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Title: Azetidinones: Synthesis, and Kinetics and Mechanism of their Gas-phase Pyrolysis
Other Titles: الأزيتيدنونات: تحضيرها و دراسة كيناتكية و ميكانيكية تفاعلات تكسرها
Authors: Nouf Salem Al-Hamdan 
Supervisor: Prof. Osman M. E. El-Dusouqui
Keywords: Azetidinones Synthesis Kinetics Gas-phase Pyrolysis antibacterial agents Chemistry structure antibiotic molecules flash vacuum pyrolysis (FVP) keto analogues
Issue Date: 2015
Publisher:  Kuwait university - college of graduate studies
Abstract: In the present study, seven 2-azetidinone derivatives (2a-g), commonly known as β-lactams, were synthesized by standard Staudinger ketene-imine [2+2]cycloaddition. The core ring structure of β-lactams is found in a large number of antibiotic molecules including antibacterial agents. In addition, seven β-thiolactams (4a-g), were prepared by functional group interconversion of the carbonyl group into thione (C=S) function using Lawesson's reagent. All the β-thiolactams and two of the keto analogues were obtained for the first time in this study. Gas phase pyrolytic reactions of the azetidinones and their thione analogues were then conducted by using two methodologies: sealed tube (static) pyrolysis (STP), and flash vacuum pyrolysis (FVP). The products of pyrolysis were identified and characterized by1H/13C NMR, FT-IR, HRMS, and elemental analysis techniques. All new compounds were fully analyzed. The stereochemical aspects of the substrates and the pyrolysates were elaborated. Mechanisms are proposed to account for synthetic routes, and pathways to the products of pyrolysis. The kinetics of the pyrolytic reactions of (2a-g) and (4a-g) were also investigated. The results are used: (i) to correlate molecular reactivity with structure, mainly the relative influence of ketone and thione moieties on the ring amide linkage, and the effect of the groups substituted at (N) and at the ring carbon atoms; (ii) and to provide support for the proposed reaction mechanism. Besides, the study includes antibiotic screening of all the β-lactams and β-thiolactams, and a preliminary study on microwave-assisted pyrolysis strategies.
Appears in Programs:0420 Chemistry (M.Sc.)

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