Trimethyldglucose diethyl mercaptal, its dibenzoate and the monobenzoate of 2,3,4, 6 -tetramethyldglucose diethyl mercaptal have been synthesized in crystalline condition.2. 2,3,6-Trimethyl-d-glucose may be prepared readily by the hydrolysis of methylated cellulose with fuming hydrochloric acid, isolation of the sugar as its diethyl mercaptal and subsequent removal of the ethylmercapto groups.

The Alkylation op Phenol with Alcohols 709 the same velocity whether the reagent is dilute sodium carbonate, water or dilute1 sulfuric acid, although both alcohol and olefin are formed in large amount. This surely indicates that the total decomposition is unimolecular, and that the speed is independent of reagent anions.The mechanisms at work here are SnI and El. The unimolecular character of the reaction in homogeneous solution has been confirmed by the writer. ExperimentalThe bimoleeular character of the alkaline hydrolysis of methyl and ethyl halides has been previously established.* The point of mechanistic change in the alkyl series is illustrated by the figures in the subjoined table, selected from dynamical experiments which will be published in detail later. They refer to experiments in which the concentration of the alkyl halide does not appreciably change during the reaction. The velocity in dilute alkaline solution is then constant and is identical with that in acid solution. The first five lines are self-explanatory. The

pounds are intermediates, and not the products of a side reaction, in equilibrium with the starting or final products, but not directly concerned in the conversion of the ones to the others.The data here presented indicate the existence of the ketone amine intermediate, but do not settle the question of its structure, or why it should decompose rapidly with respect to diacetone alcohol. In fact, a meclianism which would depend upon the concentrations of the substituted ammonium ion and hydroxide ion would be indistinguishable kinetically from one depending on the concentration of the amine.The authors wish to thank Professor M. S. Kharasch for his helpful suggestions during the course of this work. SummaryThe rate of the dealdolization of diacetone alcohol has been measured in buffered solutions containing methyl-, dimethyl-, trimethyl-and triethylamine, at several buffer concentrations and buffer ratios.2. While molecular methyl-and dimethylamine catalyze the reaction, molecular trimethylamine and molecular triethylamine are without effect . 3.It is concluded therefore that the aldol condensation is not an example of general base catalysis.4. The mechanism of the reaction, in the presence and the absence of amines, is discussed. CHICAGO, ILL.RECEIVED AUGUST 26, 1937 1.

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