SU578299A1 - Method of preparing a,a-dialkylarylacetones - Google Patents

Description

I

The invention relates to a method for the alkylation of ketones, in particular to a method for the preparation of twice aryl acetones which are twice alkylated on one of the methylene groups, which can be used in the synthesis of biologically active substances.

A known method for producing ss, a-dialkylaryl acetales by alkylation of aryl acetones with alkyl halides in a 50% solution of an alkali metal hydroxide in the presence of catalyst I.

The disadvantages of this method are the low yield of the target product, 18-35% of the theory, the need to use a catalyst and, most importantly, the preparation, in addition to the didkalkil derivative, and my mineral kil derivative compounds, which are difficult to separate from the dialkyl derivatives - the target products.

The purpose of the invention is to increase the yield of the target product and the improvement of the process technology.

This is achieved by the fact that alkylation is carried out in dimethyl sulfoxide using anhydrous alkali metal hydroxide.

Conducting alkylation in an aprotic dipolar solvent medium in the presence of anhydrous alkali metal hydroxide allows increasing the yield of the target product up to 68% of theory and eliminating the formation of bioalkyl-substituted compounds 1 that make it difficult to isolate the target product, i.e., it allows to simplify the whole process.

Example 1. 2-phenyl-2-methylbutanoi-2.

To a cooled solution of 6 g of 1-phenylpropa-Iol-2 in 30 ml of dimethylsulfoxide is poured in one portion of 10 g of KOH B powder and then 19 g is added dropwise

methyl iodide. After half an hour of aging, the reaction mass is poured into water, the product is extracted with ether, the extract is washed twice with water, dried and dispersed. 4.94 g (68%) of the product are obtained with m kip. 68 -

 mm Hg Art. and ° 1.5090.

Example 2. 1-phenyl-1-acetylcyclopetay. To a suspension of 10 g of KOH in 20 mg of dimethyl sulfoxide, cooled by water, is gradually added a mixture of 6 g of methyl benzyl ketone and 9.7 g of tetramethylene dibromide. At the end of the product, the cooling is removed, the mass is stirred for another 1 hour. After the treatment, in analogy to Example 1, 2.93 g (35%) of the desired product is obtained.

Example 3. 1-phenyl-1-acetylcyclohexane. Obtained analogously to example 2. Yield 38%.

All products described in the examples are homogeneous but according to the data of the PMR- and GHCh analysis of the spectra, and their constants coincide with those given in the literature.

Form m u l a and 3 o b e e e u u

1. A method of producing a, a-dialkyl aryl acetones by alkylation of arylacetone alkyl halide in the presence of an alkali metal hydroxide, characterized in that, in order to increase the yield of the target

product and process simplification, alkylation is carried out in dimethyl sulfoxide and anhydrous alkali metal hydroxide is used.

Sources of information taken into account in the examination

1. Gonczyk, A., Serafin, V., Makoska, M., ROCZLI chem, 45, 1027, 2097 (1971).