Patent ID: 8431724

Claim:
A compound having the structure: wherein: m=0-20; R 1-14 independently represent hydrogen or alkyl; X 1 is O; X 2 is O; X 3 is NHR h , wherein R h is a natural or unnatural amino acid residue bound to NH of X 3 by amide linkage, the unnatural amino acid residue being selected from the group consisting of: A, C and D independently represent CH 2 , CHR j or C(R j ) 2 , wherein each occurrence of R j is hydrogen or alkyl; and each B independently represents CHR 1 , wherein each R 1 is independently OR m , wherein R m is independently hydrogen or alkyl; with the proviso that the following compounds are excluded: compounds wherein the following occur simultaneously: X 1 is O (S configuration), X 2 is O, R 1 =Me, R 2 =H, A=CHCH 3 (R configuration), R 3 =R 4 =H, R 5 =Me, R 6 =H, B is CHOMe (S configuration), C is CH 2 , R 7 =R 8 =H, R 9 =Me, R 10 =H, B is CHOMe (S configuration), R 11 =R 12 =R 13 =R 14 =H, D is CHCH 3 (S configuration), m=1, and X 3 is: wherein Rn=TBS.