Tetra-and pentapeptides having antiangiogenic activity

A compound of formula (I)

• Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6(I), (SEQ ID NO:
• 1)
• or a therapeutically acceptable salt thereof, wherein
• Xaa1 is absent or R—(CH2)n—C(O)—, wherein n is an integer from 0 to 8 and R is selected from the group consisting of alkoxy, alkyl, amino, aryl, carboxyl, cycloalkenyl, cycloalkyl, and heterocycle;
• Xaa2 is selected from the group consisting of N-methylalanyl, allothreonyl, arginyl, glutaminyl, glycyl, homoseryl, leucyl, lysyl(N-epsilon acetyl), norleucyl, norvalyl, D-norvalyl, N-methylnorvalyl, omithyl(N-delta acetyl), 3-(3-pyridyl)alanyl, sarcosyl, seryl, N-methylseryl, threonyl, tryptyl, valyl, and N-methylvalyl;
• Xaa3 is selected from the group consisting of alanyl, alloisoleucyl, aspartyl, citrullyl, isoleucyl, D-isoleucyl, N-methylisoleucyl, leucyl, D-leucyl, lysyl(N-epsilon acetyl), D-lysyl (N-epsilon acetyl), norvalyl, phenylalanyl, prolyl, and D-prolyl;
• Xaa4 is selected from the group consisting of arginyl, D-arginyl, citrullyl, histidyl, lysyl, lysyl(N-epsilon isopropyl), omithyl, and 3-(3-pyridyl)alanyl;
• Xaa5 is selected from the group consisting of N-methyl-D-alanyl, 2-aminobutyryl, 2-aminoisobutyryl, D-glutaminyl, homoprolyl, hydroxyprolyl, leucyl, phenylalanyl, prolyl, D-prolyl, and D-valyl;
• and
• Xaa6 is selected from the group consisting of D-alanylamide, azaglycylamide, glycylamide, D-lysyl(N-epsilon acetyl)amide, a group represented by the formula —NH—(CH2)n—CHR1R2;
• and a group represented by the formula —NHR3, wherein n is an integer from 0 to 8;
• R1 is selected from the group consisting of hydrogen, alkyl, cycloalkenyl, and cycloalkyl;
• R2 is selected from the group consisting of hydrogen, alkoxy, alkyl, aryl, cycloalkenyl, cycloalkyl, heterocycle, and hydroxyl, with the proviso that when n is 0, R2 is other than alkoxy or hydroxyl;
• and R3 is selected from the group consisting of hydrogen, cycloalkenyl, cycloalkyl, and hydroxyl.