DD155063A1 - PROCESS FOR THE PREPARATION OF TRANS-3- [4-ALKYL-CYCLOHEXY] -PROPANSAURS AND THEIR ESTERS - Google Patents

Abstract

The invention relates to a process for the preparation of novel crystalline liquid trans-3- (4-alkylcyclohexyl) propane acids and their esters of the general formula. The aim of the invention is the preparation of novel crystalline liquid trans-3- (4-alkylcyclohexyl) propane acids and their esters. It has been found that novel crystalline liquid trans-3- (4-alkylcyclohexyl) propane acids and their esters are obtained by catalytic high pressure hydrogenation of 3- (4-alkylphenyl) -propanoic acids or their alkali metal salts under aqueous alkaline reaction conditions and use of Raney acid. Nickel can be prepared as a catalyst at 100 to 300 degrees C and 5 to 20 MPa and optionally subsequent esterification.

Description

22 5 9 45 -ί-

Title of the invention

Process for the preparation of propanoic acids and their esters

Field of application of the invention

The invention relates to a process for the preparation of novel crystalline liquid trans-3 - / "" 4-alkyl-cyclohexyl _> _7 propanoic acids and their esters of the general formula

E = -H, ^r1 "Va = I ₊ I '- ^0C m ^H 2m ₊ 1 ·" ⁰⁰⁰ Am ₊ I-

- ^OOOC m ^H _{2m +} 1 '

-P, -Cl, -Br, -OU, -CP ,, -HO ₂ -O ₂ H ₄ OlI, -OH = OCOlO ₂

with in = 1 to 10 and η ^ 2 to 10 mean.

The liquid crystals are applicable as dielectrics in optoelectronic African displays.

  - 2 - 225 945

Characteristic of the known technical solutions

In the literature so far trans-4-n.-alkylcyclohexanecarboxylic acids / H. Schubert, V. Uhlig, R. Dehn; Z. Chera. 12, 219 (1972 / and their esters / HJ Deutscher, D. Laaser, V / Dulling, H. Schubert: J. prakt. Chem., 20, 191 (1978); HJ Deutscher, F. Kuschel, S. König , H. Kresse, D. Pfeiffer, A. Y / iegeleben, J. Wulf, D. Demus: Z. Chem. YJ_ (1977), H. Zaschke: Wise, Z. Univ., Halle XZIX 80 M (3), -35 (198O) / known, further cyclohexyl and 3 ~ Z ~ 4-methylcyclohexyl-7-propanoic acid / AiI Hiyazov, KM Mavyer, NP Pavlova:

Izv. Akad. Nauk 0? Urkm. SSR, Ser. Fiz-Tekh., Khira. Geol, lauk 191 ^ 5 ¹¹ 9j 197,2, 38 / 3- / f * 4-IsopropylcyclohexylJ / '- propanoic acid /3.E. Witzel, N. Grier, RA Dybas, RA Strelitz: Ger. Open 2617 672 / and 3- / ~ 4 ~ aminocyclohexyl__7-propanoic acid / ID Pletneva, RS Muromova, IV Pervuktina: Zh. Obshch. Khim. J ^, 1815 (1964).

The cited substituted cyclohexylpropanoic acids obtained by catalytic hydrogenation of the corresponding aromatic substances on PtO _? - or Rh-Pt catalysts recovered

> 0, under which reaction conditions the cis-iso-ine preferably arises, but are not crystalline.

trans-3- / ~ "4 ~ Ethylcyclohexyl__7-propanoic acid, the longer-trans-3- / 4 ~ _{n-alkylcyclohexyl> i} _7 ~ p ^ opansäuren and their substituted phenyl and cyclohexyl esters are novel, as a result, are processes for their preparation does not known.

Aim of the invention

The aim of the invention is the preparation of novel crystalline trans-3- / T "4-Alkylcyclohexyl_J7-propanoic acids and their esters.

- 3 - 225 9-45

Darl egung the essence of the invention

The object of the invention is a process for the preparation of crystalline liquid trans-3 ~ / "~ 4-Alkyl cy el oh exyl__7-pr op acids and their esters.

It has been found that novel crystalline liquid trans-3 - / ^ - Alkylcyclohexyl ^ JZ-piOpansäuren and their esters by catalytic high-pressure hydrogenation of 3- / 4-Alkylphenyl_7-propanoic acids or their alkali metal salts under aqueous alkaline reaction conditions and using Raney -iikel as Catalyst at 100 to 300 ⁰ C and 5 to 20 M Pa and optionally subsequent esterification are prepared. can according to the general scheme:

Hrj / RaneyliTi ^C n ^H 2n ₊ r <0> -OH ₂ -CH ₂ -GOOH - * - - ^ C _n H _{2n + 1} - Q -CH.-CH, -

«COOH: -> - ° η ^Η 2η + Γ O" ^GH 2 "" ^CH 2 ~ ^C00R

The process according to the invention preferably produces the trans isomers. Complete separation of the trans isomers from the cis isomer succeeds by fractional crystallization of the cis-trans isomer mixture of the substituted cyclohexylpropanoic acids or their esters from methanol, ethanol _. η-hexane or petroleum ether.

6Sg (0.3 uiol) of 3 - /. * ~ 4 "-n-Pentylphenyl _> _7-pi ^< opansäure were in 300 ml of 10 ^ aqueous potassium hydroxide solution and 25 g Raneyliickel at 200 to 240 ⁰ C and 13-14 MPa in After completion of the reaction, the catalyst was filtered off and the filtrate was acidified with conc. HCl, then carefully taken up with ether, and water was added to the high pressure silica autoclave

- ⁴ - 2 2 5 9 4 5

lent washed, over Ha ₂ SO. dried and fractionally distilled.

Yield: 61 g (90 % of theory , cis-trans mixture) bp: 129-138 ° G / 0.1 mm

IR and H-HLiR spectroscopy revealed the absence

confirmed by aromatic components. -

Recrystallization 5 times from η-hexane gave the pure trans-3 - / - 4-n-pentylcyclohexyl-7-propanoic acid.

Yield: 34 g - 50 % d, Th.

The compound is nematic between 53 ⁰ G (melting point) and 103.5 ⁰ C (clearing point).

2. 3 ~ Z ~ * 4-n-pentylcyclohexyl_7-propanoic acid chloride

113 g (0.5 mol) of 3 ~ Z ~ 4 ~ n-pentylcyclohexyl _{<__7-propanoic} acid (crude product) was added thionyl chloride slowly at 1-5 Räumtenperatur with 71.5 g (0.6 mol) and allowed to stand Geesthacht. Thereafter, the reaction mixture was refluxed for 8 hours, the excess thionyl chloride distilled off in a water jet pump vacuum and the acid chloride fractionally distilled.

Yield: 111 g (85 % d * th.)

Bp: 176-180 ° C / 20 mm

3 · trans-3 ~ / ~ 4-n-pentylcyclohexyl _i ^_7-pi> opansäureester (Table 1) abs To a solution of 0.01 mol of the substituted phenol or cyclohexanol in 15 ml. Pyridine was added dropwise 2.6 g (0.01 mol) of 3 ->"- 4-n-pentylcyclohexylcyl-7-propanoic acid chloride The reaction was stirred for one day at room temperature and then admixed with a mixture of ice / concentrated H ₂ SO ₄ (100 g / 7 ml) The ester was taken up in ether, washed thoroughly with 1 η HaOH solution, dilute H ₂ SO 4 and water, dried and the solvent was distilled off

- ⁵ - 2 2 5 9 4 5

Residue (oil or precipitate) was recrystallized several times from Hethanol, v / obei a complete separation of the cis-trans-isomeric ester took place. The cis esters are more soluble in the solvent used and are in the mother liquor,

The yields of trans product were 50-60 % d. Th.

4 × 3/4-ethylcyclohexyl-1-propanoic acid 62 g (0.35 mol) of 3 % 4-ethylphenyl-7-propanoic acid were dissolved in 4'00 ml of 10% strength aqueous potassium hydroxide solution and after addition of Raney® lTickel (prepared from 25 g alloy) at 200 to 290 ⁰ C and 10 to 11 Pa hydrogenated H 2 to 3 days in a high-pressure rocking autoclave. Thereafter, the catalyst was filtered off and the Fil.trat acidified with cons. HGl. , The acid (oil) was taken up in ether, washed thoroughly with water, over LiapSO. dried and fractionated distilled after removal of the solvent on a rotary evaporator.

Yield: 59.9 g (.. 93% of theory, cis-trans mixture) b.p. 123-130 ° C / 0.8 mm F: 44 - 56 ⁰ C

-1

IR and H-UMR spectroscopy confirmed the absence of aromatic components.

5 x 3 / ~ 4-EthylcyclohexylJ7-propanoic acid chloride 92 g (0.5 mol) of 3- / ~ _{4-ethylcyclohexyl>} _7 ~ propane "äure (crude product) at room temperature with 71.5 g (0.5 mol) of thionyl chloride The reaction mixture was refluxed for 8 hours, the excess thionyl chloride was distilled off in a water jet pump vacuum and the acid chloride was fractionally distilled,

Yield: 93.9 g (86 % of theory ) Ep: 120-122 ° C / 11 mm

- 6 - 2 2 5 9 4 5

6. trans-3 ~ / ~ 4 ~ etyl cyclolies: yl_7-propanoic acid ester (Tab. 1) 0.01 mol of substituted phenol or cyclohexanol were dissolved in 15 ml of abs, pyridine and slowly added 2.2 g (0.01 mol) 2> - ~ l_ 4-Ethylcyclohexyl__7-propei.nsäurechlorid added. The reaction was stirred for one day at room temperature and then on ice / conc . (100 g / 7 ml). , It was then taken up with ether, the ethereal phase with 100 ml 1-n-Ua0H, 100 ml Verd. H ₂ SO, and water washed thoroughly, with lia ^ SO ^ dried and the solvent was distilled off on a rotary evaporator. The residue was recrystallized several times from methanol to give complete separation of the cis-trans isomeric esters. The cis esters are more soluble in the solvent used and can be isolated from the mother liquor. The yields of trans product were 53-61 % d. Th ..

table

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trans -R ¹ -CH ₂ -CH ₂ -COO R '

K H

-CN. 47. 79

C ₀ H

-CH ₀ -CH ₀ -CH

^ . 68 (S _A 43)

, 69. 146

-H = H- <O> -CH ₃ . 99 ♦ 228

C, H

-C .H

11 -. 53. 103.5 ♦ 36. 46

C ₅ H ₁₁ . 27 S _A 56 H 68

Claims (1)

- 8 - 22 5 945 Brfindungsa η claim 1. A process for the preparation of novel crystalline liquid trans-3-Z "" 4-Alkylcyclohexyl__7-propanoic acids and their esters of the general Pormel ¹ OR where R = HH, -ΟΟ * ¹ , - > ^C m ^H 2m ₊ 1 ~ ^OOOC m ^H 2m ₊ 1> - ^OCOOC m ^H 2m ₊ 1 '-F, -Cl, -Br, -GN, -CP ₃ , -C ₂ H ₄ CH, -CH = C (Cl) ₂ with m = 1 to 10 and η = 2 to 10, characterized in that 3- _J / r * 4 "-Alkylphenyl_J7-propanoic acids or their alkali metal salts under aqueous alkaline reaction conditions and using Raney-lTickel as a catalyst at 100 to 300 ⁰ C and 5 to 20 M Pa are catalytically hydrogenated under high pressure and optionally esterified.