1. a Chemistry Department , Faculty of Education, Tanta University (Kafr El-Sheikh Branch) , Tanta, Egypt
2. c Laboratoire de Chimie XII , Université de Poitiers et CNRS. 40 Avenue du Recteur Pineau , F-86022, Poitiers, France Fax: E-mail:
3. b Department of Pharmaceutical Chemistry, College of Pharmacy , P.O. Box 2457 King Saud University , 11451, Riyadh, Kingdom of Saudi Arabia