Very highly fluorescent product from 2′-deoxyguanosine with t-butanol in aqueous solution by exposure to cobalt-60 gamma-rays

Abstract

2′-Deoxyguanosine in aqueous solution (5 × 10 −4 mol/dm 3) was irradiated with 60Co gamma-rays in the presence of t-BuOH (10 −1 mol/dm 3) under N 2. A very highly fluorescent product was isolated by gel chromatography (Cellulofine GC-15-m) and high performance liquid chromatography (Supelcosil LC-8-DB). A longer wavelength shift of absorption maxima in UV spectrum and no C=O stretching absorption in IR spectrum as compared to the original compound were found. The mass spectra of the product and its TMS derivative suggested that the very highly fluorescent product was 2-amino-6-(t-hydroxybutyl)-9-(2′-deoxyribosyl)-purine. This was confirmed by measurements of 1H and 13C NMR and also by elemental analysis. The production yield, G value, was 0.1. The addition of alcohol radical and the elimination of OH group at the C-6 position of guanine base ring is a new finding and an interesting reaction with its very highly fluorescent nature. Therefore, this reaction is important radiochemically rather than radiobiologically.