This thesis describes the design, synthesis and characterization of organo-phosphatemonomolecular layers, so called self-assembled monolayers, using the strategy of linking organosulfur substances to a gold surface. Moreover there is also a paper included, which describes the development of synthetic pathways to various phospholipids, for which I have developed an interest in later projects.

For the first study of the properties of phosphates, and also for concomitant application of developed systems, analogues of the amino acids serine, threonine and tyrosine, phosphorylated and non-phosphorylated, were synthesized. 16-Mercaptohexadecanamide based analogues were characterized as monolayers and large polar and charge effects were observed, introduced by the phosphate. Problems were, however, encountered as a post modification of phosphates was applied and a disordering of the monolayers observed. Moreover there were no expected effects observable upon interaction with Ca²⁺ and Mg²⁺.

Based on the conclusions from the first study 3-mercaptopropionamide based analogues were used instead. Characterization of the analogues including counter ion exchange (H⁺,Na⁺, Ca²⁺ and Mg²⁺) revealed large electronic and possible structural differences depending on the counter ion.

Again the charge and polar effects induced by the phosphate were investigated, and the study was also extended to interaction of the phosphate with Ca²⁺ and Mg²⁺. Strong effects were observed, which were also dependent on the ion concentration within a significant range. The polarity and charge properties of the phosphate layer were thus found to be variable.

In the fourth study an additional Ca²⁺ and Mg²⁺ sensitive system was applied in combination with the phosphate surface. Phosphate surface/phospholipid vesicle interactions were studied under different conditions of Mg²⁺ (Ca²⁺) treatment. For comparison, the corresponding hydroxyl and sulphate surfaces were included and also the most well characterized surface concerning phospholipid vesicle interaction, SiO₂. Most importantly, supported phospholipid bilayer (SPB) formation was found to be inducible on both the phosphate and sulphate surfaces, however at defined conditions of Mg²⁺ (Ca²⁺) treatment and concentration. The conclusion is that the processes of phospholipid vesicle adsorption and SPB formation are largely dependent on vesicle/surface interaction and vesicle stability.

The last paper included in this thesis is a synthetic method development aimed at easy preparations of various phospholipid derivatives. In the future these methods could be used for synthesis of functionalized lipids and aid in the development of models mimicking biological systems such as artificial cell membranes.

This thesis describes the synthesis of a series of myo-inositol-containing oligosaccharides, and the exploration of using the chiral epoxide (S)-glycidol in short synthetic routes to glycoglycerolipids and glycerophospholipids.

In chapter 2, synthesis of the core heptasaccharyl myo-inositol Galp(α1-6)Galp(α1 -3)Galf(β1-3)[Glcp(α1-P0₄-6)Manp](α1-3)Manp(α1-4)GlcNp(α1-6)Ins-1-P0₄, found in the lipophosphoglycans of Leishmania parasites, is described. This part primarily deals with problematic deprotections of complex carbohydrates. In this context, the stability of anomeric phosphodiesters towards hydrolytic cleavage was studied.

In chapter 3, a short synthetic route to protected derivatives of 2-amino-2-deoxy-α-D-glucopyranosyl-(1➔6)-D-myo-inositol is presented. These derivatives are key building blocks in the synthesis of inositolphosphoglycans (IPGs) and glycosylphosphatidylinositol (GPI)-anchors.The building blocks were subsequently used for synthesis of IPGs, analogous to putative second messengers to insulin, to provide a small targeted library of compounds. A thiol-terminated spacer was introduced by radical elongation of allyl ethers with benzyl mercaptan, for immobilization of the IPGs by coupling to maleimide-functionalized solid phases, proteins or various probes. The aim of this project was to provide IPGs for evaluation of biological activity, isolation of antibodies, and identification of receptors for the second messengers to insulin.

Chapters 4 and 5 describe syntheses of galactoglycerolipids and glycerophospholipids via glycosylation or phosphorylation of the three-carbon synthon (S)-glycidol. Using this approach, three galactoglycerolipids and the corresponding glycerolipid were synthesized and an oxidation-reduction procedure for tritiation of the glycerolipid was developed. Two of the galactolipids have recently been identified in the human colon carcinoma cell line HT29. The synthetic method developed for the galactolipids was subsequently used to explore a new efficient route to enantiomerically pure glycerophospholipids. Lysophosphatidic acids and phosphatidic acids were obtained in good overall yields from (S)-glycidol, in only three and four steps, respectively. Moreover, a strategy for synthesis of lysophosphatidylcholines, in only three steps, is also described.