1. Department of Chemistry, University of Dschang
,
Dschang
,
Cameroon
;
2. Department of Biochemistry, University of Dschang
,
Dschang
,
Cameroon
;
3. Institute of Organic Chemistry, Johannes Gutenberg-University of Mainz
,
Mainz
,
Germany
;
4. Department of Chemistry, Faculty of Science, Eskishir Technical University
,
Eskishir
,
Turkey