Derivatives of alpha-ketoamides.

Derivatives of alpha-ketoamides. The invention relates to {the} - ketoamides of general formula (I) wherein R {sup, 1} R {sup, 12} have the meanings given in the description, and their salts which are inhibitors of viral proteinases useful as antiviral agents, especially for the treatment or prophylaxis of infections caused by hepatitis C, hepatitis G and GB humans.