Patent ID: 7163923

Claim:
A compound having the structure: wherein R 1 , R 2 are each hydrogen and R 4 , and R 5 are independently the same or different and are selected from the group consisting of hydrogen, a substituted or unsubstituted C 5 –C 14 aryl group and a substituted or unsubstituted, saturated or unsaturated C 1 –C 6 alkyl group; wherein R 3 is selected from the group consisting of a substituted or unsubstituted aryl group and a substituted or unsubstituted, saturated or unsaturated C 1 –C 6 alkyl group and —CH 2 —CH 2 —X—CH 3 , wherein X is selected from the group consisting of —O—, —S—, —NH—, —NR 6 —, and —CH 2 —; where R 6 is a lower alkyl; wherein A 1 and A 3 are independently the same or different and are selected from the group consisting of ═O, ═S, ═NH, ═N—OH, or ═N—R 7 , where R 7 is hydrogen or a C 1 –C 6 alkyl; wherein A 2 , is absent or selected from the group consisting of ═O, ═S; ═NH, ═N—OH, ═N—R 8 , or —C(R 9 )(R 10 )—, wherein R 8 , R 9 , and R 10 are independently the same or different and are selected from the group consisting of hydrogen or a C 1 –C 6 alkyl; wherein B 1 is selected from the group consisting of —O—, —S—, —NH— or —N(R 11 )—, wherein R 11 is selected from the group consisting of hydrogen and a C 1 –C 6 alkyl; wherein B 2 is absent or is selected from the group consisting of —O—, —S—, —N(R 12 ), or —C(R 13 )(R 14 )—, where R 12 , R 13 , and R 14 are independently the same or different and are selected from the group consisting of hydrogen or a substituted or unsubstituted, saturated or unsaturated alkyl; wherein the fragment —B 2 —C(R 4 )(R 5 )—C(═A 3 )— in its entirety is an naturally occurring amino acid, analog, derivative or peptidomimetic thereof; wherein B 3 is absent or is selected from the group consisting of —O—, —S—, or —NH—, or —N(R 15 )—, wherein R 15 is selected from the group consisting of hydrogen and a C 1 –C 6 alkyl; wherein B 4 is absent or is selected from the group consisting of —O—, —S—, —N(R 6 )—, and —C(R 16 )(R 17 )— wherein R 16 and R 17 are independently the same or different and are selected from the group consisting of hydrogen or a substituted or unsubstituted, saturated or unsaturated alkyl; wherein a linker is a traceless linker selected from the group consisting of —C 6 H 4 —CH 2 — and —C 6 H 4 —CH 2 —X 1 —C(═X 2 )— wherein X 1 and X 2 are independently the same or different and are selected from the group consisting of —O—, —S— and —N(R a ), and where R a is hydrogen or a lower alkyl; and —(CH 2 ) n —NR b —(C═O)— wherein n=2 or 3 and R b is hydrogen or a lower alkyl; and wherein a toxin is an agent that is toxic upon cleavage by an activating enzyme with the proviso that the toxin is not 5-fluorodeoxyuridine, or any derivative or analog thereof.