Acknowledgments
We gratefully acknowledge our research guide Prof. Dr. B. H. M. Mruthyunjayaswamy, Department of Chemistry, Gulbarga University, Kalaburgi, India, for his support, interest and guidance. Further thanks go to The Principal, Vijaya College, Bengaluru, India, and The Principal, Guru Nanak First Grade College, Bidar, Karnataka, India, for their help during the preparation of the review.
Dedication
This paper is dedicated to Dr. B. K. Shanthaveerappa, Gulbarga University, Kalaburagi, India, in honor of his long and productive career in organic and medicinal chemistry, in which he produced many outstanding research articles and patents.