SU979346A1 - Process for producing 3-acetyl-2-methyl-5-vinyl-4,5-dehydrofuran - Google Patents

Description

This invention relates to a process for the preparation of 3-acetyl-2-methyl-5-vinyl-4, 5-dihydrofuran, which can be used to synthesize biologically active compounds, in particular ferromones, and also as a monomer for the preparation of polymers with adhesion properties. .

A method of producing 3-acetyl-2-methyl-5-vinyl-4, 5-dihydrofuran is known, by reacting acetylacetone with butadiene in acetic acid in the presence of copper acetate and manganese (C. and OAcJj SHgO "p (OAc; h2H2O in nitrogen atmosphere at 75 ° C.

The selection of the desired product is carried out by cooling the reaction mixture to room temperature, filtering the precipitate of manganese acetate, diluting the filtrate with water, salting out sodium chloride and extracting the ethers. The ether extract is washed with a saturated solution of sodium carbonate, then with water, dried over sodium sulfate and the ether is removed under a residual pressure of 15 mm Hg. in a water bath at 45 ° C. The product was isolated by column chromatography. Yield (46%) 1.

The disadvantages of this method include the relatively low yield of the target product, the use of explosive gaseous butadiene as a starting material, the multistage characterization of the extraction of the target product using column chromatography, which makes the method unacceptable for industrial learning.

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

The goal is achieved in that acetyl-lacetone is reacted with 1, 4-dichlorobutene-2, taken in an equimolar amount to acetylacetone, as a catalyst for triethylamine, and as an organic solvent - ethyl alcohol and the process is carried out at boiling in the presence of potassium carbonate, taken in a molar ratio to acetylacetone, equal to {2–2.47: 1, respectively.

Claims (1)

The process is carried out by boiling the mixture for 5-6 hours in a water bath, followed by cooling the reaction mixture to room temperature, filtering, pouring a filter cake with ethyl alcohol, removing the solvent in vacuo and distilling the desired product. The yield of 3-acetyl-2-methyl-5-vinyl-4,5-dihydrofuran is 74-80%. The product is chromatographically measured using GLC analysis on an LHM 8MD instrument. Column: solid chromate AW-HflMCS with 15% Arjewop L, column temperature 180 ° C, carrier gas rate 60 l / h. The ratio of potassium carbonate in relation to acetylacetone is optimal, since a change in the ratio towards decreasing the amount of potassium carbonate leads to a decrease in yield due to incomplete consumption of acetylacetone, and a change in the ratio in the direction of increasing the amount of potassium carbonate does not lead to a noticeable increase in yield. The choice of ethyl alcohol as a solvent is due to the fact that carrying out the process in other organic solvents, such as benzene, significantly (up to 40% reduces the yield of the target product. Example. A mixture of 25 g (o, 25 mol; acetylacetone, 31.2 g (0.25 mol) 1.4 dichlorobutene-2, 150 m of ethyl alcohol, 2.5 g of triethylamine and 70 g (0.5 mol of carbonate catalysts are boiled in a water bath for 5 hours. After cooling to room temperature, the reaction mixture is filtered through a suction filter, the precipitate is washed with 50 ml of ethanol and the residue is distilled under residual pressure. After complete distillation of the solvent, the precipitate is distilled under vacuum to give 28.8 g (74%) of 3-acetyl -2-methyl-5-vinyl-, 5-dihydrofuran with t, bp 104-105® C / 8 , 4940. PRI me R 2. The process is carried out analogously to example 1, only taking 80 g (0.6 mol) of potassium carbonate and boiling for b h. 30.5 g are obtained (80% of the whole product from bp 104-105 ° C / 8 mm, 4935. The proposed method allows ensuring the safe conditions of the process, simplify it significantly and increase the yield of the target product. . The invention method for producing 3-acetyl-2-methyl-5-VINYL-4, 5-dihydrofur H9 by the interaction of acetylacetone with a unsaturated compound at elevated temperature in the presence of a catalyst in an organic solvent, characterized in that in order to increase the yield of the target product and simplify of the process, 1,4-dichlorobutene-2, taken in equimolar amount to acetylacetone, is used as an unsaturated compound, tri-ethylamine is used as a catalyst, and ethyl alcohol is used as an organic solvent. od out at reflux in the presence of potassium carbonate, taken in molar ratio of acetylacetone to equal to (2-2.4): 1, respectively. Sources of information taken into account in the examination 1. Melik G. GG, Mkrtch D. DA, Badan N. Sh. O. Synthesis of 4,5-dihydrofuran derivatives by the interaction of acetylacetone with conjugated alkenes, CHC, 1980, No. 7, p. 884 (prototype).