<p>This thesis describes a method of growing a highly adherent nano-porous alumina coating on titanium implant materials, a design which might be useful in hard tissue replacement. Alumina layers were formed by anodisation of aluminium, which had been deposited on titanium and titanium alloys by electron beam evaporation. Mechanical testing showed the coatings’ shear and tensile strength to be ~20MPa and ~10MPa respectively. </p><p>Human osteoblasts were cultured on purchased membranes, produced in the same way with similar characteristics as the coating mentioned above. Cell viability, proliferation and phenotype were assessed by measuring redox reactions, DNA, tritiated thymidine incorporation and alkaline phosphatase production. Results showed normal osteoblastic growth patterns with increasing cell numbers the first two weeks after which cell growth decreased and alkaline phosphatase production increased, indicating that osteoblastic phenotype was retained on the alumina. Flattened cell morphology with filipodia attached to the pores of the material was seen. </p><p>Implants frequently trigger inflammatory responses due to accumulation and activation of cells such as polymorphonuclear granulocytes (PMN), also called neutrophils. Activation and morphology of human PMN in response to nano-porous alumina with two pore sizes (20 and 200 nm) was investigated by luminol-amplified chemiluminescence, granule enzyme deposition measurement, optical and scanning electron microscopy. Activation was observed on both membrane types, however less pronounced on the 200 nm alumina. For both membranes a decrease in activation was seen after coating with fibrinogen, collagen I and serum (more pronounced for the two latter). On fibrinogen-coated alumina many flattened cells were observed, indicating frustrated phagocytosis. Finally when culturing osteoblasts on non-coated and collagen-coated membranes (after exposure to PMN) many more cells had established on the protein-coated surface after 24 h. </p><p>The overall results indicate that it might be possible to produce a novel bone implant coating by anodisation of aluminium deposited on titanium and that this material will support osteoblast adhesion and proliferation. Furthermore neutrophil activation can be suppressed when coating the alumina with collagen I, which is beneficial considering the fact that this protein also is essential for bone formation.</p>

<p>In this thesis electron transfer reactions and diffusion of redox molecules in three different types of self-aggregated structures are investigated. Electrochemistry was used to investigate the redox potential and diffusion coefficients for redox active molecules with different polarity. The first aggregate system studied was the micellar phase. The role of electrostatic interactions in the stability of an amphiphilic viologen was investigated for differently charged micelles. It was concluded that the electrostatic environment changed the redox potential of the viologen. In differently charged micelles the redox potential was more negative compared to when the viologen was situated in micelles with the same charge.</p><p>The second structure investigated is a very fascinating phase, the bicontinuous cubic phase, with its continuous channels of water and an apolar bilayer. Its domains with different polarity made it possible to solvate both hydrophilic and hydrophobic molecules. An amphiphilic molecule will have its head-group at the interface between the apolar and polar part, and can move lateral within the bilayer. All molecules investigated made contact with and reacted at the surface of the electrode. The diffusion of water bound species diffusing in the water channels was 3-4 times slower than in water. Hydrophobic and amphiphilic molecules were much more hindered, probably because the cubic phase was not defect free.</p><p>The third kind of structure studied was a lamellar system. This phase is built up from planar bilayers that are stacked with a repeating distance and with water in between. A hydrophilic molecule was severely hindered to move in the direction perpendicular to the bilayer plane. Upon addition of the peptide melittin the current increased, due to pore formation in the bilayer.</p>

<p>The development of new aza-bicyclic structures with potential applications as ligands synthesised <i>via</i> 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.</p><p>i) Development of large-scale aza-Diels-Alder reaction giving up to 110 g pure product, in ordinary laboratory equipment without the need of any flash chromatography.</p><p>ii) Development of a new synthetic route to bicyclic diamine ligands highly useful for asymmetric rearrangement of olefin oxides to allylic alcohols and thereby shortening the ligand synthesis dramatically and moreover providing with a faster access to those ligands.</p><p>iii) Expanding the scope of the aza-Diels-Alder reaction by the use of spirodienes and anthracene as dienes.</p><p>iv) Development and application of a new bidentate ligands for catalytic Michael addition to cyclic enones using 5 mol % ligand giving the product in 71 % ee.</p><p>v) Utilisation of Chemspeed ASW 2000 in catalytic transfer hydrogenation and solving of problems regarding use of highly air sensitive reactions in an automated environment.</p>

<p>Important information on the bioactive conformation of biologically active peptides may be obtained by studies of rigid peptides or well-defined secondary structure mimetics incorporated into pseudopeptides. The structural requirements for the interaction of angiotensin II (Ang II, Asp-Arg-Val-Tyr-Ile-His-Pro-Phe) with its AT₁ and AT₂ receptors were the subject of this study.</p><p>The main objectives of this work were to synthesize secondary structure mimetics and incorporate these into Ang II. Ang II has been suggested to adopt a turn conformation around Tyr⁴ when interacting with its AT₁ receptor. Therefore, two <i>γ</i>- and one <i>β</i>-turn mimetic scaffolds based on the benzodiazepine structure were synthesized and decorated with side chains. The scaffolds replaced the turn region around Tyr⁴. Most of the pseudopeptides obtained after incorporation into Ang II exhibited high AT₂/AT₁ selectivity and nanomolar affinity to the AT₂ receptor. One pseudopeptide encompassing a <i>β</i>-turn mimetic also displayed AT₁ receptor affinity.</p><p>We hypothesized that the position of the guanidino group of the arginine residue and the N-terminal end, in relation to the tyrosine side chain, was critical for AT₂ receptor affinity. Conformational evaluation of the pseudopeptides revealed that in all the compounds with AT₂ receptor affinity the arginine side chain and the N-terminal end could reach common regions, not accessible to the inactive compound. It is proposed that Ang II has a more extended bioactive conformation when binding to the AT₂ receptor than when binding to the AT₁ receptor.</p><p>Furthermore, in a Gly scan of Ang II only replacement of the arginine residue reduced the affinity for the AT₂ receptor considerably. Some N-terminal modified Ang II analogues were also synthesized and it was concluded that truncated Ang II analogues interact with the AT₂ receptor differently than Ang II.</p><p>Three of the synthesized pseudopeptides were evaluated in AT₂ receptor functional assays and were found to act as agonists.</p>

<p>This thesis describes synthesis and reactivity studies of 2-amino-2-siloxysilenes and 2-silenolates, species that are strongly influenced by reversed Si=C bond polarization, i.e. an Si^δ-=C^δ+ polarization as compared to the natural Si^δ+=C^δ- polarization. Because of the reversed polarization, the 2-amino-2-siloxysilenes are zwitterions and the 2-silenolates are predominantly described by the resonance structure with the negative charge at Si. </p><p>Transient zwitterionic 2-amino-2-siloxysilenes are formed thermolytically from carbamylpolysilanes (<i>tris</i>(trimethylsilyl)silylamides) and trapped with 1,3-dienes in nearly quantitative yields. These silenes have structure and reactivity characteristics that differ from earlier studied Si=C bonded compounds. They are thermodynamically stable toward dimerization and react with 1,3-dienes to give exclusively [4+2] cycloadducts. Their reactions with 1,3-dienes proceed in accordance with inverse electron demand (IED) Diels-Alder reactions which is explained by the electron-rich nature of these silenes. The 2-amino-2-siloxysilenes are also less reactive toward alcohols than earlier silenes. Hence, alcohols do not react with 2-amino-2-siloxysilenes but with the silene precursor, the carbamylpolysilanes, leading to alkoxysilanes in high yields. The latter reaction represents a novel base-free synthetic protocol for protection of primary and secondary alcohols with the fluoride resistant but photolabile <i>tris</i>(trimethylsilyl)silyl group.</p><p>Another class of formally Si=C bonded compounds, metal 2-silenolates, has been formed in high yields using a novel facile method. Reaction of acyl- and carbamylpolysilanes with potassium <i>tert</i>-butoxide in tetrahydrofurane gives potassium 2-silenolates. The potassium 2-silenolates are stable at room temperature, in contrast to earlier lithium 2-silenolates that degrade rapidly at ambient temperature. The first crystallisable complex of a 2-silenolate was formed and characterized by X-ray crystallography. This 2-silenolate has a pyramidal central Si (ΣSi = 317.8°), and an Si-C single rather than Si=C double bond (r(SiC) = 1.926 Å). The potassium 2-silenolates give exclusively Si alkylated products with alkyl halides and only [4+2] cycloadducts with 1,3-dienes.</p>

<p>This thesis describes the utilization of the matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) and electrospray ionization (ESI) MS techniques for analysis of complex brain tissue samples. </p><p>Direct molecular profiling of biological samples using MALDI MS is a powerful tool for identifying phenotypic markers. MALDI MS-profiling of proteins and peptides directly on brain tissue sections was used for the first time to study experimental models of Parkinson’s disease (PD). The mass spectrometer was used to map the peptide and protein expression directly on 12 µm tissue sections in mass-to-charge (m/z) values, providing the capability of mapping specific molecules of the original sample, that is, localization, intensity and m/z ratio. Several protein and peptide expression profile differences were found in the dopamine denervated brains when compared to the corresponding controls, for example, calmodulin, cytochrome c, cytochrome c oxidase, and the neuroimmunophilin protein FKBP-12. The increased expression of FKBP-12 from the profiling experiments was supported by mRNA expression analysis and two-dimensional gel electrophoresis separation analysis. Multiple genetic deficits have linked impaired ubiquitin-conjugation pathways to various forms of familiar PD. This study showed for the first time an increased level of unconjugated ubiquitin specifically in the dorsal striatum of the dopamine depleted PD brain. The strength of the MALDI MS-profiling technique is that a minimum of sample handling and manipulation is necessary pre-analysis. This ensures preservation of the spatial localization of the biomolecules in the tissue section.</p><p>Biological liquid samples often contain high amounts of salt that is non-compatible with the ESI MS technique. A nano-flow capillary liquid chromatography (nanoLC) system coupled on-line with ESI-MS was used to study the metabolism of the peptide LVV-hemorphin-7 in the brain and blood using in vivo microdialysis. The microdialysis technique provides capabilities for very precise sampling in specific brain regions. The combination of on-line desalting and pre-concentration by nanoLC with ESI MS is a powerful tool to detect minute concentration of metabolic fragments and endogenous biomolecules.</p><p>The utilization of mass spectrometry in neuroscience applications provides a uniquely advantageous tool for the analysis of complex biochemical events that underlie the pathological symptoms expressed in different disease states. Furthermore, the MALDI-MS profiling technique shows great potential for the future with regards to proteome analysis and drug discovery.</p>

<p>Bismuth titanate Bi₄Ti₃O₁₂, is one of the bismuth based layered ferroelectric materials that is a candidate for replacing the lead based ferroelectric materials in for instance non-volatile ferroelectric random access memories (FRAM). This is due to the fact that the bismuth based ferroelectrics consists of pseudo perovskite units sandwiched in between bismuth oxide layers, which gives them a better fatigue nature.</p><p>In this thesis thin films of Bi₄Ti₃O₁₂have been deposited by chemical vapour deposition (CVD) using the metal iodides, BiI₃ and TiI₄ as precursors. Films grown on MgO(001) substrates were found to grow epitaxially. The electrical properties were determined for films grown on Pt-coated silicon and good properties such as a high dielectric constant (ε) of 200, low <i>tan</i> δ of 0.018, a remnant polarisation (<i>P</i>_r) of 5.3 μC/cm² and coercive field (E_c) as high as 150 kV/cm were obtained. Thin films in the Bi-Ti-O system were also deposited by atomic layer deposition (ALD) using metalorganic precursors.</p><p>In addition to the ternary bismuth titanates, films in the binary oxide systems <i>i.e.</i> bismuth oxides and titanium oxides were deposited. Epitaxial TiO₂ films were deposited both by CVD and ALD using TiI₄ as precursor. The rutile films deposited by ALD were found to grow epitaxially down to a temperature of at least 375 ¢ªC on α-A1₂O₃(0 1 2) substrates. The TiO₂ ALD process was also studied <i>in-situ</i> by QCM. Different bismuth oxides were deposited by halide-CVD using BiI₃ as precursor on MgO(0 0 1) and SrTiO₃(0 0 1) substrates and the results were summarised in an experimental CVD stability diagram. The Bi₂O_2.33 phase was found to grow epitaxially on both substrates.</p>

<p> This study addresses the issue of how to convert peptides into drug-like non-peptides while retaining the biological activity at peptide receptors. Angiotensin II (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe, Ang II) was used as a model peptide.</p><p> Small bioactive peptides are in most cases conformationally flexible molecules. Rigidified peptide analogues or peptidomimetic scaffolds can be introduced into the peptide, to enforce a particular backbone conformation, and thereby locate the side-chains at defined positions in space. The conformationally constrained analogues are of considerable value in determining biologically active conformation(s) of the studied peptide. The strategy applied in this thesis includes identification of non-pharmacophoric amino acid residues, rigidification, conformational analysis and incorporation of turn mimicking scaffolds in </p><p>Ang II. Several side-chain cyclized (disulfide and methylendithioether) Ang II analogues have been synthesized. The binding studies of the rigidified analogues demonstrated that the compounds designed for the AT₁-receptor had affinity for both receptor subtypes, while the compounds designed for the AT₂-receptor displayed high selectivity only for this receptor subtype. Conformational evaluation revealed that several of the cyclized Ang II analogues most probably adopt a <i>γ</i>-turn like conformation around Tyr-4 while interacting with the </p><p>Ang II receptor. Based on this hypothesis, three different <i>γ</i>-turn mimetics replacing amino acid residues 3-5 were designed, synthesized and incorporated into Ang II. One of the synthesized pseudopeptides, incorporating an azepine-containing <i>γ</i>-turn mimetic, exerted high binding affinity and agonistic activity. These results strongly support the theory that Ang II adopts a <i>γ</i>-turn like conformation when activating the AT₁ receptor. The other Ang II analogues, incorporating bicyclic and aromatic <i>γ</i>-turn mimetics, did not display any binding to the AT₁ receptor.</p>

<p>The palladium-catalysed Heck-reaction has been utilised in organic synthesis, where the introduction of aryl groups at the internal, β<i>-</i>carbon of different allylic substrates has been achieved with high regioselectivity.</p><p>The β<i>-</i>stabilising effect of silicon enhances the regiocontrol in the internal arylation of allyltrimethylsilane, while a coordination between palladium and nitrogen induces very high regioselectivities in the arylation of <i>N,N-</i>dialkylallylamines and the Boc-protected allylamine, producing β-arylated arylethylamines, which are of interest for applications in medicinal chemistry. Phthalimido-protected allylamines are arylated with poor to moderate regioselectivity.</p><p>Single-mode microwave heating can reduce the reaction times of Heck-, Stille- and radical mediated reactions drastically from approximately 20 hours to a few minutes with, in the majority of cases, retained, high regioselectivity.</p><p>The use of heavily fluorinated tin reagents, which proved to be unreactive under thermal heating, is shown to be applicable with microwave-heating and the high fluorous content of the products is utilised with the aim of improving and simplifying the work-up procedure.</p>

<p>This thesis describes mechanistic studies, rational ligand design, and synthesis of asymmetric transition metal catalysts. The topics addressed concerned [Papers I-VII]:</p><p>[I] The asymmetric addition of diethyl zinc to <i>N</i>-(diphenylphosphinoyl)benzalimine catalyzed by bicyclic 2-azanorbornyl-3-methanols was studied. An efficient route to both diastereomers of new bicyclic 2-azanorbornyl-3-methanols with an additional chiral center was developed, in the best case 97% ee was obtained with these ligands. The experimental results were rationalized by a computational DFT-study.</p><p>[II] An aza-Diels-Alder reaction of cyclopentadiene with chiral heterocyclic imines derived from (<i>S</i>)-1-phenylethylamine and different heteroaromatic aldehydes was developed. The cycloaddition proved to be highly diastereoselective and offers a very rapid access to possible biologically active compounds and interesting precursors for chiral (<i>P,N</i>)-ligands. </p><p>[III] A convenient and high-yielding method for the preparation of (<i>R</i>)-tolterodine, utilizing a catalytic asymmetric Me-CBS reduction was developed. Highly enantio-enriched (<i>R</i>)-6-methyl-4-phenyl-3,4-dihydrochromen-2-one (94% ee) was recrystallized to yield practically enantiopure material (ee >99%) and converted to (<i>R</i>)-tolterodine in a four-step procedure. </p><p>[IV] The reaction mechanism of the iridium-phosphanooxazoline-catalyzed hydrogenation of unfunctionalized olefins has been studied by means of DFT-calculations (B3LYP) and kinetic experiments. The calculations suggest that the reaction involves an unexpected IrIII-IrV catalytic cycle facilitated by coordination of a second equivalent of dihydrogen. On the basis of the proposed catalytic cycle, calculations were performed on a full system with 88 atoms. These calculations were also used to explain the enantioselectivity displayed by the catalyst.</p><p>[V and VI] A new class of chiral (<i>P,N</i>)-ligands for the Ir-catalyzed asymmetric hydrogenation of aryl alkenes was developed. These new ligands proved to be highly efficient and tolerate a broad range of substrates. The enantiomeric excesses are, so far, the best reported and can be rationalized using the proposed selectivity model.</p><p>[VII] The complex formed between the quincorine-amine, containing both a primary and a quinuclidine amino function, and [Cp*RuCl]₄ catalyzes the hydrogenation of aromatic and aliphatic ketones in up to 90% ee approx. 24-times faster than previously reported Ru-diamine complexes. The reason for the lower but opposite stereoselectivity seen with the quincoridine-amine, as compared to the quincorine-amine, was rationalized by a kinetic and computational study of the mechanism. The theoretical calculations also revealed a significantly lower activation barrier for the alcohol mediated split of dihydrogen, as compared to the non-alchol mediated process. A finding of importance also for the diphosphine/diamine mediated enantioselective hydrogenation of ketones.</p>