Ecofriendly synthetic methodologies in organic chemistry
Author(s)
Ginnasi, Maria Cristina
Date Issued
February 28, 2011
Type
Doctoral Thesis
Abstract
The aim of this PhD has been the optimization of synthetic processes using green chemistry, a chemistry
based on the respect of the human health and environment, widely applied in our research group since many
years. In particular, ecofriendly chemicals and renewable materials have been used as starting materials in
order to produce biologically active compounds and fine chemicals.
On the basis of these principles, four main topics have been developed. The first has been the synthesis of
new complexes between methyltrioxorhenium (MTO) and bis(fluorous-ponytailed) 2,2’-bipyridines
characterized by different values of fluorophilicity. These catalysts have been characterized and utilized in
the epoxidation of olefins with hydrogen peroxide (H2O2), an ecofriendly oxidant.
A second topic has been the utilization of dimethyl carbonate (DMC), an ecofriendly chemical, in several
applications. Firstly, it has been used in the methylation reaction of a class of natural organic compounds
(flavonoids) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This system has been efficient
and alternative to the utilization of hazardous and carcinogen chemicals. Secondly, it has been utilized to
protect amino and acid group of a large panel of α-amino acids. Also the removal of the protecting group has
been optimized.
A rare amino acid (3,4-dihydroxyphenylalanine, DOPA) has been prepared by oxidation of tyrosine using
2-iodoxybenzoic acid (IBX), a selective and efficient oxidant alternative to toxic oxidizing heavy metals. On
the basis of these experimental results, the procedure has been extended to a panel of selected Tyr-containing
dipeptides and tripeptides. In order to enhance the ecofriendly aspects of the oxidations, the reactions have
been performed under heterogeneous conditions using polymer supported IBX. The oxidant has been
recovered and reused for more runs without loss of efficiency and selectivity.
Finally, new applications of glycerol carbonate have been optimized. Glicerol carbonate has been
prepared from glycerol, a by-product of the production of biofuels, and DMC. High added-value products
showing potential antioxidant activity were prepared from tosylated glycerol carbonate and a series of
phenolic compounds.
Additional information
Dottorato di ricerca in Scienze ambientali
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