Site of attack of the hydroxyl radical on the pyrimidic ring. Thymine and thymidine peroxides (in French)
BS>The action of gamma -rays on thymine in aerated aqueous solution was studied. For pH values of <1.7, the preferential formatlon of 5hydroperoxy-6- hydroxy-5,6-dihydrothymine occurs, and for pH values of >1.7 the formation of 6- hydroperoxy-5-hydroxy-5,6dihydrothyrmine occurs. Similar results are obtained for thymidine. The substitution of a halogen in position 5 in 5,6-halohydrines of 2,4-dioxopyrimidines by a perhydroxyl (or hydroxyl) ion using hydrogen peroxide (or water) in the presence of silver oxide ls accompanied by the transposition from position 6 to position 5 of the hydroxyl initially present in the ring. The entering nucleophile grouping positions itself at position 6. Thus 5-bromo-6-hydroxy-5,6-dihydrothymine yields under these conditions 6- hydroperoxy- 5-hydroxy-5,6-dihydrothymine. The stereochemistry of this reaction is given for thymidine. The action of hydrogen peroxide on the cis-glycol of thymine in an acid medium quantitatively yields 6-hydroperoxy-5-hydroxy 5,6dihydro-cis-thymine. (FR)
- Research Organization:
- CEN, Grenoble, France
- NSA Number:
- NSA-29-002532
- OSTI ID:
- 4408380
- Journal Information:
- Compt. Rend., Ser. C, v. 276, no. 25, pp. 1743-1746, Journal Name: Compt. Rend., Ser. C, v. 276, no. 25, pp. 1743-1746; ISSN CHDCA
- Country of Publication:
- France
- Language:
- French
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