SU1321721A1 - Method of producing liquid crystalline ethers of trans-6-h-alkyl-decalin-2-carboxylic acid - Google Patents

Abstract

The invention relates to decalin derivatives, in particular, trans-6-n-alkyldekalin-2-carboxylic acid (DK) esters of the general formula CH2-CH2-CH-CH.2-Sh-C (€) OXH2 CHRr CH2-Sh-CH2-CH2 where R, is C, -C1, -alkyl, X is a) n R, with Rj is H or halo; b) - p -, -CH with R - CN, C, -C, 1-alkyl; c) N - CH SK-CH N with K - n - Ri - and. R, - 0, - C, -C 1 -alkyl; XR - H, n - CN - CgH, o - R, -CgH, -C (0) - 0-CgH -n - R, with R, - CN, C, -C, 2-alkyl, O - C, -C, -alkyl; H - H or C1, which are used as components of liquid crystal materials in electro-optical devices. To simplify the preparation of DCs, other reagents are used under other conditions. Synthesis of DCs is carried out by hydrogenation of the Corresponding 6-n-alkyl-naphthapine-2-carboxylic acids in an alkaline solution in the presence of Ni-Rene under a pressure of 14 MPa at 200-260 C. Then the resulting acids are treated with thionyl chloride and then with the corresponding hydroxyl derivatives. The method provides output DK to 70% while reducing the number of stages from 9 to 3. 4 table. (L with to

Description

one

The invention relates to an improved method for the preparation of trans-6-n-alkyldecaline-2-carboxylic acid liquid crystal esters, which are used as a component of liquid crystal materials in electrical optical devices.

It is known that the hydrogenation of naphthalene-2-carboxylic acid with platinum dioxide in glacial acetic acid at 240 atm results in cis-decalin-2-carboxylic acid nemesogen as the main product (Dauben W., Hoerger E., J. Ame. r, Chemo Soc. 1951, 73. 1504).

This method can be obtained only unsubstituted decalinecarboxylic acids.

As a result of all experiments of hydrogenation with Ni-René in an alkaline medium at high pressure, 5,6,7,8-tetrahydronaphthalene-2-carboxylic acid is obtained (Stork G., J. Amer, Chem. Cos. 1947, 69, 576 ).

With a very low yield, only the synthesis of trans-decalin-2-carboxylic acid from trans-decalin is succeeded by chlorination and the subsequent Manner reaction (N. Chapman, J. Shorter, K. J. Toine, J. Chen. Soc. , 1964, 1077. Dauben W.-, Tveit R., J. Mer. Chem. Soc., 1954, 76, 3197).

Methods for the preparation of alkyl decalin-2-carboxylic acids and are known. their ether. by converting 4-substituted cyclohexanone, first with pyrrolidine and then as a result of further stepwise synthesis into 6-closed decapine-2-carboxylic acids yl from tetrahydronaphthanol-6, the synthesis of 6-alkyl-tetrahydronaphthalene-2- Carboxylic acids, which are then subjected to hydrogenation.

The disadvantages of both options are multistage and low yield (GDR Patent No. 156258, c. C 07 C 13/48, August 14, 80).

The chain of invention is an increase in yield and simplification of the process.

This goal is achieved by using 6-n-alkylnaphthalene-2-carboxylic acids as starting materials.

The proposed method for the preparation of dicocrystalline trans 6-n-alkyl-decalin-2-carboxylic acid esters of the general formula

R

Shsoohk

X

where R, - n- (C, -C „) alkyl

 hydrogen, loid

gXX with R

-cyan, (C-C, 2) alkyl;

-0- (C, -C, J- -alkyl i

X CN

25

at

RJ is cyan, (C, -C, j) -alkyl, 0 (C, -C,) -alkyl.

0

five

0

five

0

five

4 hydrogen, chlorine,

It consists in the hydrogenation of 6-n-alkyl-naphthalene-2-carboxylic acid in an alkaline solution in the presence of Ni-Pane, under a pressure of 14 MPa, at 200-260 ° C, the processing of the decalin-carboxylic acid derivative with thionyl chloride and the interaction of the acid chloride with the corresponding hydroxyl derivative.

Implementation of the proposed method allows reducing the number of stages from 9 to 3, increasing the yield of target products from 4.3 to 21%.

Naphthalene compounds used as starting materials can be made by a known method (Coates D. Gray G. W., Mol, Cryst.

Lldy, Cryst. 1976, 37, 249). I

Thus, 6-n-alkylnaphtalene-2-carboxylic acids are obtained by acylation of naphthalene by the Freedel-Crafts method, by reduction of the ketone by the Juan-Minlon method with hydrazine hydrate, by repeated acylation by the Friede-Crafts method of the resulting 2n-acylnaphtalenes with acetyl chloride or acetic anhydride and the oxidation of 6-n-apkyl-2-cetonaphton with alkali metal hypobromite.

Example 1. Getting 6-n-butyldecaline-2-carboxylic acid.

34 g (0.15 mol) of 6-n-butyl naphthalene-2-carboxylic acid are hydrogenated with 20 g of KOH in 150 ml of water and 10 g of Ni – Ren as a catalyst at 14 MPa and at 200–260 s for 100 h in an oscillating autoclave.

The potassium salt of decalin carboxylic acid precipitates; ets in the form of foam After 2 hours of boiling in concentrated HC1, the cyphaic acid was separated from the solution by extraction with ether. The ether extract is dried over, fractionally distilled, a light yellow oily liquid is obtained, b.p. 172 ° C / 40 Pa, yield 60-70% of theoretical.

The remaining 6-n-alkyl 1-decaline-2-carboxylic acids are prepared in a similar manner, and the corresponding 6-n-alkyl-naphthapine-2-carboxylic acids are used in the hydrogenation.

Example 2. Preparation of 6-n-butyldecalin-2-carboxylic acid chlorohydride.

To 23.8 g (0.1 mol) of 6-n-butyldecane-2-carboxylic acid is added 5-fold amount of thionyl chloride (40 ml). After the addition of 100 ml of ether and a few drops of pyridine, the mixture is boiled for 6 hours under reflux. ether and residual thionyl chloride are poured, the residue is distilled.

T.kipg. 129 to 128 ° C / 40 Pa., Yield 80-90% of theoretical.

Other 6-n-alkyldecaline-2-carboxylic acid chlorides are prepared in a similar manner, the corresponding acids being used.

Example 3. Preparation of 4-substituted phenyl ester of 4- (bnn-alk1xdekalin-2-carbonyloxy) benzoic acid.

The 4-hydroxybenzoic acid P-cyanophenyl ester is obtained by esterifying benzyloxycarbonyloxybenzoyl chloride with L-cyanophenol, followed by catalytic cleavage of the protective group with hydrogen in the presence of d / SrCOj as a catalyst.

Another option for the synthesis of substituted phenyl esters of 4-hydroxybenzoic acid is as follows. 8 g (0.023 mol) of 4-formylphenyl 4-n-butyldecaline-2-carboxylic acid is dissolved in 20 ml of 90% acetic acid, 5 g of CgO is added dropwise to the solution in 10 ml of 60% acetic acid and then at 40 ° C

five

0

five

0

five

6

five

0

five

the mixture is stirred for 12 hours.

After cooling, 50 ml of water are added, the precipitate is extracted with ether, the ether extract is washed with water and bicarbonate solution and dried over Na. .

After removal of the solvent, the solid, crude acid is converted into acid chloride, without further purification.

Einhorn esterification.

0.005 mol of the corresponding substituted phenol or vinyl ester of 4-hydroxybenzoic acid in 20 ml of pyridine is mixed with this to the amount of 6-n-alkyldecaline-2-carboxylic acid chloride or 4- (6-n-alkyldecaline-2-carbonyl - oxy) -benzoyl chloride. This mixture is left overnight and then another 30 minutes.

Q

The mixture is heated to 70 ° C. After cooling, it is poured onto 60 g of ice and 13 ml of concentrated sulfuric acid, the precipitated precipitate is filtered off with suction and washed with an aqueous solution of bicarbonate, water, dilute hydrochloric acid and again with water.

After 3-5 times recrystallization from absolute methanol or eta-. Zola get ether with a pure melting point and clarification. The yield is 30-70% of theoretical.

The substituted phenyl and cyclohexyl esters are not mesomorphic.

The results of the experiment are given in table. one.

Example 4. Other esters of 6-n-alkyldekalin-2-carboxylic acids are obtained by sterication of hydroxyl with biphenyl and similar other hydroxyl compounds.

The 4-substituted esters of biphenyl 6-n-alkyldekalin-2-carboxylic acid, their analogous esters and the temperature of their transformation are given in Table. 2

Physico-chemical characteristics of the compounds obtained are presented in table. 3

The implementation of the proposed method allows to increase the yield of the chain product from 4.3 to 70%, to simplify the process by reducing the number of stages from 9 to 3,

Claims (1)

Invention Formula A method for producing liquid crystal trans-6-n-alkyldecaline-2-carboxylic acid esters of the general formula. xNj COOXP where Rj is C i -C, alkyl; X N at R is hydrogen, halo; / O / (O) P - cyan. C, - -, j-alkyl N fO X) - with R - 0-C, -C, Ifi} -alkyl; X - R - hydrogen,) - (o) -R5, HgCitV Y 13217216 when R is cyan. C, -C, 1-alkyl, O -C, -C 2 -alkyl; R is hydrogen, chlorine, by hydrogenation of a yaf5 talin derivative, followed by conversion of the obtained decalin-carboxylic acid derivative to the corresponding acid chloride by treatment with thionyl chloride and reacting with corresponding hydroxyl derivatives, in order to simplify the process and increase the yield of the target product, 6-n 5-alkylnaphthapine-2-carboxylic acid is used as the starting material, the hydrogenation is carried out in an alkaline solution in the presence of Ni-Rene under a pressure of 14 MPa, at a temperature of ur 200-260 C. Table 1 ABOUT HgC /, table 2 oa COO-X-R n) a s R Yu I) H