14716-23-5Relevant academic research and scientific papers
Reactions of 2-hydroxybenzophenones with Corey-Chaykovsky reagent
Chittimalla, Santhosh Kumar,Chang, Tsung-Che,Liu, Ting-Chun,Hsieh, Hsing-Pang,Liao, Chun-Chen
, p. 2586 - 2595 (2008/09/19)
A variety of 2-hydroxybenzophenones on reaction with Corey-Chaykovsky reagent underwent unprecedented rearrangements leading to 3-substituted benzofurans 8 and one-carbon homologated compounds 9 and 12. Compounds 9 could further be quantitatively transfor
Generation and reactivity of ketyl radicals with lignin related structures. On the importance of the ketyl pathway in the photoyellowing of lignin containing pulps and papers
Fabbri, Claudia,Bietti, Massimo,Lanzalunga, Osvaldo
, p. 2720 - 2728 (2007/10/03)
(Chemical Equation Presented) Ketyl radicals with lignin related structures have been generated by means of radiation chemical and photochemical techniques. In the former studies ketyl radicals are produced by reaction of α-carbonyl-β-aryl ether lignin models with the solvated electron produced by pulse radiolysis of an aqueous solution at pH 6.0. The UV-vis spectra of ketyl radicals are characterized by three main absorption bands. The shape and position of these bands slightly change when the spectra are recorded in alkaline solution (pH 11.0) being now assigned to the ketyl radical anions and a pKa = 9.5 is determined for the 1-(3,4,5-trimethoxyphenyl)-2- phenoxyethanol-1-yl radical. Decay rates of ketyl radicals are found to be dose dependent and, at low doses, lie in the range (1.7-2.7) × 103 s-1. In the presence of oxygen a fast decay of the ketyl radicals is observed (k2 = 1.8-2.7 × 109 M-1 s -1) that is accompanied by the formation of stable products, i.e., the starting ketones. In the photochemical studies ketyl radicals have been produced by charge-transfer (CT) photoactivation of the electron donor-acceptor salts of methyl viologen (MV2+) with α-hydroxy-α- phenoxymethylaryl acetates. This process leads to the instantaneous formation of the reduced acceptor (methyl viologen radical cation, MV+?), as is clearly shown in a laser flash photolysis experiment by the two absorption bands centered at 390 and 605 nm, and an acyloxyl radical [ArC(CO 2?)(OH)CH2(OC6H5)], which undergoes a very fast decarboxylation with formation of the ketyl radicals. Steady-state photoirradiation of the CT ion pairs indicates that 1-aryl-2-phenoxyethanones are formed as primary photoproducts by oxidation of ketyl radicals by MV2+ (under argon) or by molecular oxygen. Small amounts of acetophenones are formed by further photolysis of 1-aryl-2-phenoxyethanones and not by β-fragmentation of the ketyl radicals. The high reactivity of ketyl radicals with oxygen coupled with the low rates of β-fragmentation of the same species have an important bearing in the context of the photoyellowing of lignin containing pulps and papers.
PHOTOCHEMISTRY OF α-PHENOXY-p-METHOXYACETOPHENONE
Netto-Ferreira, J. C.,Scaiano, J. C.
, p. 443 - 446 (2007/10/02)
The triplet state of the title compound decays by a competition of β-phenyl quenching and β-cleavage leading to CH3OC6H4COCH2. and phenoxyl radicals.The latter process occurs with a quantum yield of 0.020.
REDUCTION PAR LES SELS CHROMEUX DE BROMURES BENZYLIQUES ORTHO-O-ACYLES AVEC TRANSPOSITION DU GROUPEMENT ACYLE DE L'ESTER: ACCES AUX ORTHO-HYDROXYBENZYL CETONES NON MASQUEES ET UNE NOUVELLE PREPARATION DE BENZO(B)FURANNES SUBSTITUES EN POSITION-2
Ledoussal, B.,Gorgues, A.,Coq, A. Le
, p. 5841 - 5852 (2007/10/02)
The ?-bonded organochromium (III) complexes resulting from the reduction of ortho-O-acyl benzylic bromides 1 with CrCl2 undergo an 1,5-transposition of the ester acyl functional group which allows, through selected experimental conditions either a selective access to the unmasked ortho-hydroxybenzyl ketones 2 or a new preparation of the 2-substituted benzofurans 3.The scope and limitations of the method are presented.
Chromium(II) Salt mediated Reductive Transposition of an Ester Acyl Group in ortho-O-Acyl Benzylic Bromides: a Ready Access to Unmasked ortho-Hydroxybenzyl Ketones and a New Route to Benzofurans
Ledoussal, Benoit,Gorgues, Alain,Coq, Andre Le
, p. 171 - 172 (2007/10/02)
The mono-ο-bonded organochromium(III) complexes (A) derived from (1) rearrange internally into (B) through an acyl ester group transposition, selected experimental conditions allowing either a good access to the unmasked ortho-hydroxybenzyl ketones (2) or a new route to the 2-substituted benzofurans (3).
