173548-01-1Relevant academic research and scientific papers
Synthesis of photo-responsive acridine-modified DNA and its application to site-selective RNA scission
Tanaka, Keita,Yamamoto, Yoji,Kuzuya, Akinori,Komiyama, Makoto
, p. 1175 - 1185 (2008/12/23)
Photo-responsive phosphoramidite monomers, which bear an azobenzene between acridine and the phosphoramidite unit, were synthesized, and incorporated into oligonucleotides. Upon UV irradiation, the azobenzene in the modified DNA efficiently isomerized from the trans isomer into the cis isomer. Although the Tm values of their duplexes with complementary DNA were not much changed by the isomerization, site-selective RNA scission was significantly accelerated by the UV irradiation when Mn(II) ion was used as the catalyst for RNA scission. Copyright Taylor & Francis Group, LLC.
Photochemical reaction mechanisms of 2-nitrobenzyl compounds in solution I. 2-Nitrotoluene: Thermodynamic and kinetic parameters of the aci-nitro tautomer
Schwoerer, Markus,Wirz, Jakob
, p. 1441 - 1458 (2007/10/03)
The largely reversible, light-induced tautomerization of 2-nitrotoluene (1) to the quinonoid aci-nitro tautomer aci-1 was studied by flash photolysis as a benchmark for comparison with the widely used nitrobenzyl phototriggers ('caged compounds'). The pH-rate profile for the decay of aci-1 in aqueous solution exhibits downward curvature at pH 3-4, which is attributed to pre-equilibrium ionization of the nitronic acid aci-1 to its anion 1 (pKa = 3.57). Two regions of upward curvature, at pH ca. 6 and o ≈- 1), each indicate a change in the reaction mechanism. The elementary reactions that dominate between the curved regions are assigned on the basis of kinetic isotope effects and the observation of general acid catalysis: Hydronium ions regenerate 2-nitrotoluene by C-protonation of 1 in the pH range of 0-6, and H2O is the proton source at pH>6. A hird, irreversible Nef-type isomerization of aci-1 prevails in highly acidic solutions (pH0). The equilibrium constant for the thermal tautomerization of 1 to aci-1 is estimated as pKT = 17.0 ± 0.2 based on kinetic data.
