1. Natural and Medical Sciences Research Centre, University of Nizwa, Birkat Almouz, Nizwa 616, Oman
2. Department of Chemistry, Bacha Khan University Charsadda, Charsadda 24420 Khyber Pakhtunkhwa, Pakistan
3. Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
4. Department of Biological Sciences and Chemistry, University of Nizwa, Birkat Almouz, Nizwa 616, Oman
5. Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 2, Halle (Saale) d-06120, Germany