Reaction of Br3 ·2- with 2-Deoxy-D-ribose. A Preferred Attack at C-1

Abstract
In the photolysis of 5-bromouracil containing DNA Br atoms are expected intermediates. In order to evaluate the possible site of attack of the Br atom at the sugar moiety of DNA the reaction of 2-deoxy-D-ribose with the Br atom (complexed with 2 bromide ions) was investigated. Hydroxyl radicals generated by the radiolysis of N2O saturated aqueous solutions were converted into Br3.2- radicals by 1 M bromide ions. Br3.2- reacts with 2-deoxy-D-ribose (k = 3.7 .cntdot. 104 M-1 s-1, pulse radiolysis). The major product is 2-deoxy-D-erythro-pentonic acid (G = 2.4, .gamma.-radiolysis). It is formed by H abstraction from C-1 and oxidation of this radical by other radicals. An alternative route via the radical at C-2 is neglible. It follows that Br3.2- reacts preferentially at C-1 of 2-deoxy-D-ribose.

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