Bis-o-amino(thio)phenols, and their preparation

The invention relates to novel bis-o-aminophenols, and bis-o-aminothiophenols of the following structure: ##STR1## where A.sup.1 to A.sup.6 are--independently of one another--H, F, CH.sub.3, CF.sub.3, OCH.sub.3, OCF.sub.3, CH.sub.2 CH.sub.3, CF.sub.2 CF.sub.3, OCH.sub.2 CH.sub.3 or OCF.sub.2 CF.sub.3, where at least one of the radicals A.sup.1 to A.sup.6 must be F or an F-containing group; T is O or S, and m is 0 or 1; and Z is a carbocyclic or heterocyclic aromatic radical.

BACKGROUND OF THE INVENTION 
Field of the Invention 
The invention relates to novel bis-o-aminophenols and 
bis-o-aminothiophenols, which are also jointly abbreviated to 
bis-o-amino(thio)phenols, and to a process for their preparation. 
Bis-o-aminophenols are needed, in particular, for the preparation of 
high-temperature-stable polymers, such as polybenzoxazoles (PBOs) and 
their precursors and for the preparation of hydroxypolyimides (in this 
respect, see, for example, EP 0 264 678 B1 and EP 0 300 326 B1). PBO 
precursors can be prepared by reacting a dicarboxylic acid chloride with a 
bis-o-aminophenol. However, whereas numerous dicarboxylic acids and 
chlorides thereof are available owing to the wide variety of potential 
industrial applications, there are comparatively few bis-o-aminophenols. 
In addition, the nature of the aminophenol used has a strong effect on the 
property profile of the polymer 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 aminophenol used in the preparation. 
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 , compared with the cyclized final product 
they can be applied to a substrate as readily soluble precursors and then 
cyclized, during which the solubility and thus the sensitivity to solvents 
and other process chemicals decreases greatly. 
In addition to good electrical, mechanical and thermal properties, use of 
polybenzoxazoles in microelectronics, in particular as dielectric between 
two metal planes, for example in multi-chip modules and memory and logic 
chips, or as buffer coat between the chip and its housing, also requires 
low moisture absorption; this is because the moisture content in the 
polymer layer impairs the electrical properties of the polymer and also 
can result in bubble formation and flaking at high temperatures. A good 
planarization capacity of the polybenzoxazoles is likewise advantageous 
since production of components using a dielectric which produces good 
planarization allows expensive polishing procedures (chemical mechanical 
polishing, CMP) to be avoided. 
Aminophenols which are suitable for the preparation of readily soluble PBO 
precursors are disclosed, for example, in U.S. Pat. No. 4,525,539 and EP 0 
317 942 A2. However, there is no indication therein of the moisture 
absorption or planarization behavior of the resultant polymers after 
cyclization on the substrate (see EP 0 264 678 B1 and EP 0 317 942 A2). In 
the preparation of the aminophenols, a phenolic starting compound is 
nitrated. If the nitration does not take place completely, i.e. to 100%, 
and entirely free from isomers, i.e. nitration may only take place in the 
opposition to the hydroxyl group, reduction of the nitro group in some 
cases results in aminophenols, which do not allow complete cyclization in 
the PBO precursor and considerably impair the properties of the 
polybenzoxazole. This is a major disadvantage of the known preparation 
processes. SU 1 205 518 A discloses aromatic aminophenols. The preparation 
of these aminophenols uses carcinogenic hydrazine hydrate, which is a 
considerable disadvantage. In addition, there is again no indication of 
the moisture absorption and planarization behavior of the resultant 
polymers after cyclization on the substrate. 
A process for the preparation of bisaminophenols is also disclosed in 
"Polymer Preprints" 34 (1), 1993, pages 425 and 426. This process has the 
disadvantage of requiring high temperatures, i.e. significantly higher 
temperatures than 100.degree. C. (solutions in dimethylacetamide and 
toluene are refluxed). However, high reaction temperatures promote side 
reactions, which reduce the yield (which is a maximum of 73%) and make 
purification of the target product more difficult. In addition, the 
bisaminophenols so prepared are not stable to oxidation. There is likewise 
no indication herein of the moisture absorption or planarization behavior 
of the resultant polymers after cyclization on the substrate. 
SUMMARY OF THE INVENTION 
The object of the invention is to provide novel bis-o-aminophenols and 
bis-o-aminothiophenols which are particularly suitable for the preparation 
of polymers which satisfy the greatly increased demands of 
microelectronics. 
The bis-o-amino(thio)phenols 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, high heat stability and high degree of planarization. In 
addition, the bis-o-amino(thio)phenols should be stable on storage and 
should not change on storage in air. 
This object is achieved in accordance with the invention by 
bis-o-aminophenols and bis-o-aminothiophenols of the following structure: 
##STR2## 
in which A.sup.1 to A.sup.6 are--independently of one another--H, F, 
CH.sub.3, CF.sub.3, OCH.sub.3, OCF.sub.3, CH.sub.2 CH.sub.3, CF.sub.2 
CF.sub.3, OCH.sub.2 CH.sub.3 or OCF.sub.2 CF.sub.3 where at least one of 
the radicals A.sup.1 to A.sup.6 must be F or an F-containing group; 
T is O or S, m is 0 or 1; and Z is one of the following carbocyclic or 
heterocyclic aromatic radicals: 
##STR3## 
where Q=C--A or N, and A=H, F, (CH.sub.2).sub.p CH.sub.3, (CF.sub.2).sub.p 
CF.sub.3, O(CH.sub.2).sub.p CH.sub.3, O(CF.sub.2).sub.p CF.sub.3, 
CO(CH.sub.2).sub.p CH.sub.3, CO(CF.sub.2).sub.p CF.sub.3 where p=0 to 8 
(linear or branched chain), OC(CH.sub.3).sub.3, OC(CF.sub.3).sub.3, 
C.sub.6 H.sub.5, C.sub.6 F.sub.5, OC.sub.6 H.sub.5, OC.sub.6 F.sub.5, 
cyclopentyl, perfluorocyclopentyl, cyclohexyl or 
perfluorocyclohexyl,where, in the isolated aromatic rings, a maximum of 3 
N-atoms may be present per ring and only 2 N-atoms may be adjacent, and, 
in the fused ring systems, a maximum of 2 N-atoms may be present per ring, 
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.6 H.sub.5), CH(C.sub.6 F.sub.5), CF(C.sub.6 
H.sub.5), CF(C.sub.6 F.sub.5), C(CH.sub.3) (C.sub.6 H.sub.5), C(CH.sub.3) 
(C.sub.6 F.sub.5), C(CF.sub.3) (C.sub.6 H.sub.5) C(CF.sub.3) (Ch.sub.6 
F.sub.5), C(C.sub.6 H.sub.5).sub.2, C(C.sub.6 F.sub.5).sub.2, CO, 
SO.sub.2, 
##STR4## 
The novel compounds have, for example, the following structure: 
##STR5## 
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 characterizations "A.sup.1 
-A.sup.3 " and "A.sup.4 -A.sup.6 " in the structural formula means that 
the aminophenyl groups contain radicals A.sup.1, A.sup.2 and A.sup.3, and 
A.sup.4, A.sup.5 and A.sup.6 respectively. 
The bis-o-amino(thio)phenols are prepared by (a) reacting a nitro compound 
of the structure 
##STR6## 
and a nitro compound of the structure 
##STR7## 
either with an alkali metal hydroxide or alkali metal hydrogensulfide 
or--in the presence of a base--with a dihydroxy or dimercapto compound of 
the structure HT-Z-TH or with an alkali metal salt of the dihydroxy or 
dimercapto compound, in a solvent at a temperature between -10 and 
80.degree. C., where X is a halogen atom and A.sup.1 to A.sup.6, T and Z 
are as defined above; and 
(b) reducing the resultant bis-o-nitro(thio)phenol to the 
bis-o-amino(thio)phenol. 
The process of the invention does not give rise to any of the problems 
which occur in the prior art. The bis-o-amino(thio)phenols prepared by 
this process additionally have good storage stability and can be stored in 
air without problems. 
DESCRIPTION OF PREFERRED EMBODIMENTS 
Preference is given to the preparation of bis-o-amino(thio)phenols in which 
the substituents A.sup.1 and A.sup.4, A.sup.2 and A.sup.5 and A.sup.3 and 
A.sup.6 in each case correspond and are arranged in the same position 
relative to the amino group on the respective phenyl radical. This means 
that only a single nitro compound is employed in the preparation of these 
compounds. 
The compound HT-Z-TH is an aromatic or substituted aromatic compound (where 
T=O or S). Suitable compounds for the reaction with the nitro compound are 
in principle all those in which the hydroxyl or mercapto groups have 
sufficient nucleophilicity. Examples of such compounds are resorcinol, 
tetrafluororesorcinol, hydroquinone, tetrafluorohydroquinone, 
4,6-dihydroxypyrimidine, 2,4-dihydroxy-5-fluoropyrimidine, 
octafluorobiphenol, 3,3'-dihydroxy-2,2'-bipyridyl, 
2,2-bis(4-hydroxyphenyl)-perfluoropropane (6F-bisphenol A), 
bis(4-hydroxyphenyl)-sulfone and 2,6-dihydroxyanthraquinone. 
The reaction between the dihydroxy or dimercapto compound and the nitro 
compound, in which ether or thioether bridges are 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. For the (thio)ether formation and 
replacement of the halogen atom (in the opposition to the nitro group) by 
a hydroxyl or mercapto group, at least stoichiometric amounts of the base 
are necessary in each case. It may also be advantageous to employ an 
organic base containing a tertiary N atom, for example triethylamine or 
pyridine. In this case, the addition of water is necessary. The dihydroxy 
or dimercapto compound can also be replaced by a corresponding alkali 
metal salt, for example the potassium salt. 
A reaction temperature in the range from -10 to 80.degree. C. has proven 
suitable. Temperatures not above 80.degree. C. are preferred owing to the 
greater selectivity of the reaction. This is because the yields here are 
virtually quantitative, which represents a significant advantage compared 
to the prior art. 
In an advantageous procedure, a temperature of not above 25.degree. C. is 
initially maintained for some time, for example for about 16 hours, during 
which the reaction of the nitro compound with the dihydroxy or dimercapto 
compound takes place. The reaction is subsequently continued at elevated 
temperature, i.e. at .gtoreq.40.degree. C.; during which replacement of 
the halogen atom by a hydroxyl or mercapto group then takes place. This 
procedure selectively gives products in which the hydroxyl or mercapto 
group is in the opposition to the nitro group. 
Suitable solvents are, in particular, dimethylformamide, diethylformamide, 
dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, 
y-butyrolactone, acetonitrile, tetrahydrofuran and pyridine. In principle, 
however, all polar aprotic solvents in which the starting compounds are 
soluble can be used. 
The reduction of the dinitro compound gives the desired 
bis-o-amino(thio)phenol. The reduction can be carried out, for example, by 
hydrogenation using hydrogen on Pd/C. In principle, however, all the 
processes which are suitable for reducing a nitro group to an amino group 
are suitable. The reduction 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. 
The polymer precursors prepared from the bis-o-amino(thio)phenols of the 
invention are readily soluble in many organic solvents, such as acetone, 
ethyl lactate, N-methylpyrrolidone, diethylene glycol mono- or diethyl 
ether, cyclohexanone and y-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 silicon 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 
bis-o-amino(thio)phenols is their high planarization capacity and low 
moisture absorption. 
The invention will be illustrated in greater detail below with reference to 
working examples.

EXAMPLE 1 
Preparation of 
2,2-bis[4-(4-nitro-3-hydroxy-2,5,6-tri-fluorophenoxy)phenyl]hexafluoroprop 
ane 
##STR8## 
33.6 g of 6F-bisphenol A (0.1 mol) and 42.6 g of pentafluoronitrobenzene 
(0.2 mol) are dissolved in 400 ml of dimethyl sulfoxide in a 1 l 
three-neck flask fitted with nitrogen inlet and stirrer. 60 g of potassium 
carbonate (0.43 mol) are added in portions to the solution. The mixture is 
then stirred at room temperature for 24 hours, then heated in a 
temperature-controllable oil bath at 80.degree. C. for 6 hours and, after 
addition of 10 g of potassium hydrogencarbonate (0.1 mol), for a further 
18 hours. The reaction solution is then allowed to cool to room 
temperature, and the residue is filtered off via a Buchner funnel. After 2 
l of water have been added, concentrated hydrochloric acid is added drop 
wise until the solution is acidic. During this addition, a yellow reaction 
product precipitates, and is filtered off via a Buchner funnel and washed 
three times with water. The reaction product is then recrystallized from 
ethanol and then dried for 48 hours under nitrogen at 40.degree. C/10 mbar 
in a vacuum drying cabinet (yield: 91). 
Characterization: 
Mass spectrum: molecular peak at 718 
Elemental analysis: Theoretical value (in %): C: 45.1 H: 1.4 N: 3.9. Found 
(in %): C: 45.1 H: 1.3 N: 3.9 
m.p.: 70.degree. C. 
EXAMPLE 2 
Preparation of 
2,2-bis[4-(4-amino-3-hydroxy-2,5,6-tri-fluorophenoxy)phenyl]hexafluoroprop 
ane 
##STR9## 
21.5 g of 
2,2-bis[4-(4-nitro-3-hydroxy-2,5,6-tri-fluorophenoxy)phenyl]hexafluoroprop 
ane prepared as described in Example 1 (0.03 mol) are dissolved in 200 ml 
of a mixture of tetrahydrofuran and ethyl acetate (volume ratio 1:1), and 
2 g of Pd/C (palladium/ carbon) are added to the solution. The mixture is 
then hydrogenated at room temperature in an autoclave with vigorous 
stirring using hydrogen at a pressure of 1 bar; after 2 days, the reaction 
is terminated. The solution is evaporated to half in a rotary evaporator 
and left to stand overnight at room temperature, during which the reaction 
product precipitates 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%). 
Characterization: 
Mass spectrum: molecular peak at 658 
Elemental analysis: Theoretical value (in %): C: 49.3 H: 2.1 N: 4.3. Found 
(in %): C: 49.1 H: 2.2 N: 4.3 
EXAMPLE 3 
Preparation of 
1,4-bis(4-nitro-3-hydroxy-2,5,6-tri-fluorophenoxy)tetrafluorobenzene 
##STR10## 
18.6 g of tetrafluorohydroquinone (0.1 mol) and 42.6 g of 
pentafluoronitrobenzene (0.2 mol) are dissolved in 400 ml of dimethyl 
sulfoxide in a 2 l three-neck flask fitted with nitrogen inlet and 
stirrer. 60 g of potassium carbonate (0.43 mol) are added in portions to 
the solution. The mixture is then stirred at room temperature for 24 hours 
and then heated in a temperature-controllable oil bath at 60.degree. C. 
for 4 hours and, after the addition of 30 g of potassium hydrogencarbonate 
(0.3 mol), for a further 6 hours. The reaction solution is then allowed to 
cool to room temperature, and the residue is filtered off via a Buchner 
funnel. After 500 ml of water and 300 ml of ethyl acetate have been added, 
concentrated hydrochloric acid is added drop wise until the solution is 
acidic. The organic phase is then washed three times with water, dried 
over sodium sulfate and evaporated to half in a rotary evaporator. After 2 
days, the precipitated yellow crystals are filtered off, washed with 
methylene chloride and dried for 48 hours under nitrogen at 40.degree. 
C./10 mbar in a vacuum drying cabinet (yield: 93%). 
Characterization: 
Mass spectrum: molecular peak at 564 
Elemental analysis: Theoretical value (in %): C: 38.3 H: 0.4 N: 5.0. Found 
(in %): C: 38.4 H: 0.3 N: 4.9 
m.p.: 234.degree. C. (decomposition) 
EXAMPLE 4 
Preparation of 
1,4-bis(4-amino-3-hydroxy-2,5,6-tri-fluoro-phenoxy)tetrafluorobenzene 
##STR11## 
50 g of 
1,4-bis(4-nitro-3-hydroxy-2,5,6-tri-fluoro-phenoxy)tetrafluorobenzene 
prepared as described in Example 3 (0.09 mol) are dissolved in 500 ml of a 
mixture of tetrahydrofuran and ethyl acetate (volume ratio 1:1), and 5 g 
of Pd/C (palladium/carbon) are added to the solution. The mixture is then 
hydrogenated at room temperature in an autoclave with vigorous stirring 
using hydrogen at a pressure of 1 bar; after 2 days, the reaction is 
terminated. The yellow solution is evaporated to half in a rotary 
evaporator and left to stand overnight at room temperature, during which 
the reaction product precipitates in crystalline form. The reaction 
product is then collected and dried for 48 hours under nitrogen at 
40.degree. C./10 mbar in a vacuum drying cabinet (yield: 92%). 
Characterization: 
Mass spectrum: molecular peak at 504 
Elemental analysis: Theoretical value (in %): C: 42.9 H: 1.2 N: 5.6. Found 
(in %): C:41.7 H: 1.3 N: 5.7 
EXAMPLE 5 
Preparation of 4,6-bis(4-nitro-3-hydroxy-2,5,6-trifluorophenoxy)pyrimidine 
##STR12## 
11.2 g of 4,6-dihydroxypyrimidine (0.1 mol) and 42.6 g of 
pentafluoronitrobenzene (0.2 mol) are dissolved in 400 ml of dimethyl 
sulfoxide in a 2 l three-neck flask fitted with nitrogen inlet and 
stirrer. 60 g of potassium carbonate (0.43 mol) are added in portions to 
the solution. The mixture is then stirred at room temperature for 24 hours 
and then heated in a temperature-controllable oil bath at 60.degree. C. 
for 4 hours and, after the addition of 30 g of potassium 
hydrogen-carbonate (0.3 mol), for a further 6 hours. The reaction solution 
is then allowed to cool to room temperature, and the residue is filtered 
off via a Buchner funnel. After 500 ml of water and 300 ml of ethyl 
acetate has been added, concentrated hydrochloric acid is added drop wise 
until the solution is acidic. The organic phase is then washed three times 
with water, dried over sodium sulfate and evaporated to half in a rotary 
evaporator. After 2 days, the precipitated orange-brown crystals are 
filtered off, washed with petrol ether and dried for 48 hours under 
nitrogen at 40.degree. C./10 mbar in a vacuum drying cabinet (yield: 94%). 
Characterization: 
Mass spectrum: molecular peak at 494 
Elemental analysis: Theoretical value (in %): C: 38.9 H: 0.8 N: 11.3. Found 
(in %): C: 39.1 H: 0.7 N: 11.1 
EXAMPLE 6 
Preparation of 
4,6-bis(4-amino-3-hydroxy-2,5,6-tri-fluoro-phenoxy)pyrimidine 
##STR13## 
50.8 g of 4,6-bis(4-nitro-3-hydroxy-2,5,6-tri-fluoro-phenoxy)pyrimidine 
prepared as described in Example 5 (0.12 mol) are dissolved in 500 ml of a 
mixture of tetrahydrofuran and ethyl acetate (volume ratio 1:1), and 5 g 
of Pd/C (palladium/carbon) are added to the solution. The mixture is then 
hydrogenated at room temperature in an autoclave with vigorous stirring 
using hydrogen at a pressure of 1 bar; after 2 days, the reaction is 
terminated. The yellow solution is evaporated to half in a rotary 
evaporator and left to stand overnight at room temperature, during which 
the reaction product precipitates in crystalline form. The reaction 
product is then collected and dried for 48 hours under nitrogen at 
40.degree. C./10 mbar in a vacuum drying cabinet (yield: 93%). 
Characterization: 
Mass spectrum: molecular peak at 434 
Elemental analysis: Theoretical value (in %): C: 44.3 H: 1.9 N: 12.9. Found 
(in %): C: 44.3 H: 1.8 N: 12.8 
EXAMPLE 7 
Preparation of 
4,4'-bis(4-nitro-3-hydroxy-2,5,6-tri-fluorophenoxy)octafluorobiphenyl 
##STR14## 
33 g of 4,4'-octafluorobiphenol (0.1 mol) and 42.6 g of 
pentafluoronitrobenzene (0.2 mol) are dissolved in 400 ml of dimethyl 
sulfoxide in a 2 l three-neck flask fitted with nitrogen inlet and 
stirrer. 60 g of potassium carbonate (0.43 mol) are added in portions to 
the solution. The mixture is then stirred at room temperature for 24 hours 
and then heated in a temperature-controllable oil bath at 50.degree. C. 
for 48 hours. The reaction solution is then allowed to cool to room 
temperature, and the residue is filtered off via a fluted filter. After 
500 ml of water and 300 ml of ethyl acetate has been added, concentrated 
hydrochloric acid is added drop wise until the solution is acidic. The 
organic phase is then washed three times with water, dried over sodium 
sulfate and evaporated to half in a rotary evaporator. After 2 days, the 
precipitated yellow crystals are filtered off, washed with a mixture of 
methylene chloride and petrol ether (volume ratio 1:1) and dried for 48 
hours under nitrogen at 40.degree. C./10 mbar in a vacuum drying cabinet 
(yield: 90%). 
Characterization: 
Mass spectrum: molecular peak at 712 
Elemental analysis: Theoretical value (in %): C: 40.5 H: 0.3 N: 3.9. Found 
(in %): C: 40.7 H: 0.4 N: 3.8 
m.p.: &gt;300.degree. C. 
EXAMPLE 8 
Preparation of 
4,4'-bis(4-amino-3-hydroxy-2,5,6-tri-fluoro-phenoxy)octafluorobiphenyl 
##STR15## 
49.8 g of 
4,4'-bis(4-nitro-3-hydroxy-2,5,6-tri-fluoro-phenoxy)octafluorobiphenyl 
prepared as described in Example 7 (0.07 mol) are dissolved in 500 ml of a 
mixture of tetrahydrofuran and ethyl acetate (volume ratio 1:1), and 5 g 
of Pd/C (palladium/carbon) are added to the solution. The mixture is then 
hydrogenated at room temperature in an autoclave with vigorous stirring 
using hydrogen at a pressure of 1 bar; after 2 days, the reaction is 
terminated. The yellow solution is evaporated to half in a rotary 
evaporator and left to stand overnight at room temperature, during which 
the reaction product precipitates in crystalline form. The reaction 
product is then collected and dried for 48 hours under nitrogen at 
40.degree. C./10 mbar in a vacuum drying cabinet (yield: 90%). 
Characterization: 
Mass spectrum: molecular peak at 652 
Elemental analysis: Theoretical value (in %): C: 44.2 H: 0.9 N: 4.3. Found 
(in %): C: 44.0 H: 0.8 N: 4.4