Patent ID: 8729088

Claim:
A compound having a structure according to Formula I: or a pharmaceutically acceptable salt thereof, wherein: X is N; R is —OR 1 , —SR 1 , or —NR a R b , X 1 is —O—, —S—, or —NR c —; R c is hydrogen, C1-C10 alkyl, or substituted C1-C10 alkyl, or R c and R 1 taken together with the nitrogen atom can form a heterocyclic ring or a substituted heterocyclic ring; each R 1 independently is hydrogen, C1-C10 alkyl, substituted C1-C10 alkyl, C1-C10 alkoxy, substituted C1-C10 alkoxy, C1-C10 alkyl C1-C10 alkoxy, C6-C10 aryl, C5-C10 heteroaryl, substituted C5-C10 aryl, C5-C9 heterocyclic, substituted C5-C9 heterocyclic, C3-C9 carbocyclic or substituted C3-C9 carbocyclic; each R 2 independently is hydrogen, —OH, C1-C6 alkyl, substituted C1-C6 alkyl, C1-C6 alkoxy, substituted C1-C6 alkoxy, —C(O)—C1-C6 alkyl (alkanoyl), substituted —C(O)—C1-C6 alkyl, —C(O)—C6-C10 aryl (aroyl), substituted —C(O)—C6-C10 aryl, —C(O)OH (carboxyl), —C(O)O—C1-C6 alkyl (alkoxycarbonyl), substituted —C(O)O—C1-C6 alkyl, —NR a R b , —C(O)NR a R b (carbamoyl), substituted C(O)NR a R b , halo, nitro, or cyano; the substituents on the alkyl, alkoxy, aryl or heterocyclic groups are hydroxy, C1-C6 alkyl, hydroxy C1-C6 alkylene, carboxy C1-C6 alkylene, C1-C6 alkoxy, C3-C6 cycloalkyl, C1-C6 alkoxy C1-C6 alkylene, amino, cyano, halogen, or aryl; each R a and R b is independently hydrogen, C1-C20 alkyl, C3-C8 cycloalkyl, C1-C6 alkoxy, halo C1-C6 alkyl, C3-C8 cycloalkyl C1-C6 alkyl, C1-C6 alkanoyl, hydroxy C1-C6 alkyl, aryl, aryl C1-C6 alkyl, hetero C1-C10 alkyl, wherein C1-C10 alkyl is substituted with one or more O, S or N atoms, heterocyclyl, wherein the heterocyclyl is substituted with one or more O, S or N atoms, or C1-C6 alkoxycarbonyl; each R x is independently —X 2 — ((R 3 ) r —(R 4 ) s ); each X 2 independently is —C(O)NH—, —NH(O)C—, —C1-C6 alkyl-C(O)NH—, —C1-C6 alkyl-NH(O)C—, —C(O)NH—C1-C6 alkyl-, —NH(O)C—C1-C6 alkyl-, —C1-C6 alkyl—NH(O)C—C1-C6 alkyl-, —C1-C6 alkyl-C(O)NH—C1-C6 alkyl-, or —C(O)NH—(CH 2 ) t —; each R 3 independently is a polyethylene glycol (PEG) moiety; each R 4 independently is H, —C1-C6 alkyl, —C1-C6 alkoxy, —NR a R b , —N 3 , —OH, —CN, —COOH, —COOR′, —C1-C6 alkyl-NR a R b , C1-C6 alkyl-OH, C1-C6 alkyl-CN, C1-C6 alkyl-COOH, C1-C6 alkyl-COOR′, 5-6 membered ring, substituted 5-6 membered ring, —C1-C6 alkyl-5-6 membered ring, —C1-C6 alkyl-substituted 5-6 membered ring C2-C9 heterocyclic, or substituted C2-C9 heterocyclic; m is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; n is 0, 1, 2, 3 or 4; p is 1 to 100; q is 1, 2,3, 4 or 5; r is 2 to 1,000; s is 1 to 1,000; and the sum of n and q equals 5.