EXCITED STATES AND PHOTOBIOLOGICAL PROPERTIES OF POTENTIAL DNA CROSS-LINKING AGENTS, THE BENZODIPYRONES

Abstract —Potential DNA cross-linking agents, benzo{1,2-b:4,5-b'}dipyran-2,8-dione ( cis -benzodipyrone) and benzo{1,2-b:4,5-b'}dipyran-2,7-dione ( trans -benzodipyrone), have been synthesized. The excited triplet states of these reagents resemble those of other coumaryl derivatives in their spectroscopic assignments and characteristics and thus their reactivites. In particular, trans -benzodipyrone is significantly more reactive toward pyrimidine bases in solution than the other coumaryl derivatives examined, by virtue of its possessing two reactive pyrone C=C bonds within the molecular framework. The unique reactivity of trans -benzodipyrone, with its two reactive pyrone bonds across the long molecular axis, appears to be reflected in its ability to photoinduce mutation in certain Bacillus subtilis strains. This preliminary study provides data that will be useful in designing experiments to elucidate the molecular mechanisms for the biological activities of these compounds.