Patent ID: 8034780

Claim:
An isolated compound of formula I or a pharmaceutically acceptable salt thereof, wherein: R 1 =Me or H; R 2 =Me or H; R 3 =L/D N,N-dimethylvaline, L/D valine, L/D leucine, L/D isoleucine, or L/D allo-isoleucine; R 4 =O, NH, S, or NMe; R 5 =L/D 2-hydroxyisovaleric acid, L/D valine, L/D leucine, L/D isoleucine, or L/D allo-isoleucine; R 6 =H or Me; R 7 =L/D serine or L/D O-methylserine; R 8 =H or Me; R 9 =L/D leucine, L/D valine, L/D isoleucine, or L/D allo-isoleucine; R 10 =Me or H; R 11 =H, Me, CH 3 CH 2 —, or CH 3 CH 2 CH 2 —; R 12 =O, N, or S; R 13 =L/D alanine; R 14 =H or Me; R 15 =L/D tyrosine, L/D O-methyl tyrosine, or L/D phenylalanine; R 16 =H or Me; R 17 =L/D leucine, L/D valine, L/D isoleucine, or L/D allo-isoleucine; R 18 =H or Me; R 19 =L/D alanine; R 20 =H or Me; R 21 =L/D isoleucine, L/D allo-isoleucine, L/D leucine, or L/D valine; R 22 =H or Me; R 23 =L/D serine or L/D O-methyl-serine; and R 24 =H or Me, wherein R 3 , R 5 , R 7 , R 9 , R 13 , R 15 , R 17 , R 19 , R 21 , and R 23 are the amino acid side chains of the listed amino acids.