Patent ID: 8293943

Claim:
A compound of formula (I) or a salt thereof; wherein, R 1 , R 2 , and R 3 are selected from —OH, —NR 4 R 5 , amino sugar, and —OR 6 ; and X is selected from —NH-peptide, —NH—C 10 -C 20 alkanoyl, and —N═CR 7 R 8 ; and R 4 and R 5 are selected from H, alkyl, substituted alkyl, aryl, substituted aryl, heterocyclic, substituted heterocyclic, amino-alkanoyl, polyhydroxyalkyl, cycloalkyl, and amino sugar; and R 6 is selected from H, and C 1 -C 20 alkyl; and R 7 and R 8 are selected from H, alkyl, substituted alkyl, aryl, substituted aryl, heterocyclic, and substituted heterocyclic.