1. NMR Research Centre; Division of SAIF; CSIR-Central Drug Research Institute; Lucknow 226031 India
2. Academy of Scientific and Innovative Research; New Delhi 110001 India
3. Molecular and Structural Biology Division; CSIR-Central Drug Research Institute; Lucknow 226031 India
4. Present Address: Research Centre; Prince Sultan Military Medical City, Riyadh, Kingdom of; Saudi Arabia
5. Medicinal & Process Chemistry Division; CSIR-Central Drug Research Institute; Lucknow 226031 India
6. Department of Chemistry, School of Physical Sciences; Sikkim University (A Central University); Gangtok 737102 India