110457-90-4Relevant academic research and scientific papers
Anomeric 5-Aza-7-deaza-2′-deoxyguanosines in Silver-Ion-Mediated Homo and Hybrid Base Pairs: Impact of Mismatch Structure, Helical Environment, and Nucleobase Substituents on DNA Stability
Zhou, Xinglong,Kondhare, Dasharath,Leonard, Peter,Seela, Frank
, p. 10408 - 10419 (2019/07/18)
Nucleoside configuration (α-d vs. β-d), nucleobase substituents, and the helical DNA environment of silver-mediated 5-aza-7-deazaguanine-cytosine base pairs have a strong impact on DNA stability. This has been demonstrated by investigations on oligonucleotide duplexes with silver-mediated base pairs of α-d and β-d anomeric 5-aza-7-deaza-2′-deoxyguanosines and anomeric 2′-deoxycytidines incorporated in 12-mer duplexes. To this end, a new synthetic protocol has been developed to access the pure anomers of 5-aza-7-deaza-2′-deoxyguanosine by glycosylation of either the protected nucleobase or its salt followed by separation of the glycosylation products by crystallization and chromatography. Thermal stability measurements were performed on duplexes with α-d/α-d and β-d/β-d homo base pairs or α-d/β-d and β-d/α-d hybrid pairs within two sequence environments, positions 6 or 7, of oligonucleotide duplexes. The respective Tm stability increases observed after silver ion addition differ significantly. Homo base pairs with β-d/β-d or α-d/α-d nucleoside combinations are more stable than α-d/β-d hybrid base pairs. The positional switch of silver-ion-mediated base pairs has a significant impact on stability. Nucleobase substituents introduced at the 5-position of the dC site of silver-mediated base pairs affect base pair stability to a minor extent. Our investigation might lead to applications in the construction of bioinspired nanodevices, in DNA diagnostics, or metal-DNA hybrid materials.
5-Aza-7-deaza-2'-deoxyguanosine: Studies on the Glycosylation of Weakly Nucleophilic Imidazo-s-triazinyl Anions
Rosemeyer, Helmut,Seela, Frank
, p. 5136 - 5143 (2007/10/02)
5-Aza-7-deaza-2'-deoxyguanosine (1) has been synthesized by glycosylation of the anions of the imidazo-s-triazines 3 or 4b with 2-deoxydi-O-(p-toluoyl)-α-D-erythro-pentofuranosyl chloride (7a).Glycosylation was carried out under liquid-liquid or solid-liquid phase-transfer conditions with Bu4NHSO4 or the cryptand TDA-1 as catalyst as well as in the presence of NaH.In contrast to the stereospecific glycosylation occurring at hard nucleophiles, glycosylation was not stereospecific in the case of weakly nucleophilic imidazo-s-triazines; α- and β-anomerswere formed by applying the three different glycosylation methods.Configurational as well as conformational parameters of the deoxynucleosides 1 and 2 were determined by one- and two-dimensional FT-NMR spectroscopy.Both anomeric 2'-deoxyguanosine isosters exhibit the anti conformation at the N-glycosylic bond, a predominant C-2'-endo sugar puckering, and a (-sc) conformation around the C-4'-C-5' bond.
