Antioxidant inflammation modulators: novel derivatives of oleanolic acid

A compound of the formula:

• wherein:
• Ra is azido, fluoro, hydroxyamino, alkoxyamino(C≦12), substituted alkoxy-amino(C≦12), or —NH-L-Rd;
• wherein:
• L is alkanediyl(C≦8);
• and
• Rd is:
• hydroxy;
• or
• alkoxy(C≦18), aryloxy(C≦18), or acyloxy(C≦18), or a substituted version of any of these groups;
• R1is:
• hydrogen, cyano, hydroxy, halo or amino;
• or
• alkyl(C≦8), alkenyl(C≦8), alkynyl(C≦8), aryl(C≦8), aralkyl(C≦8), heteroaryl(C≦8), heteroaralkyl(C≦8), acyl(C≦8), alkoxy(C≦8), aryloxy(C≦8), acyloxy(C≦8), alkylamino(C≦8), arylamino(C≦8), amido(C≦8), or a substituted version of any of these groups;
• R4 and R5 are each independently alkyl(C≦8) or substituted alkyl(C≦8);
• R6 is hydrogen, hydroxy or oxo;
• and
• or a pharmaceutically acceptable salt, tautomers, or optical isomer thereof.