Patent ID: 7977465

Claim:
A compound having the structure: wherein Z is NH; X is O; R 3 is a member selected from the group consisting of (═O) and OR 11 , wherein R 11 is a member selected from the group consisting of C(O)R 12 , C(O)OR 12 , and C(O)NR 12 R 13 , in which R 12 and R 13 are H or R 12 and R 13 together with the nitrogen or carbon atom to which they are attached are joined to form a substituted or unsubstituted heterocycloalkyl ring system having from 4 to 6 members, optionally containing two or more heteroatoms; R 5 is H; R 4 is NHR 16 , wherein R 16 is wherein X 4 is an antibody or a reactive functional group having the structure: wherein is a single or double bond; L 3 is a linker selected from substituted or unsubstituted C 1-10 alkyl and substituted or unsubstituted C 1-10 heteroalkyl groups; AA 1 , AA c and AA c+1 are members independently selected from natural and unnatural α-amino acids; L 4 is a linker selected from substituted or unsubstituted C 1-10 alkyl, substituted or unsubstituted C 1-10 heteroalkyl groups, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and substituted or unsubstituted cycloalkyl; p and t are integers independently selected from 0 and 1; and c is an integer from 0 to 5; and R 6 is a single bond which is either present or absent and when present R 6 and R 7 are joined to form a cyclopropyl ring; and R 7 is CH 2 —X 1 or —CH 2 — joined in said cyclopropyl ring with R 6 , wherein X 1 is a leaving group, or a pharmaceutically acceptable salt thereof.