Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfur containing
Reexamination Certificate
1998-09-24
2001-11-20
Vollano, Jean F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfur containing
C568S631000, C568S045000, C568S050000
Reexamination Certificate
active
06320081
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to novel o-nitrophenol derivatives and o-nitrothiophenol derivatives, which are also jointly abbreviated to o-nitro(thio)phenol derivatives, and to a process for their preparation.
The preparation of high-temperature-stable polymers, such as polybenzoxazoles (PBOs) and their precursors, and the preparation of hydroxypolyimides requires bis-o-aminophenols (in this respect, see, for example, EP 0 264 678 B1 and EP 0 300 326 B1). These monomers can be prepared by reducing the corresponding bis-o-nitrophenols (in this respect, see EP 0 317 942 A2, SU 1 205 518 A and “Polymer Preprints” 34(1), 1993, pages 425 and 426).
Bis-o-nitrophenols can be prepared by nitrating bisphenols. However, this gives isomers and also polynitro compounds, which is very disadvantageous since, if the nitration is not complete, i.e. to 100%, and does not take place entirely isomer-free, i.e. nitration only taking place in the o-position to the hydroxyl group, then the reduction is in some cases followed by the formation of aminophenols which do not allow complete cyclization in the PBO precursor and considerably impair the properties of the polybenzoxazole.
It is also already known to prepare nitrophenol derivatives, i.e. bis(o-benzyloxynitrophenyl) compounds, for said purpose. This is achieved by nucleophilic substitution (see “Polymer Preprints”, in loco citato). However, this process requires high temperatures, namely significantly higher temperatures than 100° C. (solutions in dimethylacetamide/toluene are refluxed). However, high reaction temperatures promote side-reactions, which reduce the yield (it is a maximum of 73%) and make purification of the target product more difficult. In addition, the bis-o-aminophenols prepared in this way are not stable to oxidation.
In general, there is a lack of suitable aminophenols—and correspondingly also of nitrophenols—for the preparation of polymers which satisfy the greatly increased demands of microelectronics. In addition, the type of aminophenol employed 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.
SUMMARY OF THE INVENTION
The object of the invention is to provide o-nitrophenol derivatives and o-nitrothiophenol derivatives which are suitable for the preparation of selected o-aminophenols or o-aminothiophenols of high isomer purity and stability to oxidation which serve as particularly suitable monomers for the preparation of polymer precursors.
This is achieved in accordance with the invention by o-nitrophenol derivatives and o-nitrothiophenol derivatives of the following structure:
in which
A
1
A
3
are—independently of one another—H, F, CH
3
, CF
3
, OCH
3
, OCF
3
, CH
2
CH
3
, CF
2
CF
3
, OCH
2
CH
3
or OCF
2
CF
3
;
T=O or S;
R=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 four aliphatic carbon atoms;
R*=H or R;
provided that, in the o-nitro(thio)phenol derivative (1), R cannot be alkyl if A
1
is an F-atom in the m-position to the NO
2
group, A
2
and A3 are H, and the TH group is in the o-position to the NO
2
group.
The characterization “A
1
-A
3
” in the structural formulae means that the nitrophenyl groups contain radicals A
1
, A
2
and A
3
. In (2), the corresponding radicals in the two nitrophenyl groups may be identical or different.
The o-amino(thio)phenols which can be prepared from the o-nitro(thio)phenol derivatives of the invention result in polymer precursors which, after cyclization, give polybenzoxazoles or polybenzothiazoles which have low moisture absorption, high temperature stability and a high degree of planarization. The polymer precursors are readily soluble in many organic solvents, such as acetone, cyclohexanone, ethyl lactate, diethylene glycol mono- and diethyl ether, N-methylpyrrolidone and &ggr;-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.
The o-nitro(thio)phenol derivatives of the formula (1) can be prepared by selectively removing the radical R
2
from a compound of the structure
and replacing it by H at a temperature of from 20 to 100° C., whereby
(a) for R
1
=alkyl, alkoxyalkyl, alkenyl, alkoxyalkenyl, alkynyl or alkoxyalkynyl (each having a maximum of 6 carbon atoms) and R
2
=phenyl, phenacyl or benzyl, and benzylalkyl, benzylalkenyl, benzyloxyalkyl, benzyloxyalkenyl, benzylalkoxyalkyl or benzylalkoxyalkenyl (each having a maximum of four aliphatic carbon atoms), the removal of R
2
is carried out using trifluoroacetic acid, p-toluenesulfonic acid, lithium tert-butoxide, sodium tert-butoxide, potassium tert-butoxide, lithium aluminum hydride, sodium aluminum hydride or potassium aluminum hydride, or by hydrogenation using hydrogen on Pd/C;
(b) for R
1
=phenyl, phenacyl or benzyl, and benzylalkyl, benzylalkenyl, benzyloxyalkyl, benzyloxyalkenyl, benzylalkoxyalkyl or benzylalkoxyalkenyl (each having a maximum of four aliphatic carbon atoms), and R
2
=alkyl, alkoxyalkyl, alkenyl, alkoxyalkenyl, alkynyl or alkoxyalkynyl (each having a maximum of 6 carbon atoms), the removal of R
2
is carried out using a metal or a metal compound in a protic solvent.
The nitro compound of the structure shown above can be prepared from the corresponding dihalogen compound (X in place of R
1
T and R
2
T) by reaction with compounds R
1
TH and R
2
TH, for example allyl alcohol and benzyl alcohol, or with corresponding alkali metal salts.
Alternatively, o-nitro(thio)phenol derivatives of structure (1) can be prepared by reacting a compound of the structure
where R is as defined above and X is halogen, with an excess of a basic agent TH
−
(where T=O or S) at a temperature of from 20 to 100° C.
If the basic agent is not employed in excess, but in a stoichiometric amount, this results—under otherwise identical conditions—in an o-nitro(thio)phenol derivative of structure (2) where R*=R. In order to prepare compounds in which the two nitrophenyl groups contain different radicals A
1
to A
3
, correspondingly different halogen-containing nitro compounds are employed.
o-Nitro(thio)phenol derivatives of the structure (2) where R*=H are prepared by reacting an o-nitro(thio)phenol derivative of structure (1) with a compound of the structure
where X is halogen,
and then replacing the halogen X in the o-position to the NO
2
group by TH by reaction with an excess of a basic agent TH
−
(where T=O or S) at a temperature of from 20 to 100° C.
DESCRIPTION OF PREFERRED EMBODIMENTS
The radicals R
1
and R
2
preferably have the following meanings: methyl, ethyl, isopropyl, allyl or methoxymethyl, and phenyl, phenacyl (i.e. C
6
H
5
—CO—CH
2
—), benzyl or benzyloxymethyl.
The metals employed for the selective removal of R
2
are preferably Ni, Se, Rh, Pd, Pt and Hg, and the metal compounds can be salts, organometallic compounds or complex compounds, such as (CH
3
COO)
2
Pd(C
6
H
5
)
3
. The removal is advantageously carried out using Pd/C (palladium/carbon), SeO
2
or HgCl.
The basic agent acts as a source of the anion TH
−
and can be an alkali metal hydroxide, carbonate, or hydrogen carbonate; an alkaline earth metal hydroxide; an aqueous solution of a tertiary or quaternary nitrogen base, such as tetramethylammonium hydroxide; or an aqu
Keitmann Michael
Sezi Recai
Weber Andreas
Greenberg Laurence A.
Infineon - Technologies AG
Lerner Herbert L.
Stemer Werner H.
Vollano Jean F.
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