SU119189A1 - The method of obtaining (indolyl-3) -gamma-butyric acid - Google Patents

Description

The use of stimuli, plant growth tori, is of great national importance, and therefore the availability of various methods for synthesizing stimulators from available raw materials is of considerable practical interest. One of the most effective stimulants for root formation, significantly superior to heteroauxin, is (indolyl-3) -butyl acid (IMC)

As shown by the works of Soviet and foreign researchers, the IMC is successfully used in cutting even plants that are hardly affected by heteroauxin, such as conifers, ornamental and technical, and especially fruit (some varieties of blon, cherry and pear) .

The main obstacle to the introduction of (indolyl-3) -f-butyric acid into the practice of plant cultivation is the lack of synthesis methods suitable for industrial use, since some of them, based on indole cyclization (according to Fisher's reaction), are multistage and very time consuming. Other methods based on the use of indole are more complicated, but also have almost no practical value because of the difficult availability of the raw material, which is not Iidol, but the second component required for introduction into the indole molecule of a three-membered chain carboxyl group, i.e. the residue of H-butyric acid.

Such methods include the method of reacting indolyl magnesium iodide with butyrolactone, which is currently not produced, or the reaction of reacting indolyl magnesium iodide with t-chlorobutyronitrile, since the synthesis of the latter also requires trimethylene chlorobromide, which is not currently available.

A new method has been developed for the preparation of (indolyl-3) -f-butyric acid from indole, in which, in order to expand the raw material base, indolyl magnesium-haloginide is acted with succinic anhydride in anisole medium and the resulting - (- keto-t- (indolyl- 3) Butyric acid is reduced with an excess of zinc in the presence of hydrochloric acid.

Example A. Getting ketoacids. The reaction proceeds according to the scheme:

,

mono

MAHH- IOCA-COCOCH, CH, COOMgX CHIFC

In a dry three-neck round-bottom flask with a capacity of 500 ml, equipped with a stirrer with a stopper, a reverse ball cooler and an addition funnel, 5 g of magnesium chips and 50 ml of anisole are placed and then slowly poured in for 1.5-2 hours. 34 g of ethyl iodide. The mixture heats up noticeably (up to 40-50 °) and the magnesium gradually passes into. solution. When the addition of ethyl iodide is complete, usually a little undissolved magnesium remains; for completeness of the reaction, the mixture is heated in a water bath at 60-70 ° C and slowly rotating the stirrer for another 1.5-2 hours. until complete dissolution of magnesium. While cooling in ice water, the resulting ethyl magnesium iodide is added dropwise (23 g) of indole solution with 50 ml of anisole over 30 minutes. with good movement. After addition of the indole, the mixture is stirred at room temperature for another 15-20 minutes. until the evolution of gas bubbles (ethane) stops and then is heated for 15-20 minutes. at 60-70 °.

To the prepared solution of indolyl magnesium iodide, cooled to room temperature, a hot 20 g of solution of succinic anhydride in 100 ml of anisole is quickly (within 3-5 minutes) being poured.

At the same time, a yellow-orange thickened mass of the complex is formed immediately, which, with good mixing (about .200 rpm), quickly falls into a fine powder; the temperature in the reaction mixture rises to 100-110 ° and is kept within this range for about 10 minutes. Orange yellow precipitate for 5-10 min. acquires a brick red color.

Then the reaction mixture is heated to complete the reaction for 2 hours. in a boiling bath with vigorous stirring. To decompose the magnesium complex, dilute acetic acid (28 ml of ice or 32 ml of 80% water in 150 ml of water) is added to the mixture, and the mixture is stirred for 2 hours. when cooled with water. The keto acid that has been precipitated is filtered off, carefully drained and washed several times with water. The filtrate is transferred to a separatory funnel, where the anisole layer is rather quickly separated, from which the anisole can be easily and regenerated with good yield.

After drying in the air or in a drying oven at 50-60 °, the keto acid has a melting point of mp. 195-197 °. The yield is 28.7 g, which is 67.6% of theoretical (counting on indole). Before restoration, the product is subjected to alkaline reprecipitation and treatment with activated carbon. T. pl. 220 °. Output, based on the original indole, -54%.

jCOCH, CH, COOH

The reaction can be carried out in a similar way when replacing ethyl iodide with ethyl bromide.

B. Reduction of keto acid in (indolyl-3) -f-butyric acid. The reaction proceeds according to the scheme:

COCH, CH, COOHf CH, CH, CH, COOH,

to 20 g of zinc dust (amalgamated)), located in a three-neck round-bottomed flask emk. 50 ml, equipped with a mixer with a shutter, a reverse ball cooler and a dropping funnel, pour a solution of 8 g of keto acid (mp 218-220 °) into 150 ml of pure butanol. The mixture is heated to boiling with good stirring (150–200 rpm) and 32 ml of hydrochloric acid (sp. 1.19) (2: 1) are slowly added dropwise over 2.5–3 hours. . The mixture is heated for another 30-40 minutes. and the reaction is complete. Upon cooling, the excess zinc dust is filtered off, washed with water and weighed after drying; its weight was usually 8–9 g, therefore, I – 12 g (calculated amount 4.8 g) per 8 g of keto acid reacts. The filtrate is transferred to a separatory funnel, the lower layer of zinc chloride solution is separated from the upper butanol solution. The latter is washed 2 times with a small amount of water and is processed as follows: the butanol solution of the IMC is placed in a steam distillation apparatus, mixed with 100 ml of a 20% aqueous solution of sodium hydroxide and water vapor is passed through the mixture until complete removal of butanol. The remaining alkaline solution, usually containing a small amount of brown flocculent sludge, is heated to a boil with coal (5-10 minutes) and filtered. The filtrate is cooled to -5 ° and acidified with dilute hydrochloric acid as follows: 5-10 drops of phenolphthalein are added and hydrochloric acid (2: 1) is carefully added to neutrality. Hydrochloric acid, diluted 1: 2, is then added slowly with stirring, until the acidic reaction to congo is clearly acidic. A creamy crystalline precipitate is precipitated; the mixture is kept for 2 hours. at O-2 and then filtered. The precipitate after pressing on the funnel is washed several times with cold water until hydrochloric acid is removed in the wash water and then dried first in air and then in a desiccator. The yield of the technical product is 4.5-5.2 g, which is 60-69% of theories. Yellowish pink or cream powder, so pl. 118 °.

For purification, the technical product is recrystallized from 6 eteool and 4.05 g of pure (indolyl-3) -f-butyric acid are obtained with a melting point of 22.5 g. 123-124 °, which corresponds to a yield of 54% of theory, based on keto acid.

This method has the peculiarity that during the recovery and even after its termination there must be a certain excess of zinc dust in the reaction mixture. If this condition is not observed, amalgamation is performed by 5 minutes vzbatyvanie zinc dust with a solution of 1.5 g of mercuric chloride in 25-30 ml of water, after which the solution of mercuric chloride is poured from the precipitate with zinc nod by decantation. Instead of a ready-made mercuric chloride, a solution prepared from 1.3 g of mercuric oxide, 2 ml of concentrated hydrochloric acid and 25 ml of water is often consumed.

+ 2H, - + H, 0

No. 119189-4 -

The ICA drops sharply, and in the case of the application of a lower excess cycle and hydrochloric acid (as usually adopted in the reduction according to Clemensen), the IMC cannot be isolated from the reaction mixture at all.

Subject invention

The method of obtaining (indolyl-3) - - -laminary kilot from indole, characterized in that, in order to expand the resource base, pas indolyl magpium-halide act with succinic anhydride in anisole medium and the resulting --keto-7- (indolyl-3 a-butyl acid is reduced by excess zinc in the presence of hydrochloric acid