SUMMARY
Based on the preliminary calculated screening performed by the PASS programme the synthesis of the group of the corresponding N-phenethyl-2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides as potential antiviral agents has been carried out by the interaction of ethyl esters of 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acids with 2-arylethylamines in boiling ethanol. Their structure has been confirmed by the data of elemental analysis and NMR 1H spectroscopy. Of the Herpesviruses family such viruses as Herpes Simplex Viruses Type 1 and 2, Varicella-Zoster Virus, Epstein-Barr Virus, as well as Cytomegalovirus have been involved in the screening research. Influenza Virus was presented by two types: A (subtypes H1N1, H3N2, H5N1) and B. The group of viruses affecting different sections of the respiratory tract included Parainfluenza Virus, SARS Virus, Rhinovirus, Adenovirus and Respiratory Syncytial Virus. Besides, Measles Virus, Vaccinia Virus and related Cowpox Virus, Hepatitis B and C Viruses, as well as Venezuelan Equine Encephalitis Virus were involved. The group of viruses causing febrile states of varying severity in human was presented by Rift Valley Fever Virus, West Nile Virus, Yellow Fever Virus, Dengue Virus and Tacaribe Virus. According to the results of the tests performed N-(4-chlorophenethyl)- 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamide has been recommended for further research. Having a low cytotoxicity this compound revealed a high antiviral activity in relation to the West Nile fever virus agent.