Patent ID: 7345178

Claim:
A compound of the formula: or a salt thereof, wherein R 19 is wherein: each Z 10 , Z 11 , Z 12 and Z 13 is independently selected from CR 20 or CR 1 ′; wherein: zero to one R 20 is a solubilizing group; and zero to one R 1 ′ is an optionally substituted C 1 -C 3 straight or branched alkyl; each R 20 is independently selected from H or a solubilizing group; R 21 is —NR 1 ′—C(O)—; each R 1 ′ is independently selected from H or optionally substituted C 1 -C 3 straight or branched alkyl; and R 31 is selected from an optionally substituted monocyclic or bicyclic aryl, or an optionally substituted monocyclic or bicyclic heteroaryl, with the proviso that R 31 is not 4-cyanophenyl or