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The Friedel-Crafts reaction has been found to be well adapted to the synthesis of thymol (1). For this preparation m-cresol is alkylated with isopropyl chloride in the presence of aluminum chloride, using ethylene dichloride as solvent. When this procedure was applied to o-cresol there was obtained in good yield a product which, after crystallization, melted sharply at 36-36.5°. This material, which will be referred to as pseudo-carvacrol, gave several derivatives melting correctly for those of carvacrol; however, subsequent investigation showed that it is actually a difficultly separable mixture of carvacrol and 3-isopropyl-2-methylphenol. The latter compound, which has not previously been reported, was synthesized from 2-methyl-3-chloroaniline by two different routes, the most direct of which proceeded through 2-bromo-6-chlorotoluene and 2-isopropyl-6-chlorotoluene. Infrared analysis, using the bands at 12.34 and 12.82 µ, indicated that psewdo-carvacrol contains about 25 % of 3-isopropyl-2 methylphenol and 75% of carvacrol. Absorption curves for the mixture and its two components are given in Fig. 1.The other two isopropyl o-cresols have been reported: 6-isopropyl-2-methylphenol (2, 3) and 4-isopropyl-2-methylphenol (4), but it was considered desirable to prepare them anew and to characterize them more accurately. 6-Isopropyl-2-methylphenol was prepared by two methods. In the first, the Grignard reagent of 6-bromo-2-methylanisole was treated with isopropyl sulfate and the resulting 6-isopropyl-2-methylanisole was demethylated to the phenol.The second synthesis was an adaptation of the method first described by Behai and Tiffenau (3) in which an ester group is converted to an isopropyl group by the steps: CH, CH, CH, SUMMARY 1. Of the ten possible isomeric isopropyl cresols, nine have been described in the literature. The unknown isomer, 3-isopropyl-2-methylphenol, has been syn-

and could not be obtained in a state of purity which was satisfactory for analysis. g., 0.20 mole) in 50 ml. of methanol absorbed 1715 ml. of hydrogen at 23" with 1 g. of 5% palladium-charcoal catalyst (theoretical absorption calculated for two ethylenic links and hydrogenolysis of one bromide atom is 1470 ml.). This represents 116% of theoretical. The isolation and oxidation of the saturated alcohol to yield 3-hexanone was carried out in the manner described for 2-chloro-l,5-hexadien-3-ol. 3-Hexanone was isolated as the 2,4-dinitrophenylhydrazone, m.p. 130-132°; lit.12 m.p. 132°. Admixture with an authentic sample produced no depression in melting point.Crude 2-bromo-l,5-hexadien-3-ol (71.5 g., 0.40 mole) in 100 ml. of dry ether was added dropwise to phosphorus tribromide Professor J. L. E. Erickson, Louisiana State University, for their assistance and encouragement. We thank Mr, Harry Saunders of our perfumer staff for his help in odor evaluation of new musks. Thanks are due the Air Reduction Chemical and Carbide Company for generous samples of 2,5-dimethyI-2,5-hexanediol during the early stages of our work.

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Chloromethylation of 5-Lbutyl-l ,3-dimethylbenzene (I) yields a single product which was identified by Carpenter (1) as 2-<-butyl-4,6-dimethylbenzyl chloride (II). The symmetrical structure (III), however, was assigned to this compound by Fuson, Denton, and Kneisley (2) and by Buu-

The (erf-amyl homologs of four of the five commercial nitro musks: Musk Xylene, Musk Ketone, Musk Tibetene, and Moskene have been prepared and found to have musk odors similar in strength and quality to those of their tertbutyl prototypes. The (eri-amyl homolog of the remaining number of the group -Musk Ambrette-was reported in a previous paper of this series.

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The condensation products of methylethyl ketone under the influence of hydrogen chloride, coned, sulfuric acid, and sodium ethylate have been studied by Ekeley and Howe.1 Hydrogen chloride yielded homologs of mesityl oxide and phorone, while sulfuric acid and sodium ethylate each yielded homologs of mesityl oxide, phorone, and two isomeric homologs of isophorone. Sodium ethylate was found to be the most satisfactory condensing agent, since it gives purer products than the acid reagents. Where coned, or fuming sulfuric acid is used, the products are nearly always contaminated with sulfonic acids which are exceedingly difficult to eliminate, while hydrogen chloride has a tendency to form addition products due to the unsaturated nature of the compounds.