Peptidyl ketones as inhibitors of DPIV

A compound formula 1:

• or a pharmaceutically acceptable salts thereof, wherein:
• A is selected from:
• wherein
• X1 is H or an amino acid residue, a N-protected amino acid residue, a peptide residue or a N-protected peptide residue,
• X2 is H, —(CH)m—NH—C5H3N—Y with m=2-4, or —C5H3N—Y (a divalent pyridyl residue) and Y is selected from H, Br, Cl, I, NO2 and CN,
• X3 is H or an alkyl-, alkoxy-, halogen-, nitro-, cyano- or carboxy-substituted phenyl or from an alkyl-, alkoxy-, halogen-, nitro-, cyano- or carboxy-substituted pyridyl residue,
• X4 is H or an alkyl-, alkoxy-, halogen-, nitro-, cyano- or carboxy-substituted phenyl or an alkyl-, alkoxy-, halogen-, nitro-, cyano- or carboxy-substituted pyridyl residue,
• X5 is H or an alkyl, alkoxy or phenyl residue,
• X6 is H or an alkyl residue,
• for n=1
• X is selected from OR2 and SR2, wherein:
• R2 is an acyl residues, optionally substituted with alkyl, cycloalkyl, aryl or heteroaryl residues, or an amino acid residue or peptidic residue, or alkyl residue, which are optionally substituted with alkyl, cycloalkyl, aryl or heteroaryl residues,
• for n=0
• X is selected from:
• wherein
• B is O, S or NR5, wherein R5 is H, alkyl or acyl,
• C, D, E, F, G, Y, K, L, M, Q, T, U, V and W are independently selected from alkyl and substituted alkyl residues, oxyalkyl, thioalkyl, aminoalkyl, carbonylalkyl, acyl, carbamoyl, aryl and heteroaryl residues, and
• Z is H, or a branched or straight chain alkyl residue from C1-C9, a branched or straight chain alkenyl residue from C2-C9, a cycloalkyl residue from C3-C8, a cycloalkenyl residue from C5-C7, an aryl or heteroaryl residue, or a side chain selected from all side chains of all natural amino acids or derivatives thereof.