Sökning: "Lars Engman"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden Lars Engman.

1. 1. Construction of Five-Membered Heterocyclic Compounds via Radical Cyclization

   Författare :Stefan Berlin; Lars Engman; Mario D. Bachi; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; radical; cyclization; carbonylation; melatonin; pyrrolidine; pyrrolidin-3-one; tetrahydrofuran-3-one; Organisk kemi; Organic chemistry; Organisk kemi; organisk kemi; Organic Chemistry;

   Sammanfattning : This thesis describes how radical cyclization chemistry can be applied for the construction of heterocyclic compounds.In the first part, a series of electron deficient α-phenylselenenylalkenes were prepared via a PhSeCl-addition/HCl-elimination sequence. LÄS MER

3. 2. Synthesis of Tetrahydrofuran and Pyrrolidine Derivatives Utilising Radical Reactions : Organochalcogenides in Reductive, Carbonylative and Group-Transfer Cyclisation

   Författare :Cecilia Ericsson; Lars Engman; Ilhyong Ryu; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Organisk kemi; Organic chemistry; Organisk kemi;

   Sammanfattning : This thesis describes free-radical reactions for the construction of tetrahydrofuran and pyrrolidine derivatives. The studies are concerned with (i) diastereoselectivity in radical cyclisation, (ii) construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones via radical carbonylation/cyclisation and (iii) synthesis of tetrahydrofuran derivatives via group-transfer cyclisation of organochalcogen compounds. LÄS MER

4. 3. Exploring Novel Catalytic Chalcogenide Antioxidants

   Författare :Henrik Johansson; Lars Engman; Helena Grennberg; Troels Skrydstrup; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; antioxidant; tellurium; selenium; catalytic; toxicity; ROS; neutrophil; glutathione peroxidase mimic; macrophage.; Organic chemistry; Organisk kemi; Kemi med inriktning mot organisk kemi; Chemistry with specialization in Organic Chemistry;

   Sammanfattning : This thesis is concerned with the synthesis and evaluation of regenerable chalcogen containing antioxidants. Variously substituted 2,3-dihydrobenzo[b]selenophene-5-ol antioxidants were evaluated in order to gain information about structure/reactivity-relationships. LÄS MER

5. 4. Developments in the Field of Aza-Diels-Alder Reactions, Catalytic Michael Additions and Automated Synthesis

   Författare :Stefan Modin; Pher Andersson; Lars Engman; Hans Adolfsson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Asymmetric synthesis; aza-Diels-Alder; Michael addition; Transfer hydrogenation; automated synthesis; Catalysis; Organisk kemi; Organic chemistry; Organisk kemi;

   Sammanfattning : The development of new aza-bicyclic structures with potential applications as ligands synthesised via an aza-Diels-Alder cycloaddition has been studied. The studies are concerning the i) development of large scale aza-Diels-Alder reaction, ii) development of a fast and simple route to bicyclic diamine ligands, iii) development of new aza-Diels-Alder adducts from different dienes, iv) development and application of bicyclic N,P ligands for catalytic Michael additions and v) development of robotized asymmetric transfer hydrogenation reactions. LÄS MER

7. 5. Exploring Catalytic Tellurium-Based Antioxidants : Synthesis and Evaluation

   Författare :Jia-fei Poon; Lars Engman; John Murphy; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; antioxidant; tellurium; selenium; radical-trapping; chain-breaking; ROS; glutathione peroxidase; tocopherol; aromatic amine; oxidative stress;

   Sammanfattning : This thesis is concerned with the synthesis and evaluation of various tellurium-based chain-breaking antioxidants. The purpose is to find novel regenerable compounds with improved radical-trapping capacity.In the first part of this work, we explore the possibilities to incorporate tellurium into tocopherols and aromatic amines. LÄS MER