Poly(ADP-ribose) polymerase (PARP) represents a large family of enzymes that are activated upon DNA breakage, which are then involved in a cascade of reactions that eventually lead to cell death. PARPs, known to cause a variety of damage to the human body, are targets of many researches’ investigating potential inhibition mechanisms. To this point, plenty of PARP inhibitors have been synthesized and tested for potency against many diseases. Some have great potency against particular diseases, while others are already being used as drugs. The current research suggests a potential synthesis of novel PARP inhibitors, to be accomplished through Diels-Alder chemistry. The proposed compounds consist of an isoindolinone core bearing different functional groups. Three different strategies are described for the synthesis of the novel PARP inhibitors and all protocols involve sulfur dioxide extrusion chemistry to create a diene, the desired transient starting material. The diene is envisioned further to be reacted with a variety of dienophiles to give possibly potential PARP inhibitors. / NSERC

ABSTRACT SYNTHESIS OF FUROPYRROLONE AND FUROPYRIDAZINONE DERIVATIVES: A NEW CLASS OF COMPOUNDS Karahan, Emrah M.Sc., Department of Chemistry Supervisor: Prof. Dr. Metin Balci February 2011, 102 pages Furopyrrolone has a bicyclic structure consisting of furan and a pyrrolone ring. It is isoelectronic with isoindolinone which is also a heterocyclic organic compound. It has a bicyclic structure, consisting of a benzene ring fused to a five-membered nitrogen containing pyrrolone ring. Pyrrolones, pyrrolidines, pyrrolidinones, pyridazines and pyridazinones are precursors to many pharmaceuticals. In this project we developed new synthetic procedures leading to the synthesis of furopyrrolone derivatives. To do this, the starting compound, methyl 2-(2-methoxy-2-oxoethyl)-3-furoate, was converted to isocyanate, regioselectively. This isocyanate was converted into the corresponding urethane and/or urea derivatives by treatment with alcohol and amine, respectively. It is known that acyl chlorides are more reactive than esters and carboxylic acids. Therefore, ester was converted to more reactive compound acyl azide that was used for intramolecular cyclization to get desired furopyrrolone skeletons. In the second part, methyl 2-formylfuran-3-carboxylate was treated with hydrazine and hydrazine salts. Then, intramolecular molecular cyclization caused the formation of desired heterocycles via acyl chloride intermediate.

ABSTRACT DEVELOPMENT OF NEW SYNTHETIC METHODOLOGIES FOR ISOQUINOLONE AND ISOINDOLINONE DERIVATIVES M&uuml / jde, Berk M.Sc., Department of Chemistry Supervisor: Prof. Dr. Metin Balci July 2010, 146 pages Due to the wide range of physiological activities, heterocycles containing nitrogen and oxygen have always attracted the interest of chemists. The objective of this research is to develop new synthetic routes to the synthesis of isoquinolone and isoindolinone derivatives starting from 2-(2-carboxyethyl)benzoic acid and homophthalic acid, respectively. The half ester produced from 2-(2-carboxyethyl)benzoic acid was an important key compound for the synthesis of new isoquinolone derivatives which are expected to be biologically active. The corresponding acyl azides and isocyanates were generatedwhich might be used as a precursors to construct a variety of isoquinolone derivatives. Transformation of acyl azides into urea derivatives followed by ring-closure under the basic conditions provided isoquinolones. Bromo- and methoxyhomophthalic acid derivatives were synthesized to increase in variety of isoindolinone derivative. Then corresponding anhydrides were generated to further reactions for synthesis of isoindolinone derivatives. Surprisingly, tetrazolinone derivatives are also formed by 1,3 dipolar cycloaddition. Whole products were conscientiously purified and characterized. In addition, the similar methodology which was used for the synthesis of isoquinolone derivatives, was applied to 2-(carboxymethyl)furan-3-carboxylic acid to synthesize new nitrogen and oxygen containing heterocycles.

This thesis is divided into six parts, all centered around the development of dynamic (i.e., reversibly interacting) systems of molecules and their applications in dynamic combinatorial chemistry (DCC) and organic synthesis. Part one offers a general introduction, as well as a more detailed description of DCC, being the central concept of this thesis. Part two explores the potential of the nitroaldol reaction as a tool for constructing dynamic systems, employing benzaldehyde derivatives and nitroalkanes. This reaction is then applied in part three where a dynamic nitroaldol system is resolved by lipase-catalyzed transacylation, selecting two out of 16 components. In part four, reaction and crystallization driven DCC protocols are developed and demonstrated. The discovery of unexpected crystalline properties of certain pyridine β-nitroalcohols is used to resolve a dynamic system and further expanded into asynthetic procedure. Furthermore, a previously unexplored tandem nitroaldol-iminolactone rearrangement reaction between 2-cyanobenzaldehyde and primarynitroalkanes is used for the resolution of dynamic systems. It is also coupled with diastereoselective crystallization to demonstrate the possibility to combine several selection processes. The mechanism of this reaction is investigated and a synthetic protocol is developed for asymmetric synthesis of 3-substituted isoindolinones. Part five continues the exploration of tandem reactions by combining dynamic hemithioacetal or cyanohydrin formation with intramolecular cyclization to synthesize a wide range of 3-functionalized phthalides. Finally, part six deals with the construction of a laboratory experiment to facilitate the introduction of DCC in undergraduate chemistry education. The experiment is based on previous work in our group and features an acetylcholinesterase-catalyzed resolution of a dynamic transthioacylation system. / QC 20100628