Development of a new methodology for the synthesis of haloconduritols and gold catalyzed alkyne cyclizations of n-propargyl substituted indole derivatives /

Kaya, Serdal
Because of the biological properties and being useful intermediates, haloconduritols became synthetically important molecules. During the last decades, some methodologies have been developed for the construction of haloconduritol derivatives. Our synthetic strategy was based on stereospecific hydroxylation of one of the double bonds of commercially available cyclopentadiene. After protection of the hydroxyl groups as a ketal, the remaining double bond was submitted to the dibromocarbene addition reaction. Silver-promoted ring opening reaction of the tricyclic compound resulted in the formation of a six-membered ring with a double bond having a bromine atom. Removal of the ketal group under the acidic conditions gave bromocyclo-hexenetriols In the second part of the thesis, the main interest was concentrated on the synthesis of nitrogen containing heterocycles. For this purpose, starting from N-propargyl-2-indole carbaldehyde or N-propargyl-2-indole carboxylic acid, the synthesis of the nitrogen containing heterocycles, such as pyrazino-indole-N-oxide, pyrazolo-pyrazino-indole, diazepino-indole and pyrazolo-diazepino-indole derivatives, were planned. Ring cyclization was carried out in the presence of Au(III) salt and NaH. Cyclization of oxime derivative derived from N-propargyl-indole aldehyde gave the corresponding pyrazine oxides. In case of substituted alkynes, an oxime-oxime rearrangement was observed which was unprecedented in the literature. Gold-catalyzed cyclization of N-propargyl indoles having a pyrazole ring attached to the C-2 carbon atom underwent 6-exo-dig and 7-endo-dig cyclization reactions depending on the nature of the substituents attached to the terminal alkyne group. However, NaH-supported cyclization resulted in the formation of six-membered rings.


Synthesis of indole-fused new heterocycles via alkyne cyclizations
Şeybek, Ali Fatih; Balcı, Metin; Department of Chemistry (2015)
It is known that many natural and synthetic structures including indole ring have important biological activities. In this thesis, synthesis of pyridine, pyrazine and pyrazinone rings condensed to indole was carried out via alkyne cyclization reactions. In the first part, oxindole was synthesized by reduction of isatin. Then, aldehyde group and chlorine atom was introduced to the C-3 and C-2 positions via Vilsmeier-Haack reaction. After that, Sonagashira coupling reaction led to functionalize C-3 position w...
Development of enhanced ultrafiltration methodologies for the resolution of racemic benzoin
Olceroglu, Ayse Hande; Çalık, Pınar; Yılmaz, Levent (Elsevier BV, 2008-09-15)
In the scope of achieving the separation of chiral molecules, enzyme enhanced ultrafiltration (EEUF), a new method based on polymer enhanced ultrafiltration (PEUF), utilizing apoenzymes as ligands, was developed. Benzoin was chosen as the model chiral molecule. Bovine serum albumin (BSA) and apo form of benzaldehyde lyase (BAL) (E.C. were used as chiral ligands in PEUF and EEUF experiments, respectively. In order to bind to the target enantiomer well, the addition of ligand to the benzoin solution...
Development of new synthetic strategies for aminocyclitols
Demir (Davulcu), Emine; Balcı, Metin; Department of Chemistry (2003)
Cyclitols are of great importance due to their biological activities playing a crucial role in living organisms as well as their synthetic usefulness in the synthesis of other natural compounds or pharmaceuticals. In this study, new synthetic strategies leading to the aminocyclitols were investigated. The synthesis of aminoconduritol and aminoinositol derivatives (173 and 174) were achieved starting from easily available compound, 7-oxa-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride (166) obtained from...
Development of new synthetic methodologies for isoquinolone and isoindolinone derivatives
Müjde, Berk; Balcı, Metin; Department of Chemistry (2010)
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...
One-pot synthesis and characterization of colloidally robust rhodium(0) nanoparticles catalyst: exceptional activity in the dehydrogenation of ammonia borane for chemical hydrogen storage
Ayvalı, Tuğçe; Özkar, Saim; Department of Chemistry (2011)
The production of transition metal(0) nanoparticles with controllable size and size distribution are of great importance in catalysis since their catalytic activity decreases as nanoparticles aggregate into clumps and ultimately to the bulk metal. Reducing the particle size of heterogeneous catalyst provides a significant rise in its activity as the fraction of surface atoms increases with decreasing particle size. Therefore, transition metal(0) nanoparticles need to be stabilized to certain extend in their...
Citation Formats
S. Kaya, “Development of a new methodology for the synthesis of haloconduritols and gold catalyzed alkyne cyclizations of n-propargyl substituted indole derivatives /,” Ph.D. - Doctoral Program, Middle East Technical University, 2015.