7, R,= H; R,= R,= Li 8, R,= H; R,= R,= Na 9, R,= H; R,= R,= COOH 10, R,= CH,; R,= R,= H 11, R,= COOH; R,= R,= H and is undoubtedly a planar hydrocarbon? The addition of a methyl group at position 12 to afford 7, 12-dimethylbenz [a] anthracene (7, 12-DMBA, 2) not only increases the carcinogenic potency6 but renders the molecule nonplanar6 because of the steric effect of the 12-methyl group. We were interested to see whether the introduction of ...
