Organic Synthesis
Organic synthesis underpins all our research projects. All academic staff, apart from Professor Dean Brady, have PhD degrees in organic synthesis.
The School of Chemistry has considerable research infrastructure for conducting organic synthesis projects in the form of well-equipped laboratories and in-house instrumentation for all major techniques required by synthetic organic chemists, most notably four nuclear magnetic resonance spectrometers (300, 400 and 500MHz NMR). For X-ray crystallography, a Smart Apex II CCD area detector single crystal diffractometer; and for solving protein crystal structures a Bruker Proteum X8 is available.
Synthetic methodology
Aspects of research in organic chemistry in the School of Chemistry at the University of the Witwatersrand rely on the development of new synthetic methods. For example, the development of multicomponent reactions has led to the synthesis of imidazopyridines as well as their metal complexes that are active against cancer cell lines.
Left: Copper and zinc 2-(pyridin-2-yl)imidazo[1,2-a]pyridine imidazo[1,2a]pyridines complexes show activity against cancer cell lines from breast cancer leukemia (K562 and HL-60) and colorectal cancer (HT-29). Right: X-ray crystal structures of copper.
Another example of a project involving the development of new synthetic methodology is the use of ceric ammonium sulfate mediated oxidations of benzophenones possessing a phenolic substituent for the synthesis of xanthones and related products.
Synthesis of natural products
Many of the natural products that we have synthesized contain at least one aromatic ring. For example, the first synthesis of cardinalin 3, a biological active dimeric quinone, from 2-iodo-1,3-dimethoxybenzene in a bidirectional manner has been accomplished by our group.
Organic & Biomolecular Chemistry, 2007, 5, 2433-2440
Other natural products that that have been synthesized include the angucycline, tetrangulol, 5-methoxy-3,4-dehydrosemixanthomegnin and the insecticide, piscicide and pesticide, rotenone. Many of the syntheses rely on transition metal mediated methods as key steps. For example, ring the closing metathesis reaction and Suzuki-Miyaura coupling reactions are used as key steps.
European Journal of Organic Chemistry, 2017, 1479-1488; European Journal of Organic Chemistry, 2019, 1145-1153; Journal of Organic Chemistry, 2007, 72, 2857-2864; Tetrahedron, 2017, 73, 853-858
Research team
Prof. Charles de Koning | Charles.dekoning@wits.ac.za | Google Scholar
Prof. Jo Michael | joseph.michael@wits.ac.za
Dr Kennedy Ngwira | Kennedy.ngwira@wits.ac.za | Google Scholar
Dr Songeziwe Ntsimango | songeziwe.ntsimango@wits.ac.za | Google Scholar
