ALFA-KETOAMIDE DERIVATIVE

PROBLEM TO BE SOLVED: To obtain a new derivative which is a specific α-ketoamide derivative obtained by condensing a specified acid addition salt of α-ketoamidoamine with a peptide having a terminal carboxylic acid, and, if necessary, deprotecting the product, and useful as an antiviral medicine or the like. SOLUTION: This new derivative is a new α-ketoamide derivative represente by formula I [R is a (substituted) lower alkyl, a lower alkenyl or the like; R is a (substitute) lower alkyl or the like; R is H, a lower alkyl or the like; R is a (substituted) lower alkyl, an aryl or the like; R is a (substituted) lower alkyl, an aryl or the like; R is H or a lower alkyl; R is H, a (substituted) lower alkyl or the like; R is a (substituted) lower alkyl, a lower cycloalkyl, an aryl or the like; R is H, a lower alkyl or the like; R is a lower alkylcarbonyl or the like; R and R are each H, a lower alkyl, an aryl, a heteroaryl or the liked. The derivative is useful as an antiviral medicine or the like, and obtained by condensing an acid addition salt of an amine of formula II with an acid of formula III, and, if necessary, eliminating a protective group.