CHARACTERIZATION OF DNA-ADDUCTS FORMED BY THE 4 CONFIGURATIONALLY ISOMERIC 5,6-DIMETHYLCHRYSENE 1,2-DIHYDRODIOL 3,4-EPOXIDES

The DNA adducts formed from the racemic syn and anti dihydrodiol epoxi des of 5,6-dimethylchrysene were characterized through various spectro scopic methods. Substantial reaction with the amino groups of both deo xyadenosine and deoxyguanosine residues were detected with both the sy n and anti derivatives. The chemical shifts and coupling constants for the cis and trans opened adducts from the syn dihydrodiol epoxide wer e distinctly different, whereas for the anti dihydrodiol epoxide these properties were fairly similar for cis and trans adducts. In the latt er case, assignment of traits and cis configurations was less obvious, and the finding that trans adducts have always predominated over cis adducts for all dihydrodiol epoxides studied to date was helpful in ma king these assignments. The preferential formation of cis adducts in D NA by the syn dihydrodiol epoxide is more like the chemistry of the di hydrodiol epoxide of benzo[c]phenanthrene than of benzo[g]chrysene, al though both of these, like 5,6-dimethylchrysene, are non-planar compou nds.