1. Department of Organic Chemistry, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
2. Department of Chemistry, Faculty of Science, University of Ngaoundere, Ngaoundere, Cameroon
3. National Advanced School of Agro-Industrial Science, University of Ngaoundere, Ngaoundere, Cameroon
4. H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Science (ICCBS), University of Karachi, Karachi, Pakistan