Targeted Synthesis of New 5-Phenyl-2-[(E)-Styryl]-1H-Pyrimidin-6-One Derivatives and Their Inhibitory Activity Toward SARS-CoV-2 Major (MPRO) and Papain-Like Proteases (PLPRO)

The use of the 5-phenyl-1H-pyrimidin-6-one scaffold in the search for biologically active compounds with antiviral activity based on the pyrimidin-4-one core present in endogenous substances and drugs was substantiated. The molecular activity and pharmacokinetic descriptors for styryl derivatives of N-substituted 5-phenyl-1H-pyrimidin-6-one were predicted in silico via the SwissADME web service. The lack of crystallographic data and information about the tautomeric form of 2,4-dimethyl-5-phenyl-1H-pyrimidin-6-one necessitated the measurement and analysis of x-ray diffraction patterns of the starting substance to explain the reactivity in the styrylation reaction. New derivatives of 5-phenyl-2-[(E)-styryl]-1H-pyrimidin-6-one were synthesized. Studies of their inhibitory activity toward SARS-CoV-2 major (Mpro) and papain-like proteases (PLpro) revealed their marked antiviral activity.