This thesis focuses on the development of methods for the activation of the hydroxyl group in non-derivatized alcohols in substitution reactions. The thesis is divided into two parts, describing three different catalytic systems. The first part of the thesis (Chapter 2) describes nucleophilic allylation of amines with allylic alcohols, using a palladium catalyst to generate unsymmetrical diallylated amines. The corresponding amines were further transformed by a one-pot ring-closing metathesis and aromatization reaction to afford β-substituted pyrroles with linear and branched alkyl, benzyl, and aryl groups in overall moderate to good yields. The second part (Chapters 3 and 4) describes the direct intramolecular stereospecific nucleophilic substitution of the hydroxyl group in enantioenriched alcohols by Lewis acid and Brønsted acid/base catalysis. In Chapter 3, the direct intramolecular substitution of non-derivatized alcohols has been developed using Fe(OTf)3 as catalyst. The hydroxyl groups of aryl, allyl, and alkyl alcohols were substituted by the attack of O- and N-centered nucleophiles, to provide five- and six-membered heterocycles in up to excellent yields with high enantiospecificities. Experimental studies showed that the reaction follows first-order dependence with respect to the catalyst, the internal nucleophile, and the internal electrophile of the substrate. Competition and catalyst-substrate interaction experiments demonstrated that this transformation proceeds via an SN2-type reaction pathway. In Chapter 4, a Brønsted acid/base catalyzed intramolecular substitution of non-derivatized alcohols was developed. The direct intramolecular and stereospecific substitution of different alcohols was successfully catalyzed by phosphinic acid (H3PO2). The hydroxyl groups of aryl, allyl, propargyl, and alkyl alcohols were substituted by O-, N-, and S-centered nucleophiles to generate five- and six-membered heterocycles in good to excellent yields with high enantiospecificities. Mechanistic studies (both experiments and density functional theory calculations) have been performed on the reaction forming five-membered heterocyclic compounds. Experimental studies showed that phosphinic acid does not promote SN1 reactivity. Rate-order determination indicated that the reaction follows first-order dependence with respect to the catalyst, the internal nucleophile, and the internal electrophile. DFT calculations corroborated with a reaction pathway in which the phosphinic acid has a dual activation mode and operates as a bifunctional Brønsted acid/Brønsted base to simultaneously activate both the nucleophile and nucleofuge, resulting in a unique bridging transition state in an SN2-type reaction mechanism. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: Manuscript.</p>

This diploma thesis deals with the stereoselective addition reaction of benzothiophenone derivatives to ketimines derived from isatin using bifunctional organocatalysis. The stereoselective addition reaction was optimized to provide the appropriate reaction conditions which were subsequently used to study the scope of the reaction. Keywords Organocatalysis, stereoselective synthesis, bifunctional organocatalysts, ketimines, sulphur heterocykles.

Peptide secondary structure provides an exceptional scaffold on which to design highly reactive and selective enzyme-like catalysts. This work describes the rational design and synthesis of a suite of helical peptide catalysts that are capable of achieving proximity-induced rate enhancement in Diels-Alder cycloadditions and indole alkylations. Microwave assisted synthesis of resin-supported polypeptides enables incorporation of non-natural amino acid residues that induce helicity (Aib) or provide functional handles on which organic catalytic residues can be attached. These small peptide catalysts exhibit binding-driven selectivity rather than relying on the inherent reactivity of substrates, which allows access to products that are not obtainable with traditional catalysts in solution. Catalyst efficiency reached up to 28,000 turn overs, which mimics natural enzymatic systems. Studies were also conducted into the stabilization of peptide secondary structure via covalent linking of nucleophilic amino acid side chains with squaric acid residues. Under mild conditions, stapling of nitrogen, sulfur and oxygen residues can readily be achieved in either organic or aqueous media. Squaric acid staples display pH selectivity for specific side chains and selective removal of diester staples (diserine staple) is demonstrated with methylamine. This new method for peptide stapling is shown to dramatically increase the proteolytic stability of eIF4E cancer inhibitor proteins, which typically are prone to quick degradation. Tyrosidine and RGD peptide analogues were synthesized and cyclized on resin in order to provide a new pathway to macrocyclization of antibacterial and integrin binding cyclic peptides.

<p>  </p> <p>Cyclar process was previously developed to convert propane and butane into aromatics using gallium-promoted ZSM-5 zeolites (Ga/ZSM-5). However, it has two major limitations. Firstly, light gases (methane and ethane) limit the yield of higher molecular weight hydrocarbons for propane conversion. Secondly, ethane is unreactive on Ga/ZSM-5 catalysts. Relative rates and selectivity for propane conversion on two components, gallium (Ga/Al2O3) and acid ZSM-5 (H-ZSM-5) were investigated, and the results suggest that light gas was produced by propane monomolecular cracking on ZSM-5 due to the imbalance of alkane dehydrogenation and olefin conversion rates on two catalytic functions. A PtZn alloy catalyst, which has >99% propene selectivity and 30 times higher rate than Ga, was used for the dehydrogenation function. The bifunctional PtZn/SiO2+ZSM-5 catalyst has high yields of aromatics with low methane selectivity (<5%) at ~70% propane conversion. The results suggest methane can be minimized by utilizing the PtZn alloy and lowering the monomolecular cracking rate by ZSM-5. In addition, PtZn alloy increases aromatics selectivity. Aromatics formation pathway was investigated by studying the rate and selectivity of a model intermediate (cyclohexene) on ZSM-5, PtZn/SiO2 and Ga/Al2O3. Benzene is formed at similar rates on Ga/Al2O3 and ZSM-5 but cracking of cyclohexene on the latter is two orders of magnitude higher than the benzene formation rate, indicating cracking of cyclic hydrocarbons leads to low aromatization rate on Ga/ZSM-5. The benzene formation rate on the PtZn/SiO2 is 200 times higher than that on ZSM-5, suggesting aromatics are formed by the metal pathway on PtZn/SiO2+ZSM-5. </p> <p>Unlike Ga/ZSM-5 catalysts, PtZn/SiO2+ZSM-5 catalysts also convert propane to aromatics at low temperature (350 ℃). The temperature effect on propane dehydroaromatization pathways on the PtZn/SiO2+ZSM-5 bifunctional catalysts was investigated to develop strategies for propane conversion to valuable liquid hydrocarbons. At high temperature (550 ℃), high dehydrogenation rates and lower monomolecular cracking rates are required to minimize methane formation, leading to primarily propene and BTX (benzene, toluene, and xylenes). By recycling propene in the propane conversion range of 30-45%, >80% BTX yields is likely achievable at full recycle. At mid temperature (400-450 ℃), the product has high selectivity to gasoline-blending hydrocarbons (butanes, C5+ hydrocarbons, toluene, and xylenes) at 15-25% propane conversions because dehydrogenation rates are moderately high, and oligomerization is more favored than cracking. At low temperature (350℃), ~25% propane conversion is achieved and has high selectivity (~60%) to butanes, but the propane conversion rates are likely too low to be practical. While methane formation by monomolecular cracking limits liquid yields at high reaction temperature, at mid and low temperatures, hydrogen co-produced at high propane conversions saturates light olefins to make undesired ethane, which becomes major yield-loss reaction on the PtZn/SiO2+ZSM-5. </p> <p>Finally, PtZn/SiO2+ZSM-5 catalysts can convert ethane to C3+ and aromatics but the methane selectivity increases rapidly at high ethane conversion. The roles of two catalytic function (Pt-Zn alloy and ZSM-5) in the dehydroaromatization pathways of ethane and propane will be further studied and their product distribution will be compared to have better understandings on the differences in the dominant yield-loss reaction and dehydroaromatization pathways. </p>

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21121号 / 工博第4485号 / 新制||工||1697(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 阿部 竜, 教授 作花 哲夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第21178号 / 人博第850号 / 新制||人||203(附属図書館) / 29||人博||850(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 吉田 寿雄, 教授 内本 喜晴, 教授 田部 勢津久 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

The following chapters deal with the chemistry, catalytic poisoning, newer catalyst technologies, and possible future solutions to increase the efficiency of creating high-value products by thermochemically converting gasified biomass (producer gas). Chapter 1 puts emphasis on multifunctional catalysts containing transition metals that are used for renewable fuel production. High-value products such as gasoline-range hydrocarbons, dimethyl ether (DME), aldehydes, isobutane, isobutene and other olefins can be produced with gasified biomass due to the gas containing syngas (H2 + CO). The chemistry and production of these chemicals is discussed in the review. Chapter 2 describes the reactor design of a bench scale system and results after using a Mo/HZSM- 5 catalyst for aromatic hydrocarbon creation. This chapter also discusses issues that came with trying to control the temperature without any reactor intercooling. Chapter 3 shows the feasibility of using a particular multifunctional catalyst with a lab scale system and also shows the importance of certain process variables including temperature, space velocity, gas ratios, and pressure. The subject of the importance of the cleanliness of the producer gas is also discussed so that maximum high-value product yield can be achieved with the greatest efficiency. Chapter 4 discusses the implementation of a bench scale and pilot scale reactor design (both with intercooling) and the results of scale-up when using the catalyst mentioned in Chapter 3. Chapter 5 involves the modelling of an industrialized system with Aspen Plus. The economics of industrial plants to produce hydrocarbons from coal or wood feedstocks at scales of 5, 50 and 5000 tons per day were modeled using CAPCOST.

A recent development for selective ammonia oxidation into nitrogen and water vapor (NH3-SCO) over noble metal-based catalysts is covered in the mini-review. As ammonia (NH3) can harm human health and the environment, it led to stringent regulations by environmental agencies around the world. With the enforcement of the Euro VI emission standards, in which a limitation for NH3 emissions is proposed, NH3 emissions are becoming more and more of a concern. Noble metal-based catalysts (i.e., in the metallic form, noble metals supported on metal oxides or ion-exchanged zeolites, etc.) were rapidly found to possess high catalytic activity for NH3 oxidation at low temperatures. Thus, a comprehensive discussion of property-activity correlations of the noble-based catalysts, including Pt-, Pd-, Ag- and Au-, Ru-based catalysts is given. Furthermore, due to the relatively narrow operating temperature window of full NH3 conversion, high selectivity to N2O and NOx as well as high costs of noble metal-based catalysts, recent developments are aimed at combining the advantages of noble metals and transition metals. Thus, also a brief overview is provided about the design of the bifunctional catalysts (i.e., as dual-layer catalysts, mixed form (mechanical mixture), hybrid catalysts having dual-layer and mixed catalysts, core-shell structure, etc.). Finally, the general conclusions together with a discussion of promising research directions are provided.

The increasing knowledge of molecular drivers of tumorigenesis has fueled targeted cancer therapies based on specific inhibitors. Beyond “classic” oncogene inhibitors, epigenetic therapy is an emerging field. Epigenetic alterations can occur at any time during cancer progression, altering the structure of the chromatin, the accessibility for transcription factors and thus the transcription of genes. They rely on post-translational histone modifications, particularly the acetylation of histone lysine residues, and are determined by the inverse action of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Importantly, HDACs are often aberrantly overexpressed, predominantly leading to the transcriptional repression of tumor suppressor genes. Thus, histone deacetylase inhibitors (HDACis) are powerful drugs, with some already approved for certain hematological cancers. Albeit HDACis show activity in solid tumors as well, further refinement and the development of novel drugs are needed. This review describes the capability of HDACis to influence various pathways and, based on this knowledge, gives a comprehensive overview of various preclinical and clinical studies on solid tumors. A particular focus is placed on strategies for achieving higher efficacy by combination therapies, including phosphoinositide 3-kinase (PI3K)-EGFR inhibitors and hormone- or immunotherapy. This also includes new bifunctional inhibitors as well as novel approaches for HDAC degradation via PROteolysis-TArgeting Chimeras (PROTACs).

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