Sökning: "ring opening selective"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden ring opening selective.

1. 1. Ring-opening catalysts for cetane improvement of diesel fuels

   Författare :Ulf Nylén; Magali Boutonnet; Sven Järås; François Garin; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ring opening selective ; naphthenic structure; indan; light cycle oil LCO ; cetane; Pt-Ir catalyst; microemulsion; XPS; TPR; TEM; DRIFTS; sulphur analysis; GC-SCD; Chemical engineering; Kemiteknik;

   Sammanfattning : The global oil refining industry with its present product distribution essentially shifted towards fuels such as gasoline and diesel will most likely hold the fort for considerable time. However, conditions are changing and refinery survival will very much depend on long-term planning, process and product flexibility and being at the frontiers of refining technology, a technology where catalysts play leading roles. LÄS MER

3. 2. 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

4. 3. degradable electroactive polymers: Synthesis, Macromolecular architecture and scaffold design

   Författare :Baolin Guo; Ann-Christine Albertsson; Patric Jannasch; KTH; []
   Nyckelord :Poly lactide ; poly ε-caprolactone ; ring-opening polymerization; carboxyl-capped aniline trimer; carboxyl-capped aniline pentamer; phenyl amino-capped aniline tetramer; coupling reaction; DCC DMAP system; degradability; electroactivity; conductivity; macromolecular architecture; chitosan; hydrogel; block copolymer; functionalization; oxidative coupling reaction; self-assembly; toxicity; tubular porous scaffold; neural tissue engineering.;

   Sammanfattning : Electrically conducting polymers induce specific cellular responses at the molecular level. One of the crucial limitations of the use of conducting polymers in tissue engineering is their inability to degrade. LÄS MER

5. 4. Synthesis of Novel Homoserine Analogues - Towards t he Development of Substrate-based Peptide Inhibitors of cAMP-dependent Protein Kinase

   Författare :Anna-Carin Carlsson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; protein kinases; protein kinase inhibitors; substrate-based kinase inhibitors; cAMP-dependent protein kinase; kemptide; homoserine; asymmetric -amino acid synthesis; glycine -anion equivalents; Schöllkopf’s bislactim ether; epoxidation; nucleophilic epoxide ring opening; microwave-assisted synthesis;

   Sammanfattning : Protein kinases are enzymes that via phosphorylation of proteins/peptides regulate most aspects of cell functions and physiology. The enzymes transfer a -phosphoryl group from ATP to hydroxyl groups of Ser, Thr and Tyr residues in their substrates. LÄS MER

7. 5. Radical Cyclization Approaches to Pyrrolidines

   Författare :Magnus Beşev; Troels Skrydstrup; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Radical cyclization; diastereselectivity; pyrrolidine; pyrroline; thiazoline; aziridine; Organisk kemi; Organic chemistry; Organisk kemi; organisk kemi; Organic Chemistry;

   Sammanfattning : Five-membered rings are readily prepared by 5-exo-trig radical cyclization. This thesis is concerned with novel methodology for pyrrolidine synthesis. We have synthesised selenium containing radical precursors from aziridines and α-phenylseleno ketones, and cyclized them to 2,4- and 3,4-disubstituted pyrrolidines. LÄS MER