Streptonigrin. 1. Structure-Activity Relationships among Simple Bicyclic Analogues. Rate Dependence of DNA Degradation on Quinone Reduction Potential

A series of simple aza and diaza bicyclic quinones related to the AB ring system of streptonigrin (1) have been synthesized and tested in vitro for their ability to degrade DNA under conditions similar to those used with the parent drug. The results obtained from a study of 22 quinones indicate that there is a quantitative linear relationship between their reduction potentials and the rate at which they degrade DNA under identical conditions in vitro. Almost all of the synthetic substances were superior to 1 in their DNA-degrading ability.