SU457687A1 - Method for producing methylene 2,2-biscyclopentanone - Google Patents

Description

one

The invention relates to the field of producing methylene-2,2-bis-cyclopentanone, which finds use as a raw material for the production of a number of biologically active compounds.

A known method for producing methylene-2,2-bis-cyclopentanone by reacting cyclopentanone with morpholine and then heating the resulting enamine with paraformaldehyde in dioxane medium under nitrogen atmosphere at 140 ° C. The yield of the target product is insignificant.

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

This is achieved by the fact that the mixture of paraform and dimethylamine hydrochloride is reacted with cyclopentanone in the presence of hydrochloric acid, the Mannich base thus obtained is heated at 130-135 ° C with an excess of cyclopentanone.

The proposed method is based on the use of available raw materials and makes it possible to obtain the target product with a yield of up to 53%.

Example 1. Synthesis of methylene - 2,2-b “c-cyclopentanone.

A. To obtain a Mannich base, to a solution of 75.6 g (0.9 mol) of cyclopentanone in 300 ml of alcohol was added 1 ml of concentrated hydrochloric acid, 36 g (1.2 mol) of paraform and 73.3 g (0.9 mol) hydrochloric acid

dimethylamine. The mixture was boiled with stirring for 3 hours. After distilling off the alcohol, the crude salt is washed with absolute acetone, dried and decomposed by adding 50 g of KOH to 700 ml of ether. After distilling off the ester, 88-95 g (70-82%) of a mannich base are obtained.

B. A mixture of 88 g (0.62 mol) of the Mainikh base and 156 g (1.86 mol) of cyclopentanone is slowly heated (, 5 hours) to 130-135 ° C and kept at this temperature for 1.5 hours. The reaction mixture is cooled, dissolved in ether, washed with a dilute hydrochloric acid solution and water. The residue after distillation of the ether is distilled under vacuum, collecting cyclopentanone (68-120 ° C / 90 mmHg) and 1,5-diketane at 160-170 ° C / 15 mmHg. Art. (under nitrogen) as a mixture of isomers, which are a colorless oil, which crystallizes very quickly. Weight 47.5 g (46%).

Found,%; C, 73.40; 73.52; H 8.42; 8.41. CiiHi6O2.

Calculated,%: C 73.33; H 8.88. Example 2. Synthesis of methylene-2,2-bis - cyclopentanone.

A. To obtain a Mannich base, to a solution of 75.6 g (0.9 mol) of cyclopentanone in 300 ml of alcohol was added 1 ml of concentrated hydrochloric acid, 36 g (1.2 mol) of paraform and 73.3 g (0.9 mol) hydrochloric acid

dimethylamine. The mixture was boiled with stirring for 3 hours. After distilling off the alcohol, the crude salt is washed with a small amount of absolute acetone, dried and decomposed by adding 50 g of KOH to 700 ml of ether. After distilling off the ester, 95-99 g (75-80%) of a mannich base are obtained.

B. A mixture of 95 g (0.67 mol) of a mannich base and 156 g (1.86 mol) of cyclopent is slowly heated (3.5 hours) to 130-135 ° C and kept at this temperature for 1.5 hours. The reaction mixture is cooled, dissolved in ether, washed with a dilute hydrochloric acid solution and water. The residue after distillation of the ether is distilled under vacuum, collecting cyclonentanone (68-120 ° C / 90 mmHg) and 1,5-diketone at 160-170 ° C / 15 mmHg. Art. or at 145-155 ° C / 7 mm Hg. Art. (under nitrogen) as a mixture of isomers, representing ush, a colorless oil, crystallizing very quickly. Weight 86.7 g (71.8%).

Found,%: C 73.40; 73.52; H 8.42; 8.41.

CiiHieOg.

Calculated,%: C 73.33; H 8.88.

The total yield of 1,5-diketone in two stages is 53.7%.

Subject invention

The method of producing methylene-2,2-b "c-cyclopentanone based on cyclopentanone with isolation of the target product by known methods, characterized in that, in order to increase the yield of the target product, a mixture of paraform and dimethylamine hydrochloride is reacted with diclopenta. Acidic acid, the resulting Mannich base is heated at 130-135 ° C with an excess of cyclopentanone.