Sökning: "Piperidines"
Hittade 5 avhandlingar innehållade ordet Piperidines.
1. Reaction Between Grignard reagents and Heterocyclic N-oxides : Synthesis of Substituted Pyridines, Piperidines and Piperazines
Sammanfattning : This thesis describes the development of new synthetic methodologies for preparation of bioactive interesting compounds, e.g. substituted pyridines, piperidines or piparazines. Thesecompounds are synthesized from commercially available, cheap and easily prepared reagents, videlicet the reaction between Grignard reagents and heterocyclic N-oxides. LÄS MER
2. Iridium Catalysed Asymmetric Hydrogenation of Pyridines
Sammanfattning : This thesis presents the hydrogenation of substituted pyridines using N,P-ligated iridium catalystsin homogeneous media. These iridium catalysts were developed within this research group in thepast decade. This method of hydrogenation is highly stereoselective, and in several cases good to excellent ees were obtained. LÄS MER
3. On the Ring-Opening Reaction of Thiophene-1,1-dioxides and the Intramolecular Diels-Alder Reaction of Azanona- and AzadecatrienesI
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. Synthetic Transformations via Metal- and Enzyme-Catalyzed Dynamic Kinetic Resolution
Sammanfattning : This thesis deals with the preparation of a new half-sandwich type ruthenium(II)- catalyst for racemization of optically active secondary alcohols and the development of a highly efficient method in combination with lipases such as Candida antarctica lipase B and Pseudomonas cepacia lipase for dynamic kinetic resolution of various functionalized alcohols under mild reaction conditions.It was shown that the RuCl(CO)2(η5-C5Ph5) complex can racemize optically active aliphatic and aromatic secondary alcohols at room temperature in rather short times. LÄS MER
5. Development of Lewis acid mediated stereoselective synthesis of nitrogen containing heterocycles
Sammanfattning : This thesis deals with the development of syntheticmethodologies for the preparation of enantio- anddiastereomerically enriched nitrogen-containingheterocycles.Asymmetric Lewis acid mediated Diels-Alder reactions with2H-azirines as dienophiles have been studied. LÄS MER