The tetrabromo-cyclohexadienone formula, which was proposed for the compound resulting from the action of bromine on tribromophenol, is improbable.2. Facts are brought forward which render very remote the possibility of tribromophenol bromide being a mixture of ortho-and paraquinoid forms.3. Benedikt's original structure for tribromophenol bromide accounts for the facts introduced if a partial rearrangement of trihalogenated phenol chlorides, which contain bromine in the para position, to the isomeric trihalogenated phenol bromides, is postulated.
375Alkyl esters of aromatic sulfonic acids function as strong alkylating agents' toward various types of organic compounds, this reaction occurring by alkyl-oxygen fission2 according to the general scheme 0 1 0where R = alkyl group; Y-P a nucleophilic reagent, e. g., EtO-, PhO-, RS-, I-, etc.Although various types of substituted benzenesulfonates are known and might conceivably be used, the vast majority of experimental alkylations have been carried out with the alkyl 9toluenesulfonates. Whereas the effect of nuclear substituents on the reactions of alkyl benzoates has been investigated extensively, a no such study has been made of the effect of nuclear substituents on the reactivity of alkyl esters of arylsulfonates. To do so seemed of considerable theoretical as well as potentially practical i n t e r e~t .~ Such studies as have been made deal primarily with the hydrolysis of these compounds. It has'been noted that with increasing nuclear halogen substitution, the ester is more readily saponified by alcohol.6*6 The rate of the solvolytic reaction of ethyl toluenesulfonate and the rates of displacement of toluenesulfonate ion ,by chloride, bromide, iodide and hydroxyl ions has been studied kineti~ally.~ Demeny's study8 of the effect of a substituent in the aromatic nucleus upon the rate at which an alkyl sulfonate hydrolyzes demonstrated that a nitro group has a powerful accelerating influence while a para methyl reduces the reaction rate.In this paper we present the results of a study of the influence of the para substituent on the reactivity of ethyl benzenesulfonate with sodium ethoxide in absolute ethanol solution. 0 (1) (a) For a review of this field see Connor's chapter in Gilmao "The progress of this irreversible reaction was followed by titration of the unreacted sodium ethoxide at suitable time intervals with 0.05 N hydrochloric acid. Apparently the strong nucleophilic character of the ethoxide ion causes this reaction to take place readily at moderate temperature without observable side-effects. All of the rate constants reported in this study are based on an approximately equal initial concentration (0.05 molar) of each of the reactants. By trial, it was found that 35' was a suitable temperature a t which to measure the relative reaction rates over a major part of the reaction. The measurements were repeated a t a 10' interval to permit an approximate calculation of the energies of activation. The particular group of substituents selected represents a wide range of electronic character, varying from the electron-repulsion of the methoxy group to the electron attraction of the nitrogroup, as exhibited in the benzene series.p-Methoxybenzenesulfonyl chloride was prepared in 66% yield by the direct chlorosulfonation of anisole. High yields of the ethyl esters were obtained by reacting the corresponding sulfonyl chloride with an equimolar quantity of sodium ethoxide in alcohol or alcohol-ether solution under mild conditions. ExperimentalAryl Sulfonyl Chlorides.-p-Toluenesulfonyl chloride, benzenesulfonyl c...
In 1897 it ivas observed (1) that potassium iodide (in hot alcohol or acetone) converts ethyl p-bromobenzenesulfonate to ethyl iodide. Many years later, methyl and ethyl iodides (2, 3) and ethyl a-iodopropionate (4) were prepared in good yield by the action of the same reagent (in boiling water or alcohol) on the corresponding p-toluenesulfonates. The method was next applied (5) to the preparation of diisopropylidene-6-iododesoxygalactose from the 6-tosyl derivative, with the improvement of using Finkelstein's reagent (6), namely, sodium iodide dissolved in acetone. Further research has, however, been mainly confined to study of the behavior of tosyl esters of sugar derivatives (7) towards the reagent and it has been found that a primary tosyloxy group is much more reactive than a secondary in such aldo-sugar derivatives as methyl 2,3,4,6tetratosyl-iS-D-glucoside.The reaction is usually found to proceed as an alkyl-oxygen fission (8) in accordance with the equation: ! SUMMARYThe reaction of certain esters of p-toluenesulfonic acid with sodium iodide dissolved in acetone has been studied. Their reactivities are found to be in the same relative order as those of the corresponding organic chlorides towards the same reagent.The tosyl esters of isopropyl alcohol and thymol have been obtained in crystalline condition. The less reactive esters studied may be prepared in good yield in the presence of pyridine at room temperature.Pittsburgh 13, Pa.
petroleum ether; m. p. 138.5-139°( corr.). Solutions of the compound in alcohol have a decidedly pungent taste accompanied by a slightly bitter taste.
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