(5'S)- and (5'R)-5',8-cyclo-2'-deoxyguanosine: mechanistic insights on the 2'-deoxyguanosin-5'-yl radical cyclization.
The two diastereomeric forms (5'S) and (5'R) of 5',8-cyclo-2'-deoxyguanosine have been synthesized and fully characterized. They have been used as references for the investigation of gamma-irradiation of 2'-deoxyguanosine and photolysis of 8-bromo-2'-deoxyguanosine in aqueous solutions. The observed (5'R)/(5'S) ratio of 8:1 was obtained in both sets of experiments. The mechanism of the cyclization reaction is discussed in some detail, and the diastereomeric outcome is rationalized in terms of favorable hydrogen-bonded structures in the pro-(5'R) conformation.
Chatgilialoglu
Chryssostomos
C
ISOF, Consiglio Nazionale delle Ricerche, Bologna, Italy. chrys@isof.cnr.it
Bazzanini
Rita
R
Jimenez
Liliana B
LB
Miranda
Miguel A
MA
D003500:Cyclization; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D005720:Gamma Rays; D015394:Molecular Structure; D010782:Photolysis; D013237:Stereoisomerism
C439365:8-bromo-2'-deoxyguanosine; C050888:8,5'-cyclo-2'-deoxyguanosine; D003849:Deoxyguanosine