1. Division of Applied Informatics, Volga Region Academy of State Service, 23/25 Sobornaya Street, Saratov 410031, Russia
2. Department of Chemistry, N. G. Chernyshevskii Saratov State University, 83 Astrakhanskaya Street, Saratov 410012, Russia
3. Institute of Organic Chemistry, Bulgarian Academy of Science, 1113 Sofia, Bulgaria