Functional group transformation of perfluoroadamantane derivatives

Article abstract of DOI:10.1016/j.jfluchem.2006.06.001

An adamantane skeleton, having rigid structure, has been used for a thermally stable and/or anti-etching material. It is expected to be a material having good optical properties, if fluorine atoms are introduced into the skeleton. Thus, the investigation concerning the functional group transformation of perfluoroadamantanecarboxylic acid derivatives was performed to develop the methods for introduction of perfluoroadamantyl group into molecules. Their unique reactivities are also discussed.

Full text of DOI:10.1016/j.jfluchem.2006.06.001

Journal of Fluorine Chemistry 127 (2006) 1125–1129
www.elsevier.com/locate/fluor
Functional group transformation of perfluoroadamantane derivatives
a
a
b,1
Koichi Murata a, , Shu-Zhong Wang , Yoshitomi Morizawa , Kazuya Oharu
*
a Research Center, Asahi Glass Co. Ltd., 1150 Hazawa-cho, Kanagawa-ku, Yokohama 221-8755, Japan
b Chemicals Company, Asahi Glass Co. Ltd., 1150 Hazawa-cho, Kanagawa-ku, Yokohama 221-8755, Japan
Received 28 April 2006; received in revised form 31 May 2006; accepted 2 June 2006
Available online 7 June 2006
Abstract
An adamantane skeleton, having rigid structure, has been used for a thermally stable and/or anti-etching material. It is expected to be a material
having good optical properties, if fluorine atoms are introduced into the skeleton. Thus, the investigation concerning the functional group
transformation of perfluoroadamantanecarboxylic acid derivatives was performed to develop the methods for introduction of perfluoroadamantyl
group into molecules. Their unique reactivities are also discussed.
# 2006 Elsevier B.V. All rights reserved.
Keywords: Adamantane; Perfluorinated compound
1. Introduction
presented monomers containing polyfluoroadamantyl group
and their polymers [18–20].
Adamantane have been attracted for about a century in
academic field, since it shows unusual chemical and physical
properties derived from its highly symmetric caged structure
[1]. Thus, several polymers containing adamantane skeletons
have been synthesized, and some of them have showed good
thermal stability and transparency [2–8]. Moreover, such the
polymers are recently expected to use as highly functional
materials for state-of-the-art industry. For example, they have
been investigated for a couple of decades as material for opto-
electronics [9,10] due to their good optical property and thermal
stability, or as material for photolithography [11–13] due to
their anti-etching property and UV transparency.
Recently, our research group demonstrated that adamantyl
and/or adamantanemethyl perfluoroalkanoates were easily
fluorinated in liquid phase and then eliminated [21,22] to
obtain perfluoroadamantanols and/or perfluoroadamantanecar-
bonyl fluorides, respectively [23]. These results opened up the
way for the industrial scale preparation of perfluorinated
adamantane derivatives.
Herein we report the functional group transformation of
perfluoroadamantanecarboxylic acid derivatives. To apply
these derivatives for industrial materials, it is necessary to
know the reactivity of the functional groups, and to change the
functional groups into desired forms. After that, they can be
introduced in the materials. Throughout the investigation, they
showed unique reactivates, which are discussed hereinafter.
It is expected to be a material having better thermal stability,
transparency and so on, if fluorine atoms are introduced into the
skeleton. However, only a few highly fluorinated adamantane
derivatives are known. Adcock et al. fluorinated several
adamantane derivatives using their aerosol fluorination
technique to obtain perfluorinated adamantyl halides, hydrides
and alcohols [14–17]. A research group in Idemitsu Industries
2. Results and discussion
Pentadecafluoro-1-adamantanecarbonyl fluoride (1) was
used as the starting material in this work. Compound 1 was
prepared by the method according to the patent [23].
2.1. Ester
* Corresponding author. Tel.: +81 45 374 8888; fax: +81 45 374 8643.
The methyl ester 2 was obtained easily by the reaction of 1
with methanol in the presence of sodium fluoride as a base
(Scheme 1).
E-mail address: koichi-murata3@agc.co.jp (K. Murata).
1
Current address: Human Resources Center, Asahi Glass Co. Ltd., 1-12-1
Yuraku-cho, Chiyoda-ku, Tokyo 100-8405, Japan.
0022-1139/$ – see front matter # 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2006.06.001

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K. Murata et al. / Journal of Fluorine Chemistry 127 (2006) 1125–1129
Scheme 1. Synthesis of 2.
Scheme 4. Synthesis of 4.
Table 1
Reaction of 4:
Entry
Reagent
Condition
–X
Yield (%)
1
2
36–38% formalin
CH2 CHCH2Br
75 8C, 6 h
70 8C, 6 h
–CH2OH (5)
–CH CHMe (7)
73
74
Scheme 2. Reaction of 2 with NH3.
The attempt to obtain the amide 3 by the reaction of 2 with
ammonia in THF was unsuccessful. Instead, the hydrofluor-
ocarbon 4 and methyl carbamate were obtained (Scheme 2). It
is suggested that perfluoroadamantyl group is better leaving
group than methoxy group in this case.
ide at 220, and 160 8C in the case of their ammonium salts [29]. It
is supposed that both the steric repulsion between carbonyl group
and perfluoroadamantyl group, and high elimination ability of
perfluoroadamantyl group causes the decarboxylation easily.
Compound 4 seemed to have enough acidity to be
deprotonated. Compound 4 was already prepared and lithiated
by Adcock and Luo [15]. They also prepared 1-iodoperfluor-
oadamantane from 4. Further, Stephens, Tatlow et al. prepared
1H-perfluorobicyclo[2,2,1]heptane and 1H-perfluorobicy-
clo[2,2,2]octane, and transformed them into several derivatives
[25,30–33]. Their pH values were measured as 20.5 and 18.3,
respectively [34]. It was reported that the hydrogen of 1H-
perfluorobicyclo[2,2,1]heptane was subtracted by potassium
hydroxide in aqueous polar solvent, and the formed carboanion
behaved as nucleophile [33]. Thus, we applied the reaction
condition to the reaction of 4 with formalin, and successfully
obtained 5. Compound 4 also reacted with allyl bromide to give
7, the double bond migrated product (Table 1) [35].
Similarly, the reduction of 2 to obtain the methylol 5 was not
successful. Several reductants such as lithium aluminum
hydride, diisobutylaluminum hydride, and sodium borohydride
were applied for the reaction. However, the main product was
not 5 in all the cases (Scheme 3).
2.2. Hydride
Compound 4 was formed instead of the carboxylic acid 6 in
thecase of thereaction of1 with water(Scheme4). Itseemsthat 6
readily loses carbon dioxide at ambient temperature. Cheburkov
and Knunyants reported that perfluoropivaloyl fluoride reacted
similarly [24], though Campbell et al. stated that perfluoro-1-
bicyclo[2,2,1]heptanecarboxylic acid was synthesized [25].
Comparing with other cases, the decarboxylation of linear
perfluoroalkanoic acids was reported to occur at above 400 8C in
gas phase to produce perfluoroolefines (dehydrofluorination
occurred simultaneously) [26]. LaZerte et al. reported that their
potassium salts were decarboxylated above 170 8C in ethylene
glycol [27]. Perfluorocyclohexanecarboxylic acid was reported
to be distillated at 170 8C (740 mmHg), and released carbon
dioxide and hydrogen fluoride in gas phase at 550 8C to produce
perfluorocyclohexene [28]. According to Howell et al., tetra-
fluoro-2-perfluoroalkoxypropanoic acids released carbon diox-
2.3. Isocyanate
Commonly, isocyanates are useful substrates because of
their high reactivity. The isocyanate 9 was prepared using
Curtius rearrangement of the azide 8 (Scheme 5) [36].
Further, compound 9 was reacted with nucleophiles under
mild conditions to obtain the amine 10, the carbamate 11 and
the urea 12 (Table 2). Compound 10 has less nucleophilicity
than common amines so that it did not react with acetyl chloride
(NEt3/CH2Cl2, r.t., 22 h) to form the amide.
Scheme 3. Reaction of 2 with reductants.

K. Murata et al. / Journal of Fluorine Chemistry 127 (2006) 1125–1129
1127
Table 2
Reaction of 9 with nucleophiles:
Entry
Nuleophile
Condition
–Y
Yield (%)
1
3
2
H2O
THF, r.t. 5.5 h
R-225a, r.t. 5.5 h
R-225a, r.t. 5 h
–H (10)
–CONHPh (12)
–COOEt (11)
90
82
88
PhNH2
EtOH
a
1,3-Dichloro-1,1,2,2,3-pentafluoropropane.
Scheme 5. Synthesis of 9.
3. Conclusion
dropwise for 50 min. The reaction was exothermic and the
internal temperature raised up to 29 8C. The mixture was stirred
for 22 h at room temperature. The mixture was filtered and the
solvent was evaporated. Distillation in vacuo provided 40.0 g of
2 (86.3 mmol, Y = 86%).
In summary, a series of perfluoroadamantane derivatives
have been synthesized using the acid fluoride 1 as starting
material (Scheme 6). Compound 1 and its derivatives showed
somewhat unusual chemical properties because of the electron-
withdrawing property, the stability and the steric bulkiness of
perfluoroadamantyl group. Thus, unique methods were often
required for the functional group transformation. It is expected
that the methods described in this report will be used for the
development of high performance materials containing per-
fluoroadamantane moiety.
1
2: mp 26–28 8C; bp 81–84 8C/10 mmHg; H NMR (300.4
MHz, CDCl3, d): 4.05 cmꢀ1 (s); 19F NMR (282.7 MHz, CDCl3,
d): ꢀ111.03 cmꢀ1 (m, 6F), ꢀ121.12 cmꢀ1 (m, 6F), ꢀ219.24
cmꢀ1 (m, 3F); IR (neat): 2969.5, 1776.1, 1280.0, 974.2,
964.5 cmꢀ1
.
4.3. 1H-pentadecafluoroadamantane (4) [54767-15-6]
4. Experimental
To a stirred mixture of 27.5 g (61.3 mmol) of 1 and 3.78 g
(90.0 mmol) of sodium fluoride in 100 mL of acetone under
5 8C was added 1.14 g (63.3 mmol) of water dropwise for
10 min. The reaction was exothermic and the internal
temperature raised up to 29 8C. The mixture was stirred for
5 h at 20 8C. The mixture was filtered and the filtrate was dried
over MgSO4, filtered, and freed of solvent in vacuo.
Sublimation at 50 mmHg gave 22.0 g of 4 (54.2 mmol,
Y = 88%) as a white solid.
4.1. General
The boiling point and the melting point of 2 were not
corrected. IR spectra were recorded on a Nicolet Impact 410
spectrometer. 1H NMR (internal TMS) and 19F NMR (internal
CFCl3) were taken on a JEOL AL300 spectrometer. HRMS
were taken at the analytical science division of our research
center. Commercially obtained materials were used as received
unless otherwise noted. All reactions sensitive to oxygen and/or
moisture were conducted under nitrogen atmosphere with
magnetic stirring. Compound 1 was purified by sublimation in
vacuo (heated up to 110 8C at 30 mmHg) before use.
4: sublimed away above 90 8C/50 mmHg; 1H NMR
(300.4 MHz, CDCl3, d): 3.91 cmꢀ1 (dec, J = 5.6 Hz); 19F
NMR (282.7 MHz, CDCl3, d): ꢀ108.73 cmꢀ1 (m, 6F),
ꢀ120.33 cmꢀ1 (dm, J = 276.2 Hz, 3F), ꢀ121.72 cmꢀ1 (dm,
J = 276.2 Hz, 3F), ꢀ219.43 cmꢀ1 (m, 3F); IR (KBr): 2921.2,
2850.6, 1239.5 cmꢀ1
.
4.2. Pentadecafluoro-1-adamantanecarboxylic acid methyl
ester (2) [107376-45-4]
4.4. (Pentadecafluoro-1-adamantane)methanol (5)
To a stirred mixture of 3.90 g (122 mmol) of dry methanol
and 6.35 g (151 mmol) of sodium fluoride in 40 mL of 1,3-
dichloro-1,1,2,2,3-pentafluoropropane (R-225) at 10 8C was
added the solution of 45.2 g (100 mmol) of 1 in 20 mL of R-225
To a stirred solution of 2.03 g (5.00 mmol) of 4 in 50 mL of
dimethyl sulfoxide at 20 8C was added the solution of 1.00 g
(15.2 mmol) of potassium hydoroxide in 10 mL of water. The
internal temperature raised up to 45 8C. Formalin (36–38%,
Scheme 6.

1128
K. Murata et al. / Journal of Fluorine Chemistry 127 (2006) 1125–1129
20 mL) was successively added and the mixture was warmed to
76 8C and stirred for 6 h. The mixture was neutralized by 3 mL
of 6N-HCl, and 150 mL of water was added. The mixture was
extracted with R-225 (1 ꢁ 40 mL). The organic phase was
washed with water twice, dried over MgSO4, filtered, and the
solvent was evaporated. Compound 5 (1.58 g, 3.62 mmol,
Y = 72%) was obtained as a white solid.
4.7. Pentadecafluoro-1-adamantylamine (10)
To a stirred solution of 1.95 g (4.36 mmol) of 9 in 10 mL of
THF at 0 8C was added 0.086 g (4.8 mmol) of water. The
mixture was stirred for 5.5 h at room temperature. The solvent
was evaporated to obtain 1.65 g of 10 (3.92 mmol, Y = 90%) as
a white solid.
5: sublimed away above 62 8C; 1H NMR (300.4 MHz,
CDCl3, d): 1.91 cmꢀ1 (br, 1H), 4.64 cmꢀ1 (s, 2H); 19F NMR
(282.7 MHz, CDCl3, d): ꢀ113.90 cmꢀ1 (m, 6F), ꢀ121.17 cmꢀ1
(m, 6F), ꢀ219.34 cmꢀ1 (m, 3F); IR (KBr): 3359.3, 2975.0,
10: sublimed away above 80 8C; H NMR (300.4 MHz,
1
CDCl3, d): 2.14 cmꢀ1 (br); 19F NMR (282.7 MHz, CDCl3, d):
ꢀ120.14 cmꢀ1 (m, 6F), ꢀ121.27 cmꢀ1 (m, 6F), ꢀ221.11 cmꢀ1
(m, 3F); IR (KBr): 3430.2, 1272.4, 961.3 cmꢀ1; HRMS (EI) m/z
(M+, C10H2F15N+) calcd. 420.9948, found 420.9951.
2917.8, 1271.9, 1234.6, 1022.9, 984.7, 967.9, 905.9 cmꢀ1
;
HRMS (CI) m/z (M + H+, C11H4F15O+) calcd. 437.0023, found
437.0029.
4.8. Ethyl N-(pentadecafluoro-1-adamantyl)carbamate
(11)
4.5. Pentadecafluoro-1-(1-propenyl)adamantane (7)
To a stirred solution of 1.99 g (4.45 mmol) of 9 in 10 mL of
R-225 at 0 8C was added dropwise 0.218 g (4.73 mmol) of dry
ethanol. The mixture was stirred for 5 h at room temperature.
The solvent was removed in vacuo to afford 1.94 g of 11
(3.93 mmol, Y = 88%) as a white solid.
To a stirred solution of 2.03 g (5.00 mmol) of 4 in 50 mL of
dimethyl sulfoxide at 20 8C was added the solution of 1.00 g
(15.2 mmol) of potassium hydroxide in 10 mL of water. The
internal temperature raised up to 40 8C. Allyl bromide (0.68 g,
5.6 mmol) was further added and the mixture was warmed to
70 8C and stirred for 5 h. The mixture was neutralized by 3 mL
of 6N-HCl, and 150 mL of water was added. The mixture was
extracted with R-225 (1 ꢁ 40 mL). The organic phase was
washed with water twice, dried over MgSO4, filtered, and the
solvent was evaporated. Compound 7 (1.65 g, 3.70 mmol,
Y = 74%) was obtained as a white solid.
6: sublimed away above 69 8C; 1H NMR (300.4 MHz,
CDCl3, d): 1.95 cmꢀ1 (dd, J = 1.7, 6.6 Hz, 3H), 5.46 cmꢀ1 (d,
J = 16.5 Hz, 1H), 6.57 cmꢀ1 (dq, J = 6.6, 16.5 Hz, 1H); 19F
NMR (282.7 MHz, CDCl3, d): ꢀ113.68 cmꢀ1 (m, 6F),
ꢀ121.19 cmꢀ1 (m, 6F), ꢀ219.36 (m, 3F); IR (KBr): 3004.9,
2870.9, 1668.4, 1273.3, 957.5, 900.4 cmꢀ1; HRMS (EI) m/z
(M+, C13H5F15+) calcd. 446.0152, found 446.0154.
1
11: sublimed away above 75 8C; H NMR (300.4 MHz,
CDCl3, d): 1.32 cmꢀ1 (t, J = 7.1 Hz, 3H), 4.24 cmꢀ1 (q,
J = 7.1 Hz, 2H), 5.24 cmꢀ1 (br, 1H); 19F NMR (282.7 MHz,
CDCl3, d): ꢀ114.51 cmꢀ1 (m, 6F), ꢀ121.12 (m, 6F),
ꢀ220.67 cmꢀ1 (m, 3F); IR (KBr): 3432.0, 3283.6, 30755,
2996.5, 1756.4, 1555.2, 1276.2, 992.6, 975.6, 958.8,
+
921.2 cmꢀ1; HRMS (CI) m/z (M + H+, C13H7F15NO2 ) calcd.
494.0237, found 494.0249.
4.9. N-(Pentadecafluoro-1-adamantyl)-N0-phenylurea (12)
To a stirred solution of 2.01 g (4.50 mmol) of 9 in 10 mL of
R-225 at 0 8C was added dropwise 0.419 g (4.50 mmol) of
aniline. The mixture was stirred for 5 h at room temperature.
The white solid was participated, which was collected by
filtration and dried in vacuo. Compound 12 (1.98 g, 3.67 mmol,
Y = 82%) was obtained as a white solid.
4.6. Pentadecafluoro-1-isocyanatoadamantane (9)
In a 100-mL four-necked flask equipped with a thermometer,
a dropping funnel and a reflux condenser, are placed a solution
of 3.25 g (50.0 mmol) of previously activated sodium azide in
8 mL of water and 20 mL of FC77 (one of the FluorinertTM
solvent provided by Sumitomo 3M). Then a solution of 18.1 g
(40.1 mmol) of 1 in 20 mL of FC77 (Sumitomo 3 M) was
dropped in with vigorous stirring for 80 min. The internal
temperature should not rise above 5 8C. Stirring was continued
for 1 h with cooling, then for 4 h at room temperature. The
organic layer was separated and dried over MgSO4. The dried
FC77 solution was placed in a flask with a reflux condenser, and
allowed to stand at 80–100 8C till the gas had ceased to evolve
(about 1 h). FC77 was removed in vacuo (ca. 20 mmHg) to
afford 15.7 g of 9 (35.0 mmol, Y = 88%) as a white solid.
9: sublimed away above 50 8C; 19F NMR (282.7 MHz,
CDCl3, d): ꢀ117.13 cmꢀ1 (m, 6F), ꢀ121.06 cmꢀ1 (m, 6F),
ꢀ220.89 cmꢀ1 (m, 3F); IR (KBr): 2276.4, 1277.3, 1244.1,
1
12: sublimed away above 168 8C; H NMR (300.4 MHz,
acetone-d6, d): 3.79 cmꢀ1 (s, 2H), 7.06 cmꢀ1 (m, 1H),
7.31 cmꢀ1 (m, 2H), 7.48 cmꢀ1 (t, J = 7.5 Hz, 2H); 19F NMR
(282.7 MHz, CDCl3, d): ꢀ112.66 cmꢀ1 (m, 6F), ꢀ120.37 cmꢀ1
(m, 6F), ꢀ220.00 cmꢀ1 (m, 3F); IR (KBr): 3345.6, 3103.7,
1692.9, 1564.8, 1501.8, 1447.8, 1273.8, 1028.8, 997.4, 976.2,
958.8, 938.4, 856.5 cmꢀ1
;
HRMS (EI) m/z (M+,
C17H7F15N2O+) calcd. 540.0319, found 540.0316.
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