Patent ID: 8871720

Claim:
A compound having the formula: or a pharmaceutically acceptable salt thereof; wherein: R 2 is selected from the group consisting of H and C 1 -C 8 alkyl; R 3 is selected from the group consisting of C 1 -C 8 alkyl; R 4 is selected from the group consisting of C 1 -C 8 alkyl; R 5 is H; R 6 is selected from the group consisting of H and C 1 -C 8 alkyl; R 7 is selected from the group consisting of H and C 1 -C 8 alkyl; each R 8 is independently selected from the group consisting of H, OH,and O—(C 1 -C 8 alkyl); and the moiety —NR 9 Z 1 is a bioisostere having Formula A wherein: R 9 is selected from the group consisting of H and an amino protecting group; R 10 is selected from the group consisting of C 1 -C 8 alkyl, C 1 -C 8 heteroalkyl, CH 2 —(C 3 -C 8 carbocycle), CH 2 -aryl and CH 2 —(C 3 -C 8 heterocycle); and Z 2 is selected from the group consisting of: