Synthesis of the Fully Protected Phosphoramidite of the Benzene-DNA Adduct, N²-(4-Hydroxyphenyl)-2′-Deoxyguanosine and Incorporation of the Later into DNA Oligomers

Abstract

N²- (4-Hydroxyphenyl)-2 ′-deoxyguanosine-5 ′-O-DMT-3 ′-phosphoramidite has been synthesized and used to incorporate the N²-(4-hydroxyphenyl)-2 ′-dG (N²-4-HOPh-dG) into DNA, using solid-state synthesis technology. The key step to obtaining the xenonucleoside is a palladium (Xantphos-chelated) catalyzed N²-arylation (Buchwald-Hartwig reaction) of a fully protected 2 ′-deoxyguanosine derivative by 4-isobutyryloxybromobenzene. The reaction proceeded in good yield and the adduct was converted to the required 5 ′-O-DMT-3 ′-O-phosphoramidite by standard methods. The latter was used to synthesize oligodeoxynucleotides in which the N²-4-HOPh-dG adduct was incorporated site-specifically. The oligomers were purified by reverse-phase HPLC. Enzymatic hydrolysis and HPLC analysis confirmed the presence of this adduct in the oligomers.

Keywords:

• Benzene DNA adduct
• hydroquinone
• p-benzoquinone
• buchwald-hartwig reaction
• N ²-(4-hydroxyphenyl)-2′-deoxyguanosine

Acknowledgments

This work was supported by NIH grant CA72079 (to B. H.) and was administrated by the Lawrence Berkeley National Laboratory under Department of Energy contract DE-AC03-76SF00098.