PHOTOCHEMICAL COUPLING OF BENZO[a]PYRENE WITH 1‐METHYLCYTOSINE; PHOTOENHANCEMENT OF CARCINOGENICITY

Abstract— Irradiation of the carcinogenic benzo[a]pyrene(I) with 1‐methylcytosine hydro‐chloride(II) (molar ratio 1:10) at 3500 Å in methanol‐acetone produces the 6‐(1‐methylcytos‐5‐yl)‐benzo[a]pyrene(III). The structure of the product shows the hydrocarbon bound through the most active 6‐carbon atom to the nucleophilic 5‐position of the base. In the second part, the possibility of observing carcinogenic effects on the mouse skin from non‐carcinogenic hydrocarbons under the action of u.v. light is investigated. Both experiments provide evidence that the 4,5‐double bond (K region) of I presumably does not play a role in triggering the cancer process.

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