1. Department of Chemistry University of Calcutta 92, A. P. C. Road Kolkata 700 009 West Bengal India
2. Department of Medicinal and Process Chemistry CSIR-Central Drug Research Institute Lucknow 226031 U. P. India
3. Department of Chemistry, School of Science São Paulo State University Bauru São Paulo Brazil 17033-360
4. Department of Chemistry Imam Abdulrahman Bin Faisal University, P.O. Box 1982 Dammam 31441 Saudi Arabia
5. Department of Physical Chemistry, Institute of Chemistry Campinas State University Campinas São Paulo Brazil 13083-970