<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Vrantza, Despoina</style></author><author><style face="normal" font="default" size="100%">Kaloudis, Panagiotis</style></author><author><style face="normal" font="default" size="100%">Leondiadis, Leondios</style></author><author><style face="normal" font="default" size="100%">Gimisis, Thanasis</style></author><author><style face="normal" font="default" size="100%">Georgios C. Vougioukalakis</style></author><author><style face="normal" font="default" size="100%">Orfanopoulos, Michael</style></author><author><style face="normal" font="default" size="100%">Gasparutto, Didier</style></author><author><style face="normal" font="default" size="100%">Cadet, Jean</style></author><author><style face="normal" font="default" size="100%">Encinas, Susana</style></author><author><style face="normal" font="default" size="100%">Paris, Cecilia</style></author><author><style face="normal" font="default" size="100%">Miranda, Miguel A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">{Modification of Guanine with PhotolabileN-Hydroxypyridine-2(1H)-thione: Monomer Synthesis, Oligonucleotide Elaboration, and Photochemical Studies}</style></title><secondary-title><style face="normal" font="default" size="100%">Helv. Chim. Acta</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">oct</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://doi.wiley.com/10.1002/hlca.200690220</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">10</style></number><volume><style face="normal" font="default" size="100%">89</style></volume><pages><style face="normal" font="default" size="100%">2371–2386</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The photochemistry of N-hydroxypyridine-2(1H)-thione (NHPT), inserted as a photolabile modifier at the 6-position of 2′-deoxyguanosine or guanosine, has been evaluated. In particular, 6-[(1-oxidopyridin-2-yl)sulfanyl]- (1a) and 6-[(pyridin-2-yl)sulfanyl]-2′,6-dideoxyguanosine (2a), novel photolabile derivatives of the natural nucleosides, were synthesized and characterized. The observed photolysis products of 1a in organic solvents could only be rationalized by assuming a rapid equilibrium with the corresponding 6-[(2-thioxopyridin-1(2H)-yl)oxy] analogue 3a (Scheme 5). Transient spectroscopy of 1a indicated a strong triplet-excited state suitable for triplet → triplet energy transfer or singlet-oxygen generation. The NHPT function was stable enough for (slightly modified) automated solid-phase oligonucleotide synthesis. The utility of the above compounds is discussed, as well as their potential use in photosensitization of reactive oxygen species in DNA. © 2006 Verlag Helvetica Chimica Acta AG.</style></abstract></record></records></xml>