Enzyme catalyzed cross acyloin reactions via C-C bond cleavage

Bilir, Gökçil
Enzyme-catalysis is an effective tool for asymmetric synthesis under environmentally-friendly conditions, with an increasing number of examples at industrial scale. The optically active enzyme scaffold creates a microenvironment responsible for the chirality generation. Benzaldehyde lyase (BAL; E.C., is the first and well-known thiamine diphosphate (ThDP)- and Mg2+-dependent enzyme from Pseudomonas fluorescens Biovar I with its capability to catalyze various C-C bond cleavage and C-C bond formation. In this work, this enzyme was used for the synthesis of unsymmetrical acyloin products of a functionalized acetaldehyde (benzyloxyacetaldehyde) with (rac)-Benzoin derivatives to selectively obtain optically active functionalized acyloin product with promising biological activity and (S)-benzoin derivative which remains unreacted in the reaction medium. As a result of this trans-condensation reaction –with benzyloxyacetaldehyde as the acceptor and different derivatives of aromatic benzaldehydes as the donor most of the cases- stereoselective (R)-HPP derivatives were obtained enantioselectively. In the second part of this work, the synthesis of thiamine-amino acid conjugates and asymmetric thiazolium salts have been tried to be used as organocatalysis in benzoin condensation reactions.


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Ölçeroğlu, Ayşe Hande; Yılmaz, Levent; Department of Chemical Engineering (2006)
In this study, a methodology for separation of chiral molecules, by using enhanced ultrafiltration system was developed. Benzoin was the model chiral molecule studied. In the scope of developing this methodology, some parameters were investigated in the preliminary ultrafiltration experiments in order to set the operation conditions for enhanced ultrafiltration experiments. Due to the slight solubility of benzoin in pure water, 15% (v/v) Polyethylene glycol (PEG 400) and 30 % (v/v) Dimethyl sulfoxide (DMSO)...
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Seyidoğlu, Tijen; Yılmazer, Ülkü; Department of Chemical Engineering (2010)
The potential use of Reşadiye/Tokat bentonite as a reinforcement in polypropylene (PP) and linear low density polyethylene (LLDPE) polymer matrix nanocomposites filler was investigated. At first, organoclays (OC) were prepared by cation exchange reaction (CER) between the raw bentonite (RB) and three quaternary ammonium salts with long alkyl tails (QA): hexadecyl trimethyl ammonium bromide [HMA] [Br], tetrabutyl ammonium tetrafluoroborate [TBA] [BF4], tetrakisdecyl ammonium bromide [TKA] [Br] and one quater...
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Baskin, Dilges; Cetinkaya, Yasin; Balcı, Metin (2018-07-26)
A regioselective approach was developed for the synthesis of dipyrrolo-diazepine derivatives. The synthetic route to dipyrrolo-diazepines first involves the synthesis of dipyrromethanes, followed by reaction of propargyl bromide in the presence of NaH to attach one alkyne functionality to the pyrrole nitrogen atom. Intramolecular heterocyclization with NaH in DMF between the alkyne functionality and pyrrole nitrogen atom gave the desired structures in good yields.
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Baskın, Dılgeş; Balcı, Metin; Department of Chemistry (2016)
A new methodology was developed for the synthesis of dipyrromethane and diazepine derivatives. In the first section of this thesis, synthesis of various dipyrromethanes from aromatic aldehydes was carried out. Dipyrromethanes were used as starting materials for the next step. In the second part of the study, introduction of a propargyl group to nitrogen atom to one of pyrrole units of dipyrromethane gave the expected mono-propargylated compounds which were the key compounds for further cyclization reactions...
Metal polymer composite nanofiber production by electrospinning
Karakoç, Nihan; Gündüz, Güngör; Department of Chemical Engineering (2009)
This study aims synthesis of metal/polymer one dimensional nanostructures by micelle formation, reduction, and electrospinning route, and to analyze the morphological characteristics of composite nanofibers. The study was carried out in three main steps. First, the reverse micelle structures were established between the anionic surfactant and the metal ion. The surfactant acts as an agent to bind metal ions together so that the arrangements of metal ions can be controlled in the solution. As the surfactant ...
Citation Formats
G. Bilir, “Enzyme catalyzed cross acyloin reactions via C-C bond cleavage,” M.S. - Master of Science, Middle East Technical University, 2015.