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Title Ενζυμική υδρόλυση ακυλαλών
Alternative Title Enzymatic hydrolysis of acylals
Author Αγγελής, Ιωάννης Στ
Thesis advisor Σμόνου, Ιουλία
Abstract The enzymatic hydrolysis of acylals and structurally related compounds has been studied in this Ph.D thesis. Acylals - protected aldehydes - have been proven to be an excellent new class of substrates for hydrolytic enzymes. A new method for the optical resolution of aldehydes has been developed thrugh the enzymatic hydrolysis of acylals. The enantiomeric excess obtained was in several cases over 95% e.e. This study was focused mainly on - The selection of enzymes capable to hydrolyze acylals to yield aldehydes with high enantioselectivity. The best results were obtained with Candida Rugosa Lipase (CRL). - The study of the factors which govern the stereoselectivity in the hydrolysis of acylals with CRL. The stereoselectivity of CRL to depends on the length of the acyl chains of acylals and the highest was observed with acylals of acetic anhydride. - The stereoselectivity in the hydrolysis of acylals with CRL is governed by the distant β-asymmetric center and not from pro-R, pro-S selectivity for the diastereotopic acyl groups. The products of the enzymatic reaction are aldehydes with R absolute configuration. - The presence of organic cosolvents in the reaction medium does not influence the stereoselectivity of the enzymatic reaction. - In the case of aryl- substituted acylals, the stereoselectivity of the enzymatic hydrolysis is influenced by the presence of alkyl- substituents on the aromatic ring. In the case of 2-aryl-propionacylals the stereoselectivity depends on the size and the position of the alkyl substituent on the aromatic ring.
Language Greek
Issue date 1998-07-01
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
  Type of Work--Doctoral theses
Permanent Link https://elocus.lib.uoc.gr//dlib/f/0/3/metadata-dlib-1998DIS0804.tkl Bookmark and Share
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