An account of organic chemistry research in Botswana

Abstract

The present paper gives an account of research in different areas of organic chemistry carried out at the University of Botswana. It describes the results of phytochemical investigations carried out on eight species of genus Erythrina. Several new alkaloids and non-alkaloids have been isolated and screened for different biological activities. Physicochemical properties and fatty acids composition of some oils are described as well. The paper also documents some synthetic approaches to natural products and their derivatives, β-amino acids, β-lactams, 1,3,4-oxadiazolines, spirooxindole-2-azetidinones and spirooxindole-oxiranes. The synthetic approaches include the elaboration of the Diels-Alder product of furan and some dienophiles to give the natural product oryzoxymycin and cyclohexyl-β-amino acids. In addition, studies on synthesis of chromane/chromene ring systems are summarized. The application of α-diazoketones and ethyl diazoacetate in the synthesis of βlactams, 1,3,4-oxadiazoline, spirooxindole-2-azetidinones, and spirooxindole-oxiranes is described. Some oxidative, reductive, and other reactions of β-lactams are discussed. In the green chemistry domain, results on grinding-induced synthesis of benzoxazines and microwave-assisted synthesis of benzil diimines are presented. Bis(acetylacetonato)copper(II)-catalyzed oxidation reactions of hydrazones and the sec-alcoholic group of benzoins to azines and 1,2-diketones, respectively, are described. In addition, the PdCl2-catalyzed transfer hydrogenation of alkenes to alkanes in the presence Zn powder is accounted.