Peptidyl ketones as inhibitors of DPIV

Compounds of the general formula 1

• 13
• and pharmaceutically acceptable salts thereof, wherein:
• A is selected from the following structures:
• 14
• wherein
• X1 is H or an acyl or oxycarbonyl group including 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, N2 or CN,
• X3 is H or selected from 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 selected from an alkyl-, alkoxy-, halogen-, nitro-, cyano- or carboxy-substituted phenyl or from 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:
• H, OR2, SR2, NR2R3, N+R2R3R4, wherein:
• R2 stands for acyl residues, which are optionally substituted with alkyl, cycloalkyl, aryl or heteroaryl residues, or for amino acid residues or peptidic residues, or alkyl residues, which are optionally substituted with alkyl, cycloalkyl, aryl or heteroaryl residues,
• R3 stands for alkyl or acyl residues, wherein R2 and R3 may be part of a saturated or unsaturated carbocyclic or heterocyclic ring,
• R4 stands for alkyl residues, wherein R2 and R4 or R3 and R4 may be part of a saturated or unsaturated carbocyclic or heterocyclic ring,
• for n=0
• X is selected from:
• 15
• wherein
• B stands for:
• 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 selected from 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.