Patent ID: 8080563

Claim:
A compound of structural Formula VI or a salt thereof, wherein: R 1 and R 2 are independently selected from the group consisting of —(CH 2 ) s G 1 G 2 G 3 , acyl, acylalkyl, carboxyalkyl, cyanoalkyl, alkoxy, alkoxyalkyl, amidoalkyl, amino, alkyl, alkylalkoxy, aminoalkyl, alkenyl, alkynyl, carboxyl, carboxyalkyl, ether, heteroalkyl, haloalkyl, cycloalkyl, cycloalkylalkyl, heterocycloalkyl, heterocycloalkylalkyl, aralkyl, aryl, guanidine, heteroaryl, heteroaralkyl, and hydroxyalkyl, any of which may be optionally substituted; s is 1-8; G 1 is selected from the group consisting of alkoxy, amino, amido, carbonyl, hydroxy, ether, an amino acid, and null; G 2 is selected from the group consisting of alkyl, alkoxy, amino, aryl, halo, haloalkyl, heterocycloalkyl, heteroaryl, carboxylalkylamino, guanidine, an amino acid, and null, any of which may be optionally substituted; G 3 is selected from the group consisting of alkyl, alkoxy, amino, hydroxy, ether, carboxyl, hydroxamic acid, an amino acid, phosphonate, phosphoamide, and null, any of which may be optionally substituted; and R 20 and R 24 are independently selected from the group consisting of hydrogen, halogen, hydroxyl, lower alkyl, lower alkoxy, lower haloalkyl, lower haloalkoxy, amino, and carboxyl.