4783-79-3Relevant academic research and scientific papers
A directing group-assisted ruthenium-catalyzed approach to access: Meta -nitrated phenols
Sasmal, Sheuli,Sinha, Soumya Kumar,Lahiri, Goutam Kumar,Maiti, Debabrata
supporting information, p. 7100 - 7103 (2020/07/14)
meta-Selective C-H nitration of phenol derivatives was developed using a Ru-catalyzed σ-activation strategy. Cu(NO3)2·3H2O was employed as the nitrating source, whereas Ru3(CO)12 was found to be the most suitable metal catalyst for the protocol. Mechanistic studies suggested involvement of an ortho-CAr-H metal intermediate, which promoted meta-electrophilic aromatic substitution and silver-assisted free-radical pathway.
Influence of chlorine substitution on the hydrolytic stability of biaryl ether nucleoside adducts produced by phenolic toxins
Kuska, Michael S.,Majdi Yazdi, Mohadeseh,Witham, Aaron A.,Dahlmann, Heidi A.,Sturla, Shana J.,Wetmore, Stacey D.,Manderville, Richard A.
, p. 7176 - 7185 (2013/08/23)
A kinetic study is reported for the acid-catalyzed hydrolysis of oxygen (O)-linked biaryl ether 8-2′-deoxyguanosine (dG) adducts produced by phenolic toxins following metabolism into phenoxyl radical intermediates. Strikingly, the reaction rate of hydrolysis at pH 1 decreases as electron-withdrawing chlorine (Cl) substituents are added to the phenoxyl ring. The Hammett plot for hydrolysis at pH 1 shows a linear negative slope with ρX = -0.65, implying that increased Cl-substitution diminishes the rate of hydrolysis by lowering N7 basicity. Spectrophotometric titration provided an N7H+ pKa value of 1.1 for the unsubstituted adduct 8-phenoxy-dG (Ph-O-dG). Model pyridine compounds suggest N7H+ pKa values of 0.92 and 0.37 for 4-Cl-Ph-O-dG and 2,6-dichloro-Ph-O-dG (DCP-O-dG), respectively. Density functional theory (DFT) calculations also highlight the ability of the 8-phenoxy substituent to lower N7 basicity and predict a preference for N 3-protonation for highly chlorinated O-linked 8-dG adducts in water. The calculations also provide a rationale for the hydrolytic reactivity of O-linked 8-dG adducts in the gas-phase, as determined using electrospray mass spectrometry (ESI-MS). The inclusion of our data now establishes that the order of hydrolytic reactivity at neutral pH for bulky 8-dG adducts is N-linked > C-linked > O-linked, which correlates with their relative ease of N 7-protonation.
