Reducing agents and uses thereof

A compound having the formula:

• wherein,
• R1 is —W1-L1-R4;
• R2 is halogen or —W2-L2-R5;
• R3 is halogen or —W3-L3-R6;
• W1, W2, and W3 are independently —O—, —S—, or —NH—;
• L1, L2, and L3 are independently a substituted or unsubstituted alkylene, substituted or unsubstituted heteroalkylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted heterocycloalkylene, substituted or unsubstituted arylene, or substituted or unsubstituted heteroarylene;
• R4 is
• wherein
• is
• R5 is hydrogen, —OH, NH2, —COOH, —CONH2, —SH, —SO3H, —SO4H, —SO2NH2, or
• R6 is hydrogen, —OH, NH2, —COOH, —CONH2, —SH, —SO3H, —SO4H, —SO2NH2, or
• and
• wherein R4A, R4B, R5A, R5B, R6A, and R6B are independently substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl.