1. Department of Chemistry Faculty of Science University of Dschang P. O. Box 67 Dschang Cameroon
2. Department of organic Chemistry Faculty of science University of Yaoundé P. O. Box 812 Yaoundé Cameroon
3. Department of Chemistry Higher Teacher Training College University of Yaoundé I P. O. Box 47 Yaoundé Cameroon
4. Organic and Bioorganic Chemistry Department of Chemistry Bielefeld University D-33501 Bielefeld Germany
5. Department of Chemistry Faculty of science The University of Bamenda P. O. Box 39 Bambili Cameroon