1. Faculty of Science, Department of Organic Chemistry, University of Yaounde I, Yaoundé, Cameroon
2. International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi, Pakistan
3. Institute for Organic and Biomolecular Chemistry, Georg-August University, Göttingen, Germany
4. Higher Teachers’ Training College, University of Yaoundé I, Yaounde, Cameroon