Abstract: A class of ketoamide-based compounds, in particular, a ketoarnide-based compound as represented by general formula A is provided. The ketoamide compound may be used as a 2019 novel coronavirus (2019-nCov) 3 CL protease inhibitor and/or human cathepsin L inhibitor, and/or may be used in the preparation of a medicament for treating and/or preventing and relieving respiratory tract infection, pneumonia and other related diseases caused by 2019 novel coronavirus infection. Pharmaceutical compositions of the class of compounds, pharmaceutical salts, enantiomeric forms, diastereoisomers and racemic compounds thereof in the preparation of a medicament for treating and/or preventing and relieving respiratory tract infections and other related diseases caused by the 2019 novel coronavirus infection are also provided.

Abstract: Use of an aldehyde-based compound as represented by general formula I, a pharmaceutical composition, a pharmaceutical salt, an enantiomer, a diastereomer and a racemic compound thereof as a novel coronavirus 2019 (2019-nCov) 3CL protease inhibitor in preparation of a medicament for treating and/or preventing and relieving respiratory tract infections, pneumonia and other related diseases caused by the novel coronavirus infection 2019.

Abstract: Disclosed are a novel tetrahydroisoquinoline compound, a method for preparing intermediates thereof, a pharmaceutical composition thereof and the use thereof. The tetrahydroisoquinoline compound of the present invention has a good inhibitory effect on phosphodiesterase (PDE4), and can be used in the prevention, treatment or auxiliary treatment of multiple diseases associated with the activity or expression of phosphodiesterase, especially PDE4-associated immune and inflammatory diseases, such as psoriasis and arthritis.