Currently there is considerable interest in the discovery and development of small molecules such as pyrrolo[2,1-c][1,4]benzodiazepines (PBD's) as potential antitumor and gene targeted drugs. 1 The PBD class of antitumor antibiotics exert their biological activity by covalently binding to the N-2 of guanine in the minor groove of DNA through the imine or imine equivalent functionality at N10−C11 of the PBD's. Anthramycin (1) and DC-81 (2) are two well-known and ...