Orientation in the Acylation of Phenol and in the Rearrangement of Phenolic Esters

Abstract

It has long been known that both the Friedel-Crafts acylation of phenol and the Fries rearrangement of phenolic esters yields a mixture of ortho and para hydroxy ketones, but a systematic study of the factors which influence the relative amounts of isomers obtained has not been reported. It is the purpose of this work to study the influence of conditions upon orientation in these two reactions, and it is hoped that this study may throw some light upon the reaction-mechanisms.Earlier work upon the acylation of phenol has been directed more to ascertaining the optimum conditions for the preparation of specific compounds than to a study of the reaction itself. We have confined this study to the acylation of phenol with straight chain saturated acid chlorides and to the rearrangement of phenyl esters of the saturated fatty acids in the presence of aluminum chloride. It was undertaken with the purpose of determining the effect of reaction conditions upon orientation. It is believed that the major factors which affect orientation under these conditions are: the molecular proportions of the reactants, the order of addition, temperature, time, the chain-length of the acylating group, and the solvent.It is known that phenol and acid chlorides can form complexes with the aluminum chloride, and that the formation of one or both of these complexes precedes the formation of a ketone complex. Sandulesco and Girard (1) have shown the formation of CeHsOAlCL when phenol and aluminum chloride react in equal molecular proportions, and that this compound can react with acid chlorides to form ketones. Where these authors used equal molecular proportions of phenoxyaluminum dichloride and acid chlorides at 125°in the absence of a solvent, both ortho and para ketones were obtained. When caprylyl chloride was used as the acylating agent, the amount of para and ortho hydroxy ketones was 38% and 45%, respectively, and when nonoyl chloride was used, 35% para and 55% ortho hydroxy ketones were obtained. The ratio (p/o) is, therefore, 0.85 in the former case and 0.64 in the latter. It is sig-645 SUMMARY 1. The effect of the molecular proportions of aluminum chloride used, the temperature, and the solvent employed in the acylation of phenol

Alkylated phenol series in lacustrine black shales from the Nördlinger Ries, southern Germany

“…The 2‐ n ‐hexadecyl and 4‐ n ‐hexadecyl phenols were synthesized by acylation of phenol with n ‐hexadecanoyl chloride obtained by treatment of commercially available n ‐hecadecanoic acid with thionyl chloride. The resulting mixture of 2‐ n ‐hexadecyl and 4‐ n ‐hexadecanoyl phenols was dissolved in 30 ml of dichloromethane and extracted twice with a solution of 0.6 g KOH in 48 ml of water and 14 ml of ethanol.…”

Contact allergy to capryloyl salicylic acid: a mechanistic chemistry and structure–activity perspective

“…Particularly relevant is a paper by Ralston et al on the acylation of phenol (related to methyl salicylate by the absence of the –CO 2 Me group) with capryloyl chloride and aluminium trichloride. In a series of 18 experiments in which the proportions of reagents, the order of addition, the reaction time and the temperature were all varied, the yields of ortho and para reaction products were determined.…”

“…Overall, therefore, from consideration of the literature on electrophilic aromatic substitution , we expect significant quantities of 3‐CSA ( 6 ) (> 10% of the total of 3‐CSA plus 5‐CSA) to be formed, via its methyl ester 5 , in the synthetic route, as shown in Fig. .…”

Novel Fluorescent Quater‐ and Quinquifurans: Syntheses and Photophysical Properties.

“…The classic method of Clemmensen reduction, when applied to 4-dodecanoylphenol, was poorly described with no yields given [19,20] and failed altogether in our hands. (In fact the prior Fries rearrangement of the phenyl ester does not give a clean 4-isomer [21]). So taking advantage of the discovery that PdCl 2 .…”