1. Medicinal Chemistry Laboratory, A. K. Tibbiya College, Aligarh Muslim University, Aligarh ‐ 202001, India, and Dr. Moghis U. Ahmad, Department of Chemistry, Aligarh Muslim University, Aligarh – 202001, India. (Present address: Department of Biochemistry and Biophysics, Texas A & M University, College Station, Texas 77843, USA.)