Patent ID: 8377896

Claim:
A compound of formula I: or a pharmaceutically acceptable salt thereof, wherein: each R 1 and R 2 is, independently, H or an amino protecting group; each R 3 is, independently, H or a hydroxyl protecting group; R 4 and R 5 are each, independently, H, amino protecting group, C 1 -C 12 alkyl, substituted C 1 -C 12 alkyl, C 2 -C 12 alkenyl, substituted C 2 -C 12 alkenyl, C 2 -C 12 alkynyl or substituted C 2 -C 12 alkynyl; Q 1 is cyano, azido, or NR 8 R 9 ; Q 2 is NH 2 or N(CH 2 R 6 )R 7 ; R 6 and R 7 are each, independently, H, C 1 -C 12 alkyl, substituted C 1 -C 12 alkyl, C 7 -C 9 alicyclic radical, substituted C 7 -C 9 alicyclic radical, C 2 -C 12 alkenyl, substituted C 2 -C 12 alkenyl, C 2 -C 12 alkynyl or substituted C 2 -C 12 alkynyl; and R 8 and R 9 are each, independently, H, CN, C 1 -C 12 alkyl, substituted C 1 -C 12 alkyl, C 7 -C 9 alicyclic radical, substituted C 7 -C 9 alicyclic radical, C 2 -C 12 alkenyl, substituted C 2 -C 12 alkenyl, C 2 -C 12 alkynyl or substituted C 2 -C 12 alkynyl; wherein said substituents are each, independently, NJ 1 J 2 or C 5 -C 20 aryl; and wherein each J 1 and J 2 is, independently, H, C 1 -C 12 alkyl or C 5 -C 20 aryl.