DD156258A5 - LIQUID CRYSTALLINE MIXTURES - Google Patents

Abstract

The present invention relates to liquid crystalline mixtures containing novel hydrogenated naphthalenes and their use in electro-optical devices as well as in all fields where liquid crystals are commonly used. The mixture according to the invention, which consists of at least 2 components, is characterized in that at least one component is a compound of general formula I in which A, R, R, R 2 have the meaning given in the description.

Description

232526 3

Berlin, 3.2.1982 AP C 07 C / 232 526 59 4-95 / 18

Flow! Crystalline mixtures Field of application of the invention

The invention relates to liquid-crystalline mixtures containing novel hydrogenated naphthalenes and their use in electro-optical devices and in all fields in which liquid crystals are commonly used.

Characteristic of the known technical solutions

In an electric field, liquid-crystalline compounds and mixtures with positive anisotropy of the dielectric constant are oriented with the direction of their largest dielectric constant parallel to the field direction. This effect is u. a. in the interaction between intercalated molecules and the guest-host interaction described by J.H. Heilmeier and L.A. Zanoni (Applied Physics Letters 1J3, 91 (I963)). Another interesting application of dielectric field orientation is that of M. Schadt and Y /. HeIfrieh (Applied Physics Letters 1S3, (1971)) and the Kerr cell described in Molecular Crystals to Liquid Crystals 1, 355 (1972).

232526 3 .- ² - ³ · ¹² · ⁸¹

59 495 18

This electro-optical rotary cell is essentially a capacitor with translucent electrodes whose dielectric is of a nematic crystal with E "> j. is formed. The molecular longitudinal axes of the liquid crystal are helically arranged in the field-free state between the capacitor plates, wherein the screw structure is determined by the predetermined wall orientation of the molecules. After applying an electrical voltage to the capacitor plates, the molecules with their longitudinal axes in the field direction, d. H. perpendicular to the plate surface, whereby linearly polarized light in the dielectric is no longer rotated (the liquid crystal is perpendicular to the surface of the plates uniaxial). This effect is reversible and can be used to electrically control the optical transparency of the capacitor »

Liquid crystals containing decalins and tetralins, or decalins and tetralins with liquid-crystalline properties, have not previously been known.

Object of the invention

The aim of the invention is to provide novel liquid-crystalline mixtures having improved chemical, physical and optical properties, in particular improved chemical and photometric stability, mesophase and viscosity.

232526 3

-3- 3.2.1982

AP C 07 C / 232 526 59 4-95 / 18

Explanation of the reading of the invention;

The invention has for its object to find compounds with the desired properties.

Invention 3gemaß be new hydrogenated naphthalenes of the general formula

R ²

R ¹

provided,

wherein A is A saturated or aromatic and an optionally present saturated A is trans-linked to the second Hing; E denotes a straight-chain alkyl or alkoxy group having 1 to 11 carbon atoms;

E cyano, a straight-chain alkyl group having 1 to 11 carbon atoms, an ester group of the general formula

-C-X ( B \ E ³ II

or, if In A is saturated, additionally a straight-chain alkoxy group having 1 to 11 carbon atoms; in the ester group of formula II, B is either aromatic and X is oxygen or sulfur and Ir is cyano or a straight chain alkyl or alkoxy group of 1 to 10 carbon atoms, or King B is a trans-1, A-disubstituted cyclohexane ring and X is oxygen and cyano or a straight-chain alkyl group having 1 to 10 carbon atoms

23 2 5 2 6 3

59 495 18

atoms means; and the total number of carbon atoms in the alkyl and / or alkoxy groups is at most 12.

In the context of the present invention, the term "straight-chain alkyl group" means, depending on the number of carbon atoms specified, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and uhdecyl and the term "straight-chain alkoxy group" corresponding to methoxy, Ethoxy, propyloxy, butyloxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy and undecyloxy.

The compounds according to the invention are particularly valuable as components in liquid-crystalline mixtures.

Compounds of the formula I in which R is an ester group of the formula II are for the most part themselves liquid-crystalline. The remaining compounds of formula I, d. H. those

wherein R is cyano or a straight-chain alkyl or alkoxy group, are particularly suitable as dopants in liquid crystal mixtures. ,

Those compounds of the formula I which have a cyano group have a high positive dielectric constant anisotropy (ε ₍₁ >& _L , where ε "denotes the dielectric constant along the molecular longitudinal axis and * C _X the dielectric constant perpendicular thereto) of the formula i, in which R or R 1 represents an alkyl group, only a small anisotropy of the dielectric constant,

Since the compounds according to the invention have different anisotropy of the dielectric constants, depending on the nature of the substituents, they can be used to adjust the threshold voltage of mixtures of the electro-optical cell used.

It would further be found that the compounds of the

Formula I, wherein R represents an ester group of the formula II, have a particularly large nematic mesophase range, in particular in comparison to known esters having similarly low melting points. In addition, they have good chemical stability, low viscosity, easy orientability, low smectic tendencies, and provide high contrast in display devices.

The compounds of formula I wherein R is cyano, alkyl

or alkoxy, have excellent chemical stability and low viscosity. They are therefore particularly suitable for improving the viscosity and thus also the electro-optical response time of liquid-crystalline mixtures. The high boiling points of these compounds (in comparison to previously used dopants) also facilitate the exact production of mixtures in predetermined proportions, since in this case the evaporation can be kept very low.

The compounds according to the invention are colorless and have a high UV stability, since they absorb at short wavelengths and also with small extinctions.

^to brew. The optical anisotropy differs depending on the molecular structure; in general, the larger the unsaturated moiety, the larger it is. By suitable choice of the compounds according to the invention, therefore, the optical anisotropy of mixtures can be varied, ie their contrast in a given cell can be optimized.

The compounds of the invention are also good

L · O L · J

miscible with all known liquid crystals.

The compounds according to the invention which fall under the general formula I are either trans-decalins of the general formula

IA

or tetralins (1,2,3,4-tetrahydronaphthalenes) of the general formula

) 2

IB

1 2

i ⁿ which the radicals R and R have the above meaning.

The compounds according to the invention have at least one chiral center and can therefore be present in optically active or racemic form.

However, the compounds of the formula I mentioned below are-unless expressly stated otherwise-generally present as racemates, specifically the compounds of the formula IA as racemate consisting of the compounds of the formulas

H H

and

and the compounds of the formula IB as a racemate consisting of the compounds of the formulas

and

The symbol (? * »·) Means that the corresponding bond to the substituent is directed upwards (above the plane of the drawing; ß-position), and the symbol (vuimu) that is down (under the plane of the drawing, α-position) is directed.

In the context of the present invention, a representation analogous to formulas I, IA and IB was also used for the other decalins and tetralins.

On the basis of the H-NMR spectrum of some compounds prepared according to the invention, it is assumed that the remainder

R in the compounds of the formula IA in equatorial position. The position of the substituent R could not be clarified. Due to the pronounced liquid crystalline properties of the decalin esters, however, it is assumed that the substituent R is also in an equatorial position. If this assumption is true, the compounds of the formula IA Raceraate would be composed of the compounds of the formulas

and

1 2 wherein R and R have the above meaning. An exception

23ZbZb ό

- t

however, form the compounds of formula IA, wherein R

and R have the same meaning, since in this case

the two above formulas are identical and correspond to an optically inactive form

 5

The above formula I preferably comprises the racemic

see connections.

Furthermore, of the compounds of the above formulas IA and IB, those of the formula IA are preferred. Of the compounds of formula I, those are further preferred

wherein R is an ester group of the formula II. Preferred ester groups of formula II are those in which ring B is aromatic and also those in which X is oxygen and preferred radicals R are the cyano group and the alkyl groups, especially the cyano group. Particularly preferred liquid crystal components are thus the trans-decalin-2-carboxylic acid phenyl esters and in particular the trans-decalin-2-carboxylic acid p-cyanophenylester. Preferred dopants are those

Compounds of the formula I in which R is the cyano or an alkyl group, in particular the cyano group. Preferred radicals R in the compounds of the formula I are those

Alkyl groups. Preferred alkyl and alkoxy groups R and 2, respectively

R are those of Γ to 8 carbon atoms, especially those of 3 to 7 carbon atoms. Of the alkyl and alkoxy groups R in the ester group of the formula II, those having 1 to 7 carbon atoms are preferable, and those having 1 to 5 carbon atoms are particularly preferable.

As examples of preferred compounds of the formula I, the following may be mentioned:

6-methyl-trans-decalin-2-carboxylic acid p-cyanophenyl,

G-ethyl-trans-decalin ^ -carbonsä.ure-p-cyanophenyl,

L · O ά. JLUJ

e-propyl-trans-decalin - ^ - carboxylic acid p-cyanophenyl,

p-Cyanophenyl e-butyl trans-decalin - ^ -carboxylic acid, p-cyanophenyl G-pentyl trans-decalin carboxylic acid ester,

P-cyanophenyl 6-hexyl-trans-decalin-2-carboxylate, p-cyanophenyl G-heptyl-trans-decalin-carboxylic acid ester,

e-octyl-trans-decalin-Z-carboxylic acid p-cyanophenyl ) ester,

6-Methyl-trans-decalin-2-carboxylic acid p-butylphenyl ester, 6-ethyl-trans-decalin-2-carboxylic acid p-ethylphenyl ester,

6-Propyl-trans-decalin-2-carboxylic acid p-methylphenyl ester, 6-butyl-trans-decalin-2-carboxylic acid p-methylphenyl ester,

e-pentyl-trans-decalin ^-carboxylic acid p-rnethylphenylester,

6-hexyl-trans-decalin-2-carboxylic acid-p-methylphenyl ester,

J 25 6-heptyl-trans-decalin-2-carboxylic acid p-methylphenyl ester,

6-Propyl-trans-decalin-2-carboxylic acid p-ethylphenyl ester, 6-butyl-trans-decalin-2-carboxylic acid p-ethylphenyl ester,

6-pentyl-trans-decalin-2-carboxylic acid p-äthylphenylester,

6-hexyl-trans-decalin-2-carboxylic acid p-ethylphenyl ester, 6-heptyl-trans-decalih-2-carboxylic acid p-ethylphenyl ester,

6-propyl-trans-decalin-2-carboxylic acid p-propylphenylester,

6-Butyl-trans-decalin-2-carboxylic acid p-propylphenyl ester, 6-pentyl-trans-decalin-2-carboxylic acid p-propylphenyl ester,

6-hexyl-trans-decalin-2-carboxylic acid p-propylphenyl ester, p-propylphenyl o-heptyl-trans-decalin-Z-carboxylic acid,

ö-propyl-trans-decalin ^-carboxylic acid p-hydroxybenzoate,

P-butylphenyl 6-butyl-trans-decalin-2-carboxylate, p-butylphenyl e-pentyl-trans-decalin-carboxylic acid ester,

6-hexyl-trans-decalin-2-carboxylic acid p-butylphenyl ester,. , 6-heptyl-trans-decalin-2-carboxylic acid p-butylphenyl ester,

6-propyl-trans-decalin-2-carboxylic acid p-pentylphenyl,

6-butyl-trans-decalin-2-carboxylic acid p-penty! Phenyl ester, G-pentyl-trans-decalin-carboxylic acid p-pentylphenyl ester,

6-hexyl-trans-decalin-2-carboxylic acid p-pentylphenyl ester, p-pentylphenyl 6-heptyl-trans-decalin-2-carboxylic acid,

6-propyl-trans-decalin-2-carboxylic acid-p-methoxyphenyl ester,

e-Pentyl-trans-decalin-carboxylic acid p-methoxyphenyl ester, ''

e-heptyl-trans-decalin ^-carboxylic acid p-methoxyphenyl,

Δό L D L ö

6-propyl-trans-decalin-2-carboxylic acid p-äthoxyphenylester,

6-Penty1-trans-decalin-2-carboxylic acid p-äthoxyphenylester,

6-heptyl-trans-decalin-2-carboxylic acid p-äthoxyphenylester,

6-propyl-trans-decalin-2-carboxylic acid p-propyloxyphenylester,

6-pentyl-trans-decalin-2-carboxylic acid p-propyloxyphenylester,

6-heptyl-trans-decalin-2-carboxylic acid p-propyloxy- J phenyl ester,

6-propyl-trans-decalin-2-carboxylic acid p-pentyloxyphenylester,

e-pentyl-trans-decalin ^-carboxylic acid p-pentyloxyphenylester,

e-methoxy-trans-decalin ^ -carboxylic acid, p-cyanophenyl,

6-ethoxy-trans-decalin-2-carboxylic acid p-cyanophenyl,

6-propyloxy-trans-decalin-2-carboxylic acid p-cyanophenyl,

6-Butyloxy-trans-decalin-2-carboxylic acid p-cyano- _N . phenylester,

6-pentyloxy-trans-decalin-2-carboxylic acid p-cyanophenyl,

6-hexyloxy-trans-decalin-2-carboxylic acid p-cyanophenyl,

6-heptyloxy-trans-decalin-2-carboxylic acid p-cyano-

30

phenylester,

6-Octy1oxy-trans-decalin-2-carboxylic acid p-cyanophenyl,

6-propyloxy-trans-decalin-2-carboxylic acid p-methy1-phenyl ester,

° e-pentyloxy-trans-decalin-carboxylic acid p-methylphenyl ester,

6-heptyloxy-trans-decalin-2-carboxylic acid p-methy1-phenyl ester,

LOL ·, JL · U ^

-M-

ö-propyloxy-trans-decalin-Z-carboxylic acid p-propylphenylester,

6-pentyloxy-trans-decalin-2-carboxylic acid p-propylphenylester,

6-Heptyloxy-trans-decalin-2-carboxylic acid p-propylphenyl ester, · _

6-propyloxy-trans-decalin-2-carboxylic acid p-pentylphenyl,

6-Penty1oxy-trans-decalin-2-carboxylic acid p-peηty1-phenyl ester,

6-heptyloxy-trans-decalin-2-carboxylic acid p-pentylphenyl,

6-propyl-trans-decalin-2-carboxylic acid p-cyanophenylthioester,

6-butyl-trans-decalin-2-carboxylic acid p-cyanophenylthioester,

6-pentyl-trans-decalin-2-carboxylic acid p-cyanophenylthioester,

6-hexyl trans-decal in 2-carboxylic acid p-cyanophenyl thioester,

6-heptyl-trans-decalin-2-carboxylic acid p-cyanophenylthioester,

6-propyl-trans-decalin-2-carboxylic acid-trans-4-cyano-1-cyclohexyl ester,

6-butyl-trans-decalin-2-carboxylic acid-trans-4-cyano-1-cyclohexyl ester,

6-Penty1-trans-decalin-2-carboxylic acid-trans-4-cyano-1-cyclohexyl ester,

6-hexyl-trans-decalin-2-carboxylic acid-trans-4-cyanol-cyclohexyl ester,

6-Heptyl trans-decal in 2-carboxylic acid trans-4-cyano-1-cyclohexyl ester,

6-Pr-opyl-tr ans -dec al-in-2-carboxylic acid -tr ans -4 -me thy 1-1-cyclohexyl ester,

6-Penty1 trans-decal in 2-carboxylic acid trans-4-methyl-1-cyclohexyl ester,

6-heptyl-trans-decalin-2-carboxylic acid-trans-4-methyl-1-cyclohexyl ester,

L ό LOL O O

al

6-Propy1-trans-decalin-2-carboxylic acid-trans-4-propyl-1-cyclohexyl ester,

6-pentyl trans-decal in 2-carboxylic acid trans-4-propyl-1-cyclohexyl ester,

5. 6-heptyl-trans-decalin-2-carboxylic acid-trans-4-propyl-1-cyclohexyl ester. -

6-propyl-trans-decalin-2-carboxylic acid-trans-4-pentyl-1-cyclohexyl ester,

6-butyl trans-decalin-2-carboxylic acid trans-4-penty1-O-1-cyclohexyl ester,

6-pentyl-trans-decalin-2-carboxylic acid trans-4-penty1- J 1-cyclohexyl ester,

6-heptyl-trans-decalin-2-carboxylic acid-trans-4-pentyl-1-cyclohexyl ester,

6-ethyl-trans-decalin-2-carbonitrile, 6-propyl-trans-decalin-2-carbonitrile, 6-pentyl-trans-decalin-2-carbonitrile, 6-heptyl-trans-decalin-2-carbonitrile, 6- Pentyloxy-trans-decalin-2-carbonitrile, 2-ethyl-6-propyl-trans-decalin, 2-ethyl-6-pentyl-trans-decalin, 2-ethyl-6-heptyl-trans-decalin, 2,6- dipropyl-trans decaliη,

2-butyl-6-propyl trans-decalin,

2-pentyl-6-propyl-trans-decalin, 2-pentyl-6-butyl-trans-decalin, 2,6-dipentyl-trans-decalin, 2-hexyl-6-propyl-trans-decalin, 2-hexyl 6-pentyl-trans-decalin, 2-heptyl-6-propyl-trans-decalin, 2-heptyl-6-butyl-trans-decalin, 2-heptyl-6-pentyl-trans-decalin, 2-propyloxy-6- propyl-trans-decalin, 2-propyloxy-6-pentyl-trans-decalin, 2-propyloxy-6-heptyl-trans-decalin, 2-pentyloxy-6-propyl-trans-decal in, 2-pentyloxy-6-pentyl trans-decal in, 2-pentyloxy-6-heptyl-trans-decalin,

L ό L D L Ό

^ -Heptyloxy-ö-propyl-trans-decalin,

p-cyanophenyl-2-methyl-l, 2,3,4-tetrahydro-6-naphthoate, p-cyanophenyl-2-ethyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-Cyanophenyl 2-propyl, 1, 2, 3, 4-tetr-ahydro-6-naphthoate, p-cyanophenyl-2-butyl-l, 2,3,4-tetrahydro-6-naphthoate, p-cyanophenyl 2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate, p-cyanophenyl-2-hexyl-l, 2,3,4-tetrahydro-6-naphthoate, p-cyanophenyl-2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate, p-cyanophenyl-2-octyl-l, 2,3,4-tetrahydro-6-naphthoate, p-methylphenyl-2-propyl-l, 2,3,4- tetrahydro-6-naphthoate,

p-methylphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-methylphenyl-2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate, p-propylphenyl-2-propyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-Propylphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate, p-propylphenyl-2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-butylphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-pentylphenyl-2-propyl-l, 2,3,4-tetrahydro-6-naphthoate, p-pentylphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-pentylphenyl-2-heptyl-1,2,3 ', 3,4-tetrahydro-6-naphthoate, p-cyanophenyl-2-propyloxy-l, 2,3,4-tetrahydro-6-naphthoate,

p-Cyanophenyl-2-pentyloxy-l, 2,3,4-tetrahydro-6-naphthoate, p-cyanophenyl-2-heptyloxy-l, 2,3,4-tetrahydro-6-naphthalene

232526 3

thoat,

p-methylphenyl-2-pentyloxy-l, 2,3,4-tetrahydro-6-naphthoate,

p-propylphenyl-2-pentyloxy-l, 2,3,4-tetrahydro-6-naphthoate,

p-pentylphenyl-2-pentyloxy-l, 2,3,4-tetrahydro-6-naphthoate,

p-methoxyphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-ethoxyphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-propyloxyphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

p-Aethoxyphenyl-2-heptyl-1,2,3,4-tetrahydro-6-naphthoate,.

S- (p-cyanophenyl) -2-propyl-l, 2,3,4-tetrahydro-thio-6-naphthoate,

S- (p-cyanophenyl) -2-butyl-l, 2,3,4-tetrahydro-thio-6-naphthoate,

S- (p-cyanophenyl) -2-pentyl-l, 2,3,4-tetrahydro-thio-6-naphthoate,

S- (p-cyanophenyl) -2-hexyl-l, 2,3,4-tetrahydro-thio-6-naphthoate,

S- (p-cyanophenyl) -2-heptyl-1,2,3,4-tetrahydro-thio-6-naphthoate,

S- (p-ethoxyphenyl) -2-pentyl-l, 2,3,4-tetrahydro-thio-6-naphthoate,

(Trans-4-cyano - - cyclohexyl) -2-propyl-l, 2,3,4-tetrahydro-6-naphthoate,

(Trans-4-cyano-l-cyclohexyl) -2-butyl-l, 2,3,4-tetrahydro-6-naphthoate,

(Trans-4-cyano-l-cyclohexyl) -2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

(trans - ^ - cyano-1-cyclohexyl) -2-hexyl-1,2,3,4-tetrahydro-6-naphthoate,. .

(Trans-4-cyano-l-cyclohexyl) -2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate,

(Trans-4-methyl -? - cyclohexyl) -2-propyl-l, 2,3,4-tetra-

- FeS -

hydro-6-naphthoate,

(Trans-4-methyl-l-cyclohexyl) -2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate,

(Trans-4-methyl-l-cyclohexyl) -2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate,

(Trans-4-propyl-l-cyclohexyl) -2-propyl-l, 2,3,4-tetrahydro-6-naphthoate,

(trans-4-propyl-1-cyclohexyl) -2-pentyl-1,2,3,4-tetrahydro-6-naphthoate,. ,

(Trans-4-propyl-l-cyclohexyl) -2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate,

2-propyl-l, 2,3,4-tetrahydro-6-naphthonitrile, 2-pentyl-l, 2,3,4-tetrahydro-6-naphthonitrile, 2-heptyl-l, 2,3,4-tetrahydro- 6-naphthonitrile, 2-pentyloxy-l, 2,3,4-tetrahydro-6-naphthonitrile, 2,6-dipropyl-l, 2,3,4-tetrahydro-6-naphthalene, 2-propyl-6-pentyl- l, 2,3,4-tetrahydro-6-naphthalene, 2-propyl-6-heptyl-l, 2,3,4-tetrahydro-6-naphthalene, • 2-pentyl-6-propyl-l, 2,3 , 4-tetrahydro-6-naphthalene, 2,6-dipentyl-l, 2,3,4-tetrahydro-6-naphthalene, 2-pentyl-6-heptyl-l, 2,3,4-tetrahydro-6-naphthalene , 2-heptyl-6-propyl-l, 2,3,4-tetrahydro-6-naphthalene, 2-heptyl-6-pentyl-l, 2,3,4-tetrahydro-6-naphthalene, 2-propyloxy-6 -pentyl-l, 2,3,4-tetrahydro-6-naphthalene, 2-pentyloxy-6-pentyl-l, 2,3,4-tetrahydro-6-naphthalene.

The compounds of formula I can be prepared according to the invention characterized in that

_a ) for the preparation of the compounds of formula I, wherein

R is an ester group of the formula II, a compound of the general formula

XOOH j

I 'I A I III

23 * 52

wherein R and A have the above meaning, or a reactive derivative thereof with a compound of the general formula

HX

IV

wherein X, B and R have the above meaning, or esterified to a suitable salt thereof,

b)

for the preparation of the compounds of formula I, wherein

R Cyano means a compound of the general formula

CONH ₂

wherein R and A have the above meaning, dehydrated,

c) .2

for the preparation of the compounds of the formula I in which R ** is a straight-chain alkyl group having 1 to 11 carbon atoms, a compound of the general formula

CO (CH ₉ ) H ^{A n} l

VI

wherein n ₁ denotes an integer of 0 to 10 and

1 R and A have the above meaning,

with hydrazine in the presence of a base,

35 d) .2

for the preparation of the compounds of the formula I in which R "denotes a straight-chain alkyl group having 2 to 11 carbon atoms, a compound of the general formula

232526 3

CH = CH- (CH-) H I ⁿ 2

VII

wherein η ₉ denotes an integer of 0 to 9 and

  1

R and A have the above meaning,

catalytically hydrogenated,

e) for the preparation of the compounds of formula I, wherein

Ring A is saturated and R is a straight-chain alkoxy group, a compound of the general formula

! R

VIII

where R has the above meaning, etherified.

The esterification of a compound of the formula III or a reactive derivative, for example an anhydride or acid halide, with a compound of the formula IV or a suitable salt thereof, for example the sodium salt, can be carried out in a manner known per se. The reaction of an acid of formula III with a compound of formula IV is conveniently in

DZ D J

Presence of a catalytic amount of acid, for example sulfuric acid or hydrohalic acid, carried out with or without an inert organic solvent. But it can also be done in the presence of N, N ¹ -Dicyciohexyl-carbodiimide and 4- (dimethylamino) pyridine. The preferred method, however, is the reaction of the acid chloride (Formula IX in Scheme 3) of a compound of Formula III with a compound of Formula IV. This reaction is conveniently carried out in an inert organic solvent, for example.

Example, an ether such as diethyl ether or tetrahydrofuran, or dimethylformamide, benzene, toluene, cyclohexane, tetra-. J chlorocarbon and the like. In order to bind the hydrogen chloride liberated in the reaction, it is expedient to use an acid binder, for example tertiary amines, pyridines and the like.

Preferably, the acid binder is used in large excess, so that it can serve as a solvent at the same time. Temperature and pressure are not critical and generally this reaction is carried out at atmospheric pressure and a temperature between room temperature and the boiling temperature of the reaction mixture.

The dehydration of a compound of the formula V%. can be carried out with any suitable dehydrating agent such as phosphorus oxychloride, phosphorus pentoxide, thio-nylchloride, acetic anhydride or, especially, benzenesulfonyl chloride and the like. The dehydration may be carried out in an inert organic solvent such as, for example, a hydrocarbon or halogenated hydrocarbon, optionally in the presence of a base such as sodium acetate, pyridine or triethylamine. However, it can also be carried out without organic solvents. The reaction temperature is preferably between about 50 ⁰ C and the reflux temperature of the reaction mixture. The pressure is not critical and the reaction is advantageously carried out at atmospheric pressure.

The reaction of a compound of the formula VI with hydrazine in the presence of a base, for example potassium hydroxide, sodium ethylate, potassium tert-butoxide and the like, is conveniently carried out in an inert organic solvent such as dimethyl sulfoxide or an alcohol, for example ethanol, di- or triethylene glycol and the same. In general, the hydrazone formed only at elevated temperature, for example, about 200 ⁰ C, decomposed. However, if dimethyl sulfoxide is used as the solvent, the decomposition often takes place at room temperature. If the decomposition temperature is above the boiling point of the reaction mixture, it must be carried out under elevated pressure. The preferred method is the Huang-Minlon reaction, ie

Heating a ketone of the formula VI under reflux in a high-boiling, water-miscible solvent, for example di- or triethylene glycol, together with • hydrazine hydrate and potassium hydroxide, then distilling off the water until the decomposition of the hydrazone, and further refluxing until the reduction is complete is. ,

The catalytic hydrogenation of a compound of formula VII can be carried out with any conventional hydrogenation catalyst such as palladium, platinum, Raney nickel and the like, optionally on an inert support material. Preferred catalysts are palladium and platinum. As the solvent, any inert organic solvents such as saturated alcohols, ethers, esters, carboxylic acids and the like, for example, ethanol, dioxane, ethyl acetate or glacial acetic acid may be used. Conveniently, with the addition of a base, such as triethylamine or 4- (dimethylamino) pyridine worked. Temperature and pressure are not critical aspects in this reaction. Conveniently, a temperature between room temperature and the boiling temperature of the reaction mixture and a pressure of about 1 to about atmospheres are applied.

For the etherification of a compound of formula VIII it is expedient to use a corresponding alkoxide, e.g. the sodium alcoholate, reacted with a corresponding alkyl halide, preferably the alkyl bromide or iodide. The alkoxide can be obtained in a manner known per se, e.g. by reacting the alcohol with an alkali metal or alkali metal hydride. The etherification is conveniently carried out in an inert organic solvent, for example a hydrocarbon or ether. One. A preferred variant of this process is the reaction of an alcohol of the formula VIII with sodium hydride and an alkyl bromide or iodide in monoglyme, if appropriate in the presence of sodium iodide. Temperature and pressure are not critical. However, the reaction is preferably carried out at atmospheric pressure and room temperature.

The compounds of formula IV are known or analogous known compounds. The compounds of formulas III and V-IX are new and also form counterparts.

20

stood the present invention. The acids of formula III have for the most part liquid crystalline properties. The compounds of formulas III, V, VI and IX can be summarized by the general formula

25

30

1 4

wherein R and A have the above meaning and R

Hydrogen, chlorine, the hydroxy or amino group or a straight-chain alkyl group having 1 to 10 carbon atoms

 35

The novel compounds of formulas III and V-IX can be prepared according to the following Reaction Schemes 1-3, wherein R, A, n and n _? have the above meaning, n, an integer

2325b.J

from 1 to 10, the symbol {i ^ -s ^) indicates that the substituent in question may be in the α or β position (below or above the plane of the drawing), and the interrupted one

Line () indicates that one of the designated bindings

a double bond is produced.

LO L

Scheme 1

0 ^NH

1) 2)

CH = CHCOCH ·

CH COOH / CH COONa

1) Li / NH.

2) NH ₄ Cl

NaCN

LiAlH

POCl.

VIII

KOH

COOH

COOH

III A

scheme

LiAlH ₄

(C H) PCHJCHJ 6 5 3 2 ^

E (CBJ _n CH

^{2 n} i

Close

CH (CH) Br 3 2 n H ₂ / Pd

CH 2 COCl / AlCl

COCH ₃

1) NaOBr

2) H ⁺

COOH

III B

23IbZb ό

Scheme 3 COOH

CHO

CONH,

b. ν

(C _C H _) - PCH ₀ (CH) H ^w Br

O J J ^ - Z Π a

C ₆ H ₅ SO ₂ Cl

CH = CH- (CH ₀₎ H 2 N ₂

VII

1) H (CH) MgBr

2) HCl ⁿ 3

3) H ₂ O

C0 (CH_) H 2 H ₃

VI a

3 2 5263

The reaction of a cyclohexanone with pyrrolidine (according to Scheme 1) can be carried out, for example, in toluene with a catalytic amount of p-toluenesulfonic acid. The water formed is conveniently separated by means of a water separator.

The reaction of 1-pyrrolidinyl-1-cyclohexene with. Methyl vinyl ketone is most suitable in absolute

Toluene and inert gas atmosphere by dropwise addition of the methyl '0 vinylketone and, after a few hours, heating to reflux with dropwise addition of a sodium acetate / acetic acid solution.

1 9 solution. This is a mixture of 6-pentyl-octahydro-A '-

9 10 naphthalen-2-one and 6-pentyl-octahydro-A 'naphthalen-2-one, which can be used without separation. "

The reduction of the mixture of the unsaturated ketones can be carried out, for example, with lithium in liquid ammonia. After addition of ammonium chloride and work-up, the corresponding trans-decalin-2-one is obtained in a mixture with the cis-decalin-2-one.

The decalin-2-one mixture dissolved in an inert organic solvent, e.g. Aether, for example, can

* be converted with a sodium cyanide solution and hydrochloric acid at about Q ⁰ C in the corresponding cyanohydrin mixture.

The dehydration of the cyanohydrin mixture can

with any suitable dehydrating agent such as phosphorus oxychloride, phosphorus pentoxide and the like, in an inert organic solvent or solvent mixture, preferably pyridine, benzene and the like, and heating to reflux. The resulting

1 2

containing mixture of octahydro-Δ- and -Δ -naphthalene-2

Carbonitrile can be further processed without separation. The saponification of the mixture of unsaturated nitriles

For example, with a solution of potassium hydroxide in diethylene glycol and heated to about 200 ⁰ C can be performed. After acidification and extraction, a mixture of the corresponding octahydro-Δ and -Δ-naphthalenecarboxylic acids is obtained.

The catalytic hydrogenation of the unsaturated acids can be carried out with any commonly used hydrogenation catalyst such as palladium, platinum, Raney nickel and the like, optionally on an inert support material. · be performed. Suitable solvents are saturated alcohols, ethers, esters, carboxylic acids and the like, preferably ethanol. The resulting crude trans-decalin-2-carboxylic acid of formula IIIA, which usually still contains cis isomer, can be purified by recrystallization and sublimation under high vacuum.

The reaction of the above-described trans-decalin-2-one, optionally in admixture with the cis isomer, to give an alcohol of the formula VIII can, for example, with

Lithium aluminum hydride in an inert organic solvent such as tetrahydrofuran, diethyl ether and the like. The resulting crude product of formula (VIII) can be purified by recrystallization and chromatography.

2-tetralone can be reacted (according to Scheme 2) for example by Wittig alkylation with an alkyltriphenylphosphonium bromide to give the corresponding 2-alkylidene-l, 2,3,4-tetrahydronaphthalene. The reaction is conveniently carried out in an inert organic solvent, for example an ether or a saturated or aromatic hydrocarbon, such as diethyl ether, tetrahydrofuran, dioxane, dimethoxyethane, toluene and the like, at a temperature between room temperature and boiling temperature of the reaction mixture. The bases used are preferably alkali metal alkoxides, such as potassium tert-butylate and sodium methylate.

"Jj? £ a ^ Ji ψ

The catalytic hydrogenation of a 2-alkylidene-1,2,3,4-tetrahydronaphthalene can be carried out in an analogous manner to the above-described hydrogenation of a compound of formula VII.

The reduction of 2-tetralone to alcohol can be

spiked with lithium aluminum hydride in an inert organic solvent such as tetrahydrofuran, diethyl ether, and the like.

The etherification of the alcohol (or an alcoholate) to 2-alkoxy-l, 2,3,4-tetrahydronaphthalene can be carried out in an analogous manner to the above-described etherification of an alcohol of the formula VIII. -

The 2-alkyl or 2-alkoxy-l, 2,3,4-tetrahydronaphthalenes can be prepared in a manner known per se by Friedel-Crafts acylation, for example with acetyl chloride and aluminum chloride in dichloromethane, and oxidation with Na.

triumhypobromite, preferably in dioxane, in a mixture of the corresponding 1,2,3,4-tetrahydronaphthalene-6 and -7-carboxylic acids are converted. This mixture can be separated by recrystallization; easier is however

the separation of the corresponding amides. 25

The carboxylic acids of the formula III can be reacted in a manner known per se, for example with thionyl chloride, to give acid chlorides of the formula IX.

The reaction of an acid chloride of the formula IX for

corresponding amide of the formula V can, for example, with ammonia gas in an inert organic solvent, e.g. a halohydrocarbon such as dichloromethane.

The dehydration of an amide of the formula V to form a nitrile of the formula Ib has already been described above.

b ό

The nitriles of formula Ib can be alkylated with a Grignard solution, for example a solution of the corresponding alkylmagnesium bromide in an ether such as diethyl ether, tetrahydrofuran and the like, and converted to irine hydrochloride by passing hydrogen chloride gas. These can then be heated by gentle heating

be reacted with water to form ketones of the formula VIa.

The above-described acid chlorides of the formula IX can furthermore be synthesized in a manner known per se, e.g. be converted by Rosenmund reaction with hydrogen and a partially poisoned palladium catalyst in a boiling hydrocarbon, into aldehydes of formula VIb.

Finally, the aldehydes of the formula VIb can be converted into compounds of the formula VII by Wittig alkylation, analogously to the above-described alkylation of 2-tetralone.

For the preparation of optically active compounds of the formula I, the compounds of the formulas III or VIII are advantageously already cleaved by known methods of racemate resolution (for example via diastereomeric amides or esters) into the optical antipodes and then further reacted in an analogous manner. For example, the acids of the formula IIIA (which have 4 chiral centers) can be reacted with a-phenylethylamine, the resulting diastereomeric amides are separated and then hydrolyzed to the optically active acid.

'

The compounds of formula I can be used as mixtures consisting of two or more compounds of formula I or in the form of their mixtures with other nematic and / or non-nematic substances, e.g. with substances from the classes of Schiff bases, azo- or azoxybenzenes, phenylbenzoates, cyclohexanecarboxylic acid phenyl esters, bi- and terphenyls, phenylcyclohexanes, cinnamic acid derivatives, phenyl- and diphenylpyrimidines, cyclo-

30 59 - 3.12,81

59 495 18

hexylphenylpyrimidines, phenyldioxanes and the like. Such compounds are known and known to the person skilled in the art, eg. From DE-OSs 2,306,738, 2 306 739, 2 429 093, 2 356 085, 2 636 684, 2 459 374, 2 547 737, 2 641 724, 2 708 276, 2 811 001 and from Z. Nature Research. 34b, 1535 (1979). Many such nematic or non-nematic substances are also commercially available. The connections

However, the formula I in which R is an ester group of the formula II can also be used in pure form.

The liquid-crystalline mixtures according to the invention must contain at least one compound having liquid-crystalline properties in sufficient quantity so that the total mixture also has liquid-crystalline properties. The weight ratio of the mixture components preferably corresponds to the eutectic composition. The amount

However, if R is an ester group of the formula II, ρ of the compounds of the formula I can generally be chosen as desired and preferably from about 1 to about 80 mol% of

and R, if R is alkyl, alkoxy or cyano, are generally up to about 40 mol percent, preferably between about 1 and about 30 mol percent.

The compounds of the invention may further contain optically active compounds, for example optically active biphenyls, and / or dichroic dyes, for example azo, azo2y and anthraquinone dyes. The proportion of such compounds is determined by the desired pitch, color, extinction, solubility and the like.

The preparation of mixtures which u. a "Compounds of the formula I and other liquid-crystalline and / or non-liquid-crystalline compounds and / or dichroic dyes, can be done in per se known ¥ feise»

L Ό ά - K> - 3.12.81

59 495 18

a. B. by heating a mixture of the components to a temperature just above the clearing point and subsequent cooling.

The invention further relates to all novel compounds, mixtures, processes, uses and devices as described herein.

Execution example

The invention is explained in more detail below with reference to some examples. As examples of preferred nematic mixtures, the following compounding examples 1-13 may be mentioned. Mixing Examples 1-10 illustrate the influence of the compounds according to the invention when added to mixtures of known liquid crystals (basic mixtures AC). "% m / ¹ X _h is the ratio of the viscosity of a

Mixture ( ⁴ Z m) ^{between the} viscosity of the base mixture used (^ jj)

Base mixture A

5.77% by weight of p-cyanophenyl p-butylbenzoate, 5.19% by weight of p-5-pentyl-2-pyrimidinylbenzonitrile, 11.54% by weight of p- (5-heptylbenzene) 2-pyrimidinyl) benzonitrile ,, 12.15 wt .-% propylcyclohexane p ~ ^l ~ 4 ~ trans -cyanophenylester,

12.37% by weight of trans-4-pentylcyclohexanecarboxylic acid p'-cyanophenyl ester,

22.02% by weight of trans-4-butylcyclohexanecarboxylic acid p- (ethoxy) -phenyl ester,

19.92% by weight of tr3ns-4-pentylcyclohexanecarboxylic acid p- (methoxy) -phenyl ester,

u .

3.12.81 59 495

11.04 wt _e -% trans ~ p _J / 5- (4-Aethylcyclohexyl) -2-pyrimidinyl7-

benzonitrile; ,

Sap. · <-10 ⁰ C, KIp. 72.7 - 73.0 ⁰ C.

Easy mix B

8.00% by weight of p-butylbenzoic acid p-cyano-phenyl ester, 7.19% by weight of p- (5-pentyl-2-pyrimidinyl) -benzonitrile, 15.00% by weight of p- (5-heptyl-2 ~ pyrimidinyl) benzonitrile, 15 * _e 54 wt -% trans ~ 4 ~ propylcyclohexane-p-cyano-

D L ö

phenyl ester, 9.71% by weight of trans-4-butylcyclohexanecarboxylic acid p-cyano-

phenyl ester, 15.54% by weight of trans-4-pentylcyclohexanecarboxylic acid p-cyanophenyl ester, 12.52% by weight of trans-p- [5- (4-ethylcyclohexyl) -2-pyrimidinyl] benzonitrile, 16.50% by weight % trans-p- [5- (4-heptylcyclohexyl) -2-pyrimidinyl] benzonitrile; Mp <-10 ⁰ C, KIp. 104.6 to 106.8 ⁰ C.

Base mix C

28.34% by weight of 4'-pentyl-4-cyanobiphenyl, 7.94% by weight of trans-4-propylcyclohexanecarboxylic acid p-cyano-

phenyl ester, 7.22% by weight of trans-4-pentylcyclohexanecarboxylic acid p-cyano

phenyl ester, 14.68% by weight of trans-4-butylcyclohexanecarboxylic acid p- (ethoxy) -phenyl ester, 13.11% by weight of trans-4-pentylcyclohexanecarboxylic acid p- (methoxy) -

phenyl ester, 8.03% by weight of trans-p- [5- (4-ethylcyclohexyl) -2-pyrimidinyl] -

benzonitrile, 5.74 weight percent trans-p- [5- (4-pentylcyclohexyl) -2-pyrimidinyl] benzonitrile, 14.94 weight percent trans-p- [5- (4-heptylcyclohexyl) -2 -pyrimidinyl] -benzonitrile;

Mp <-10 ⁰ C, KIp. 97.5 ° C. 30

Mixing Example 1

90.0% by weight / base mixture A, 10.0% by weight of 6-butyl trans-decalin-2-carboxylic acid trans-4-pentyl-1-cyclohexyl ester;

Mp <-10 "C, total 75.4-75.7 ° C.

- 3 = 2 -

Mixture example 2

87.53% by weight of base mixture A, 12.47% by weight of 6-pentyl-trans-decalin-2-carboxylic acid p-ethoxyphenyl ester; Mp.- £ -10 ⁰ C, KIp. From 80.7 to 81, l ° C.

Mixture example 3

87.47 wt .-% base mixture A, 12.53 wt .-% p-cyanophenyl-2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate;

Mp. <- 10 ° C, KIp. 79, 7 to 80.2 ⁰ C.

Mixture example 4

86.87% by weight of base mixture A, 13.13% by weight of p-ethoxyphenyl 2-heptyl-1,2,3,4-tetrahydro-6-naphthoate; Mp. <- 10 ° C, KIp. From 78.8 to 79, l ° C.

Mixture example 5

87.33% by weight of base mixture A, 12.67 parts by weight of p-butylphenyl-2-pentyl-1,2,3,4-tetrahydro-6-naphthoate; Mp. -C-IO ⁰ C, KIp. 73.3 to 73.6 ° C.

Mixing Example 6 30

91.73 % by weight of base mixture A,

8.27% by weight of 2-ethyl-6-pentyl-trans-decalin; Mp. <- 10 ° C, KIp. 61.7 to 62.5 ° C; ? _M / 7 _H = .783

Mixture example 7

91.73% by weight of base mixture C, 8.27% by weight of 2-ethyl-6-pentyl-trans-decalin;

Mp <-10 ° C, KIp. 83.4 to 86.2 ° C; η _R / ? _R = 0.80 Mixture Example 8

91.73 wt.% Base mixture B,

8.27% by weight of 2-ethyl-6-pentyl-trans-decalin; Mp. <- 10 ° C, KIp. 89.7 to 91.9 ° C; η / η ^ = 0.63 "

Mixing Example 9 10

90.80 wt.% Base mixture A,

9.20% by weight of 2-ethyl-6-heptyl-trans-decalin; Mp. <- 10 ^e C, KIp. 62.0-62.7 ⁰ C; V _M / 7 _H - 0.771

Mixture example 10

88.87% by weight of base mixture A,

11.13% by weight of δ-propyl trans-decalin-carboxylic acid p-ethyl phenyl ester; Mp. <- 10 ° C, KIp. 74.0-74.4 ⁰ C

Mixing Example 11

8.00% by weight of p-butylbenzoic acid p'-cyanophenyl ester, 7.20% by weight of p- (5-pentyl-2-pyrimidinyl) benzonitrile, 16.00% by weight of p- (5) Heptyl-2-pyrimidinyl) benzonitrile, 29.07 g / l trans-4-butylcyclohexanecarboxylic acid p- (ethoxy phenyl ester,

6.22% by weight of 6-propyl trans-decalin-2-carboxylic acid p-cyano phenyl ester,

13.62% by weight of p-ethyl 6-pentyl-trans-decalin-2-carboxylate,

19.89% by weight of 6-butyl trans-decalin-2-carboxylic acid trans-4-pentyl-1-cyclohexyl ester; smp. - £ -10 ° C, KIp. 70.4 to 70.5 ⁰ C.

ö L · Ό L

mixture example

22.97% by weight of 4'-heptyl-4-cyanobiphenyl, 24.24% by weight of trans-4-butylcyclohexanecarboxylic acid p- (a'thoxy) phenyl ester, 21.33% by weight of trans-4- pentylcyclohexanecarbonic-p- (methoxy)

phenyl ester, 5.18% by weight of 6-propyl-trans-decalin-2-carboxylic acid p-cyano-

phenyl ester, 11.35% by weight of 6-pentyl-trans-decalin-2-carboxylic acid p-ethylphenyl ester, 14.93% by weight of 6-butyl-trans-decalin-2-carboxylic acid trans-4- pentyl-1-cyclohexyl ester;

Mp. - ^ - 10 ⁰ C, KIp. 70.6-70.7 ⁰ C. 15

mixture example

22> 19% w / w trans-4-butylcyclohexanecarboxylic acid p- (ethoxy) -phenyl ester, 20.18% by weight trans-4-pentylcyclohexanecarboxylic acid p- (methoxy) phenyl ester, 29.63% by weight of p [2- (trans-4-propylcyclohexy, 1) -1-ethyl] benzonitrile,

4.31% by weight of 6-propyl-trans-decalin-2-carboxylic acid p-cyanophenyl ester, 9,45% by weight of 6-pentyl-trans-decalin-2-carboxylic acid p-ethyl

phenyl ester, 14.24% by weight of 6-butyl trans-decalin-2-carboxylic acid trans-4-pentyl-1-cyclohexyl ester; Mp <-10 ° C, KIp. 64.2 to 64.3 ° C.

The preparation of the novel compounds of the formula I is illustrated by the following examples. 35

L ό L ί) L b J

_ 33 Example 1

6.16 g (25 mmol) of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid are boiled with 62.5 ml of thionyl chloride with exclusion of moisture for 2 hours at reflux. After removal of the excess thionyl chloride

the acid chloride is obtained as a yellowish OeI. '

To a cooled to 3 ⁰ C solution of 2.99 g (25 mmol) of p-cyanophenol in 15 ml of absolute pyridine is added dropwise with stirring at 3-7 ° C with 10 ml of absolute benzene ~ "dilute acid chloride, the reaction mixture stand overnight, then poured onto a mixture of 30 g of ice and 30 ml of hydrochloric acid (1: 1), extracted exhaustively with ether and the organic phases are washed once with 35 ml ice-cold 1N sodium hydroxide solution and water After drying with sodium sulfate and removing the Solvent in vacuo, a crystalline residue (8.6 g) of the p-cyanophenyl ester of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid is obtained, which is chromatographed for purification on 230 g of silica gel Benzene / hexane 1: 1 and benzene elute 8.1 g of substance, which is recrystallized from acetone / hexane to constant mp and KIp., And in the "Y. High vacuum (0.01 mbar) is dried to constant weight. There are obtained colorless crystals of p-cyanophenyl-2-pentyl-1,2,3,4-tetrahydro-6-naphthoate: mp. 72.7-73.3 ° C; Cl.p.. 127.7 ° C.

The 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid used as starting material can be prepared as follows:

a) To a suspension of 178 g (0.431 mol) of n-Pentyltriphenylphosphoniumbromid in 1560 ml of absolute toluene. 35 are added 51.6 g (0.456 mol) of potassium tert-butoxide, stirred for 45 minutes at room temperature, added dropwise within 50 minutes, a solution of 41.9 g (0.287 mol) of 2-tetralone in 300 ml of absolute toluene and heated while 3 hours on 75

Cool 80 ⁰ C. The mixture is left, the reaction mixture is poured onto 1500 ml ice-water, the organic phase is separated, the water phase extracted twice more with toluene and the combined toluene phases washed with water. After drying over sodium sulfate and removal of the solvent in vacuo, 175 g of a brownish suspension are obtained, which is filtered through a column of 450 g of silica gel for purification. Hexane and benzene / hexane 1: 1 elute 53.2 g of 2-perityliden-l, 2,3,4-tetrahydronaphthalene as a yellowish oil.

b) A mixture of 53.2 g (0.268 mol) of 2-pentylidene-1, 2, 3, 4-tetrahydronaphthalene, 275 ml of fine spirits, 1.4 ml of triethylamine and 1.44 g of palladium / carbon (5%) is added at Room temperature shaken in a hydrogen atmosphere until the hydrogenation is complete (24 hours). The catalyst is then filtered off and the solvent is removed in vacuo. The residual 49.4 g of 2-pentyl-l, 2,3,4-tetrahydronaphthalene are distilled for purification under high vacuum: 47.3 g of colorless liquid; Bp 106-110 ⁰ C (0.5 mbar).

c) To a mixture of 47.3 g (0.234 mol) of 2-pentyl-1,2,3,4-tetrahydronaphthalene, 22.1 g (0.281 mol) of acetyl chloride and 380 ml of absolute dichloromethane is added with stirring at room temperature within 1 Hourly 37.6 g (0.282 mol) of anhydrous aluminum chloride, the yellow-brown reaction mixture boils for 3 hours under reflux, allowed to stand overnight and then poured into a

.30 Mixture of 500 ml of ice-water and 165 ml of concentrated hydrochloric acid. The organic layer is separated off, the aqueous phase is extracted twice more with dichloromethane, the organic phases are washed with 230 ml of 3N sodium hydroxide solution and with water, dried over sodium sulphate and the solvent is removed in vacuo. This gives 57.8 g of a mixture of 2-pentyl-6-acetyl and 2-pentyl-7-acetyl-l, 2,3,4-tetrahydronaphthalene as a brownish liquid, which is further reacted directly.

- -3c? -

d) A solution of 54.6 g (0.223 mol) of the mixture of 2-pentyl-6-acetyl and 2-pentyl-7-acetyl-l, 2,3,4-tetrahydronaphthalene in 450 ml of dioxane is 60 ⁰ C is heated and allowed to flow with stirring within 30 minutes to a solution of sodium hypobromite (prepared from 261 ml of 28% sodium hydroxide, 202 g of ice and 112 ml of water by dropwise addition of '51.5 ml of bromine at 0 ° C within 35 minutes) , The brownish reaction mixture is then heated to 30 ⁰ C, with discoloration using the exothermic reaction. The reaction is allowed to continue for 1 hour, the excess hypobromite is reduced by adding sodium bisulfite solution, 102 ml of concentrated hydrochloric acid are added and the mixture is extracted with dichloromethane. After washing with water, drying with sodium sulfate and evaporation of the solvent in vacuo, 5.7.9 g of a crude mixture of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6 and -7-carboxylic acid as a yellowish crystalline residue , The mixture ^{v of} the two acids can be separated by repeated recrystallization from hexane, ethanol, isopropanol and the like. However, it is easier to separate the corresponding amides (preparation according to Example 10) by recrystallization from suitable solvents, for example from acetone and subsequent hydrolysis, for example with potassium hydroxide in diethylene glycol. 2-Pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxamide melts at 166.4-167.8 ° C and 2-pentyl-l, 2,3,4-tetrahydronaphthalene-7-carboxamide at 112.9 -123.5 ⁰ C. The liquid crystalline 2-pentyl-1,2,3,4-tetrahydronaphthalen-6-carboxylic acid has a melting point of 122.9 to 123.1 ° C and a clearing point of 174.9 to 177.6 ⁰ C; the 2-pentyl-l, 2,3,4-tetrahydronaphthalene-7-carboxylic acid melts at 103.6-105.5 ⁰ C and is not liquid crystalline.

In an analogous manner, the following compounds can be prepared:

p-cyanophenyl-2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate; Mp 73.4 ° C, KIp. 123.5 ° C

26 ZbZb

2-heptyl-l, 2,3,4-tetrahydronaphthalen-6-carboxylic acid; Mp. 126.0 to 126.5 ⁰ C Kip. 168.4-169.5 ⁰ C

2-heptyl-l, 2,3,4-tetrahydronaphthalen-7-carboxylic acid; Srap. 118.4 to 119.0 ⁰ C.

2-heptyl-l, 2,3,4-tetrahydronaphthalen-6-carboxamide; Mp. 133.5-133.9 ° C. '

2-heptyl-l, 2,3,4-tetrahydronaphthalen-7-carboxamide; Mp 113.2-113.7 ° C.

Example 2

6.16 g (25 mmol) of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid are converted analogously to Example 1 in the acid chloride and then with 3.45 g (25 mmol) of p-Aethoxyphenol in 15 ml of absolute pyridine reacted.

This gives 8.9 g of crude p-Aethbxyphenylester of 2-pentyl · - 1, 2, 3, 4-tetrahydronaphthalene-6-carboxylic acid, which is chromatographed for purification on 230 g of silica gel. Toluene / hexane 1: 1 and toluene / hexane 7: 3 elute 8.8 g of the substance from acetone / hexane to constant mp. And KIp.

recrystallized and dried under high vacuum (0.01 mbar). There are obtained colorless crystals of p-Aethoxyphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate: mp. 95.4-96.2 ° C; Cl.p.. 119.0-119.4 ⁰ C.

In an analogous manner, the following compound can be prepared:

p-ethoxyphenyl-2-heptyl-l, 2,3,4-tetrahydro-6-naphthoate; Mp 83.8 ° C, KIp. 116 ° C.

Example 3

2.0 g (8.12 mmol) of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid are converted analogously to Example 1 with 20 ml of thionyl chloride in the acid chloride and then with 1.234 g (8.00 mmol ) p-Aethoxy-thiophenol in 5 ml of absolute pyridine. This gives 2.9 g of crude p-ethoxy

232526 3

"ti

thiophenyl ester of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid, which is chromatographed for purification on 95 g of silica gel. Hexane / toluene and toluene elute 2.7 g of the substance from acetone / hexane to constant mp and KIp. recrystallized and dried under high vacuum (0.01 mbar) to constant weight. ETs are obtained colorless crystals of S- (p-Aethoxyphenyl) -2-pentyl-l, 2,3,4-tetrahydro-thio-6-naphthoate. Mp. 82 "C, KIp.

145 ^e C

 10

Example 4

2.0 g (8.12 mmol) of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid are converted analogously to Example 1 into the acid chloride and then with 1.202 g (8.0 mmol) of p-butylphenol in 5 ml of absolute pyridine. This gives 3.0 g of crude p-butylphenyl ester of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid, which is chromatographed for purification on 95 g of silica gel. Hexane / toluene 1: 1 elute 2.8 g of the substance, which from ether / hexane to constant mp and KIp. recrystallized and dried under high vacuum (0.01 mbar) to constant weight. There are obtained colorless crystals of p-butylphenyl-2-pentyl-l, 2,3,4-tetrahydro-6-naphthoate. Mp 48.1 ° C, KIp. 80.7 ⁰ C.

Example 5

1.893 g (7.50 mmol) of 6-pentyl-trans-decalin-2 ·

carboxylic acid are boiled with 15 ml of thionyl chloride with exclusion of moisture for 2 hours at reflux. After removal of the excess thionyl chloride in vacuo, the acid chloride is obtained as a brownish liquid

 35

To a cooled to 3 ⁰ C solution of 0.883 g (7.497 mmol) of p-cyanophenol in 7.5 ml of absolute pyridine is added dropwise with stirring at 3-7 ° C with 10 ml of absolute

, internal benzene diluted acid chloride, the reaction mixture heated to 50-55 ⁰ C for 3.5 hours and allowed to stand overnight at room temperature. It is then poured onto a mixture of 15 g of ice and 15 ml of hydrochloric acid (1: 1), extracted.

scooping with ether and washing the organic phases

once with 11.5 ml of ice-cold IN sodium hydroxide solution and with water. The crystalline residue obtained after drying with sodium sulfate and removing the solvent in vacuo (2.6 g) of the p-cyanophenyl ester of 6-pentyl-trans-decalin-2-carboxylic acid is chromatographed on 90 g of silica gel for purification. Hexane / toluene and toluene elute 2.5 g of the substance, which until constant m.p. and KIp. recrystallized from hexane and dried under high vacuum (0.01 mbar) to constant weight. It will be colorless

Crystals of the 6-pentyl-trans-decalin-2-carboxylic acid-pcyanophenyl ester obtained: mp. 79.9 ° C, KIp. 148.0 ⁰ C.

The 6-pentyl-transdecalin-2-carboxylic acid used as starting material can be prepared as follows: 20

a) A mixture of 84.1 g (0.5 mol) of 4-pentylcyclohexanone, 51.3 g (0.72 mol) of pyrrolidine, 120 ml of toluene and 0.62 g of p-toluenesulfonic acid with the upstream of a water separator 2 hours to Boil and heat that

separated, pyrrolidine-containing water separated. Of the 4-pentyl-l-pyrrolidinyl-l-cyclohexen-containing residue is first removed in vacuo from the excess toluene, and then distilled under high vacuum. B.p. 107-113 ⁰ C (0.16 mbar), yellowish liquid.

b) 35.9 g (0.512 mol) of methyl vinyl ketone are added dropwise with stirring and nitrogen gassing to a mixture of 98.4 g (0.444 mol) of 4-pentyl-1-pyrrolidinyl-1-cyclohexene and 315 ml of absolute toluene within 1 hour ( Temperature rise to 42 ° C). It is allowed to stand overnight, then boiled for 3 hours under reflux, added dropwise to the boiling mixture, a solution of 19.6 g (0.238 mol) of anhydrous sodium acetate and 39.1 ml of glacial acetic acid in 39.1 ml of water and

Hi

Boil for a further 8 hours under reflux. After cooling, the toluene layer is separated, the aqueous phases are extracted twice more with toluene and the organic phases are washed successively with water, IN hydrochloric acid, water, saturated sodium bicarbonate solution and water and then dried over sodium sulfate.

net. After removal of the solvent in vacuo

19 9 10 a mixture of 6-pentyl-octahydro-A '- and -Δ' naphthalen-2-one as a brown liquid (106 g). For purification, it is distilled under high vacuum. Yield: 69.4 g of yellowish liquid; Bp 127-132 ° C (0.22 mbar).

c) To a solution of 17.2 g (2.479 g atoms) lithium wire in 2 liters of liquid ammonia (dry ice condenser) is added dropwise with stirring, a solution of 71.2 g (0.323 mol) of the mixture obtained above of 6-pentyl-octahydro

1 9 9 10 Δ '- and -Δ' - naphthalen-2-one in 450 ml of absolute ether, allowed to react for 1 hour, the reaction mixture is diluted with 1 liter of absolute ether and gives por

113 g (2.121 mol) of ammonium chloride until it decolorizes. The ammonia is allowed to evaporate overnight at room temperature, the reaction mixture is cooled with ice and coconuts with concentrated hydrochloric acid.

After addition of water and an additional amount of ether

If the ethereal layer is separated off, the aqueous phase is extracted twice more with ether, the organic phases are washed with water and dried over sodium sulphate. After removal of the solvent in vacuo, 69.4 g of a mixture of predominantly 6-pentyl-trans-decalin

2-on and 6-pentyl-cis-decalin-2-one as a brown liquid, which is further processed raw.

d) To 69.4 g (0.312 mol) of the mixture of 6-pentyltrans- and -cis-decalin-2-one dissolved in 350 ml of ether,

is added under nitrogen a solution of 23.6 g (0.482 mol) of sodium cyanide in 54 ml of water, cooled to 0 ⁰ C and added dropwise with stirring within 2 hours 69.9 ml of 25% hydrochloric acid. Afterwards, another 1 hour at room

Stirred, the organic phase separated, the aqueous phase extracted twice with ether, the combined organic phase washed with water and dried with sodium sulfate. The cyanohydrin mixture obtained after removal of the solvent in vacuo (75.6 g of brown oil) is reacted further in crude form.

e) 75.6 g (0.303 mol) of the crude cyanohydrin mixture are dissolved with stirring in 81 ml of absolute pyridine and 67 ml of absolute benzene, cooled to -2 ° C, within 20 minutes dropwise with a mixture of 42.0 ml ( 0.460 mol) of phosphorus oxychloride and 53.4 ml of absolute pyridine and then boiled under reflux for 4 hours. The initially formed precipitate dissolves on heating, but forms anew on cooling overnight. It is poured onto 375 g of ice, diluted with ether, the ethereal layer is separated off and the aqueous phase is extracted twice more with ether. The ether phases are washed with water, dried over sodium sulphate and freed from the solvent in vacuo. This gives 72.5 g of a dark brown oil which consists predominantly of 6-

1 2

Pentyl trans-octahydro-Δ and -Δ-naphthalene-2-carbo-

, nitrile, but also contains the corresponding 9,10-cis compounds. The mixture is reacted further crude.

f) The resulting nitrile mixture (72.5 g, 0.313 mol) is heated with a hot solution of 35.1 g (0.625 mol) of potassium hydroxide in 355 ml of diethylene glycol for 6.5 hours under nitrogen gassing to 200 ⁰ C bath temperature. After this time, the ammonia development is practically over. It is allowed to cool, the alkaline solution, diluted with 500 ml of water, extracted three times with ether and the organic phases are washed twice with water. The 17.2 g of dark brown oil obtained after drying with sodium sulfate and evaporating the ether are discarded. The aqueous phases (including wash water) are made congenital with 3N sulfuric acid.

- 43 -

represents, wherein a precipitate or a turbidity occurs. It is exhaustively extracted with ether, the organic phases are washed with water and dried with sodium sulfate. After evaporation in vacuo 57.6 g of a brown, solid residue are obtained, which consists predominantly of 6-pentyl

1 2

trans-octahydro-Δ - and -Δ -naphthalene-2'-carboxylic acid

exists, but still contains the corresponding 9,10-cis compounds. This residue is dissolved in warm toluene for purification and filtered through a column of 300 g of silica gel. Toluene, and toluene containing 1% or _2%% '. Acetone elutes a total of 45.9 g of brownish, crystalline substance, which is further reacted directly.

g) The resulting mixture of unsaturated acids (45.9 g) is dissolved in 700 ml of fine spirits warm, cooled to room temperature and shaken after the addition of 4.3 g of palladium / carbon (5% palladium) in a hydrogen atmosphere until the Hydrogenation comes to a halt (24 hours). Subsequently, the catalyst is filtered off and the solvent evaporated in vacuo. This gives 45.9 g of yellowish crystalline residue which consists predominantly of 6-pentyl-trans-decalin-2-carboxylic acid and also contains the cis isomer. For purification, more than one corn is recrystallized from ether / hexane or hexane, the purification being carried out by means of gas chromatogram, mp and KIp.

is pursued. Sublimation under high vacuum (0.01 mbar) gives 13.7 g of pure liquid-crystalline 6-pentyltrans-decalin-2-carboxylic acid as colorless crystals; M.p. 113.5-114.3 ° C, KIp. 165.8 to 167.1 ° C.

30

In an analogous manner, the following compounds can be prepared:

6-ethyl-trans-decalin-2-carboxylic acid p-cyanophenyl; Mp. 62.9 C ⁰ Kip. 122 ° C

6-propyl-trans-decalin-2-carboxylic acid p-cyanophenyl; Mp. 79.9 ° C, KIp. 147.6 ° C

6-heptyl-trans-decalin-2-carboxylic acid p-cyanophenyl

L ·

ester; Mp 76.4 ° C, KIp. 141 ° C (monotropic smectic below 56.5 ° C)

6-ethyl-trans-decalin-2-carboxylic acid; Mp. 113.0 to 114.5 ⁰ C Kip. 142.2 to 142.9 ° C

6-propyl-trans-decalin-2-carboxylic acid; Mp 123.7-124.5 ° C, KIp. 165.0-166.0 ⁰ C

6-butyl-trans-decalin-2-carboxylic acid; Mp. 113.9 to 114.6 ⁰ C Kip. 159.3 to 162.0 ° C

6-heptyl-trans-decalin-2-carboxylic acid; Mp. 114.8 ^0C, cl.p.. 162, O ⁰ C.

Example 6

1.893 g (7.50 mmol) of e-pentyl trans-decalin-carboxylic acid are converted into the acid chloride analogously to Example 5 and then reacted with 1.036 g (7.498 mmol) of p-ethoxyphenol in 7.5 ml of absolute pyridine. After the same reaction procedure and working up as in Example 5, 2.6 g of crude, crystalline p-Aethoxyphenylester of 6-pentyl-trans-decalin-2-carboxylic acid, which is chromatographed for purification on 90 g of silica gel. Hexane / toluene 1: 1 and toluene elute 2.5 g of the substance, which remains constant until constant and KIp. Recrystallized from acetone / hexane and dried under high vacuum (0.01 mbar) to constant weight. 6-Pentyl-trans-decalin-2-carboxylic acid p-ethoxyphenyl ester is obtained as colorless crystals; Mp 90.0 ° C, KIp. 142.6 ⁰ C.

Example 7

1.893 g (7.50 mmol) of 6-pentyl-trans-decalin-2-carboxylic acid are converted into the acid chloride analogously to Example 5 and then reacted with 0.916 g (7.498 mmol) of p-ethylphenol in 7.5 ml of absolute pyridine. After gleieher reaction and work up to obtain 2.5 g of crude, crystalline p-Aethylphenylester of 6-pentyltrans-decalin-2-carboxylic acid, which is chromatographed for purification on 90 g of silica gel. Hexane / toluene 1: 1 elution

* - *> * - ü L UJ

- 45 -

2.3 g of substance, which until constant m.p. and Klp. recrystallized from ether / hexane and hexane and dried under high vacuum (0.01 mbar) to constant weight. This gives 6-pentyl-trans-decalin-2-carboxylic acid-päthylphenylester as colorless crystals; Mp. 54.1 ° C, cl. 95.4 ° C.

In an analogous manner, the following compounds can be prepared: 10

6-methyl-trans-decalin-2-carboxylic acid-p-hydroxybenzoate; Mp 59.5 ° C, Klp. 48.9 ° C (monotrophic)

6-Aethy1-trans-decalin-2-carboxylic acid p-äthylphenylester; Mp. 56.4 ° C, cl. 57.5 ° C

6-propyl trans-decal in 2-carboxylic acid p-ethyl phenyl ester; Mp. 74.9-75.4 ° C, cl. 88.0 ⁰ C

6-butyl-trans-decalin-2-carboxylic acid p-äthylphenylester; Mp. 66.9 ⁰ C, Klp. 84.5 ° C

6-Hepty1-trans-decal in-2-carboxylic acid p-ethyl phenyl ester; Mp. 66.0 ⁰ C

6-Hepty1-trans-decalin-2-carboxylic acid p-phenyl buty!; Mp. 56.4 ° C, cl. 94.8 ° C (monotropic smectic below 54.4 ° C).

Example 8

8.95 g (35.60 mmol) of 6-pentyl-trans-decalin-2-carboxamide are suspended in 94 ml of absolute pyridine and mixed with 12.94 g (73.29 mmol) of benzenesulfonyl chloride with stirring. The clearing solution is allowed to stand overnight at room temperature, then to a mixture of. Poured 190 g of ice and 180 ml of hydrochloric acid (1: 1) and extracted exhaustively with ether. The ether solutions are washed neutral with water, dried over sodium sulfate and the solvent evaporated in vacuo. This gives 11.0 g of crude 6-pentyl-trans-decalin-2-carbonitrile as a yellowish, later crystallizing OeI, which is chromatographed for purification on 200 g of silica gel.

2 * 3 7 C O C O w ^ 3 t U Ο

Hexane / toluene mixtures with 30%, 40% and 50% toluene elute 8.1 g of substance, which is recrystallized from hexane to constant mp. And then distilled under high vacuum; Bp. 115-120 ⁰ C (0.02 mbar). 6-Pentyl-trans-decalin-2-carbonitrile is obtained as colorless crystals; Mp. 41.9 ° C.

The 6-pentyl-transdecalin-2-carboxamide used as starting material can be prepared as follows: 10

31.0 g (0.123 mol) of the mother liquor acid obtained in Example 5, which still contains the cis isomers in addition to 6-pentyl-trans-decalin-2-carboxylic acid are converted analogously to Example 5 with 133 ml of thionyl chloride in the acid chloride , After removal of the excess thionyl chloride is diluted with 100 ml of absolute dichloromethane and this solution was added dropwise with stirring and cooling to a solution saturated with ammonia solution of 465 ml of absolute dichloromethane. The reaction mixture is evaporated to dryness in vacuo, mixed with 530 ml of water and 500 ml of ether and stirred for 30 minutes at room temperature. The precipitate is sucked, washed with 'water and ether and dried. This gives 8.9 g of 6-pentyl-trans-decalin-2-carboxamide, which is recrystallized for purification from dioxane and sublimed in a high vacuum (0.01 mbar); colorless crystals, mp 211.6-212.7 ° C. From the ether solutions obtained by repeated recrystallization (control by gas chromatogram) further 1.1 g of the trans-amide and by recrystallization of the mother liquors from ether, the 6-pentylcis-decalin-2-carboxamide as colorless crystals (mp 126.7-128 , 0 ⁰ C).

In an analogous manner, the following compounds can be prepared:

6-ethyl-trans-decalin-2-carbonitrile; M.p. 34.7 ° C 6-propyl trans-decalin-2-carbonitrile; Mp. 63.8 ° C

e-ethyl-trans-decalin-Z-carboxamide; Mp 224.6-225.0 ⁰ C

6-propyl-trans-decalin-2-carboxamide; . Mp 225.0 to 226.0 ⁰ C 6-ethyl-cis-decalin-2-carboxamide; M.p. 129.5-13 1.5 ⁰ C 6-propyl cis-decalin-2-carboxamide; Mp 126.6-127.1 ° C.

Example 9

A mixture of 3.478 g (11.89 mmol) of 6-pentyl-2-valeryl-trans-decalin, 11.4 ml of absolute ethanol and 1.339 g (26.75 mmol) of hydrazine hydrate is dissolved with heating and allowed to stand overnight. After addition of 12.2 ml of diethylene glycol and 1.8 g (32.08 mmol) of potassium hydroxide is heated at the descending condenser in the course of 2 hours at 200 ⁰ C bath temperature and left for 1.5 hours at this temperature. Distillate and residue are combined, mixed with 25 ml of water and extracted with ether and the organic phases are washed with water and dried over sodium sulfate. After evaporation of the solvent in vacuo, 3.35 g of crude 2,6-dipentyl trans-decalin, which is chromatographed for purification on 90 g of silica gel. Hexane elutes 1.74 g of substance which is distilled under high vacuum at 145 ° C / 0.03 mbar.

This gives colorless crystals of 2,6-dipentyl transdecalin; Smp.'47,8 ⁰ C.

The 6-pentyl-2-valeryl-trans-decalin used as starting material can be prepared as follows: 30

A Grignard solution is made by dropwise addition of a mixture of 2.890 g (21.09 mmol) of n-butyl bromide and 3.5 ml of absolute ether to a suspension of 0.513 g (21.10 mg atoms) of magnesium in 7 ml of absolute ether prepares. After dissolving the magnesium, a solution of 4.101 g (17.57 mmol) of 6-pentyl-trans-decalin-2-carbonitrile (prepared according to Example 8) in 7 ml of absolute ether at 35-37 ° C is added dropwise with stirring Reaction mixture 7

232526 3

so

- 48. -

Cooked under reflux for a few hours and allowed to stand overnight. Then 3.326 g (0.104 mol) of methanol are added dropwise and after stirring for 30 minutes, the precipitate formed is filtered off with suction and washed well with absolute ether. Then, for 1 hour while cooling to 0 ⁰ C hydrogen chloride gas is introduced into the filtrate and concentrated to dryness. This gives 6.9 g of imine hydrochloride of 6-pentyl-2-valeryl-trans-decalin as a brownish, turbid OeI. This is heated with 50 ml of water for 30 minutes at 50 ⁰ C, wherein the 6-pentyl-2-valeryl-trans-decalin oily and later deposited crystalline. It is extracted with ether, the organic phase is washed with water, dried over sodium sulfate and the solvent is removed in vacuo. There remain 5.3 g of brownish, crystallizing OeI, which can be recrystallized for example from hexane for purification. This gives colorless crystals of 6-pentyl-2-valeryltrans-decalin; Mp. 47.0-48.5 ⁰ C.

in an analogous manner, the following compounds can be prepared:

2-ethyl-6-propyl-trans decalin; Bp 90 ° C / 0.007 mbar 2-ethyl-6-pentyl-trans-decaline; B.p. 110 ° C / 0.007 mbar 2-ethyl-6-heptyl-trans-decaline; B.p. 140 ° C / 0.007 mbar 6-ethyl-2-propionyl-trans-decaline; liquid 6-ethyl-2-valeryl-trans-decalin; oily 6-ethyl-2-heptanoyl-trans-decalin; crystalline.

Example 10

2.605 g (10.6 mmol) of 2-pentyl-1,2,3,4-tetrahydronaphthalene-6-carboxamide are suspended in 40 ml of absolute pyridine and 2.86 g (16.2 mmol) of benzenesulphonyl chloride are added with stirring. The clearing solution is allowed to stand overnight at room temperature, then to a mixture of 50 g of ice and 40 ml of conc. Hydrochloric acid poured and exhaustively extracted with dichloromethane. The orga-

¹ H

nical phases are washed neutral with water, dried over sodium sulfate and the solvent evaporated in vacuo. This gives 2.390 g of crude 2-pentyl-l, 2,3,4-tetrahydrqnaphth.alin-6-carbonitrile as-yellowish OeI, which is chromatographed for purification on 90 g of silica gel. Hexane / toluene 1: 1 and toluene elute 2.35 g of yellowish OeI, which crystallized at -10 ⁰ C. It is recrystallized to constant m.p. From little Aethanöl by the solution cooled to -10 ° C and the mother liquor excreted from the. • which crystals eg by decantation, pipetting or

-v filtration through a cooled suction filter is separated. On-) . * · '.

Finally, in a high vacuum (0.01 mbar) until

Constant weight dried. Colorless crystals (or colorless oil) of 2-pentyl-1,2,3,4-tetrahydronaphthalene-6-carbonitrile are obtained. Mp 18.2 ⁰ C.

The starting 2-pentyl-l, 2,3,4-tetrahydrono-phthalene-6-carboxamide can be prepared as follows:

, - ·. ' · '· · ·

7.4 g (30.0 mmol) of the example. 1 of 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxylic acid obtained with 68 ml of thionyl chloride as in Example 1 in the acid. "·>) Chloride is added after removing the excess

^y pe; ·

Thionyl chloride is diluted with 100 ml of dichloromethane and this solution is added dropwise with stirring and cooling to a saturated with ammonia gas solution of 200 ml of absolute dichloromethane. Ammonia gas is passed on for a further 2 hours and the reaction mixture is evaporated to dryness in vacuo.

Put with 200 ml of water, shake for 30 minutes / sucks the precipitate, wash with water and dry. This gives 7.66 g of crude 2-pentyl-l, 2,3,4-tetrahydronaphthalene-6-carboxamide, which is recrystallized for purification from dioxane and sublimed in a high vacuum (0.01 mbar): colorless Kristal'-Ie, - mp. 166, .4-167,8 ° C.

In an analogous manner, the following compounds can be prepared:

2-heptyl-l, 2,3,4-tetrahydronaphthaiin-6-carbonitrile; 'Mp. 36.5 ° C

2-heptyl-l, 2,3,4-tetrahydronaphthalen-6-carboxamide; Mp. 133.5-133.9 ° C

 5

Example 11

2.10 g (10 mmol) of 6-ethyl-trans-decalin-2-carboxylic acid (prepared according to Example 5) are dissolved in 30 ml of absolute methylene chloride and treated with a solution of 1.87 g (11 mmol) of 4-pentyl- trans-cyclohexanol in 20 ml of absolute methylene chloride. Subsequently, 0.20 g (1.637 mmol) of 4- (dimethylamine) pyridine and, after cooling to 5 ° C., 2.48 g (12.02 mmol) of dicyclohexylcarbodiimide in solid form are added with stirring. After a short time • dicyclohexylurea begins to precipitate. After 1 hour at 2 ° C and 1.25 hours at room temperature, the precipitate is filtered off with suction and washed with methylene chloride and hexane. Evaporation of the filtrate under reduced pressure gives 4.80 g of crude 6-ethyl-trans-decalin-2-carboxylic acid trans-4-pentyl-1-cyclohexyl ester, which is chromatographed on 90 g of silica gel for purification. Hexane / toluene 1: 1 elute 3.22 g of substance, which is recrystallized from hexane to constant melting point and clearing point and dried under high vacuum (0.01 mbar) to constant weight. 6-ethyl-trans-decalin-2-carboxylic acid trans-4-pentyl-1-cyclohexyl ester is obtained as colorless crystals; Mp. 50.4 C ⁰ Kip. 86.3 ° C.

in an analogous manner, the following compound can be prepared:

6-butyl-trans-decalin-2-carboxylic acid-trans-4-penty1-1-cyclohexyl ester; Mp. 62.2-65.4 ° C, KIp. 109.3 ⁰ C. 35

Example 12

0.952 g (3.99 mmol) of 6-butyl trans-decalin-2-carboxylic acid (prepared according to Example 5) are combined with 0.500 g (3.99 mmol) of trans-4-hydroxycyclohexanecarbonitrile

and 0.081 g (0.663 mmol) of 4- (dimethylaminol) pyridine are dissolved in 18 ml of absolute methylene chloride and then 0.992 g (4.801 mmol) of dicyclohexylcarbodiimide are added to the cooled solution. After a short time dicyclohexylurea starts

"Fall Ό After 1 hour at 2 ⁰ C and 1.25 hours at room · -. ^ Temperature, the precipitate is filtered off and" washed ^ methylene chloride and hexane. Evaporation of the filtrate in vacuo gives 1.831 g of crude 6-butyl trans-decalin-2-carboxylic acid trans-4-cyanocyclohexylester, which is chromatographed for purification on 50 g of silica gel. Toluene and toluene / 0.5 or 1% acetone elute 1.240 g of substance, which is recrystallized from acetone / hexane to constant melting point and clearing point and dried under high vacuum (0.01 mbar) to constant weight. E-Butyl trans-decalin-carboxylic acid trans -cyano-cyclohexyl ester is obtained as colorless crystals; Mp 103.3 ⁰ C.

Example 13

For purifying the crude 6-alkyl-trans-decalin-2-carboxylic acids obtained according to Example 5, it is also possible with advantage to prepare the corresponding 6-alkyl-trans-decalin-2-carboxylic acid anilides:

3.144 g (12.5 mmol) of crude 6-pentyl-trans-decalin-2-carboxylic acid are converted analogously to Example 5 into the acid chloride. After removal of the excess thionyl chloride in vacuo, the crude acid chloride is dissolved in 15 ml of absolute methylene chloride and added dropwise with stirring to a cooled solution of 2.56 g (27.5 mmol) of aniline in 35 ml of absolute methylene chloride, immediately causing a precipitate of Aniline hydrochloride forms. After stirring at room temperature for 2.5 hours, 50 ml of water are added

.54 ',

- sowing -

and exhaustively extracted with methylene chloride. The organic extracts are washed with water, dried over sodium sulfate and the solvent removed in vacuo. The crystalline residue of crude 6-pentyl-trans-decalin-2-carboxylic acid anilide is recrystallized, for example, from ethanol to the constant melting point and disappearance of the impurities in the gas chromatogram. The pure colorless 6-pentyl-trans-decalin-2 is thus obtained. carboxanilide; Mp. • 177.9 to 178.6 ⁰ C.

In an analogous manner, the following compounds can be prepared:

6-methyl-trans-decalin-2-carboxanilide; Mp 188.2-189.4 ° C

6-AethyI-trans-decalin-2-carboxanilide; M.p. 189.4-190.8 ⁰ C

6-propyl-trans-decalin-2-carboxanilide; Mp 194.5-196.3 ° C

6-butyl-trans-decalin-2-carboxanilide; Mp 185.7-186.7 ° C

6-heptyl-trans-decalin-2-carboxanilide; Mp 171.9-173.0 ⁰ C.

The anilides can be removed by hydrolysis, e.g. with potassium. hydroxide in ethylene glycol at boiling temperature and subsequent acidification again the pure 6-alkyl-trans-decalin-2-carboxylic acids are converted.

*

Claims (6)

232526 3 03/02/1982 AP C 07 C / 232 59 4-95 / 18 invention claim 1. A liquid-crystalline mixture having at least 2 components, characterized in that at least one component comprises a compound of the general formula (I) I, wherein A is A saturated or aromatic and an optionally present saturated In A is trans-linked to the second In; E is a straight-chain alkyl or alkoxy group having 1 to 11 carbon atoms 2
called atoms; E cyano, a straight-chain alkyl group having 1 to 11 carbon atoms, an ester group of the general formula II or, if In A is saturated, additionally a straight-chain alkoxy group having 1 to 11 carbon atoms; in the ester group of formula II, B is either aromatic and X is oxygen or sulfur and E 1 is cyano or a straight chain alkyl or alkoxy group of 1 to 10 carbon atoms, or B 1 is a trans-1,4-disubstituted cyclohexane ring and X is oxygen and E ^ is cyano or a straight-chain alkyl group having 1 to 10 carbon atoms; 2 5 2 6 3 -2- 3.2.1982 AP C 07 C / 232 59 4-95 / 18 and the total number of carbon atoms in the alkyl and / or alkoxy group is at most 12. Liquid-crystalline mixture according to item 1, characterized in that it contains a compound of the formula I which is saturated or saturated in Hing A, 3. Liquid-crystalline mixture according to item 1 or 2, characterized ge characterized in that it is a compound of formula I, -vaorin Ir means an ester group of formula II, 4> Liquid-crystalline mixture according to one of the items 1 to 3, characterized in that it contains a compound of formula I, inorin ring B in the ester group of the formula II is aromatic. 5. Flussigkristal ^ Lines mixture according to one of the points 1 to 4, characterized in that it contains a compound of formula I, ^ orin X in the ester group of the formula II oxygen means » 6 _e Liquid-crystalline mixture according to one of the items 1 to 5, characterized in that it contains a compound of formula I, vaorin Ir in the ester group of the formula II cyano or a straight-chain Alky! Group, preferably cyano. 7β characterized liquid crystal mixture according to item 1 or 2, characterized in that it is a compound of formula I viorin E. Cyano, a straight-chain alkyl group or, if ring A is saturated, additionally a straight-chain 23252 6 3 57
-> - 3.2.1982 AP C 07 C / 232 526 59 495/18 means chained alkoxy group. 8, liquid crystalline mixture according to item 7, characterized in that it contains a compound of the formula in which R is cyano or a straight-chain alkyl group ,. 9. Liquid-crystalline mixture according to one of the points 1 to 8, characterized in that it is a compound of the formula I in which R is a straight-chain alkyl group, 10. A liquid-crystalline mixture according to any one of items 1 to 9, characterized in that it contains about 1 to about 80 mole percent of one or more compounds of formula I, but at most et a 40 mole percent Compounds of the formula I, tiorin E cyano or a straight-chain alkyl or alkoxy group, and contains as Best a nematogenic material consisting of other nematic and / or non-nematic substances, 11, use of the compounds of formula I according to item 1, characterized in that they are used for electro-optical purposes.