U.S. patent application number 09/842006 was filed with the patent office on 2001-12-13 for novel ester compounds having alicyclic structure and method for preparing same.
This patent application is currently assigned to Shin-Etsu Chemical Co., Ltd.. Invention is credited to Hasegawa, Koji, Hatakeyama, Jun, Kinsho, Takeshi, Nakashima, Mutsuo, Nishi, Tsunehiro, Tachibana, Seiichiro, Watanabe, Takeru.
Application Number | 20010051742 09/842006 |
Document ID | / |
Family ID | 18640113 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010051742 |
Kind Code |
A1 |
Hasegawa, Koji ; et
al. |
December 13, 2001 |
Novel ester compounds having alicyclic structure and method for
preparing same
Abstract
Ester compounds of formula (1) are useful as monomers to form
base resins for use in chemically amplified resist compositions
adapted for micropatterning lithography. 1 R.sup.1 is H or
C.sub.1-6 alkyl, R.sup.2 is an unsubstituted or halo-substituted
acyl or alkoxycarbonyl group of 1-15 carbon atoms, R.sup.3 is an
acid labile group, k is 0 or 1, and m is an integer from 0 to
5.
Inventors: |
Hasegawa, Koji;
(Niigata-ken, JP) ; Watanabe, Takeru;
(Niigata-ken, JP) ; Kinsho, Takeshi; (Niigata-ken,
JP) ; Nakashima, Mutsuo; (Niigata-ken, JP) ;
Tachibana, Seiichiro; (Niigata-ken, JP) ; Nishi,
Tsunehiro; (Niigata-ken, JP) ; Hatakeyama, Jun;
(Niigata-ken, JP) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD.
SUITE 1400
ARLINGTON
VA
22201
US
|
Assignee: |
Shin-Etsu Chemical Co.,
Ltd.
Tokyo
JP
|
Family ID: |
18640113 |
Appl. No.: |
09/842006 |
Filed: |
April 26, 2001 |
Current U.S.
Class: |
560/116 ;
560/120; 560/126; 560/128 |
Current CPC
Class: |
C07C 67/343 20130101;
C07C 69/732 20130101; G03F 7/039 20130101; C07C 67/343 20130101;
C07C 69/732 20130101 |
Class at
Publication: |
560/116 ;
560/120; 560/126; 560/128 |
International
Class: |
C07C 069/74 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2000 |
JP |
2000-131164 |
Claims
1. An ester compound of the following general formula (1):
11wherein R.sup.1 is hydrogen or a straight, branched or cyclic
alkyl group of 1 to 6 carbon atoms, R.sup.2 is an acyl or
alkoxycarbonyl group of 1 to 15 carbon atoms in which some or all
of the hydrogen atoms on the constituent carbon atoms may be
substituted with halogen atoms, R.sup.3 is an acid labile group, k
is 0 or 1, and m is an integer from 0 to 5.
2. The ester compound of claim 1 having the following general
formula (2) or (3): 12wherein m and R.sup.2 are as defined above,
R.sup.4 is hydrogen or methyl, R.sup.5 to R.sup.8 are independently
selected from straight, branched or cyclic alkyl groups of 1 to 15
carbon atoms, the sum of carbon atoms in R.sup.5, R.sup.6 and
R.sup.7 is at least 4, and Z is a divalent hydrocarbon group of 4
to 15 carbon atoms which forms a ring with the carbon atom to which
it is connected at opposite ends.
3. A method for preparing the ester compound of claim 1 or 2,
comprising the steps of effecting addition reaction of a metal
enolate of acetate of the following formula (5) to a carbonyl
compound of the following formula (4) to form a .beta.-hydroxyester
compound of the following formula (6), and effecting acylation or
alkoxycarbonylation of the hydroxyl group on the
.beta.-hydroxyester compound, 13wherein k, m, R.sup.1 and R.sup.3
are as defined above, M is Li, Na, K, MgY or ZnY, and Y is a
halogen atom.
Description
[0001] This invention relates to novel ester compounds useful as
monomers to form base resins for use in chemically amplified resist
compositions adapted for micropatterning lithography, and a method
for preparing the same.
BACKGROUND OF THE INVENTION
[0002] While a number of recent efforts are being made to achieve a
finer pattern rule in the drive for higher integration and
operating speeds in LSI devices, deep-ultraviolet lithography is
thought to hold particular promise as the next generation in
microfabrication technology. In particular, photolithography using
a KrF or ArF excimer laser as the light source is strongly desired
to reach the practical level as the micropatterning technique
capable of achieving a feature size of 0.3 .mu.m or less.
[0003] The resist materials for use in photolithography using light
of an excimer laser, especially ArF excimer laser having a
wavelength of 193 nm, are, of course, required to have a high
transmittance to light of that wavelength. In addition, they are
required to have an etching resistance sufficient to allow for film
thickness reduction, a high sensitivity sufficient to eliminate any
extra burden on the expensive optical material, and especially, a
high resolution sufficient to form a precise micropattern. To meet
these requirements, it is crucial to develop a base resin having a
high transparency, rigidity and reactivity. None of the currently
available polymers satisfy all of these requirements. Practically
acceptable resist materials are not yet available.
[0004] Known high transparency resins include copolymers of acrylic
or methacrylic acid derivatives and polymers containing in the
backbone an alicyclic compound derived from a norbornene
derivative. All these resins are unsatisfactory. For example,
copolymers of acrylic or methacrylic acid derivatives are
relatively easy to increase reactivity in that highly reactive
monomers can be introduced and acid labile units can be increased
as desired, but difficult to increase rigidity because of their
backbone structure. On the other hand, the polymers containing an
alicyclic compound in the backbone have rigidity within the
acceptable range, but are less reactive with acid than
poly(meth)acrylate because of their backbone structure, and
difficult to increase reactivity because of the low freedom of
polymerization. Additionally, since the backbone is highly
hydrophobic, these polymers are less adherent when applied to
substrates. Therefore, some resist compositions which are
formulated using these polymers as the base resin fail to withstand
etching although they have satisfactory sensitivity and resolution.
Some other resist compositions are highly resistant to etching, but
have low sensitivity and low resolution below the practically
acceptable level.
SUMMARY OF THE INVENTION
[0005] An object of the invention is to provide a novel ester
compound useful as a monomer to form a polymer for use in the
formulation of a photoresist composition which exhibits a high
reactivity and transparency when processed by photolithography
using light with a wavelength of less than 300 nm, especially ArF
excimer laser light as the light source. Another object is to
provide a method for preparing the ester compound.
[0006] The inventor has found that an ester compound of formula (1)
can be prepared in high yields by a simple method, that a polymer
obtained from this ester compound has high transparency at the
exposure wavelength of an excimer laser, and that a resist
composition comprising the polymer as a base resin is improved in
sensitivity and resolution.
[0007] The invention provides an ester compound of the following
general formula (1). 2
[0008] Herein R.sup.1 is hydrogen or a straight, branched or cyclic
alkyl group of 1 to 6 carbon atoms, R.sup.2 is an acyl or
alkoxycarbonyl group of 1 to 15 carbon atoms in which some or all
of the hydrogen atoms on the constituent carbon atoms may be
substituted with halogen atoms, R.sup.3 is an acid labile group, k
is 0 or 1, and m is an integer from 0 to 5.
[0009] Preferably the ester compound has the following general
formula (2) or (3). 3
[0010] Herein m and R.sup.2 are as defined above, R.sup.4 is
hydrogen or methyl, R.sup.5 to R.sup.8 are independently selected
from straight, branched or cyclic alkyl groups of 1 to 15 carbon
atoms, the sum of carbon atoms in R.sup.5, R.sup.6 and R.sup.7 is
at least 4, and Z is a divalent hydrocarbon group of 4 to 15 carbon
atoms which forms a ring with the carbon atom to which it is
connected at opposite ends.
[0011] A method for preparing the ester compound forms another
aspect of the invention, which involves the steps of effecting
addition reaction of a metal enolate of acetate of the following
formula (5) to a carbonyl compound of the following formula (4) to
form a .beta.-hydroxyester compound of the following formula (6),
and effecting acylation or alkoxycarbonylation of the hydroxyl
group of the .beta.-hydroxyester compound. 4
[0012] Herein k, m, R.sup.1 and R.sup.3 are as defined above, M is
Li, Na, K, MgY or ZnY, and Y is a halogen atom.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] The ester compounds of the invention are of the following
general formula (1). 5
[0014] Herein R.sup.1 is hydrogen or a straight, branched or cyclic
alkyl group of 1 to 6 carbon atoms. Exemplary alkyl groups include
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,
tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl, and
cyclohexyl. R.sup.2 is an acyl or alkoxycarbonyl group of 1 to 15
carbon atoms in which some or all of the hydrogen atoms on the
constituent carbon atoms may be substituted with halogen atoms.
Exemplary of R.sup.2 are formyl, acetyl, ethylcarbonyl, pivaloyl,
methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl,
trifluoroacetyl, trichloroacetyl, and 2,2,2-trifluoroethylcarbonyl.
R.sup.3 is an acid labile group. The letter k is 0 or 1, and m is
an integer from 0 to 5 (i.e., 0.ltoreq.m.ltoreq.5), and preferably
from 0 to 3.
[0015] The preferred acid labile group represented by R.sup.3 are
those of the following formulas. 6
[0016] R.sup.5 to R.sup.8 and Z are as defined below.
[0017] Preferred among the ester compounds of formula (1) are ester
compounds of the following general formula (2) or (3). 7
[0018] Herein m and R.sup.2 are as defined above. R.sup.4 is
hydrogen or methyl. R.sup.5 to R.sup.8 are independently selected
from straight, branched or cyclic alkyl groups of 1 to 15 carbon
atoms. The total number of carbon atoms in R.sup.5, R.sup.6 and
R.sup.7 is at least 4. Examples of the straight, branched or cyclic
alkyl groups of 1 to 15 carbon atoms include methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl,
tert-amyl, n-pentyl, n-hexyl, cyclopentyl, cyclohexyl,
cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl,
cyclohexylethyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl,
bicyclo[3.3.1]nonyl, bicyclo[4.4.0]decanyl,
tricyclo[5.2.1.0.sup.2,6]decanyl,
tetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecanyl, and adamantyl. Z
stands for divalent hydrocarbon groups of 4 to 15 carbon atoms,
such as alkylene and alkenylene groups, which each forms a ring
with the carbon atom to which it is connected at opposite ends.
Examples of the rings that Z forms include cyclopentane,
cyclopentene, cyclohexane, cyclohexene, bicyclo[2.2.1]heptane,
bicyclo[4.4.0]decane, tricyclo[5.2.1.0.sup.2,6]dec- ane,
tetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecane, and adamantane.
[0019] Illustrative, non-limiting, examples of the ester compounds
of formula (1) and formulas (2) and (3) are given below. 8
[0020] As seen from the reaction scheme shown below, the ester
compound of formula (1) can be prepared by the first step of
causing a base to act on a corresponding acetate of formula (7)
(where X is hydrogen) or a corresponding haloacetate of formula (7)
(where X is halogen) to form a metal enolate of formula (5) and
effecting nucleophilic addition reaction of the metal enolate to a
carbonyl compound of formula (4) to form a .beta.-hydroxyester
compound of formula (6), and the second step of effecting acylation
or alkoxycarbonylation (or esterification) of the hydroxyl group on
the .beta.-hydroxyester compound. 9
[0021] Herein, k, m, R.sup.1, R.sup.2 and R.sup.3 are as defined
above. X is hydrogen or halogen. M is Li, Na, K, MgY or ZnY, and Y
is halogen.
[0022] In the first step, a base acts on a corresponding acetate
(where X is hydrogen) or a corresponding haloacetate (where X is
halogen) to form a metal enolate, and nucleophilic addition
reaction is effected between the metal enolate and a carbonyl
compound to form a .beta.-hydroxyester compound. The bases used
herein include metal amides such as sodium amide, potassium amide,
lithium diisopropylamide, potassium diisopropylamide, lithium
dicyclohexylamide, potassium dicyclohexylamide, lithium
2,2,6,6-tetramethylpiperidine, lithium bistrimethylsilylamide,
sodium bistrimethylsilylamide, potassium bistrimethylsilylamide,
lithium isopropylcyclohexylamide, and bromomagnesium
diisopropylamide; alkoxides such as sodium methoxide, sodium
ethoxide, lithium methoxide, lithium ethoxide, lithium
tert-butoxide, and potassium tert-butoxide; inorganic hydroxides
such as sodium hydroxide, lithium hydroxide, potassium hydroxide,
barium hydroxide, and tetra-n-butylammonium hydroxide; inorganic
carbonates such as sodium carbonate, sodium hydrogen carbonate,
lithium carbonate and potassium carbonate; metal hydrides such as
boranes, alkylboranes, sodium hydride, lithium hydride, potassium
hydride, and calcium hydride; alkyl metal compounds such as trityl
lithium, trityl sodium, trityl potassium, methyl lithium, phenyl
lithium, sec-butyl lithium, tert-butyl lithium, and ethyl magnesium
bromide; and metals such as lithium, sodium, potassium, magnesium,
and zinc, but are not limited thereto. It is noted that reaction
using haloacetate and zinc is known as Reformatsky reaction.
[0023] In the addition reaction of the carbonyl compound of formula
(4) with the metal enolate of formula (5), 0.8 to 1.5 mol of the
metal enolate is preferably used per mol of the carbonyl compound.
Useful solvents are ethers such as tetrahydrofuran, diethyl ether,
di-n-butyl ether, 1,4-dioxane, ethylene glycol dimethyl ether, and
ethylene glycol diethyl ether and hydrocarbons such as hexane,
heptane, benzene, toluene, xylene and cumene, alone or in admixture
thereof. The reaction temperature and time vary with particular
starting reactants used. In one example where an acetate of formula
(7) wherein X is hydrogen and a strong base such as lithium
diisopropylamide or lithium bistrimethylsilylamide are used, the
preferred reaction conditions include a reaction temperature in the
low range of -80.degree. C. to -30.degree. C. and a reaction time
of about 1/2 to about 3 hours because the metal enolate is
thermally unstable. In another example where a haloacetate of
formula (7) wherein X is halogen and a metal such as zinc or
magnesium are used, it is generally preferred to keep the reaction
temperature in the range of 20 to 80.degree. C. and the reaction
time in the range of about 1 to 20 hours. The reaction conditions
are not limited to these ranges.
[0024] The second step is to esterify the alcoholic hydroxyl group
produced in the first step. The reaction readily proceeds under
well-known conditions. Preferably in a solventless system or in a
solvent such as methylene chloride, toluene or hexane, the
.beta.-hydroxyester compound resulting from the first step, a
corresponding acid anhydride such as acetic anhydride or
trifluoroacetic anhydride, and a base such as triethylamine,
pyridine or 4-dimethylaminopyridine are sequentially or
simultaneously added while heating or cooling the system if
necessary.
[0025] A polymer is prepared using the inventive ester compound as
a monomer. The method is generally by mixing the monomer with a
solvent, adding a catalyst or polymerization initiator, and
effecting polymerization reaction while heating or cooling the
system if necessary. This polymerization reaction can be effected
in a conventional way.
[0026] A resist composition is formulated using as a base resin the
polymer resulting from polymerization of the ester compound.
Usually, the resist composition is formulated by adding an organic
solvent and a photoacid generator to the polymer and if necessary,
further adding a crosslinker, a basic compound, a dissolution
inhibitor and other additives. Preparation of the resist
composition can be effected in a conventional way.
[0027] The resist composition formulated using the polymer
resulting from polymerization of the inventive ester compound lends
itself to micropatterning with electron beams or deep-UV rays since
it is sensitive to high-energy radiation and has excellent
sensitivity, resolution, and etching resistance. Especially because
of the minimized absorption at the exposure wavelength of an ArF or
KrF excimer laser, a finely defined pattern having sidewalls
perpendicular to the substrate can easily be formed. The resist
composition is thus suitable as micropatterning material for VLSI
fabrication.
EXAMPLE
[0028] Synthesis Examples and Reference Examples are given below
for further illustrating the invention. It is not construed that
the invention be limited to these examples.
[0029] Synthesis Examples are first described. Ester compounds
within the scope of the invention were synthesized in accordance
with the following formulation.
Synthesis Example 1
Synthesis of 1-ethylcyclopentyl
3-acetoxy-3-(5-norbornen-2-yl)propionate (Monomer 1)
[0030] First, in a nitrogen atmosphere, 184 g of lithium
bis(trimethylsilyl)amide and 172 g of 1-ethylcyclopentyl acetate
were reacted in 1 kg of dry tetrahydrofuran at -60.degree. C. to
form lithium enolate. Then 122 g of 5-norbornene-2-carbaldehyde was
slowly added, following which the temperature was raised to
-20.degree. C. over one hour, at which reaction was effected. Then
1 kg of a saturated ammonium chloride aqueous solution was added to
stop the reaction, whereupon hexane was added for extraction. The
organic layer was washed with water, dried over anhydrous sodium
sulfate, filtered, and concentrated in vacuum, obtaining an alcohol
intermediate. In 127 g of pyridine in the presence of 6 g of
4-dimethylaminopyridine, the alcohol intermediate was reacted with
123 g of acetic anhydride at 25.degree. C. for 10 hours. Water, 30
g, was added to stop the reaction whereupon hexane was added for
extraction. The organic layer was washed with water, dried over
anhydrous sodium sulfate, filtered, concentrated in vacuum, and
purified by silica gel column chromatography, obtaining 295 g
(yield 92%) of 1-ethylcyclopentyl
3-acetoxy-3-(5-norbornen-2-yl)propionate, designated Monomer 1.
[0031] IR (thin film): .nu.=3059, 2968, 2872, 1740, 1371, 1340,
1238, 1157, 1026, 953 cm.sup.-1
[0032] .sup.1H-NMR of main diastereomer (270 MHz in CDCl.sub.3):
.delta.=0.58 (1H, ddd, J=11.7, 4.9, 2.4 Hz), 0.82 (3H, t, J=5.4
Hz), 1.10-2.15 {(16H, m) including 2.04 (3H, s)}, 2.36 (1H, dd,
J=15.1, 7.3 Hz), 2.52 (1H, dd, J=15.1, 3.8 Hz), 2.61 (1H, m),
2.75-2.85 (2H, m), 4.60 (1H, ddd, J=10.7, 7.3, 3.8 Hz), 5.94 (1H,
m), 6.18 (1H, m).
Synthesis Example 2
Synthesis of 2-methyl-2-butyl
3-acetoxy-3-(5-norbornen-2-yl)propionate (Monomer 2)
[0033] By following the procedure of Synthesis Example 1 except
that 2-methyl-2-butyl acetate was used instead of
1-ethylcyclopentyl acetate, there was obtained 2-methyl-2-butyl
3-acetoxy-3-(5-norbornen-2-yl)propion- ate. Yield 93%.
Synthesis Example 3
Synthesis of 2-ethyl-2-exo-norbornyl
3-acetoxy-3-(5-norbornen-2-yl)propion- ate (Monomer 3)
[0034] By following the procedure of Synthesis Example 1 except
that 2-ethyl-2-exo-norbornyl acetate was used instead of
1-ethylcyclopentyl acetate, there was obtained
2-ethyl-2-exo-norbornyl 3-acetoxy-3-(5-norbornen-2-yl)propionate.
Yield 91%.
[0035] IR (thin film): .nu.=3057, 2966, 2872, 1740, 1371, 1332,
1288, 1238, 1174, 1159, 1132, 1026, 951 cm.sup.-1
[0036] .sup.1H-NMR of main diastereomer (270 MHz in CDCl.sub.3):
.delta.=0.58 (1H, ddd, J=11.2, 4.9, 2.4 Hz), 0.79 (3H, t, J=7.3
Hz), 0.95-2.00 (12H, m), 2.04 (3H, s), 2.10-2.70 (6H, m), 2.75-2.85
(2H, m), 4.60 (1H, m), 5.94 (1H, m), 6.16 (1H, m).
Synthesis Example 4
Synthesis of 1-cyclohexylcyclopentyl
3-acetoxy-3-(5-norbornen-2-yl)propion- ate (Monomer 4)
[0037] By following the procedure of Synthesis Example 1 except
that 1-cyclohexylcyclopentyl acetate was used instead of
1-ethylcyclopentyl acetate, there was obtained
1-cyclohexylcyclopentyl 3-acetoxy-3-(5-norbornen-2-yl)propionate.
Yield 90%.
[0038] IR (thin film): .nu.=3057, 2933, 2854, 1741, 1448, 1371,
1338, 1238, 1155, 1147, 1024 cm.sup.-1
[0039] .sup.1H-NMR of main diastereomer (300 MHz in CDCl.sub.3):
.delta.=0.58 (1H, ddd, J=11.6, 4.7, 2.5 Hz), 0.90-2.00 (21H, m),
2.04 (3H, s), 2.25-2.70 {(4H, m) including 2.36 (1H, dd, J=15.1,
7.4 Hz), 2.51 (1H, dd, J=15.1, 3.6 Hz)}, 2.75-2.85 (2H, m), 4.61
(1H, m), 5.95 (1H, m), 6.18 (1H, m).
Synthesis Example 5
Synthesis of 2-ethyl-2-exo-norbornyl
3-acetoxy-4-(5-norbornen-2-yl)butyrat- e (Monomer 5)
[0040] By following the procedure of Synthesis Example 3 except
that 2-(5-norbornen-2-yl)acetoaldehyde was used instead of
5-norbornene-2-carbaldehyde, there was obtained
2-ethyl-2-exo-norbornyl 3-acetoxy-4-(5-norbornen-2-yl)butyrate.
Yield 90%.
[0041] IR (thin film): .nu.=3057, 2966, 2872, 1741, 1458, 1441,
1373, 1240, 1192, 1171, 1132, 1025 cm.sup.-1
[0042] .sup.1H-NMR of main diastereomer (300 MHz in CDCl.sub.3):
.delta.=0.56 (1H, m), 0.79 (3H, t, J=7.3 Hz), 1.00-2.10 {(18H, m)
including 2.02 (3H, s)}, 2.10-2.30 (2H, m), 2.40-2.60 (3H, m),
2.70-2.85 (2H, m), 5.20 (1H, m), 5.92 (1H, m), 6.11 (1H, m).
Synthesis Example 6
Synthesis of 2-ethyl-2-exo-norbornyl
3-(5-norbornen-2-yl)-3-trifluoroaceto- xypropionate (Monomer 6)
[0043] By following the procedure of Synthesis Example 1 except
that trifluoroacetic anhydride was used instead of acetic
anhydride, there was obtained 2-ethyl-2-exo-norbornyl
3-(5-norbornen-2-yl)-3-trifluoroacetoxyp- ropionate. Yield 85%.
[0044] IR (thin film): .nu.=3061, 2970, 2875, 1786, 1730, 1383,
1358, 1265, 1221, 1167 cm.sup.-1
[0045] .sup.1H-NMR of main diastereomer (300 MHz in CDCl.sub.3):
.delta.=0.60 (1H, m), 0.77 (3H, t, J=6.8 Hz), 0.95-2.00 (12H, m),
2.10-2.25 (2H, m), 2.30-2.90 (6H, m), 4.87 (1H, m), 5.96 (1H, m),
6.23 (1H, m).
Synthesis Example 7
Synthesis of 1-ethylcyclopentyl
3-acetoxy-3-(5-norbornen-2-yl)butyrate (Monomer 7)
[0046] By following the procedure of Synthesis Example 1 except
that 5-acetyl-2-norbornene was used instead of
5-norbornene-2-carbaldehyde, there was obtained 1-ethylcyclopentyl
3-acetoxy-3-(5-norbornen-2-yl)butyr- ate. Yield 80%.
Synthesis Example 8
Synthesis of 1-ethylcyclohexyl
3-acetoxy-3-methyl-4-(5-norbornen-2-yl)buty- rate (Monomer 8)
[0047] The procedure of Synthesis Example 1 was repeated except
that 1-ethylcyclohexyl acetate was used instead of
1-ethylcyclopentyl acetate, and 3-(5-norbornen-2-yl)acetone was
used instead of 5-norbornene-2-carbaldehyde. There was obtained
1-ethylcyclohexyl 3-acetoxy-3-methyl-4-(5-norbornen-2-yl)butyrate.
Yield 81%.
Synthesis Example 9
Synthesis of 8-ethyl-8-exo-tricyclo[5.2.1.0.sup.2,6]decanyl
3-acetoxy-5-(5-norbornen-2-yl)valerate (Monomer 9)
[0048] The procedure of Synthesis Example 1 was repeated except
that 8-ethyl-8-exo-tricyclo[5.2.1.0.sup.2,6]decanyl acetate was
used instead of 1-ethylcyclopentyl acetate, and
3-(5-norbornen-2-yl)propionaldehyde was used instead of
5-norbornene-2-carbaldehyde. There was obtained
8-ethyl-8-exo-tricyclo[5.2.1.0.sup.2,6]decanyl
3-acetoxy-5-(5-norbornen-2- -yl)valerate. Yield 89%.
Synthesis Example 10
Synthesis of 2-ethyl-2-adamantyl
3-acetoxy-5-(5-norbornen-2-yl)valerate (Monomer 10)
[0049] The procedure of Synthesis Example 9 was repeated except
that 2-ethyl-2-adamantyl acetate was used instead of
8-ethyl-8-exo-tricyclo[5.- 2.1.0.sup.2,6]decanyl acetate. There was
obtained 2-ethyl-2-adamantyl
3-acetoxy-5-(5-norbornen-2-yl)valerate. Yield 91%.
Synthesis Example 11
Synthesis of 2-ethyl-2-exo-norbornyl
3-acetoxy-3-methyl-5-(5-norbornen-2-y- l)valerate (Monomer 11)
[0050] The procedure of Synthesis Example 3 was repeated except
that 4-(5-norbornen-2-yl)butanone was used instead of
5-norbornene-2-carbaldeh- yde. There was obtained
2-ethyl-2-exo-norbornyl 3-acetoxy-3-methyl-5-(5-no-
rbornen-2-yl)valerate. Yield 81%.
Synthesis Example 12
Synthesis of 2-(1-adamantyl)-2-propyl
3-acetoxy-6-(5-norbornen-2-yl)hexano- ate (Monomer 12)
[0051] The procedure of Synthesis Example 1 was repeated except
that 2-(1-adamantyl)-2-propyl acetate was used instead of
1-ethylcyclopentyl acetate, and 4-(5-norbornen-2-yl)butyrylaldehyde
was used instead of 5-norbornene-2-carbaldehyde. There was obtained
2-(1-adamantyl)-2-propyl 3-acetoxy-6-(5-norbornen-2-yl)hexanoate.
Yield 90%.
Synthesis Example 13
Synthesis of 2-(2-norbornyl)-2-propyl
3-acetoxy-6-(5-norbornen-2-yl)hexano- ate (Monomer 13)
[0052] The procedure of Synthesis Example 12 was repeated except
that 2-(2-norbornyl)-2-propyl acetate was used instead of
2-(1-adamantyl)-2-propyl acetate. There was obtained
2-(2-norbornyl)-2-propyl 3-acetoxy-6-(5-norbornen-2-yl)hexanoate.
Yield 91%.
Synthesis Example 14
Synthesis of 3-ethyl-3-pentyl
3-acetoxy-3-methyl-6-(5-norbornen-2-yl)hexan- oate (Monomer 14)
[0053] The procedure of Synthesis Example 1 was repeated except
that 3-ethyl-3-pentyl acetate was used instead of
1-ethylcyclopentyl acetate, and 5-(5-norbornen-2-yl)-2-pentanone
was used instead of 5-norbornene-2-carbaldehyde. There was obtained
3-ethyl-3-pentyl 3-acetoxy-3-methyl-6-(5-norbornen-2-yl)hexanoate.
Yield 83%.
Synthesis Example 15
Synthesis of 1-ethylcyclopentyl
3-acetoxy-3-(8-tetracyclo[4.4.0.1.sup.2,5.-
1.sup.7,10]dodecen-3-yl)propionate (Monomer 15)
[0054] The procedure of Synthesis Example 1 was repeated except
that
8-tetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecene-3-carbaldehyde was
used instead of 5-norbornene-2-carbaldehyde. There was obtained
1-ethylcyclopentyl
3-acetoxy-3-(8-tetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]d-
odecen-3-yl)propionate. Yield 92%.
Synthesis Example 16
Synthesis of 1-ethylcyclopentyl
3-tert-butoxycarbonyloxy-3-(5-norbornen-2-- yl)propionate (Monomer
16)
[0055] The procedure of Synthesis Example 1 was repeated except
that di-tert-butyl pyrocarbonate was used instead of acetic
anhydride. There was obtained 1-ethylcyclopentyl
3-tert-butoxycarbonyloxy-3-(5-norbornen-2- -yl)propionate. Yield
85%.
[0056] The structural formulas of Monomers 1 to 16 are shown below.
10
Reference Example
[0057] Polymers were synthesized using the ester compounds obtained
in the above Synthesis Examples and examined for transparency.
[0058] Polymerization reaction was effected between Monomer 1 and
maleic anhydride using the initiator V65 (by Wako Junyaku K.K.),
yielding an alternating copolymer of 1-ethylcyclopentyl
3-acetoxy-3-(5-norbornen-2-yl- )propionate/maleic anhydride. The
polymer was measured for transmittance at a wavelength of 193 nm,
finding 78.0% at a film thickness of 500 nm.
Comparative Reference Example
[0059] For comparison purposes, an alternating copolymer of
tert-butyl 5-norbornene-2-carboxylate/maleic anhydride was measured
for transmittance at a wavelength of 193 nm, finding 55.0% at a
film thickness of 500 nm.
[0060] It was confirmed that polymers resulting from the inventive
ester compounds have very high transparency as compared with prior
art polymers.
[0061] Japanese Patent Application No. 2000-131164 is incorporated
herein by reference.
[0062] Although some preferred embodiments have been described,
many modifications and variations may be made thereto in light of
the above teachings. It is therefore to be understood that the
invention may be practiced otherwise than as specifically described
without departing from the scope of the appended claims.
* * * * *