Patent ID: 7754681

Claim:
A drug-ligand conjugate compound comprising a cell-specific ligand and a drug moiety conjugated by a linker wherein said linker comprises a heterocyclic self-immolative moiety of Formula I where the wavy lines indicate the covalent attachment sites to the cell-specific ligand and the drug moiety, and wherein: U is O, S or NR 6 ; Q is CR 4 or N; T is NH, NR 6 , O or S pending from said drug moiety; R 1 , R 2 , R 3 and R 4 are independently selected from H, F, Cl, Br, I, OH, —N(R 5 ) 2 , —N(R 5 ) 3 + , C 1 -C 8 alkylhalide, carboxylate, sulfate, sulfamate, sulfonate, —SO 2 R 5 , —S(═O)R 5 , —SR 5 , —SO 2 N(R 5 ) 2 , —C(═O)R 5 , —CO 2 R 5 , —C(═O)N(R 5 ) 2 , —CN, —N 3 , —NO 2 , C 1 -C 8 alkoxy, C 1 -C 8 halosubstituted alkyl, polyethyleneoxy, phosphonate, phosphate, C 1 -C 8 alkyl, C 1 -C 8 substituted alkyl, C 2 -C 8 alkenyl, C 2 -C 8 substituted alkenyl, C 2 -C 8 alkynyl, C 2 -C 8 substituted alkynyl, C 6 -C 20 aryl, C 6 -C 20 substituted aryl, C 1 -C 20 heterocycle, and C 1 -C 20 substituted heterocycle; or when taken together, R 2 and R 3 form a carbonyl (═O), or spiro carbocyclic ring of 3 to 7 carbon atoms; and R 5 and R 6 are independently selected from H, C 1 -C 8 alkyl, C 1 -C 8 substituted alkyl, C 2 -C 8 alkenyl, C 2 -C 8 substituted alkenyl, C 2 -C 8 alkynyl, C 2 -C 8 substituted alkynyl, C 6 -C 20 aryl, C 6 -C 20 substituted aryl, C 1 -C 20 heterocycle, and C 1 -C 20 substituted heterocycle; where C 1 -C 8 substituted alkyl, C 2 -C 8 substituted alkenyl, C 2 -C 8 substituted alkynyl, C 6 -C 20 substituted aryl, and C 2 -C 20 substituted heterocycle are independently substituted with one or more substituents selected from F, Cl, Br, I, OH, —N(R 5 ) 2 , —N(R 5 ) 3 + , C 1 -C 8 alkylhalide, carboxylate, sulfate, sulfamate, sulfonate, C 1 -C 8 alkylsulfonate, C 1 -C 8 alkylamino, 4-dialkylaminopyridinium, C 1 -C 8 alkylhydroxyl, C 1 -C 8 alkylthiol, —SO 2 R 5 , —S(═O)R 5 , —SR 5 , —SO 2 N(R 5 ) 2 , —C(═O)R 5 , —CO 2 R 5 , —C(═O)N(R 5 ) 2 , —CN, —N 3 , —NO 2 , C 1 -C 8 alkoxy, C 1 C 8 trifluoroalkyl, C 1 -C 8 alkyl, C 3 -C 12 carbocycle, C 6 -C 20 aryl, C 2 -C 20 heterocycle, polyethyleneoxy, phosphonate, and phosphate.