5122-36-1Relevant articles and documents
γ Irradiation of 2'-deoxyadenosine in oxygen-free aqueous solutions: Identification and conformational features of formamidopyrimidine nucleoside derivatives
Raoul,Bardet,Cadet
, p. 924 - 933 (1995)
The two major radiation-induced decomposition products of 2'- deoxyadenosine in oxygen-free aqueous solution have been isolated by reverse- phase HPLC. The 1H and 13C NMR features of the two modified nucleosides obtained in DMSO-d6 are indicative of a similar formamidopyrimidine structure for the base residue (the ring-opened form of a C-8 hydroxylated purine). Interestingly, the sugar moiety exhibits a pyranose configuration, the two nucleosides being a pair of α and β anomers. One-bond and long- range 1H-13C 2D NMR experiments have allowed the complete assignment of the carbon atoms. Confirmation of the base structure was obtained by 1H- 15N scalar-correlated 2D NMR experiments. Attempts were made to characterize the expected furanose form of the initially generated formamidopyrimidine derivative. In this respect, isomerization reaction of the sugar moiety of the latter compound takes place rapidly after γ- irradiation as inferred from 1H NMR analysis. The conformational study of the sugar moiety of the two pyranose anomers was inferred from detailed 600.13 MHz 1H NMR analysis in D2O. The α anomer exhibits a predominant 1C4 conformation whereas the β anomer adopts preferentially a 4C1 conformation. In addition, the dynamic study of the restricted rotation of the formamido bond has revealed a 1/5 ratio in favor of the s-cis rotamer for both nucleosides. The energy barrier at coalescence was determined to be ΔG = 75.5 kJ · mol-1 (T(c) = 370 K).
Mechanism of degradation of purine nucleosides by formamide. Implications for chemical DNA sequencing procedures
Saladino, Raffaele,Mincione, Enrico,Crestini, Claudia,Negri, Rodolfo,Di Mauro, Ernesto,Costanzo, Giovanna
, p. 5615 - 5619 (1996)
We describe the reaction of formamide with 2'-deoxyadenosine and 2'-deoxyguanosine to give imidazole ring opening by nucleophilic addition on the electrophilic C(8)-position of the purine ring. This information allows improvement of the one-lane chemical DNA sequencing procedure based on the base-selective reaction of formamide with DNA. The reactivity with formamide of several 7-deazapurine analogues (7-deaza-2'-deoxyinosine, 7-deaza-2'-deoxyguanosine, and 7-deaza-2'-deoxyadenosine) incorporated into polynucleotides is also described. The wide spectrum of different sensitivities to formamide displayed by these purine analogues provides the single-lane DNA chemical sequencing procedures with the possibility of wide-ranging signal intensity modulation and thus increased specificity.
Reaction of purines with hydroxyl radical generated by photolysis of mercaptopyridine-N-oxides
Vieira,Telo,Dias
, p. 318 - 325 (2007/10/03)
The UV-photolysis of 4-mercaptopyridine-N-oxyde in aqueous solution is shown to be an efficient method of generating HO. radicals, as an alternative to the radiolysis of water. The reaction of adenine with HO. produced by the photolytic method resulted in the formation of 8-hydroxyadenine and 4,6-diamino-5-formamidopyrimidine in conditions and yields similar to those observed when HO. is produced by water radiolysis. ESR studies of the transients formed upon reaction of HO. with xanthine showed the formation of a radical anion in neutral conditions and a radical dianion at high pH values, due to the oxidation of the substrate by the conjugate base of HO., the O.- radical.