Sökning: "Ring opening"

Visar resultat 11 - 15 av 110 avhandlingar innehållade orden Ring opening.

1. 11. On the Ring-Opening Reaction of Thiophene-1,1-dioxides and the Intramolecular Diels-Alder Reaction of Azanona- and AzadecatrienesI

   Författare :Anders Sebastian Tsirk; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transition states; 3-21G * ; intramolecular Diels-Alder reactions; asymmetric induction; multivariate optimization; kinetic isotope effects; rearrangements; secondary amines; 1-dioxides; Ring-opening reaction; thiophene-1; stereoselectivity.; Organic chemistry; Organisk kemi;

   Sammanfattning : Substituted thiophene-1,1-dioxides were synthesized and their ring-opening reactions with omega-unsaturated secondary amines were investigated; this led to a synthetic route to azatrienes and to the preparation of some polyhydroisoindoles and polyhydroisoquinolines via an intramolecular Diels-Alder reaction. By using 2-substituted pyrrolidines and piperidines various tetrahydrobenzo[f]indolizidines, benzo[b]quinolizidines, tetrahydrobenzo[a]indolizidines and tetrahydro[a]pyrrolizidines could be synthesized via the ring-opening of 3-bromo-2,5-dimmethylthiophene-1,1-dioxide and a subsequent intramolecular Diels-Alder reaction. LÄS MER

3. 12. A Regio- and Stereodivergent Route to All Isomers of vic-Amino Alcohols

   Författare :Berit Olofsson; KTH; []
   Nyckelord :amino alcohols; vinylepoxides; vinylaziridines; oxazolines; oxazolidinones; ring-opening; regioselective; diastereoselective; sphingosine; configuration; NMR spectroscopy;

   Sammanfattning : The first part of this thesis describes a synthetic strategythat provides all eight possible isomers of a given vic-aminoalcohol starting from vinylepoxides. The value of a generalroute is evident, as several isomers are needed ininvestigations of structure-activity relationships forpharmacologically active derivatives, and for optimizing theperformance of chiral ligands containing the amino alcoholmoiety. LÄS MER

4. 13. Bispyridylamides as ligands in asymmetric catalysis

   Författare :Oscar Belda de Lama; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asymmetric catalysis; chiral ligand; pyridine; amide; allylic alkylation; enantioselective; cyanation; ring-opening; chiral Lewis acid;

   Sammanfattning : This thesis deals with the preparation and use of chiralbispyridylamides as ligands in metal-catalyzed asymmetricreactions. The compounds were prepared by amide formation usingdifferent coupling reagents. LÄS MER

5. 14. Synthesis of Ring-fused Peptidomimetics : Interacting with Amyloid Fibrils

   Författare :Dan E. Adolfsson; Fredrik Almqvist; Anna Linusson; Morten Grötli; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; organic chemistry; synthesis; peptidomimetics; thiazoline fused 2-pyridones; Alzheimer s disease; Parkinson s disease; Amyloid; Amyloid-beta; alfa-Synuclein; method development; organisk kemi; Organic Chemistry;

   Sammanfattning : Parkinson's and Alzheimer's disease are the two most common neurological disorders in humans. Both conditions involve progressive death of neurons in the central nervous system, decline in bodily functions and eventually (and invariably), death. So far, no cure exists and the available treatments can only ease symptoms. LÄS MER

7. 15. Hydrodeoxygenation (HDO) catalysts Characterization, reaction and deactivation studies

   Författare :Houman Ojagh; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Poisoning; Carbon deposition; Ring opening; Hydrodeoxygenation HDO ; Deactivation; Hydroconversion; Brønsted acid sites; Renewable diesel; Sulfided phase;

   Sammanfattning : Production of biomass derived fuels such as renewable diesel, are primarily intended to reduce the reliance of the conventional engines on petroleum fuels as well as the emission of CO2 from fossil hydrocarbons. Hydrodeoxygenation (HDO) is a powerful technique that has been regularly used in the fuel upgrading processes. LÄS MER