Patent ID: 7247629

Claim:
A compound of the formula: wherein: R′ is selected from the group consisting of —CH 2 —N(R a ) 2 and —CH 2 —OR a , where R a is selected from the group consisting of H; alkyl-CO—; haloalkyl-CO—; cycloalkylalkyl-CO—; haloalkyl-O—CO—; arylalkyl-CO—; arylalkenyl-CO—; heteroaryl-CO—; alkenyl-CO—; alkeny; and amino acid acyl; R 5 is —OR″, where R″ is selected from the group consisting of H; alkyl-CO—; cycloalkyl—CO—; and haloalkyl-CO—; R 18 is —OR, where R is selected from the group consisting of H, alkyl-CO—; and cycloalkylalkyl—CO—; and R 21 is —OH; or a pharmaceutically acceptable salt thereof.