Patent ID: 8273875

Claim:
A compound having the formula: or a pharmaceutically acceptable salt thereof, wherein: R 1 , R 2 , and R 3 are each independently alkyl, phenyl, polyethylene glycol, alkyl-phosphonate, alkyl-sulfonate, methylene-triazole-alkyl-sulfonate, methylene-triazole-alkyl-phosphonate, methylene-triazole-methylene-dimethylammonium-alkyl-sulfonate, or methylene-dimethylammonium-alkyl-phosphonate; X=alkyl, phenyl, alkyl-carboxylic acid, alkyl ester, alkyl hydroxysuccinimde ester, alkyl maleimide, alkyl isothiocyanate, alkyl azide, alky alkyne, alkyl haloacetamido, aryl ester, aryl hydroxysuccinimde ester, aryl maleimide, aryl isothiocyanate, aryl azide, aryl alkyne, or aryl haloacetamido; Y 1 and Y 2 are each independently H, alkoxy-triazole-methylene-sulfonate, alkoxy-triazole-methylene-dimethylammonium-alkyl-sulfonate, alkoxy-triazole-methylene-phosphonate, alkoxy-triazole-methylene-dimethylammonium-alkyl-phosphonate, triazole-methylene-sulfonate, triazole-methylene-phosphonate; triazole-methylene-dimethylammonium-alkyl-sulfonate, triazole-methylene-methylene-dimethylammonium-alkyl-phosphonate, alkyl, phenyl, alkyl-carboxylic acid, alkyl ester, alkyl hydroxysuccinimde ester, alkyl maleimide, alkyl isothiocyanate, alkyl azide, alky alkyne, alkyl haloacetamido, aryl ester, aryl hydroxysuccinimde ester, aryl maleimide, aryl isothiocyanate, aryl azide, aryl alkyne, or aryl haloacetam; Z 1 and Z 2 are each independently CH or N; and W 1 , W 2 , W 3 , and W 4 are each independently H or OH, at least one of W 1 , W 2 , W 3 , and W 4 being OH.