Efficient syntheses of C(8)-aryl adducts of adenine and guanine formed by reaction of radical cation metabolites of carcinogenic polycyclic aromatic hydrocarbons with DNA

J Org Chem. 2007 Jun 22;72(13):4856-63. doi: 10.1021/jo070518m. Epub 2007 May 27.

Abstract

The synthesis of the C(8)-aryl adducts of adenine and guanine formed by reaction of the radical cation metabolites of carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BP) and dibenzo[def,p]chrysene (DBC), with DNA is reported. The synthetic approach involves in the key step direct reaction of a PAH aldehyde with a di- or triamine precursor of a purine. The method is operationally simple, affords good yields of adducts, and is broad in its scope. The C(8)-aryl adducts of adenine and guanine derived from BP (6-BP-8-Ade and 6-BP-8-Gua) and DBC (10-DBC-8-Ade and 10-DBC-8-Gua) were synthesized in good yields by this method. Analogous C(8)-aryl adenine and guanine derivatives of other PAHs (anthracene, benz[a]anthracene, and chrysene) were also readily prepared via this approach. This method of synthesis is superior to the only method that is currently available. It entails direct reaction of short-lived PAH radical cations (generated electrochemically or chemically) with 2'-deoxyribonucleosides or the corresponding purine bases. It provides the adducts in low yields accompanied by complex mixtures of secondary products. An alternative synthesis that involves Pd-catalyzed Suzuki-Miyaura coupling of arylboronic acids with 8-bromopurine nucleosides was also investigated. Although the C(8)-purine adducts of PAHs, such as naphthalene, phenanthrene, pyrene, and chrysene, could be prepared by this method, analogous adducts of carcinogenic PAHs and other structurally related PAHs, e.g., anthracene, benz[a]anthracene, benzo[a]pyrene, and dibenzo[def,p]chrysene, could not be obtained. This difference was shown to be a consequence of the facility of competing hydrolytic deboronation of the corresponding arylboronic acids.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenine / chemistry*
  • Benzo(a)pyrene / chemistry
  • Boronic Acids / chemistry
  • Carcinogens / chemistry*
  • Cations / chemistry*
  • DNA / chemistry*
  • Free Radicals / chemistry
  • Guanine / chemistry*
  • Molecular Structure
  • Polycyclic Aromatic Hydrocarbons / chemistry*

Substances

  • Boronic Acids
  • Carcinogens
  • Cations
  • Free Radicals
  • Polycyclic Aromatic Hydrocarbons
  • Benzo(a)pyrene
  • Guanine
  • DNA
  • Adenine