Synthesis of New C2-symmetric Chiral Ligands Which Contain Piperazine And Their Application of Asymmetric Henry Reaction
Project no. 525 · Status: Kapanmış · 2018
Summary
The Henry reaction (nitroaldol) is one of the most useful methods for the formation of C-C bonds in organic synthesis. The resulting product of this reaction is optically active ß-nitroalcohol in which hydroxyl and nitro groups have a vicinal relationship. This allows the preparation of valuable chemical entities including pharmaceuticals. Therefore, nowadays the development of new catalysts which are enable to highly enantiselective synthesis are great attention. In this project, chiral ligands which contain piperazine ligands were synthesized. First of all, a series of reaction were carried out starting (S)-2-amino-3-phenyl-1-propanol. OH group was replaced to Cl group in amino alcohol then was protected amino alcohol with Boc group. After reaction with 1-methylpiperazine, an amine derivative was obtained by deprotecting Boc group. Chiral Schiff bases were synthesized as a result of reaction this amine with salicylaldehyde and 2,4-dihydroxybenzaldehyde. After the products obtained at each stage were purified by appropriate methods, their structures were determined by spectroscopic and analytical methods. Secondly, the catalytic effects of the synthesized chiral Schiff bases in the presence of Cu2+ salts were investigated in the asymmetric Henry reaction. The enantiomeric excess (ef) values of the products were determined by HPLC. Keywords: Piperazine, Schiff base, Asymmetric Henry reaction