n-Propyldiazonium ion alkylates O6 of guanine with rearrangement, but alkylates N-7 without rearrangement

Cancer Lett. 1982 May-Jun;16(1):51-6. doi: 10.1016/0304-3835(82)90090-8.

Abstract

Treatment of guanosine with n-propylnitrosourea yields 7-n-propylguanine (after acid hydrolysis) but O6-isopropylguanosine. Similarly, injection of [3H]di-n-propylnitrosamine into Sprague--Dawley rats resulted in isolation of 7-n-propylguanine from RNA, but O6-isopropylguanosine. The amounts of the different adducts indicate that attack at both N-7 and O6 of guanine proceed by bimolecular substitution (otherwise significant levels of 7-isopropylguanine should have been seen), but the observed rearrangement indicates that the transition state for reaction at O6 may be much looser than that for reaction at N-7.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkylation
  • Animals
  • Chemical Phenomena
  • Chemistry
  • Chromatography, Thin Layer
  • Guanine / analogs & derivatives*
  • Guanine / isolation & purification
  • Guanine / metabolism
  • Guanosine / analogs & derivatives*
  • Guanosine / isolation & purification
  • Guanosine / metabolism*
  • Liver / metabolism
  • Male
  • Nitrosamines / pharmacology*
  • Nitrosourea Compounds / metabolism
  • RNA / analysis
  • Rats
  • Rats, Inbred Strains

Substances

  • Nitrosamines
  • Nitrosourea Compounds
  • Guanosine
  • N-nitroso(di-n-propyl)amine
  • 7-n-propylguanine
  • Guanine
  • RNA
  • propylnitrosourea
  • O-isopropylguanosine