14906-55-9Relevant articles and documents
A Biocatalytic Synthesis of Heteroaromatic N-Oxides by Whole Cells of Escherichia coli Expressing the Multicomponent, Soluble Di-Iron Monooxygenase (SDIMO) PmlABCDEF
Petkevi?ius, Vytautas,Vaitekūnas, Justas,Taurait?, Daiva,Stankevi?iūt?, Jonita,?arlauskas, Jonas,??nas, Narimantas,Me?kys, Rolandas
supporting information, p. 2456 - 2465 (2019/01/25)
Aromatic N-oxides (ArN?OX) are desirable biologically active compounds with a potential for application in pharmacy and agriculture industries. As biocatalysis is making a great impact in organic synthesis, there is still a lack of efficient and convenient enzyme-based techniques for the production of aromatic N-oxides. In this study, a recombinant soluble di-iron monooxygenase (SDIMO) PmlABCDEF overexpressed in Escherichia coli was showed to produce various aromatic N-oxides. Out of 98 tested N-heterocycles, seventy were converted to the corresponding N-oxides without any side oxidation products. This whole-cell biocatalyst showed a high activity towards pyridines, pyrazines, and pyrimidines. It was also capable of oxidizing bulky N-heterocycles with two or even three aromatic rings. Being entirely biocatalytic, our approach provides an environmentally friendly and mild method for the production of aromatic N-oxides avoiding the use of strong oxidants, organometallic catalysts, undesirable solvents, or other environment unfriendly reagents. (Figure presented.).
Acetyl exchange between pyridine N-oxides in acetonitrile solutions: An attempt to apply the Marcus equation to acetyl transfer
Rybachenko,Schroeder,Chotii,Titov,Kovalenko,Leska,Grebenyuk
, p. 1608 - 1615 (2007/10/03)
Forty-three (including eight identical) reactions of acetyl transfer from N-acetyloxypyridinium salts to pyridine N-oxides in acetonitrile solutions were studied. The rate constants k2 vary in the range 107-10-1 1 mol-1 s-1; the equilibrium constants K, in the range 107-10-7; the activation enthalpy ΔH≠, in the range 17-30 kJ mol-1; the activation entropy -ΔS≠, in the range 60-85 J mol-1 K-1; and the heat of reaction -ΔH0, within ±50 kJ mol-1. All reactions occur in a single stage by the concerted SN2 mechanism with a low degree of bond cleavage in the transition state. The rate and equilibrium of the acetyl exchange are satisfactorily described by the Bronsted equation. The quality of predicting the reactivity is substantially improved by introducing into the correlation equation a second parameter, the rates of identical reactions.
Biotransformation of phenyl- and pyridylalkane derivatives in rat liver 9,000xg supernatant (S-9)
Takeshita, Mitsuhiro,Miura, Masatomo,Unuma, Yukiko,Iwai, Sakiko,Sato, Izumi,Hongo, Takahiko,Arai, Toshie,Kosaka, Kazuhiro
, p. 831 - 836 (2007/10/03)
When phenylpropanes were incubated with phenobarbital-pretreated rat liver 9,000xg supernatant (S-9), oxidative hydroxylation occurred to give phenylpropanol (racemic), (1R, 2S)- and (1R, 2R)-phenylpropanediols, (2S)-hydroxyphenylpropanone. Incubation of pyridylethane and propane with S-9 afforded α-pyridylethanol and propanol, but those were optically inactive. During the incubation of 1-phenylpropanone, an asymmetric redox reaction simultaneously occurred to give (2S)-phenylpropanol, (1R, 2S)- or (1R, 2R)-phenylpropanediols and (2R)-hydroxyphenylpropanone. Acetylpyridines were enantioselectively reduced to afford α-pyridylethanols in high optical yields (94-98%ee). The oxidation of pyridylalkane was significantly inhibited by cytochrome P-450 inhibitor (SKF-525A), but reduction of acetylpyridines was not inhibited. Thus, cytochrome P-450 was found to be responsible for the oxidation of pyridylalkane, but not for the reduction of the ketone.