U.S. patent application number 09/901218 was filed with the patent office on 2001-12-27 for o-aminophenolcarboxylic acid and o-aminothiophenolcarboxylic acid.
This patent application is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Keitmann, Michael, Sezi, Recai.
Application Number | 20010056203 09/901218 |
Document ID | / |
Family ID | 7843502 |
Filed Date | 2001-12-27 |
United States Patent
Application |
20010056203 |
Kind Code |
A1 |
Sezi, Recai ; et
al. |
December 27, 2001 |
O-aminophenolcarboxylic acid and o-aminothiophenolcarboxylic
acid
Abstract
The invention relates to novel o-aminophenolcarboxylic acids or
o-aminothiophenolcarboxylic acids of the following structure 1 in
which: A.sup.1 to A.sup.7 are--independently of one another--H,
CH.sub.3, OCH.sub.3, CH.sub.2CH.sub.3 or OCH.sub.2CH.sub.3; T is O
or S, and m is 0 or 1; Z is a carbocyclic or heterocyclic aromatic
radical.
Inventors: |
Sezi, Recai; (Rottenbach,
DE) ; Keitmann, Michael; (Weisendorf, DE) |
Correspondence
Address: |
LAURENCE A. GREENBERG
P.O. Box 2480
Hollywood
FL
33022
US
|
Assignee: |
Siemens Aktiengesellschaft
|
Family ID: |
7843502 |
Appl. No.: |
09/901218 |
Filed: |
July 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09901218 |
Jul 9, 2001 |
|
|
|
09161147 |
Sep 24, 1998 |
|
|
|
Current U.S.
Class: |
562/426 ;
562/452 |
Current CPC
Class: |
C07D 213/643 20130101;
C07C 217/90 20130101; C07C 69/92 20130101 |
Class at
Publication: |
562/426 ;
562/452 |
International
Class: |
C07C 321/28 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 24, 1997 |
DE |
197 42 194.6 |
Claims
We claim:
1. An o-aminophenolcarboxylic acid or o-aminothiophenolcarboxylic
acid of the structure 21in which: each of A.sup.1 to A.sup.7 is a
ring substituent independently selected from H, CH.sub.3,
OCH.sub.3, CH.sub.2CH.sub.3 or OCH.sub.2CH.sub.3; T is O or S, and
m is 0; provided that a 3-amino-4-hydroxyphenoxy group cannot be in
the p-position to the carboxyl group.
2. An o-aminophenolcarboxylic acid according to claim 1 of the
structure 22
3. An o-aminophenolcarboxylic acid according to claim 2 in which
each of the A.sup.1-A.sup.3 and A.sup.4-A.sup.7 is a hydrogen
atom.
4. An o-aminophenolcarboxylic acid according to claim 4 of the
structure 23
5. A process for the preparation of an o-aminophenolcarboxylic acid
or o-aminothiophenolcarboxylic acid as claimed in claim 1, which
comprises (a) reacting a halogen compound of the structure 24 with
a nitrophenol or nitrothiophenol of the structure 25 in the
presence of at least the stoichiometric amount of a base, or with
an alkali metal salt of the nitro(thio)phenol, in a solvent at a
temperature between -10 and 80.degree. C., where X is a halogen
atom, E is CN or COOR.sup.1, where R.sup.1=alkyl (having 1 to 5
carbon atoms), phenyl or benzyl, A.sup.1 to A.sup.7 and T are as
defined above, and R is one of the following radicals: alkyl,
alkoxyalkyl, alkenyl, alkoxyalkenyl, alkynyl or alkoxyalkynyl, each
having a maximum of 6 carbon atoms, phenyl, phenacyl or benzyl, and
benzylalkyl, benzylalkenyl, benzyloxyalkyl, benzyloxyalkenyl,
benzylalkoxyalkyl or benzylalkoxyalkenyl, each having a maximum of
4 aliphatic carbon atoms; and (b) reducing the resultant nitro
compound to the amino compound, hydrolyzing the latter, and
removing the group R.
6. A process for the preparation of an o-aminophenolcarboxylic acid
or o-aminothiophenolcarboxylic acid as claimed in claim 1, which
comprises (a) reacting a nitro compound of the structure 26 with a
phenol or thiophenol of the structure 27 in the presence of at
least the stoichiometric amount of a base, or with an alkali metal
salt of the (thio)phenol, in a solvent at a temperature between -10
and 80.degree. C., where X is a halogen atom, E is CN or
COOR.sup.1, where R.sup.1=alkyl (having 1 to 5 carbon atoms),
phenyl or benzyl, A.sup.1 to A.sup.7 and T are as defined above,
and R is one of the radicals: alkyl, alkoxyalkyl, alkenyl,
alkoxyalkenyl, alkynyl or alkoxyalkynyl, each having a maximum of 6
carbon atoms, phenyl, phenacyl or benzyl, and benzylalkyl,
benzylalkenyl, benzyloxyalkyl, benzyloxyalkenyl, benzylalkoxyalkyl
or benzylalkoxyalkenyl, each having a maximum of 4 aliphatic carbon
atoms; and (b) reducing the resultant nitro compound to the amino
compound, hydrolyzing the latter, and removing the group R.
7. A process as claimed in claim 5, wherein the base used is a
carbonate or hydrogencarbonate of an alkali metal or alkaline earth
metal.
8. A process as claimed in claim 5, wherein an organic base
containing a tertiary N atom is used.
9. A process as claimed in claim 5, wherein the reduction and the
removal of the group R and--if E=COOR.sup.1--the hydrolysis are
carried out by means of hydrogen and catalyzed by Pd/C.
10. A process as claimed in claim 6, wherein the base used is a
carbonate or hydrogen carbonate of an alkali metal or alkaline
earth metal.
11. A process as claimed in claim 6, wherein an organic base
containing a tertiary N atom is used.
12. A process as claimed in claim 6, wherein the reduction and the
removal of the group R and--if E=COOR.sup.1--the hydrolysis are
carried out by means of hydrogen and catalyzed by Pd/C.
13. A process as claimed in claim 6 for producing an
o-aminophenolcarboxylic acid of the structure 28which comprises (a)
reacting 5-fluoro-2-nitrophenyl-benzylether with the potassium salt
of benzyl 4-hydroxybenzoate, and (b) reducing and hydrolyzing,
thereby removing the benzyl group, the resulting nitro compound of
the structure 29 to the amino compound.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a divisional of application Ser. No. 09/161,147,
filed on Sep. 24, 1998.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to novel o-aminophenolcarboxylic acids
and o-aminothiophenolcarboxylic acids, which are also jointly
abbreviated to o-amino(thio)phenolcarboxylic acids, and to a
process for their preparation.
[0004] o-Aminophenolcarboxylic acids are needed, in particular, for
the preparation of high-temperature-stable polymers, such as
polybenzoxazoles (PBOs) and their precursors. Compared with the
preparation of polybenzoxazoles or PBO precursors from
bis-o-aminophenols and dicarboxylic acids, the use of
o-aminophenolcarboxylic acids has significant advantages. For
example, an o-aminophenolcarboxylic acid can be reacted with
itself, i.e. a second monomer is not absolutely necessary for the
polymerization. This allows purity monitoring and storage to be
simplified. In addition, the stoichiometry is predefined, i.e.
errors in the calculation or weighing-out of the reactants, as can
occur in the reaction of bis-o-aminophenols with dicarboxylic
acids, are excluded if o-aminophenolcarboxylic acids are used.
Furthermore, the nature of the monomer used has a strong effect on
the property profile of the PBO precursor or polybenzoxazole
prepared therewith. For example, not only the thermal, electrical
and mechanical behavior, but also the solubility and hydrolysis
stability and numerous other properties of the polymer are greatly
affected by the monomer used in the preparation.
[0005] PBO precursors in the form of a photosensitive composition
can be structured inexpensively by direct methods, i.e. without an
auxiliary resist. Compared with other dielectrics which can be
photostructured directly, such as polyimide (PI) and
benzocyclobutene (BCB), PBO precursors offer the advantage of
positive structurability and aqueous-alkaline development (see EP 0
023 662 B1 and EP 0 264 678 B1). To this end, the PBO precursors
used must be substantially transparent at the exposure wavelength
and sufficiently soluble in the developer, which preferably
contains no metal ions. Like polyimides, polybenzoxazoles also have
the major advantage that they--compared with the cyclized final
product--as readily soluble precursors, can be applied to a
substrate and then cyclized, during which the solubility and thus
the sensitivity to solvents and other process chemicals decreases
greatly.
[0006] Besides good solubility of the precursors, advantages for
the use of polybenzoxazoles in microelectronics are low moisture
absorption and a good planarization capacity. Production of
components using a dielectric which produces good planarization
allows expensive polishing procedures (chemical mechanical
polishing, CMP) to be avoided.
[0007] o-Aminophenolcarboxylic acids are disclosed, for example, in
GB 811,758 and GB 1,283,476. In PBO films produced from the known
monomers, the water absorption in boiling water after 24 h is
0.77%. No mention is made of the planarization behavior of the
polymers produced after cyclization on the substrate or their
suitability as base polymers for compositions which can be
photostructured positively.
SUMMARY OF THE INVENTION
[0008] The object of the invention is to provide
o-aminophenolcarboxylic acids and o-aminothiophenolcarboxylic acids
which are suitable for the preparation of polymers which satisfy
the greatly increased demands of microelectronics. The
o-amino(thio)phenolcarboxylic acids should, in particular, enable
the preparation of readily soluble polymer precursors which, after
cyclization on a substrate, give polybenzoxazoles or
polybenzothiazoles of low moisture absorption and high degree of
planarization.
[0009] This is achieved in accordance with the invention by
o-aminophenolcarboxylic acids and o-aminothiophenolcarboxylic acids
of the following structure: 2
[0010] in which
[0011] A.sup.1 to A.sup.7 are--independently of one another--H,
CH.sub.3, OCH.sub.3, CH.sub.2CH.sub.3 or OCH.sub.2CH.sub.3;
[0012] T is O or S,; m is 0 or 1;
[0013] Z is one of the following carbocyclic or heterocyclic
aromatic radicals: 3
[0014] wherein Q=C--A or N,
[0015] and A=H, F, (CH.sub.2).sub.pCH.sub.3,
(CF.sub.3).sub.pCF.sub.3, O(CH.sub.2).sub.pCH.sub.3,
O(CF.sub.2).sub.pCF.sub.3, CO(CH.sub.2).sub.pCH.sub.3,
CO(CF.sub.2).sub.pCF.sub.3 where p=0 to 8 (linear or branched
chains, OC(CH.sub.3).sub.3, OC(CF.sub.3).sub.3, C.sub.6H.sub.5,
C.sub.6F.sub.5, OC.sub.6H.sub.5, OC.sub.6F.sub.5, cyclopentyl,
perfluorocyclopentyl, cyclohexyl or perfluorocyclohexyl,
[0016] where, in the isolated aromatic rings, a maximum of 3
nitrogen atoms may be present per ring and only 2 nitrogen atoms
may be adjacent, and, in the fused ring systems, a maximum of 2
nitrogen atoms may be present per ring,
[0017] M=a single bond, (CH.sub.2).sub.n, (CF.sub.2).sub.n,
CH(CH.sub.3), CH(CF.sub.3), CF(CH.sub.3), CF(CF.sub.3),
C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, CH(C.sub.6H.sub.5),
CH(C.sub.6F.sub.5), CF(C.sub.6H.sub.5), CF(C.sub.6F.sub.5),
C(CH.sub.3)(C.sub.6H.sub.5), C(CH.sub.3)(C.sub.6F.sub.5),
C(CF.sub.3)(C.sub.6H.sub.5), C(CF.sub.3)(C.sub.6F.sub.5),
C(C.sub.6H.sub.5).sub.2, C(C.sub.6F.sub.5).sub.2, CO, SO.sub.2
4
[0018] with the proviso that, when m=0, a 3-amino-4-hydroxyphenoxy
group cannot be in the p-position to the carboxyl group.
[0019] The novel compounds have, for example, the following
preferred structure: 5
[0020] In compounds of this type, the ether bridges are apparently
responsible for the good solubility and the good planarization
properties of the polymer precursors prepared therewith. By the
way, the characterization "A.sup.1-A.sup.3" and "A.sup.4-A.sup.7"
in the structural formula means that the aminophenyl groups and
carboxyphenyl groups contain radicals A.sup.1, A.sup.2 and A.sup.3,
and A.sup.4, A.sup.5, A.sup.6 and A.sup.7 respectively.
[0021] The o-amino(thio)phenolcarboxylic acids can be prepared
by
[0022] (a) reacting a halogen compound of the structure 6
[0023] with a nitrophenol or nitrothiophenol (abbreviated to
"nitro(thio)phenol") of the structure 7
[0024] in the presence of at least a stoichiometric amount of a
base, or with an alkali metal salt of the nitro(thio)phenol, in a
solvent at a temperature between -10 and 80.degree. C.,
[0025] where X is a halogen atom, E is CN or COOR.sup.1, where
R.sup.1=alkyl (having 1 to 5 carbon atoms), phenyl or benzyl,
A.sup.1 to A.sup.7, T and Z are as defined above, and R is one of
the following radicals: alkyl, alkoxyalkyl, alkenyl, alkoxyalkenyl,
alkynyl or alkoxyalkynyl, each having a maximum of 6 carbon atoms,
phenyl, phenacyl or benzyl, and benzylalkyl, benzylalkenyl,
benzyloxyalkyl, benzyloxyalkenyl, benzylalkoxyalkyl or
benzylalkoxyalkenyl, each having a maximum of 4 aliphatic carbon
atoms; and
[0026] (b) reducing and hydrolyzing the resultant nitro compound to
the amino compound, and removing the group R.
[0027] In this synthesis, which is very economical, a
halogen-containing ester or a corresponding nitrile is thus reacted
with a nitro(thio)phenol having an R-protected hydroxyl or mercapto
group in the o-position to the nitro group. The nitro compound
formed is then reduced to the corresponding amino compound, the
ester or nitrile group is hydrolyzed to the carboxyl group, and the
protecting group R is removed.
[0028] Alternatively, the o-amino(thio)phenolcarboxylic acids can
also be prepared by
[0029] (a) reacting a nitro compound of the structure 8
[0030] with a phenol or thiophenol (abbreviated to (thio)phenol) of
the structure 9
[0031] in the presence of at least a stoichiometric amount of a
base, or with an alkali metal salt of the (thio)phenol, in a
solvent at a temperature between -10 and 80.degree. C.,
[0032] where X is a halogen atom, E is CN or COOR.sup.1, where
R.sup.1=alkyl (having 1 to 5 carbon atoms), phenyl or benzyl,
A.sup.1 to A.sup.7, T and Z are as defined above, and R is one of
the above mentioned radicals; and
[0033] (b) reducing and hydrolyzing the resultant nitro compound to
the amino compound, and removing the group R.
[0034] In this preparation process, which is likewise very
economical, a halogen-containing nitro compound having a protected
hydroxyl or mercapto group in the opposition to the nitro group is
thus reacted with a (thio)phenol containing an ester or nitrile
group. The nitro compound formed is then--in the manner indicated
above--subjected to a reduction, hydrolysis and removal of
protecting group.
[0035] The preparation of nitro(thio)phenols containing a protected
hydroxyl or mercapto group in the o-position to the nitro group has
been described in the parallel German patent application serial no.
197 42 135.0 "o-Nitro(thio)phenol derivatives, and their
preparation" (docket GR 97 P 3683).
DESCRIPTION OF PREFERRED EMBODIMENTS
[0036] The protecting group R is preferably an alkyl, alkoxyalkyl,
phenyl or benzyl group. It is an important advantage that the
radical RT is stable in the reaction between the halogen compound
and the nitro(thio)phenol, but can subsequently be removed.
[0037] The reaction between the halogen compound and the nitro
(thio)phenol, in which an ether or thioether bridge is formed, is
carried out in the presence of a base. This base is preferably a
carbonate or hydrogencarbonate of an alkali metal or alkaline earth
metal, such as sodium carbonate or potassium carbonate. Formation
of the (thio ether requires at least a stoichiometric amount of the
base. It may also be advantageous to use an organic base containing
a tertiary N atom, for example triethylamine or pyridine.
[0038] The nitro(thio)phenol can also be replaced by a
corresponding alkali metal salt, for example the potassium salt. In
this case, a base is not absolutely necessary for the reaction with
the halogen compound.
[0039] A reaction temperature in the range from -10 to 80.degree.
C. has proven suitable. Temperatures .ltoreq.80.degree. C. are
preferred owing to the greater selectivity of the reaction.
[0040] Suitable solvents are, in particular, dimethylformamide,
diethylformamide, dimethylacetamide, dimethyl sulfoxide,
N-methylpyrrolidone, .gamma.-butyrolactone, acetonitrile,
tetrahydrofuran and pyridine. In principle, however, all polar
aprotic solvents in which the starting compounds are soluble can be
used.
[0041] The reduction of the nitro compound can be carried out, for
example, by catalytic hydrogenation using, for example hydrogen on
Pd/C catalyst. In principle, however, all the processes which are
suitable for reducing the nitro group to the amino group are
suitable. The hydrolysis of the ester or nitrile group can be
carried out, for example, using potassium hydroxide. The protecting
group can be removed using, for example, trifluoroacetic acid or
titanium tetrachloride. These reactions can be carried out in
separate process steps; the sequence of the process steps is
unimportant.
[0042] It is also possible to remove the protecting group and carry
out the hydrolysis simultaneously, i.e. in one step. In the
presence of an ester group, these two reactions are particularly
advantageously carried out together with the reduction of the nitro
group, preferably by hydrogenation using hydrogen on Pd/C.
Hydrogenation is preferably carried out at temperatures of from 25
to 50.degree. C. Suitable solvents are esters and ethers, for
example ethyl acetate and tetrahydrofuran.
[0043] The polymer precursors prepared from the
o-amino(thio)phenolcarboxy- lic acids of the invention and having
improved properties compared with the prior art are soluble in many
organic solvents, such as acetone, cyclohexanone,
N-methylpyrrolidone, diethylene glycol mono- or diethyl ether,
ethyl lactate and .gamma.-butyrolactone, and in aqueous-alkaline
developers containing no metal ions. They are therefore highly
suitable as base polymers for dielectrics which can be
photostructured positively and can be developed in aqueous-alkaline
media. The precursors can easily be applied to substrates, such as
silicone wafers, by spin-coating methods, they form uniform films,
and can readily be cyclized on the substrate. A particular
advantage of the precursors prepared from these
o-amino(thio)phenolcarboxylic acids is their high planarization
capacity and low moisture absorption.
[0044] The invention will be illustrated in greater detail below
with reference to working examples.
EXAMPLE 1
Preparation of 4-(4-benzyloxycarbonylphenoxy)nonafluorobiphenyl
[0045] 10
[0046] 37.4 g of decafluorobiphenyl (0.112 mol) are dissolved in
700 ml of dimethylformamide, the mixture is cooled to -10.degree.
C. using a cryostat, and a solution of 29.8 g of potassium
4-benzyloxycarbonylphenox- ide (0.112 mol) in 300 ml of
dimethylformamide is then added dropwise over the course of 2
hours. After 48 hours at -10.degree. C., the potassium salt has
reacted. The dimethylformamide is then removed in a rotary
evaporator, the residue is taken up in a little tetrahydrofuran,
and the solution is filtered through a silica-gel column. The clear
solution obtained is evaporated in a rotary evaporator until a
white solid precipitates out. The solid is then stirred in
n-hexane, filtered off using a fluted filter and then dried for 48
hours under nitrogen at 40.degree. C./10 mbar in a vacuum drying
cabinet (yield: 92%).
[0047] Characterization:
[0048] Mass spectrum: molecular peak at 542. Elemental analysis:
Theoretical value (in %): C: 57.6; H: 2.0. Found (in %): C: 57.5;
H: 1.9. m.p.: 120.degree. C.
EXAMPLE 2
Preparation of
4-(4-nitro-3-benzyloxyphenoxy)-4'-(4-benzyloxycarbonylpheno-
xy)octafluorobiphenyl
[0049] 11
[0050] 49.9 g of the
4-(4-benzyloxycarbonylphenoxy)nonafluorobiphenyl prepared as
described in Example 1 (0.092 mol) and 26.1 g of potassium
4-nitro-3-benzyloxyphenoxide (0.092 mol) are dissolved in 400 ml of
dimethylformamide, and the solution is heated to 80.degree. C.; the
reaction is complete after 24 hours. The solvent is then removed in
a rotary evaporator. The solid residue obtained is washed three
times with methanol, filtered off via a Buchner funnel and
subsequently dried for 48 hours under nitrogen at 40.degree. C./10
mbar in a vacuum drying cabinet (yield: 94%).
[0051] Characterization: Mass spectrum: molecular peak at 767.
Elemental analysis: Theoretical value (in %): C: 61.0; H: 2.8; N:
1.8. Found (in %): C: 60.8; H: 2.7; N: 1.9. m.p.: 152.degree.
C.
EXAMPLE 3
Preparation of
4-(4-amino-3-hydroxyphenoxy)4'-(4-carboxyphenoxy)octafluoro-
biphenyl
[0052] 12
[0053] 49.9 g of the
4-(4-nitro-3-benzyloxyphenoxy)-4'-(4-benzyloxycarbony-
lphenoxy)octafluorobiphenyl prepared as described in Example 2
(0.065 mol) are dissolved in 400 ml of a mixture of tetrahydrofuran
and ethyl acetate (volume ratio 1:1), and 5 g of Pd/C
(palladium/carbon) are then added to the solution. The mixture is
then hydrogenated using hydrogen at a pressure of 1 bar a room
temperature in an autoclave with vigorous stirring; the reaction is
terminated after 3 days. The yellow-beige solution is evaporated to
half in a rotary evaporator and left to stand overnight at room
temperature, during which the reaction product precipitates out in
crystalline form. The reaction product is then separated off and
dried for 48 hours under nitrogen at 40.degree. C./10 mbar in a
vacuum drying cabinet (yield: 91%).
[0054] Characterization: Mass spectrum: molecular peak at 557.
Elemental analysis: Theoretical value (in %): C: 53.9; H: 2.0; N:
2.5. Found (in %) C: 53.7; H: 2.1; N: 2.5. m.p.: 180.degree. C.
(decomposition).
EXAMPLE 4
Preparation of benzyl 4-(4-nitro-3-benzyloxyphenoxy)benzoate
[0055] 13
[0056] 24.7 g of 5-fluoro-2-nitrophenyl benzyl ether (0.1 mol) are
dissolved in 250 ml of dimethyl sulfoxide, and a solution of 26.6 g
of the potassium salt of benzyl 4-hydroxybenzoate (0.1 mol) in 250
ml of dimethyl sulfoxide is then slowly added dropwise with
stirring at room temperature. The mixture is then stirred first at
room temperature for 1 hour and then at 50.degree. C. for 24 hours.
The reaction solution is then allowed to cool to room temperature
and is filtered through a fluted filter, the filtrate is diluted
with 700 ml of water, and the crude product is washed by shaking
with 300 ml of ethyl acetate. The organic phase is then washed
three times with water, dried over sodium sulfate and evaporated in
a rotary evaporator until the reaction product precipitates out.
The reaction product is stirred in petroleum ether (boiling range
40 to 60.degree. C.) for 2 hours, filtered off via a Buchner funnel
and then dried for 48 hours under nitrogen at 40.degree. C./10 mbar
in a vacuum drying cabinet (yield: 91%).
[0057] Characterization: Mass spectrum: molecular peak at 455.
Elemental analysis: Theoretical value (in %): C: 71.2; H: 4.6; N:
3.1. Found (in %): C: 71.0; H: 4.7; N: 3.0. m.p.: 96.degree. C.
EXAMPLE 5
Preparation of 4-(4-amino-3-hydroxyphenoxy)benzoic acid
[0058] 14
[0059] 46.6 g of the benzyl 4-(4-nitro-3-benzyloxyphenoxy)benzoate
prepared as described in Example 4 (0.11 mol) are dissolved in 500
ml of a mixture of tetrahydrofuran and ethyl acetate, and 5 g of
Pd/C (palladium/carbon) are added to the solution. The mixture is
then hydrogenated using hydrogen at a pressure of 1 bar at room
temperature in an autoclave with vigorous stirring; the reaction is
terminated after 3 days. The pale violet solution is evaporated to
half in a rotary evaporator and left to stand overnight at room
temperature, during which the reaction product precipitates out in
crystalline form. The reaction product is then separated off and
dried for 48 hours under nitrogen at 40.degree. C./10 mbar in a
vacuum drying cabinet (yield: 93%).
[0060] Characterization: Mass spectrum: molecular peak at 245.
Elemental analysis: Theoretical value (in %): C: 63.7; H: 4.5; N:
5.7. Found (in %): C: 63.5; H: 4.5; N: 5.8. m.p.: 190.degree. C.
(decomposition).
EXAMPLE 6
Preparation of
2-(4-benzyloxycarbonylphenoxy)-3,4,5,6-tetrafluoropyridine
[0061] 15
[0062] 33.8 g of pentafluoropyridine (0.2 mol) are dissolved in 500
ml of dimethylformamide, the solution is cooled to 0C by means of a
cryostat, and a solution of 53.3 g of potassium
4-benzyloxycarbonylphenoxide (0.2 mol) in 400 ml of
dimethylformamide is then added dropwise over the course of 2
hours. After 24 hours at 0.degree. C., the potassium salt has
reacted. The dimethylformamide is then removed in a rotary
evaporator, the residue is taken up in a little tetrahydrofuran,
and the solution is filtered through a silica-gel column. The clear
solution obtained is evaporated in a rotary evaporator until the
reaction product precipitates out. The reaction produce is then
stirred in n-hexane, filtered off via a fluted filter and then
dried for 48 hours under nitrogen at 40.degree. C./10 mbar in a
vacuum drying cabinet (yield: 91%).
[0063] Characterization: Mass spectrum: molecular peak at 377.
Elemental analysis: Theoretical value (in %): C: 60.5; H: 2.9; N:
3.7. Found (in %): C: 60.6; H: 2.9; N: 3.6.
EXAMPLE 7
Preparation of
4-(4-nitro-3-benzyloxyphenoxy)-2-(4-benzyloxycarbonylphenox-
y)-3,5,6-trifluoropyridine
[0064] 16
[0065] 40 g of the
2-(4-benzyloxycarbonylphenoxy)-3,4,5,6-tetrafluoropyrid- ine
prepared as described in Example 6 (0.106 mol) and 30 g of
potassium 4-nitro-3-benzyloxyphenoxide (0.106 mol) are dissolved in
500 ml of dimethyl sulfoxide. 30 g of potassium carbonate (0.22
mol) are added in portions to the solution. The mixture is then
stirred at room temperature for 24 hours, then heated at 60.degree.
C. for 24 hours, and 15 g of potassium hydrogencarbonate (0.15 mol)
are then added. The reaction solution is then cooled to room
temperature and filtered through a fluted filter. The crude product
is washed by shaking with 300 ml of ethyl acetate and 700 ml of
water, and the organic phase is washed three times with water and
evaporated in a rotary evaporator until the reaction product
precipitates out. The reaction product is then recrystallized from
a mixture of ethyl acetate and n-hexane (volume ratio 1:1) and then
dried for 48 hours under nitrogen at 40.degree. C./10 mbar in a
vacuum drying cabinet (yield: 92%).
[0066] Characterization: Mass spectrum: molecular peak at 602.
Elemental analysis: Theoretical value (in %): C: 63.8; H: 3.5; N:
4.6. Found (in %): C: 63.7; H: 3.5; N: 4.6.
EXAMPLE 8
Preparation of
4-(4-amino-3-hydroxyphenoxy)-2-(4-carboxyphenoxy)-3,5,6-tri-
fluoropyridine
[0067] 17
[0068] 40 g of the
4-(4-nitro-3-benzyloxyphenoxy)-2-(4-benzyloxycarbonylph-
enoxy)-3,5,6-trifluoropyridine prepared as described in Example 7
(0.066 mol) are dissolved in 600 ml of a mixture of tetrahydrofuran
and ethyl acetate (volume ratio 1:1), and 4 g of Pd/C
(palladium/carbon) are added to the solution. The mixture is then
hydrogenated using hydrogen at a pressure of 1 bar at room
temperature in an autoclave with vigorous stirring; the reaction is
terminated after 3 days. The orange solution is evaporated to half
in a rotary evaporator and left to stand overnight at room
temperature, during which the reaction product precipitates out in
crystalline form. The reaction product is then dried for 48 hours
under nitrogen at 40.degree. C./10 mbar in a vacuum drying cabinet
(yield: 91%).
[0069] Characterization: Mass spectrum: molecular peak at 392.
Elemental analysis: Theoretical value (in %): C: 55.1; H: 2.8; N:
7.1. Found (in %): C: 55.1; H: 2.8; N: 7.2.
EXAMPLE 9
Preparation of
2-(4-benzyloxycarbonylphenoxy)-1-trifluoromethyl-3,4,5,6-te-
trafluorobenzene
[0070] 18
[0071] 35.4 g of octafluorotoluene (0.15 mol) are dissolved in 400
ml of dimethylformamide, the solution is cooled to 0.degree. C.
using a cryostat, and a solution of 40 g of potassium
4-benzyloxycarbonylphenoxid- e (0.15 mol) in 300 ml of
dimethylformamide is then added dropwise over the course of 2
hours. After 24 hours at 0.degree. C., the potassium salt has
reacted. The dimethylformamide is then removed in a rotary
evaporator, the residue is taken up in a little tetrahydrofuran,
and the solution is filtered through a silica-gel column. The clear
solution obtained is evaporated in a rotary evaporator until the
reaction product precipitates out. The reaction product is then
stirred in n-hexane, filtered off through a fluted filter and then
dried for 48 hours under nitrogen at 40.degree. C./10 mbar in a
vacuum drying cabinet (yield: 95%).
[0072] Characterization: Mass spectrum: molecular peak at 444.
Elemental analysis: Theoretical value (in %): C: 56.8; H: 2.5.
Found (in %): C: 56.8; H: 2.5.
EXAMPLE 10
Preparation of
4-(4-nitro-3-benzyloxyphenoxy)-2-(4-benzyloxycarbonylphenox-
y)-1-trifluoromethyl-3,5,6-trifluorobenzene
[0073] 19
[0074] 40 g of the
2-(4-benzyloxycarbonylphenoxy)-1-trifluoromethyl-3,4,5,-
6-tetrafluorobenzene prepared as described in Example 9 (0.09 mol)
and 25.5 g of potassium 4-nitro-3-benzyloxyphenoxide (0.09 mol) are
dissolved in 400 ml of dimethyl sulfoxide. 30 g of potassium
carbonate (0.22 mol) are added in portions to the solution. The
mixture is then stirred at room temperature for 24 hours and then
heated at 60.degree. C. for 24 hours, and 15 g of potassium
hydrogencarbonate (0.15 mol) are then added. The reaction solution
is then allowed to cool to room temperature and is filtered through
a fluted filter. The crude product is washed by shaking with 300 ml
of ethyl acetate and 700 ml of water, and the organic phase is
washed three times with water and evaporated in a rotary evaporator
until the reaction product precipitates out. The reaction product
is then recrystallized from a mixture of ethyl acetate and n-hexane
(volume ratio 1:1) and then dried for 48 hours under nitrogen at
40.degree. C./10 mbar in a vacuum drying cabinet (yield: 94%).
[0075] Characterization: Mass spectrum: molecular peak at 669.
Elemental analysis: Theoretical value (in %): C: 61.0; H: 3.2; N:
2.1. Found (in %): C: 61.1; H: 3.2; N: 2.1.
EXAMPLE 11
Preparation of
4-(4-amino-3-hydroxyphenoxy)-2-(4-carboxyphenoxy)-1-trifluo-
romethyl-3,5,6-trifluorobenzene
[0076] 20
[0077] 40.4 g of the
4-(4-nitro-3-benzyloxyphenoxy)-2-(4-benzyloxycarbonyl-
phenoxy)-1-trifluoromethyl-3,5,6-tri-fluorobenzene prepared as
described in Example 10 (0.06 mol) are dissolved in 500 ml of a
mixture of tetrahydrofuran and ethyl acetate (volume ratio 1:2),
and 4 g of Pd/C (palladium/carbon) are added to the solution. The
mixture is then hydrogenated using hydrogen at a pressure of 1 bar
at room temperature in an autoclave with vigorous stirring; the
reaction is terminated after 3 days. The orange solution is
evaporated to half in a rotary evaporator and left to stand
overnight at room temperature, during which the reaction product
precipitates out in crystalline form. The reaction product is then
dried for 48 hours under nitrogen at 40.degree. C./10 mbar in a
vacuum drying cabinet (yield:95%).
[0078] Characterization: Mass spectrum: molecular peak at 459.
Elemental analysis: Theoretical value (in %): C: 52.3; H: 2.4; N:
3.0. Found (in %): C: 52.3; H: 2.4; N: 3.0.
* * * * *