Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 11 of 11 for “"Hemiacetal"”.
-
Sulfoxide Catalyzed Dehydrative Glycosylation. Reaction Development and Mechanistic Analysis
… glycosylation for the coupling of carbohydrate hemiacetals and nucleophilic alcohols has been developed. In this procedure, a glycosyl hemiacetal is treated with the reagent combination of benzenesulfonic anhydride and a substoichiometric amount of n-butyl sulfoxide, followed by the addition of …
-
Development and Investigation of a Dehydrative Glycosylation With Activated Diphenyl Sulfonium Reagents
… activated via nucleophilic attack of the hemiacetal hydroxyl upon the sulfonium center of diphenylsulfide bis(trifluoromethanesulfonate), leading to formation of a glycosyl oxosulfonium. Low temperature NMR studies have revealed that a glycosyl pyridiniurn is subsequently formed in the …
-
Structural characterisation and absolute stereochemistry of some degraded carotenoids from New Zealand honeys
… study (MacroModel) of the diastereoisomeric hemiacetal MPA esters. The results of the determination, coupled with a consideration of crystallographically-determined hemiacetal ester conformations obtained from a search of the Cambridge Structural Database, supported the use of the …
-
I. Chemoselective Dehydrative Glycosylation With Application Toward Oligosaccharide Synthesis. II. Sulfide-Mediated Direct Glycosylation of C(1)-Hydroxyl Glycosyl Donors. III. Studies Toward the Total Synthesis of Auriside A
… in the third part of the dissertation. The hemiacetal disaccharide portion of auriside A is successfully synthesized. The convergent synthesis of the auriside aglycon component is accomplished in 17 linear steps using the Mukaiyama aldol reaction, the intramolecular Mitsunobu …
-
Entwicklung einer modularen Synthese chimärer Makrolidantibiotika aus Zuckern
… die intramolekulare WITTIG-Olefinierung eines ω-Hemiacetal-Phosphoniumylids geschlossen werden. Die Vorstufe sollte dabei aus zwei Building-Blocks aufgebaut werden, einem Zuckerbaustein und einem Spacer. Zur Darstellung des Zuckerbausteins wurde von Cellulose ausgegangen, welche um eine …
-
Total Synthesis of the Actinoallolides and a Designed Photoaffinity Probe for Target Identification
… installation of the labile transannular hemiacetal motif. Late-stage diversi cation then provides ready access to the congeneric (+)-actinoallolides B-E. The unknown mechanism of action of the actinoallolides poses a barrier to their potential utilisation as lead compounds for drug …
-
Understanding the mechanism of androgen biosynthesis
… state permitted identification of a new peroxo hemiacetal intermediate species initiated by nuclophilic attack on the substrate molecule by the peroxoanion. As a whole, this work details the structural and functional properties of CYP17A1 active in human androgen biosynthesis.
-
Part I. Rhodium-catalyzed asymmetric functionalization of allylic amines Part II. Harnessing kinetic driving forces in alkyne metathesis for the synthesis of complex molecular architectures
… water leads to the formation of a hemiaminal or hemiacetal depending on the nucleophile. The hydrogen on the methine carbon in the resulting intermediate is hydridic in nature. We hypothesized that the Rh(I) catalyst could perform a dual role in the reaction where after the allylic isomerization, …
-
Synthesis of Polysaccharide Aldehydes or Ketones and Fabrication of Derived Hydrogels or Microgels
… is in equilibrium between a ring-closed hemiacetal and an open-chain aldehyde form, we developed a novel method to prepare polysaccharide aldehydes by attaching monosaccharides to polysaccharide chains. Herein, we describe the approach of attachment through amination between amine group …
-
Catalytic routes for oxygenate conversion on solid acids and supported metal nanoparticles
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01
-
Synthesis and Characterization of a Novel Polyacetal & Design and Preparation of Superhydrophobic Photocatalytic Surfaces
… of co-monomer units. By interrupting the facile hemiacetal hydrolysis reaction that can propagate along the macromolecular chain, these co-units function as a "stopper" against degradation of the main block, -(CH<sub>2</sub>O)<sub>n</sub>-. The copolymer can also be blended with additives such as …