3669-52-1Relevant articles and documents
Photo-fries rearrangement of naphthyl acetate in supercritical carbon dioxide: Chemical evidence for solvent-solute clustering
Andrew, David,Des Islet, Brian T.,Margaritis, Argyrios,Weedon, Alan C.
, p. 6132 - 6133 (1995)
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Laser flash photolysis and CIDNP studies of 1-naphthyl acetate photo-fries rearrangement
Gritsan, Nina P.
, p. 4448 - 4458 (1996)
The steady-state and time-resolved CIDNP and flash photolysis methods were used in a detailed study of the photo-Fries rearrangement of 1-naphthyl acetate (I) in acetonitrile and methanol. The main reaction channel is the decay of I through the excited singlet state with the quantum yields 0.17 ±0.02 in acetonitrile and 0.42 ± 0.04 in methanol at room temperature. The absorption spectra of the naphthoxyl radical and triplet state of 1-naphthyl acetate were detected. The quantum yield of triplet was estimated as 0.4 ±0.2 and 0.35 ± 0.17 in acetonitrile and methanol, respectively. It has been established that the triplet-born radical pairs make a main contribution to the CIDNP of the photo-Fries rearrangement products. The involvement in the process of two different triplet states of I was supposed. The main decay channel of the lowest triplet state is the triplet-triplet annihilation, while the CIDNP of photo-Fries rearrangement products results from the decay of the upper triplet state of I with a lifetime of a few nanoseconds. The kinetics of CIDNP formation in reaction products has been analyzed, and the rate constants of the rearrangement of the preceding intermediates at room temperature have been estimated.
Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
experimental part, p. 641 - 649 (2011/03/19)
Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
Linear Bronsted-type behavior in the aminolysis of substituted naphthyl acetates
Rajarathnam,Ananthakrishna Nadar
, p. 157 - 164 (2007/10/03)
The reactions of 4-acetyl-1-naphthyl acetate (1) and 6-acetyl-2-naphthyl acetate (2) with a series of amines of varying pKa, viz. morpholine, ammonia, ethanolamine, glycine, n-butylamine, piperidine, hydrazine, imidazole, and hydroxylamine, are subjected to a kinetic investigation in aqueous medium, 30 °C, ionic strength 0.1 M (KCl). Pseudo-first-order rate coefficients (kobs) are found under amine excess. The plots of (kobs-kH) against free amine concentration are linear at constant pH. The macroscopic nucleophilic substitution rate coefficients (kN) are obtained as the slopes of these plots and found to be pH-independent for all the amines employed. The Bronsted-type plots obtained (log kN against amine pKa) for the aminolysis of both esters 1 and 2 are linear with slope values of β = 0.74 and β = 0.94, respectively. From these values, the kinetic law and the analysis of products, it is deduced that for both esters aminolysis proceed through a zwitterionic tetrahedral addition intermediate (T±) whereby its dissociation into products is rate-limiting (k2 step). Comparison of kN values among them shows that both esters follow an identical mechanistic pathway with 1 having higher reactivity than 2, the reasons for which are discussed.