Condensation of Dimethylamyl Carbinols With Benzene in the Presence of Aluminum Chloride

Abstract

In continuation and extension of previous work from this laboratory (1), the following tertiary dimethylamyl carbinols, viz: 2-methylheptanol-2 (2), 2,3-dimethylhexanol-2 (3), 2,4-dimethylhexanol-2 (4, 5), 2,5-dimethylhexanol-2 (6), 2-methyl-3-ethylpentanol-2 (7), 2,3,3-trimethylpentanol-2 (8), 2,3,4-trimethylpentanol-2 (9), and 2,4,4-trimethylpentanol-2 (10) were prepared and condensed with benzene.The resulting alkyl benzenes were separated from the reaction-mixtures by repeated fractionation under reduced pressure. Physical constants were determined. In cases where sufficient quantity of the alkylated product was available, it was nitrated, reduced, diazotized, and hydrolyzed to the corresponding phenol (9). In some cases, the monoacetamino derivative (11), was prepared.The alcohols were prepared as reported in a previous communication (9) with these exceptions. Some of the 2-methyl-3-ethylpentanol-2 was prepared by a modification of the Whitmore (12) procedure, by reacting the Grignard reagent of 3-bromopentane with acetyl chloride, treating the ketone with methylmagnesium bromide and finally hydrolyzing to give the tertiary alcohol; yield, 11%. A part of the 2,4,4-trimethylpentanol-2 was prepared by oxidation of di-isobutylene (13) to 2,2-dimethylpentanone-4 and subsequent reaction of this ketone with methylmagnesium bromide. This method gave a 22% yield of the carbinol based on diisobutylene. The method of Butlerow (10) gave a 46% yield based on diisobutylene. The physical constants of the alcohols were carefully determined and are included in summary in Table I.

The Reaction of 1,2-Epoxy-2-Methylpropane With Aklylmagnesium Bromides

“…2-Methyl -2-butanol (10) 3,5-dinitrobenzoate 116 (11) B.p.74,mm102°;n" 1.4020 2-Methyl-3-pentanol (12) 3,5-dinitrobenzoate 85 (11) B.p.7íomml27-128°; nZ 1.4168 3-nitrophthalate 150.5 ( 122-Methyl-2-pentanol (11) 3,5-dinitrobenzoate 72 (11) B.p.74ommll7-118°; »" 1.4125 2-Methyl-3-hexanol (14) 3,5-dinitrobenzoate 59-60 2-Methyl -2-hexanol (15) 3,5-dinitrobenzoate 53-54°9.03 9.10 2,4-Dimethyl-3-pentanol (12) 3,5-di nitrobenzoate 75 9.03 9.27 B.p.74omml37-138°; " 1.4250 phenylurethan 94-94.5 (17) 2-Methyl-3-heptanol (12) 3,0-dinitrobenzoate 53-54 2-Methyl-2-heptanol (18) 3,5-dinitrobenzoate [43][44] 8.64 8.40 B.p.ismm65°; " 1.4248 2,2,4-Trimethyl-3-pentanol (18) B.p.I6mm55°; nl 1.4038 One molecular equivalent of diethylmagnesium in ether was added to two equivalents of l-bromo-2-methyl-2-propanol in an equal volume of ether. After centrifuging and removing ether in a vacuum, the precipitate was analyzed.…”

A Study of the Reduction and Fragmentation of Some Tertiary Carbinols When Condensed With Benzene in the Presence of Aluminum Chloride

“…The identification of 2-methyl-2-phenylpropane was accomplished by its physical constants and the acetamino derivative. The other alkylbenzenes were identified by their physical constants which have been reported in earlier work (23,24).…”

Rearrangements in the Friedel-Crafts Alkylation of Benzene

“…2,2,4-Trimethylpentanol-2 gave, in addition to the expected Z-octylbenzene, about 17 to 42% of Z-butylbenzene (45). Toussaint and Hennion (46) alkylated benzene by a number of alcohols in the presence of zinc chloride, sulfuric acid, aluminum chloride, or boron fluoride.…”