DD249277A1 - METHOD OF PREPARING CRYSTALLINE-FLUID R-2-SUBST. C-5-CYAN-1,3-DIOXANE-T-5-CARBONIC ACID ESTERS - Google Patents

Abstract

The invention relates to a process for the preparation of novel crystalline liquid r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acid esters of the general formula. The object of the invention is to prepare new crystalline liquid esters of r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acids. According to the invention, these compounds are prepared from r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acids obtained by reacting the correspondingly substituted aldehydes with bis (hydroxymethyl) -cyanessigsÄureethylestern in the presence of acidic catalysts , subsequent hydrolysis of the ester function with alkaline earth metal hydroxides and esterification with phenols in the presence of a water-soluble carbodiimide are obtained.

Description

A =

H V-R, cholesteryl,

R ² , - (CH ₂ Jq COOR ²

= R ", - (CH ₂ )

OR ³ , - (CH) p- <O) -R ^:

With

R ¹ = R ² , OR ² , OOCR ² , COOR ² , OCOOR ² , COR ² , halogen,

COOCH ₂ -C ₂ H ₅ , COO cholesteryl, CN CH ₃

R = C _n H _2n + 1 r 3 _ ρ u

·> ~ ^ M ⁿ 2m + 1 X = -COO -, - OOC, single bond Y = O, SZ = OS

R ⁴ = H, CH 3 / CH 3, H / CN, H / H, CN / H, H / CN, CN and η = 1 to 16, m = 1 to 16

ρ = 0.1, q = 2 to 8, characterized in that r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acids of the general formula II, by reacting the corresponding substituted aldehydes of general formula III with bis (hydroxymethyl) -cyanessigsäureethylestern in the presence of acidic catalysts and subsequent hydrolysis of the carboxylic acid ester function with alkali or alkaline earth metal hydroxides in solvents are obtained with alcohols or substituted phenols of general formula IV in the presence of a water-soluble carbodiimide and catalytic Amounts of an acylation catalyst in organic solvents, preferably methylene chloride, esterified and the stereoisomerically pure form is obtained by recrystallization from organic solvents.

Field of application of the invention

The invention relates to a process for the preparation of novel crystalline liquid r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acid esters of the general formula:

/ O - \, CN

"\ o- / coc

COOA

A =

, Cholssteryl,

CH

(CH ₂ Jq COOR

B = R ³ . - (CH) / h \ -R ³ , - (CH ₂ ) p- / oV ^0r3 '

R ¹ = R ² , OR ² , QOCR ² , COOR ² , OCOOR ² , COR ² , halogen,

COOCH ₂ CH -C ₂ H ₅ , COO cholestaryl, CN CH ₃

X = -COO-Z-OOC, single bond Y = O, S Z = O, S

R ⁴ = H, CH 3 / CH 3, H / CN, H / H, CN / H, H / CN, CN and η = 1 to 16, m = 1 to 16

ρ = 0.1, q = 2 to 8

mean, which can be used in electro-optical components for displaying numbers, characters and images, for information storage, transmission and processing.

Characteristic of the known technical solutions

The substances synthesized by the method according to the invention are new. So far, no process for their preparation has been described.

Object of the invention

The object of the invention is the preparation of new crystalline liquid esters of r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acid, which can be used in electro-optical components.

Explanation of the essence of the invention

The object of the invention is a process for the preparation of crystalline liquid r-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acid ester.

According to the invention, crystalline liquid r-2-subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acid esters are prepared by reacting r-2-subst.-c-5-cyano-1,3- dioxane-t-5-carboxylic acids of general formula II with alcohols or substituted phenols in the presence of a water-soluble carbodiimide, z. B. 1- (3-dimethylaminopropyl) -3-ethylcarbimide methiodide and catalytic amounts of an acylation catalyst, e.g. As 4-dimethylaminopyridine, in organic solvents, preferably in CH ₂ Cl ₂ . The r-2-Subst-c-5-cyano-1, S-dioxane-t-ö-carboxylic acid esters are already after one to two-fold recrystallization from a suitable solvent, preferably ethanol, ethyl acetate, acetone and hydrocarbons or Mixtures of these in melting and clear point pure form in surprisingly high yields (60-95% of theory) won (equation 1).

! - / y ( + R ¹ OH -ΤΠΤ * ' ^R -C Λ

\ <XJ ^N C00H 2 'V) - / ^x

-3- Z4S Z //

CN.

R-

\ / V t-III X X \

^ COOR '

II IV.

Other esterification processes yield lower yields and products of significantly lower purity. The r-2-naphth-c-5-cyano-1,3-dioxane-t-5-carboxylic acids which are not known in the literature are obtainable by reactions of corresponding aldehydes of the general formula III with bis-ihydroxymethyl-cyanoacetic acid ethyl esters in the presence of acid Catalysts and subsequent selective hydrolysis of the carboxylic acid ester function with alkali metal or alkaline earth metal hydroxides in suitable solvents or solvent mixtures, preferably at room temperature. Surprisingly, the desired isomer with an axial position of the CN function and equatorial position of the COOH function, which is capable of forming crystalline-liquid regions of existence, is preferably produced (the other isomers are not crystalline liquid). This isomer can be obtained in pure form by simple recrystallization from a suitable solvent mixture (ζ, B, benzene, hexane)

 Equation 2

NC CH ₂ OH

'CH OH. "- ^H JV) - / ^{% x} COOEt ^r \ o - / * ^x * COOH

The transformation temperatures of substances according to the invention are summarized in Tables 1-4, where:

K = crystalline-solid S = smectic N = nematic I = isotropic-liquid

Table 1 r-2-n-alkyl-c-5-cyano-1,3-dioxane-t-5-carboxylic acid (trans-4-n-alkylcyclohexyl) ester

rO-Λ, CN

^v C00

m>

3 5 • 105.5 (• 67.5) 5 3 • 107 - - 5 5  111 (• 91)

Table 2 r-2-n-alkyl-c-5-cyano-1,3-dioxane-t-5-carboxylic acid cholesteryl ester

ch

3 -172 -185.5 -215

5 -180 -219

Table 3 r ^ -n-alkyl-c-B-cyano-i ^ -dioxane-t-B-carboxylic acid W-subst-phenyl ester

η 2η +

^ COO- / C) \ - R

- ^{0C H} 3 17

-ooc- (o) -oc ₆ H _l3

-coo- <o) -hour ₃

15

C ₃ H ₇

-OCH

° ch

, 82 66) ( * "* a , 85 (. , 162 , 146 169 , 132 153 , 155 , 113 , 168 , 150 175 ^- i , 129 100.5) mm _β , 103 (. 146 * " M , 102 , 151 "" * , 63 51) "™ · , 62 (. "** , 68 82 "~ · , 80.5. , 160.5. , 122 137 , 157 , 136 , 162 , 138 159 "" · , 92 158 , 92 '. 74). , 130

Table 4 R ^ -Subst.-c-o-cyano-i ^ -dioxane-t-ö-carboxylic acid n-alkyl ester

COO C H_ "η 2η + 1

R η K S N I

embodiment

Example 1:

Synthesis of 4-2-Subst.-c-5-cyano-1,3-dioxane-t-5-carboxylic acid ethyl ester

A mixture of 0.2 mol (34.6 g) of ethyl bishydroxymethylcyanoacetate, 0.2 mol of freshly distilled aldehyde, 5 g of p-toluenesulfonic acid and 11 benzen is heated to completion of the water separation with stirring on a water. After cooling, the reaction mixture is saturated with 250ml. NaHCO ₃ solution and then washed with 500 ml of water, dried over Na ₂ SO ₄ and the solvent was distilled off on a rotary evaporator. The residue is treated with 250 ml of petroleum ether (bp 30-60 ⁰ C) and cooled to -20 ⁰ C, whereby the product crystallized. It is recrystallized again from n-hexane / ethyl acetate.

Table 5 r ^ -n-alkyl-c-cyan-i, 3-dioxane-t-5-carboxylic acid ethyl ester

/ 0-Λ CN

C η 2n + l " ₂ h ₅ Mp [° C] η 41.5 3 50.5 5 \ o_ / ^s cooc Y. [%] 58 62

Example 2:

Synthesis of r ^ -Subst.-c-o-cyano-i ^ -dioxane-t-ö-carboxylic acids

0.2 mol r ^ -Subst.-c-cyan-i ^ -dioxane-t-ö-carboxylic acid ethyl ester is dissolved in 400 ml of methanol and at 2O ⁰ C with a solution of 0.24 mol (16.4g - 83% pure KOH) in 200 ml of methanol and 4 ml of water. After about 10 minutes, the ester is completely saponified. The solvent is distilled off at about 30 ⁰ C on a rotary evaporator in vacuo and the residue dissolved in 800 ml of ethyl acetate. At -15 to -20 ⁰ C is treated with 0.236 ml (24ml - 32%) hydrochloric acid and vigorously shaken for about 1 min. The precipitate, consisting of KCl, is filtered off with suction and washed three times with 200 ml of ethyl acetate. The solution is dried with Na ₂ SO ₄ and the solvent is distilled off on a rotary evaporator and the residue is treated with 150 ml of petroleum ether. At -20 ° C, the product crystallizes, which is recrystallized from CHCl ₃ / n-hexane. Table 6 r ^ -n-alkyl-c-cyano-i ^ -dioxane-t-ö-carboxylic acids

^C n ^H 2n + l ' \ A \ qJ "COOH Fp [ ⁰ C] η Y. [%] 129.5 3 75 101 5 62

Example 3:

Synthesis of r ^ -Subst.-c-cyan-i-dioxane-t-o-carboxylic acid esters

0.021 mol of r ^ -Subst-c-o-cyart-i ^ -dioxane-t-ö-carboxylic acid, 0.020 mol of 4-substituted phenol or trans ^ -alkylcyclohexanol and 100 mg of DMAP are dissolved in 50 ml of absolute methylene chloride.

Under ice-cooling and stirring, 0.025 mol (7.5 g) of i-P-dimethyl-aminopropyl O-S-ethylcarbodiimide methiodide is added.

The mixture is then stirred for 30 min in an ice bath and 12 h at 20 ⁰ C. For workup, the reaction mixture is diluted with 250 ml of methylene chloride, washed four times with je200ml H ₂ O, once with 5% NaHCO ₃ solution and once with 100ml H ₂ O, dried over Na ₂ SO ₄ and the solvent was distilled off on a rotary evaporator. The residue is recrystallized from ethanol.

Yield: 60 to 95% d. Th.

The compounds thus synthesized are summarized in Tables 1 to 3.

Claims (1)

Invention claim: A process for the preparation of crystalline liquid R - ^ - Subst.-c-B-cyano-i ^ -dioxane-t-B-carboxylic acid ester of general formula I. / O-, CN
B- / X ^x 0 V ^S COOA