69267-29-4Relevant academic research and scientific papers
Photocatalytic reduction of acetylpyridine to pinacol using [fac-Re(bpy)(CO)3{4-(MeCO)py}]+ (bpy = 2,2′-bipyridine, py = pyridine)
Hori, Hisao,Koike, Kazuhide,Takeuchi, Koji,Ishitani, Osamu
, p. 376 - 377 (2000)
[fac-Re(bpy)(CO)3{4-(MeCO)py}]+ can act as an efficient photocatalyst for the reduction of 4-acetylpyridine to a pinacol (py-CMeOHCMeOH-py) in the presence of triethanolamine. The reaction proceeds via formation of a pinacol complex [fac-Re(bpy)(CO)3(py-CMeOHCMeOH-py)]+.
SIMULTANEOUS TIME-RESOLVED ESR AND OPTICAL ABSORPTION SPECTROSCOPY. THE PHOTOLYSIS OF 4-ACETYLPYRIDINE IN PROPANOL(-2).
Leuschner,Dohrmann
, p. 50 - 54 (2007/10/02)
A novel technique is described for the simultaneous in situ measurement of ESR and optical transients from intermediates produced by intermittent photolysis in solution. The technique has been applied to the photoreduction ( lambda ca. 300 plus or minus 30 nm) of 4-acetylpyridine (AP) in propanol(-2) at room temperature. The measurements gave the absorption spectrum and the molar extinction coefficients of the intermediate 1-hydro-4-acetylpyridinyl radical ( multiplied by (times) APH) in the 300-550 nm range as well as the ratio of the quantum yields for formation of multiplied by (times) APH and disappearance of AP. Absolute values of the quantum yields of 300 nm have been determined by additional ESR and spectrophotometric measurements under steady-state conditions. The various results are discussed in terms of a mechanism proposed for the photoreduction of AP in propanol(-2).
A CONVENIENT SYNTHESIS OF SUBSTITUTED PYRIDYLGLYCOLS PROMOTED BY AQUEOUS TITANIUM TRICHLORIDE
Clerici, Angelo,Porta, Ombretta
, p. 1239 - 1246 (2007/10/02)
2- and 4-Acetylpyridines, and 2- and 4-pyridinealdehydes when allowed to react with two-equiv. of aqueous titanium trichloride add to the carbonyl carbon atom of simple ketones (acetone, cyclopentanone, cyclohexanone) and aldehydes (acetaldehyde, propionaldehyde, benzaldehyde) affording substituted pyridylglycols in very good yields.The present one-pot method has considerable advantage over the existing procedure.The reaction is discussed in terms of a radical mechanism in which the Ti(III) species plays the fundamental role.
A Novel Reaction Type Promoted by Aqueous Titanium Trichloride. Synthesis of Allylic Pinacols
Clerici, Angelo,Porta, Ombretta
, p. 1690 - 1694 (2007/10/02)
Electron-withdrawing substituted carbonyl compounds which are allowed to react with 2 equiv of aqueous titanium trichloride selectively add to the carbonyl carbon atom of α,β-unsaturated aldehydes.Highly functionalized allylic pinacols are obtained in good yields under very simple experimental conditions.The fundamental role played by the titanium(III) ion is discussed.
REDUCTIVE REACTIONS OF SUBSTITUTED PYRIDINES BY AQUEOUS TITANIUM TRICHLORIDE
Clerici, Angelo,Porta, Ombretta
, p. 1293 - 1297 (2007/10/02)
Aqueous titanium trichloride reductively removes cyano and halo groups from the correspondingly substituted pyridines by a two electron-transfer process and promotes reduction of pyridyl-ketones and aldehydes to glycols by one electron-transfer process under very simple experimental conditions.
A Novel Reaction Type Promoted by Aqueous Titanium Trichloride. Synthesis of Unsymmetrical 1,2-Diols
Clerici, Angelo,Porta, Ombretta
, p. 2852 - 2856 (2007/10/02)
Electron-withdrawing substituted carbonyl compounds when allowed to react with 2 equiv of aqueous titanium trichloride in the presence of acetone, acetaldehyde, or benzaldehyde afford unsymmetrical 1,2-diols in high yields under very simple experimental conditions.
Termination Rates by Time-Resolved ESR. The N-Hydro-4-acetylpyridinyl Radical in Solution
Krohn, Holger,Leuschner, Rainer,Dohrmann, Juergen K.
, p. 139 - 143 (2007/10/02)
The second-order rate constants for the self-termination reaction of the N-hydro-4-acetylpyridinyl radical in propanol(-2) and propanol(-2)/acetone have been measured by time-resolved ESR during intermittent photolysis.The radical was generated from 4-acetylpyridine via different photochemical reactions.The rate constants were measured in the temperature range -10 to 26 deg C.The frequency factor and the activation energy from the Arrhenius plot are (1.1 +/- 0.4) * 1010 M-1 * s-1 and 16.6 +/- 0.6 kJ * mol-1, respectively.The Arrhenius parameters were independent of the solvent composition and the method of radical generation.The termination reaction is attributed to the formation of the respective pinacol by the combination of two radicals.The reaction rate is not diffusion-controlled.Possible mechanisms are proposed and discussed.
