43179-28-8Relevant academic research and scientific papers
Conformational and electronic properties of the two cis (5S,6R) and (5R,6S) diastereoisomers of 5,6-dihydroxy-5,6-dihydrothymidine: X-ray and theoretical studies
Jolibois, Franck,Voituriez, Lucienne,Grand, Andre,Cadet, Jean
, p. 298 - 305 (2007/10/03)
The structure of (+)-cis-(5S,6R)-5,6-dihydroxy-5,6-dihydrothymidine was obtained using X-ray crystallography [space group P21 with a = 10.130(3) A, b = 6.434(9) A, c = 11.02(5)A, and β = 112.646(2)°]. The comparison of the two cis diastereoisomers of thymidine glycol (I, II) showed several structural and conformational differences. The solid state structures appear to be in agreement with the results of 1H NMR studies which were carried out in aqueous solution. Conformational and electronic properties of the ground state of the molecules I and II were obtained using ab initio LSD-DFT theory. Only slight differences between the crystal structure and the optimized geometry are observed for each of the two oxidized nucleosides. On the other hand, molecules I and II exhibit significant differences in their electronic properties. In particular, the dipole moment of (5S,6R)-thymidine glycol (I) is twice smaller than that of the (5R,6S) diastereoisomer (II). It is noteworthy that these differences in the electronic properties between the two compounds may be related to changes in the rotameric population around the C4'-C5' bond. The repartition of the electrostatic potential is different in the two compounds. These observations lead to a better understanding of the structural changes when the above lesions are included within a DNA molecule.
Reactions des radicaux 6-hydroxy-5,6-dihydrothymid-5-yles en solution aqueuse
Berger, M.,Sarrazin, F.,Cadet, J.
, p. 853 - 862 (2007/10/02)
The main reactions of 6-hydroxy-5,6-dihydrothymid-5-yl radicals, specifically obtained by electron capture dissociation of the trans diastereomers of 5-bromo-6-hydroxy-5,6-dihydrothymidine, were determined in aqueous solutions on the basis of final product analysis.In oxygen-free aqueous solutions a complex mixture of both monomeric and dimeric decomposition products was produced.It is worth mentioning the radiation-induced formation of modified nucleosides which involves the transient generation of 5-(2'-deoxyuridyl)methyl radical.This may be explained in terms of initial formation of 6-hydroxy-5,6-dihydrothymid-5-yl radicals, followed by dehydration and subsequent deprotonation.
Stereo-structures of Reaction Products of Thymidine Epoxides with Amines and L-Amino Acid Ethyl Esters
Harayama, Takashi,Yanada, Reiko,Tanaka, Mihoko,Taga, Tooru,Machida, Katsunosuke,et al.
, p. 2555 - 2562 (2007/10/02)
Reaction of thymidine epoxide (6) derived from (5R,6R)-trans-(+)-5-bromo-6-hydroxy-5,6-dihydrothymidine (2) with amines and L-amino acid ethyl esters afforded cis adduct (10) and that of the epoxide (8) derived from (5S,6S)-trans-(-)-5-bromo-6-hydroxy-5,6
Identification of the Products resulting from the Direct effects of γ-Radiation on Thymidine
Shaw, Anthony A.,Voituriez, Lucienne,Cadet, Jean,Gregoli, Silvano,Symons, Martyn C.
, p. 1303 - 1308 (2007/10/02)
The products formed upon γ-irradiation of thymidine in frozen aqueous solution have been identified.These products may all be explained in terms of the fates of now well documented primary charged radical species, and our results complement well those of previous e.s.r. studies on those primary and secondary radicals.In order to probe the mechanisms of formation of the major products, we have carried out experiments using heavy isotopes, including deuterium oxide and (18)O2.The radical cation undergoes both hydration, yielding the four isomers of 6-hydroxy-5,6-dihydrothymidine, and deprotonation at the methyl group to yield 5-hydroxymethyl-2'-deoxyuridine.As expected, the radical anion reacts primarily by protonation at C-6 to yield the (5R)- and (5S)-diastereoisomers of 5,6-dihydrothymidine and 5-hydroxy-5,6-dihydrothymidine.Excitation processes were shown to occur by the observation of the thymidine cyclobutane dimers.The release of significant amounts of thymine and 2-deoxy-D-ribono-1,4-lactone indicates the formation of radicals centred within the sugar moiety.The proposed role of the initial charged radicals in the formation of certain products has been supported by quantitative experiments carried out using compounds expected to be electron scavengers and electron donors with respect to thymidine.Finally, subsequent to our earlier paper on the e.s.r. identification of the radicals formed upon irradiation of thymidine bromohydrin in frozen aqueous solution, we have isolated the products formed on annealing and identified them as thymidine and 5-hydroxymethyl-2'-deoxyuridine.We discuss their mechanisms of formation.
