presence of plasmid pBR322 DNA. Significant conversions of the supercoiled circular pBR322 DNA (form I) to the open circular DNA (form II) have been found by treatment with the reductively activated 6-nitro-5-deazaflavin derivatives. Their DNA damaging effects have been found to be enhanced as the number of pyrrolecarboxamide group as the DNA binder increases. Antitumor activities of the hybrid molecules
Several benzophenone-β-turned dipeptide-alkyl chain molecules were prepared. In acetonitrile, intramolecular photochemical reaction of the synthetic molecules was investigated. The photoexcited benzophenone moiety abstracted selectively a hydrogen of the alkyl chain in the molecule. Such a site selectivity showed that the β-turned conformation might be rigid enough for the hydrogen abstraction in the excited state.