CS216572B1 - Method of preparation of the 1-+l3-pentadecylphenoxy +p butyrate acid - Google Patents

Abstract

A new method for the preparation of 1-(3-pentadecylphenoxy) butyric acid by the reaction of sodium 3-pentadecylphenolate with ethyl ester of 1-bromobutyric acid in the environment of protic and aprotic organic solvents, preferably in ethanol or dimethyl sulfoxide.

Description

The invention relates to a process for the preparation of 1- (3-pentsdecylphenoxy) butyric acid by reaction of an acid ester

1-bromobutyric with 3-pentadecylphenol sodium.

11 (3-Pentedeeylphenoxy) butyric acid of formula VI below, used as an intermediate in the preparation of dispersed so-called protected coloring agents and prepared according to the patent literature by condensation of the sodium salt of 3-pentadecylphenol of formula II below, prepared in aqueous-ethenolic potassium hydroxide solution; with 1-bromo-methanoic acid. The advantage of this method, which does not require condensation of the 1-bromobutyric acid ester of formula III below, is merely apparent, since the yields of the final product are relatively low, in practice mostly lower than the patent literature. pat.č. 904 852).

A second process, starting from the general laboratory procedure for preparing the above-described aryloxyethers of fatty acids, is carried out by etherifying the sodium 3-pentadecylphenol of formula II below with a 1-oro-butyric acid ester of formula III below in a non-polar solvent, usually xylene. or toluene. The yields of this method are very good, the quality of the final product after crystallization from ethanol is satisfactory and mostly suits for further synthesis, although it contains a small amount (2-5%) of the unreacted starting phenol. The procedures are illustrated by the following reaction scheme:

-0J-I

-0V®,

₃ .CH ₂ CH ₂ H -CHBr.COOC _5/111 /

C-2. Hy

0-C.ri.COOH.

HCL -. ->

The inventors have found that 1- (3-pentadecylphenoxy) butyric acid (VI) is readily prepared by reacting the sodium salt of 3-pentadecylphenol (11), prepared using ethanolate or sodium methoxide in ethanol or methanol, with a 1-bromobutyric acid ester (111) in an environment of a polar protic or aprotic organic solvent.

In a first variant of this process, ethanol or methanol was used as the protic solvent of the invention. In alcohols, the corresponding sodium alcoholate is prepared by dissolving the sodium metal and 3-pentadecylphenol (1) is added to the prepared alcoholic and alcoholate solution. After brief heating, ethyl 1-bromobutyrate (MI) was added to the solution. After heating for 3 hours and the ignited 1- (3-pentadecylphenoxy) butyric acid ethyl ester is saponified in aqueous-ethhenolic medium with sodium hydroxide to sodium salt, the acid (V) which is acidified with concentrated hydrochloric acid to the free 1- (3-pentadecylphenoxy) butyric acid. VI /. The material was recrystallized from ethanol while wet to give the product, m.p. 75-76 ° C in a yield of 50.9% of theory. The product obtained contains a small percentage (2-3%) of unreacted starting phenol. The product is suitable for further preparation of color-forming components.

The second variant of the preparation of 1- (3-pentadecylphenoxy) -butyric acid is a two-stage process and uses various aprotic agents, such as acetone, dimethylformamide or dimethylsulfoxide, for its own condensation.

The sodium salt of 3-pentedecylphenol (11) is prepared in ethanolic medium with sodium ethanolate and, after distilling off the ethanol, it is dissolved in dimethylsulfoxide. After 1-bromobutyric acid (111) was added dropwise, the reaction was completed by briefly assigning the reaction solution and the dimethylsulfoxide solution was poured onto ice and water. After the ice has been dissolved, the dimethylsulfoxide is carefully separated in a separator (together with water), ethanol and sodium hydroxide are added to the remaining organic layer and the free acid (VI) is treated in a similar manner as in the previous variant. The final product is obtained in high yield (80% of theory) and in high purity. It contains practically no starting phenol.

The process for preparing 1- (3-pentadecylphenoxy) butyric acid according to the invention represents a substantial improvement in its production, resulting in higher yields and, in particular, better product quality.

Example 1

To a solution of sodium ethanolate prepared from 6.5 g of sodium and 285 ml of anhydrous sodium hydroxide. ethanol, 86 g of 3-pentadecylphenol was added. The solution was heated to boiling for 1 hour, and after formation of the sodium salt of 3-pentadecylphenol, 55.5 g of 1-bromobutyric acid methyl ester was added to the reaction mixture.

After boiling for 3 hours, the resulting 1,3-pentadecylphenoxy / butyric acid ester was saponified by boiling with a solution of 32.5 g of potassium hydroxide in 250 ml of water. After heating for 1 h, the reaction solution was poured into a mixture of 250 mL water, 250 mL ice and 50 mL conc. hydrochloric acid. The precipitated product was aspirated / m.p. 68-68.5 ° C / and recrystallized twice with β ethanol. A product of m.p. 75 to 76 ° C / lit. 81-84 [deg.] C.), in an amount of 56 g, i.e., 50.96 of theory.

Example 2 *

To a sodium methoxide solution prepared from 6.5 g of sodium and 285 ml. bezv. methanol, 86 g of 3-pentadecylphenol was added. The longer procedure is identical to the previous example. The final product was also obtained in the same quality and yield.

Example 3

A sodium ethanolate solution according to Example 1 was prepared from 6.5 g of sodium and 285 ml of anhydrous. ethanol. After the addition of 86 g of 3-pentadecylphenol, the solution was heated to boiling for 1 hour, evaporated to dryness and the sodium salt of 3-pentadecylphenol was dissolved in 50 ml of dimethylsulfoxide. To the solution was added 55.5 g of 1-bromobutyric acid methyl ester. After a vigorous reaction, the solution was heated to reflux for 1 hour, then cooled and poured onto ice. After melting the ice, the aqueous dimethylsulfoxide layer was carefully separated and the remaining oily ethyl ester of 1- (3-pentadecylphenoxy) butyric acid was dissolved in 250 ml of ethanol and after adding 32.5 g of potassium hydroxide dissolved in 250 ml of water the solution was heated for 1 hour. boiling. After saponification, the solution was poured into a mixture of 250 ml of water, 250 ml of ice and 50 ml of hydrochloric acid. The precipitated product was aspirated and recrystallized from ethanol. + ^Yield: 89 g, mp 80% of theory.

Example 4

The sodium salt of 3-pentadecylphenol according to Example 1 was prepared from 6.5 g of sodium, 285 ml of ethanol and 86 g of 3-pentadecylphenol. After boiling for one hour, 100 ml of acetone and 55.5 g of 1-bromobutyric acid methyl ester were added to the solution. After vigorous reaction, the solution was heated to boiling for 1 hour. The resulting 1- (3-pentadecylphenoxy) butyric acid methyl ester was saponified by the addition of a solution of 32.5 g of potassium hydroxide in 250 ml of water, followed by boiling for one hour. After saponification, the solution was poured into a mixture of 250 ml water, 250 g ice and 50 ml conc. hydrochloric acid. The precipitated product was aspirated and recrystallized from ethanol. M.p. 81 DEG-84 DEG C. in an amount of 89 g, i.e. 80% of theory.

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of 1- (3-pentadecylphenoxy) butyric acid of formula VI C _t % -O-CH.COOH from sodium 3-pentadecylphenolate and ethyl 1-bromobutyrate in an organic solvent medium characterized in that the reaction is carried out in a polar protic or aprotic organic solvent medium, preferably in ethanol or dimethylsulfoxide. Moravian printing factories