title: (5'S)- and (5'R)-5',8-cyclo-2'-deoxyguanosine: mechanistic insights on the 2'-deoxyguanosin-5'-yl radical cyclization.
abstract: 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.
authors.affiliation: ISOF, Consiglio Nazionale delle Ricerche, Bologna, Italy. chrys@isof.cnr.it
authors.forename: Chryssostomos
authors.initials: C
authors.lastname: Chatgilialoglu
authors.forename: Rita
authors.initials: R
authors.lastname: Bazzanini
authors.forename: Liliana B
authors.initials: LB
authors.lastname: Jimenez
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
mesh_terms: 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
chemical_list: C439365:8-bromo-2'-deoxyguanosine; C050888:8,5'-cyclo-2'-deoxyguanosine; D003849:Deoxyguanosine