3133-07-1Relevant academic research and scientific papers
Photoinduced C-Br homolysis of 2-bromobenzophenones and Pschorr ring closure of 2-aroylaryl radicals to fluorenones
Moorthy, Jarugu Narasimha,Samanta, Subhas
, p. 9786 - 9789 (2008/03/17)
(Chemical Equation Presented) A variety of diversely substituted 2-aroylaryl radicals, generated by photoinduced homolysis of 2-bromoarylketones, is shown to undergo Pschorr cyclization to yield fluorenones in moderate to excellent yields. The photochemical results illustrate that the substituents in the two phenyl rings of the 2-bromobenzophenone skeleton exert a dramatic influence on the reactivity of the derived 2-aroylaryl radicals. The disubstitution by methoxy groups in the radical ring renders the aryl σ-radical highly electrophilic and unreactive for hydrogen abstraction and cyclization. On the other hand, the substituents in the non-radical ring that strongly stabilize the hydrofluorenyl π-radical, formed subsequent to the attack of the 2-aroylaryl radical on the non-radical ring, promote cyclization to furnish fluorenones in excellent isolated yields.
Kinetics and Mechanism of Oxidation of Fluoren-9-ol and Substituted Fluoren-9-ols by Bromamine-T
Gunasekaran, S.,Venkatasubramanian, N.
, p. 774 - 777 (2007/10/02)
The title reactions have been investigated in aq. acetic acid medium both in the presence and absence of perchloric acid.The reactions are first order each in and under both the conditions.There is unit dependence in perchloric acid.The effects of change in polarity of the solvent medium, added toluene-p-sulphonamide and sodium perchlorate have been studied.The reaction exhibits kinetic isotope effect (kH/kD = 2.2).Hammett ρ is found to be -2.8.Activation parameters have been evaluated.A mechanism consistent with rate data has been proposed.
