title: Synthesis of [1,3, NH2-(15)N3] (5'S)-8,5'-cyclo-2'-deoxyguanosine.
abstract: To facilitate NMR studies and low-level detection in biological samples by mass spectrometry, [1,3, NH2-(15)N3] (5'S)-8,5'-cyclo-2'-deoxyguanosine was synthesized from imidazole-4,5-dicarboxylic acid in 21 steps. The three (15)N isotopes were introduced during the chemo-enzymatic preparation of [1,3, NH2-(15)N3]-2'-deoxyguanosine using an established procedure. The (15)N-labeled 2'-deoxyguanosine was converted to a 5'-phenylthio derivative, which allowed the 8-5' covalent bond formation via photochemical homolytic cleavage of the C-SPh bond. SeO2 oxidation of C-5' followed by sodium borohydride reduction and deprotection gave the desired product in good yield. The isotopic purity of the [1,3, NH2-(15)N3] (5'S)-8,5'-cyclo-2'-deoxyguanosine was in excess of 99.94 atom% based on liquid chromatography-mass spectrometry measurements.
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.
authors.forename: Chanchal K
authors.initials: CK
authors.lastname: Malik
authors.forename: Rajat S
authors.initials: RS
authors.lastname: Das
authors.forename: Ashis K
authors.initials: AK
authors.lastname: Basu
mesh_terms: D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D007553:Isotope Labeling; D009587:Nitrogen Isotopes / Q000138:chemical synthesis
chemical_list: D009587:Nitrogen Isotopes; C050888:8,5'-cyclo-2'-deoxyguanosine; D003849:Deoxyguanosine
keywords: 15N-S-cdG; cyclo-dG; tandem DNA lesion; γ-radiation damage