. This enzyme can therefore be exploited in large-scale production of enantio-pure compounds. Structural characterization of this amidase would yield …
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Escherichia coli 2-oxoglutarate dehydrogenase multienzyme complex: e1 and e2 substrate specificty, e1 carboligase activity, and e2 interchain succinyl transfer
… (E1 o), a di hydrol i poylsucci nyl transferase (E2o), and a di hydrol i poyl dehydrogenase (E3). The first two components carry out the principal reactions for succinyl CoA formation while the third one reoxidizes dihydrolipoamide to lipoamide. This mechanism is similar to other …
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Development of asymmetric catalysts based on planar-chiral [pi]-complxes of nigrogen heterocycles with iron
… that it was active as a catalyst for acylation of alcohols with acetic anhydride, acylation of alcohols with diketene, cyanosilylation of aldehydes with triethylsilylcyanide, and addition of alcohols to ketenes. The DMAP analog was resolved by chiral HPLC, but resulted in a …