Patent ID: 8722715

Claim:
A compound of Formula I or a salt thereof, wherein: n is 0; W is NR 4 , or O; R 1 is Cl, or Br; R 2 and R 3 are each independently H, -L-X or optionally substituted alkyl or heteroalkyl or R 2 and R 3 together with the carbon to which they are attached form a carbonyl, or an optionally substituted cycloalkyl or heterocycloalkyl group; R 4 is -L-X or optionally substituted alkyl or heteroalkyl; R 5 and R 6 are each independently H, -L-X or optionally substituted alkyl or heteroalkyl; or R 5 and R 6 together with the carbon to which they are attached form a carbonyl, or an optionally substituted cycloalkyl or heterocycloalkyl group; R 7 and R 8 are each independently H, -L-X or optionally substituted alkyl or heteroalkyl; or R 7 and R 8 together with the carbon to which they are attached form a carbonyl, or an optionally substituted cycloalkyl or heterocycloalkyl group; each L is independently an optionally substituted C 1-6 alkyl, heteroalkyl, cycloalkyl or heterocycloalkyl group; and each X is independently —SO 3 H, —N + R a R b R c , —CO 2 H, —PO 3 H 2 or —PO 3 HR a and R a , R b , and/or R c are independently a bond or an optionally substituted alkyl or heteroalkyl groups, or may form, together with the N to which they are attached, a heterocycloalkyl group with the provisos that: at least one of R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , or R 8 is -L-X; and one of R 2 and R 3 , R 5 and R 6 , or R 7 and R 8 , together with the carbon to which they are attached, form a carbonyl.