CS262772B1 - Process for the preparation of 9-methyl-7- (1,1,5-trimethylcyclohexen-5-yl) -8-biene-10-alu - Google Patents

Abstract

The solution is used for the preparation of an intermediate in the synthesis of vitamin A and can be used in pharmaceutical production. The aim is to increase the yield and reduce the raw material costs. The aim is to reduce the raw material costs. The aim is achieved by carrying out the condensation reaction of beta-ionone and monochloroacetic acid ester in the presence of an alkali metal alcoholate in an amount of 2 to 1.5 mol per mol of beta-ionone in a mixture containing solvents with nitrile and hydroxyl groups in a volume ratio of 1 to 5 and using a solvent with nitrile groups in a volume ratio to beta-ionone of 1.5 to 0.5. Methanol, ethanol or isobutanol are used as hydroxyl groups and acetonitrile is used as the nitrile compound.

Description

3 4 262772

The invention relates to the preparation of 9-methyl-7- (1,1,5-trimethyl-1-cyclohexen-5-yl) -8-butone-10-al, a shortened C 14 -aldehyde, of formula CM ·;

CH = O and can be used in the industrial synthesisevitamin A. The C 14 -aldehyde can be prepared by condensation of beta-ionone with a mono-chloroacetic acid ester by a variety of methods (S. Ishikawa, T. Matsuura, C. 1937, II. 3 452; Isler et al. , Helv, Ghim, Acta 30, 1911 (1947), Eng., 870, 31, Heilbron et al., J. Chem Coc., 1942, 729, 1946, 1520, Inhoffena et al., Ann. (1948); Milas et al., J. Am. Chem. S-oc., 70, 1 584, (1948); Navse, Bull. Soc. Chim. France (M) 1950 1189; , 260 481, AO 107 108 (CSSR), AO 202 102 (USSR), according to which the condensation is carried out in the presence of alkali metal alcoholates such as sodium methylate, sodium ethylate, potassium isobutylate without organic solvent or most commonly in the presence of an organic solvent such as dimethylformamide, pyridine, picoline.

The drawback of these processes is the difficult availability, high cost and energy-saving regeneration of the used dissipative parts. A) the yield of the above processes is lower, at most 85%.

It is an object of the invention to increase the C 14 -aldehyde extract and to reduce the raw material cost of the needle.

This objective is achieved when the condensation of the beta -ononone with the monochloroacetic acid ester is carried out in the presence of an alcohol-alkali metal such as sodium ethylate or methyl in a mixture of acetonitrile and methanol, ethanol or isobutanol in certain volume ratios. as well as beta-ionone.

Table Preparation of C 14 -aldehyde using Ethyl Ethanol.

In the present case, the acetonitrile promotes the condensation reaction, the hydroxyl solvent increases the solubility of the salts present in the reaction mixture, thereby providing favorable conditions for a sufficiently high concentration of the RO and CO-anions.

In the proposed technical solution, said mixture of acetonitrile with alcohol (in a volume ratio of 1 to 5) makes it possible to obtain a C 14 aldehyde yield of 89 to 91% while reducing the consumption of the alkali alcoholate (from 2 to 1.5 moles per liter). mole of beta-ionone) and the use of acetonitrile in a beta-ionone volume ratio of 1.5 to 0.5.

The following examples illustrate the proposed method. Example 1

To a mixture of 9.61 g of beta-ionone, 9.19 g of monochloroacetate of ethyl alcohol, cooled to -25 ° C, a certain volume of acetonitrile and alcohols, is gradually added sodium otylate over a period of 8 to 10 minutes while maintaining the temperature. in the range of -15 to -20 ° C. At this temperature, the mixture was stirred for 1 hour. Tvorbaglycidester is controlled spectrophotometrically. Then 20 ml of tallow is added to the reaction mixture and 25 ml of a 15% strength aqueous sodium hydroxide solution are added over 5 minutes so that the temperature does not rise above 0 ° C. The mixture is stirred for 1 hour at -5 to 2 ° C and added. into it 35 ml of hot water (60-70 ° C). Stirring for 20-30 minutes at 40-45 ° C. The reaction mixture is cooled to 20 ° C and a solution of sulfuric acid (15% to pH 6 to 7) is added. The organic phase is cooled, the aqueous phase is extracted with toluene. the C 1-4 aldehyde distilled at 0.133 kPa, t, 105-115 ° C. When converting this reaction, solvent ratios and condensation reagent ratios were used, the data being summarized in sodium and various acetonitrile quantities

Experiment C3H5ONa g Mole C2H5ONana mol of ionon M1 acetonitrile ml C2, H5OH M1 acetonitrile ml ionone C14-aldehyde extract in% 1 6.8 2.0 1.0 0.5 89.5 2 6.8 2.0 1.4 1, 2 91.1 3 6.8 2.0 5.0 1.5 90.3 4 6.1 1.8 0.8 0.45 87.3 5 5.4 1.6. 3.0 1.5 89.0 6 5.1 1.5 2.0 1.0 87.3

Claims (5)

of alkali metal in an amount of from 2 to 1.5 moles per mole of beta-ionone in a mixture comprising solvents ecetonitrile and methanol, ethanol or isobutanol or mixtures thereof in a volume ratio of 1 to 5 and using acetonitrile in volume ratio to betajonone of 1.5 to 0 , fifth