Amination of octafluoronaphthalene in liquid ammonia. 2,6- and 2,7-Diaminohexafluoronaphthalenes selective preparation

Article abstract of DOI:10.1016/j.jfluchem.2007.11.010

Monoamination of octafluoronaphthalene by liquid ammonia affords 2-aminoheptafluoronaphthalene mainly (isolated yield 85-90%). Diamination of octafluoronaphthalene or amination of 2-aminoheptafluoronaphthalene affords a mixture of isomeric 1,6-, 1,7-, 2,6-, and 2,7-diaminohexafluoronaphthalenes with considerable prevalence of the 2,7-isomer (～70%), thus being the first example of the predominant substitution at position 7 in 2-substituted polyfluoronaphthalenes. The 2,7/2,6 ratio of 2-X-heptafluoronaphthalene (X = ^-NH, NH₂ and NHAc) amination diminishes with the decrease of electron-donating effect of the substituent; 2,7-diaminohexafluoronaphthalene forms in the reactions of 2-aminoheptafluoronaphthalene or octafluoronaphthalene with excess of NaNH₂ in liquid ammonia and 2,6-diaminohexafluoronaphthalene-in the reaction of 2-acetylamidoheptafluoronaphthalene with liquid ammonia followed by acetylamido group hydrolysis. The method of the selective preparation of these diamines based on the reversible transformation of amino group and a convenient technique of their high purity isolation by complexation with crown ether have been elaborated.

Full text of DOI:10.1016/j.jfluchem.2007.11.010

Available online at www.sciencedirect.com
Journal of Fluorine Chemistry 129 (2008) 253–260
www.elsevier.com/locate/fluor
Amination of octafluoronaphthalene in liquid ammonia
2,6- and 2,7-Diaminohexafluoronaphthalenes
selective preparation
Tamara A. Vaganova a, Soltan Z. Kusova, Vladimir I. Rodionov a, Inna K. Shundrina a,
Georgij E. Sal’nikov a, Victor I. Mamatyuk a, Evgenij V. Malykhin a,b,
*
a N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences,
Lavrentiev Avenue 9, 630090 Novosibirsk, Russian Federation
b Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russian Federation
Received 1 October 2007; received in revised form 21 November 2007; accepted 26 November 2007
Available online 4 December 2007
Abstract
Monoamination of octafluoronaphthalene by liquid ammonia affords 2-aminoheptafluoronaphthalene mainly (isolated yield 85–90%).
Diamination of octafluoronaphthalene or amination of 2-aminoheptafluoronaphthalene affords a mixture of isomeric 1,6-, 1,7-, 2,6-, and 2,7-
diaminohexafluoronaphthalenes with considerable prevalence of the 2,7-isomer (ꢀ70%), thus being the first example of the predominant
substitution at position 7 in 2-substituted polyfluoronaphthalenes. The 2,7/2,6 ratio of 2-X-heptafluoronaphthalene (X = ÀNH, NH2 and NHAc)
amination diminishes with the decrease of electron-donating effect of the substituent; 2,7-diaminohexafluoronaphthalene forms in the reactions of
2-aminoheptafluoronaphthalene or octafluoronaphthalene with excess of NaNH2 in liquid ammonia and 2,6-diaminohexafluoronaphthalene—in
the reaction of 2-acetylamidoheptafluoronaphthalene with liquid ammonia followed by acetylamido group hydrolysis. The method of the selective
preparation of these diamines based on the reversible transformation of amino group and a convenient technique of their high purity isolation by
complexation with crown ether have been elaborated.
# 2007 Elsevier B.V. All rights reserved.
Keywords: Octafluoronaphthalene; Diaminohexafluoronaphthalenes; Liquid ammonia; Aminodefluorination; Nucleophilic substitution; Regioselectivity
1. Introduction
perfluoro-2,6-diphenylnaphthalene [6]), while 2,7-isomers have
not been isolated at all. Diamination of 1 has not been reported,
though polyfluoroaromatic diamines and diaminohexafluoro-
naphthalenes in particular are prospective monomers for
condensation polymers, whose physicochemical characteristics
depend strongly on the framework as well as presence of fluorine
atoms [9].
The known reactions of octafluoronaphthalene (1) with both
charged and neutral nucleophiles [1,2] proceed mainly by
fluorine displacement at the b-carbon atom (b/a > 9/1).
Nucleophilic substitution in b-X-heptafluoronaphthalenes or
insertion of two substituents into 1 results in the mixture of b,b-
disubstituted isomers with the 2,6 being predominant (>75%)
[3–8]. Only some of the individual 2,6-disubstituted hexafluor-
onaphthalenes have been reported (2-methoxy-6-thiomethox-
yhexafluoronaphthalene [3], 2-methoxy-6-piperidinohexa-
fluoronaphthalene [4], 1,3,4,5,7,8-hexafluoronaphthalene [5],
We have shown [10] the use of liquid ammonia as a reagent/
medium system provides for selective preparation of mono- and
diaminopolyfluoro(get)arenes with high purity and yields. The
present work goals are (i) the investigation of the direct
amination of 1 by liquid ammonia or its solutions as the shortest
route to diaminohexafluoronaphthalenes; (ii) the development
of the methods for 2,6- and 2,7-diaminohexafluoronaphthalenes
selective preparation based on the reversible transformation of
2-aminoheptafluoronaphthalene (2a); (iii) the elaboration of the
procedure for product isolation and purification based on
complexation with crown ether.
* Corresponding author at: N.N. Vorozhtsov Novosibirsk Institute of Organic
Chemistry, Siberian Branch of the Russian Academy of Sciences, Lavrentiev
Avenue 9, 630090 Novosibirsk, Russian Federation. Fax: +7 383 3309752.
E-mail address: malykhin@nioch.nsc.ru (E.V. Malykhin).
0022-1139/$ – see front matter # 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2007.11.010

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T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
Table 1
Experimental conditions and product yields for reactions of octafluoronaphthalene (1) with amination reagents
Entry
Reactant amounts
Reaction conditions
Product
mixture
yields (g)
Product mixture composition (%, GC data)a
Product isolated yields
(g/% calculated to 1);
purification method
1 (g)
NH3 (ml)
Temperature
Time
1
2a
2b
3a
3b
3c
3d
(8C, Æ5)
(h)
1
10.0
10.0
5.0
50 (liq)
50 (liq)
30 (aq)
30 (aq)
60 (aq)
30 (aq)
30 (liq)
80 (liq)
80 (liq)
15
90
9
24
5
9.5
8.0
4.8
4.7
8.6
4.7
4.6
1.9
1.8
95
1
2
<1
71
2
2a 8.5/87; crystallization
3a + 3b (9:1) 6.2/63; complexation
2
12
<1
1
10
3
3
120
120
130
110
90
19
5
72
81
6
6
4
5.0
8
5
2a 3.0/61; complexation
3a + 3b (7:2) 5.9/60; complexation
5b
6c
7c
8d
9e
10.0
5.0
48
5
62
1
16
8
7
4
3
2
81
45
64
9
5.0
5
4
1
31
5
2.0
À55
0.15
2a 1.0/52; sublimation
3a 1.1/55; complexation
2.0
À55
1
72
a
Average values from the results of at least three experiments, the error for the main products does not exceed 2%.
b
c
The product mixture contains three additional diaminopentafluoronaphthalenes ꢀ7% in total (M 248, GC–MS data).
EtOH (30 mL) was used as co-solvent. The product mixture contains additional isomeric aminoethoxyhexafluoronaphthalenes ꢀ5% in total (M 295, GC–MS
data).
d
Na (0.35 g) was used for NaNH2 preparation (NaNH2/1 mole ratio = 2). The product mixture also contains N,N-bis(heptafluoro-2-naphthyl)amine, 7% (M 521), 2-
amino-7-(N-heptafluoro-2-naphthylamino) naphthalene, 8% (M 518) (GC–MS data), and non-volatile compounds (ꢀ20%).
e
Na (0.85 g) was used for NaNH2 preparation (NaNH2/1 mole ratio = 5). The product mixture also contains non-volatile compounds (ꢀ25%).
2. Results and discussion
fluoronaphthalenes is ꢁ96%, at that 2,7-diaminohexafluor-
onaphthalene (3a) is the major product. The proportions of 2,6-
diaminohexafluoronaphthalene (3b) and 1,6-diaminohexafluor-
onaphthalene (3c) in the product mixture are considerably
lower, and the minor product is 1,7-diaminohexafluoronaphtha-
lene (3d). Aminodefluorination of 2a affords the same result
(Entry 1, Table 2), i.e. the ratio of diamines 3a–d does not
depend on the identity of starting compound (1 or 2a). Isomeric
diamines 3a–d obtained for the first time have been isolated and
characterized.
2.1. Amination of octafluoronaphthalene by liquid
ammonia and its solutions
The processes were carried out in a steel autoclave under
pressure to keep ammonia as a liquid up to ꢀ120 8C
(tcritNH3 = 1328C [11]). Both mono- and diamination of 1 by
liquid ammonia can be realized selectively due to the large
difference in temperature conditions required (Entries 1 and 2,
Table 1, Scheme 1). Proportion of b/a substitution in
monoamination of 1 is 95/2, and so the major product – 2a
– has been isolated from the product mixture with yield >85%
by crystallization. Thus, this mode of 2a preparation has a clear
advantage towards the known method (via amination of 1 by
aqueous-ethanolic ammonia), which is characterized by low
yield (44%) [4].
Aqueous or ethanolic ammonia are widespread amination
systems for polyfluoroarenes in spite of their lower efficiency as
compared with liquid ammonia ([10] and references therein)
caused by hydrogen bonding [12]. Actually, amination of 1 by
aqueous ammonia occurs at harder conditions. The reaction
becomes efficient only at 120 8C, however under this
temperature, mono- and diamination processes cannot be
separated. Thus, diamination is appreciable at 80% conversion
of 1 (Entry 3, Table 1), and an increase of the reaction duration
Under the optimal conditions of 1 bis-aminodefluorination
(Entry 2, Table 1, Scheme 1) content of isomeric diaminohexa-
Scheme 1.

T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
255
Table 2
Experimental conditions and product yields for reactions of 2a and 2c with amination reagents
Entry
Reactant amounts
Reaction conditions
Product
mixture
yields (g)
Product mixture composition
(%, GC data)a
Product isolated yields
(g/% calculated to 1);
purification method
2a/2c (g)
NH3 (ml)
Temperature
Time
(h)
3a
3b
3c
3d
(8C, Æ5)
1
2a (2.0)
2a (2.0)
2a (2.0)
2c (5.0)
30 (liq)
30 (aq)
90
130
À40
50
15
45
1
1.9
1.9
1.9
3.9c
76
64
93
16
11
15
8
10
4
<1
5
2
3b
100 (liq)
50 (liq)
3a 1.6/82; complexation
3b 2.0/47; complexation
4
8
76
1
3
a
Average values from the results of at least three experiments, the error for the main products does not exceed 2%.
Na (0.69 g) was used for NaNH2 preparation (NaNH2/1 mole ratio = 4).
Weight of the product mixture obtained by acetamido group hydrolysis; mixture weight before hydrolysis was 4.9 g.
b
c
results in the accumulation of diamines simultaneously with
experimentally determined. The proportion of the major isomer
3a in the product mixture has been shown to increase with
temperature decrease (Table 3). This indicates the regioselec-
tivity of aminodefluorination in the given temperature interval
is controlled by enthalpy of activation, the formation of 3a
being enthalpically preferred than that of 3b or 3c. Assuming
that the differences of solvation terms contributing to the
enthalpy are negligible [5,12], we conclude the aminodefluor-
ination regioselectivity of 1 is controlled by intrinsic structural
features of the transition state (TS), namely by the electronic
effects of substituents.
amination of 1 (Entry 4, Table 1). It should be noted that the b/a
ratio of nucleophilic attack on 1 diminishes when liquid NH3 is
replaced by aqueous NH3. Complete diamination of 1 or
amination of 2a by aqueous ammonia (Entry 5, Table 1 and Entry
2, Table 2 correspondingly) results in the decreased proportion of
3a in the product mixture as compared with the reaction in liquid
ammonia. Together with diaminohexafluoronaphthalenes 3a–d,
three isomeric diaminopentafluoronaphthalenes were found.
Formation of hydrodehalogenation products is typical for the
reactions of polyfluoroarenes in aqueous ammonia at high
temperature and occurs under the action of the reactor material
(steelautoclave)andwater[13]. Monoaminationof1 inaqueous-
ethanolic ammonia is somewhat more effective (compare Entries
6 and 3, Table 1). At the same time the contribution from a-
amination increases by ꢀ1.5 times. Moreover, hexafluoro-
naphthalenes containing NH2 and OEt groups are found in the
product mixture. In liquid ammonia/ethanol mono- and
disubstituted products form in equal amounts even at lower
temperature (compare Entries 6 and 7, Table 1), thus testifying to
the considerably higher reaction rate in anhydrous medium.
However, the product mixture also contains aminoethoxyhexa-
fluoronaphthalenes. The formation of hydro- and ethoxyde-
fluorination products of 1 when reaction is carried out in
ammonia/water or ammonia/ethanol mixtures reduces the
preparative value of these amination systems.
Predominance of b-replacement in nucleophilic reactions of
1 and its derivatives is rationalized by the activating electronic
effect of two ortho-fluorines versus one in a-replacement
[5,14]. However this effect was shown [14,15] to reduce with
decrease of polyfluoroarene electrophilicity followed by the
shift of TS to the intermediate. In going from 1 to 2a the
substrate reactivity decreases (compare temperatures in Entries
1, Table 1 and Table 2 correspondingly), therefore, orientation
of 2a amination depends on ortho-fluorine effect to a lesser
degree. It provides the increase of a-replacement shown by the
value (3a + 3b)/(3c + 3d) = 83/13 versus 2a/2b = 95/2.
The values 3a/3b (2,7/2,6) for b-replacement and 3c/3d (1,6/
1,7) for a-replacement in 2a are both >1 and indicate the
predominant replacement at pseudo-meta positions to amino
group. Thus, the regioselectivity of the both routes is in
agreement with a stronger electron-donating effect of pseudo-
para-located NH2 group relative to fluorine. On the other hand,
the reaction of 1 with cyclic amines results in pseudo-para (2,6)
replacement mainly [4]. There is an analogy in a benzene
series; in the reactions of pentafluoroaniline, pentafluoro-N-
methylaniline and pentafluoro-N,N-dimethylaniline with N-
nucleophiles the meta/para ratio decreases from 7 to 0.07 [16].
A rationalization of these results is based on the conception of
b-Aminodefluorination of 1 by NH3 ([4] and this work) is
typical for nucleophilic substitution in this substrate [1,2].
Predominance of 2,7 over 2,6 replacement as well as realization
of a-replacement in remote ring (1,6 and 1,7) are found for the
first time. Obviously it is caused by a difference between
electronic effects of fluorine, NH2 group, and other sub-
stituents. To conform this assumption temperature dependence
of the regioselectivity of 1 diamination by liquid NH3 has been
Table 3
Temperature dependence of 3a/3b and 3a/3c ratios in the reaction of 1 with liquid NH3
Entry
Temperature
Time (h)
Product mixture composition (%, GC-MS data)
3a/3b ratio
3a/3c ratio
(8C, Æ5)
S aminoheptafluoro naphthalenes 2
S diaminohexafluoro naphthalenes 3
1
2
3
90
70
50
15
24
14
50
14
82
49
85
5.6
6.5
9.9
5.1
6.2
100
12.8

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T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
steric inhibition of electron-donating resonance effect by the
interaction of bulky substituent NR2 with ortho-fluorines. In
total these facts indicate NR2 group is a weaker electron-donor
versus NH2 and fluorine. Thus, the regioselectivity of
nucleophilic substitution in 2-X-heptafluoronaphtalenes is
determined by the substituent electronic effect. Taking into
account this regularity we have developed methods governing
the orientation of aminodefluorination of 2a based on the
reversible transformations of the substituent.
preparation than amination of 1 by NH3. The competition of
amide and naphthylamide 4 anions as nucleophiles reacting
with 1 was changed in favor of the former by using a fivefold
excess. In these conditions the process cannot be interrupted at
2a formation, and diamines 3a and 3c (3a/3c = 18/1) formed in
total yield ꢀ75% (Entry 9, Table 1). Thus, one-pot synthesis of
3a directly from 1 can be realized due to the use of the excess of
amide anion as aminating reagent.
Decrease of pseudo-meta-replacement in 2a could be
achieved by acylation of amino group weakening its
electron-donating effect and increasing spatial inhibition of
resonance. Similar method was used for tetrafluoro-para-
phenylenediamine preparation by the reaction of hexafluor-
obenzene with potassium phthalimide [19].
2.2. Selective preparation of 2,7- and 2,6-
diaminohexafluoronaphthalenes
Reactions of pentafluoroanisole with nucleophiles result in
para-replacement of fluorine [17], whereas hydroxylation of
pentafluorophenol by KOH/t-BuOH or H2O [17,18] provides
meta-replacement exclusively. It is caused by ionization of
pentafluorophenol hydroxyl group being accompanied by
substantial increase of its electron-donating effect. Accordingly
the predominant pseudo-meta-replacement in 2a is expected to
become exclusive due to ionization of NH2 group, which can be
carried out in liquid ammonia by the action of NaNH2 on 2a
with formation of sodium heptafluoronaphthylamide (4).
Interaction of 2a with four equivalents of NaNH2 in NH3 at
À55 8C in open glass vessel affords products of amination at
pseudo-meta-positions, the formation of 3a over 3c being
overwhelming (Scheme 2, Entry 3, Table 2). Thus both
negatively charged substituent in amide 4 and nucleophile
suppress the pseudo-para-amination. In addition, the extent of
b-amination increases as against the reaction of 2a with
ammonia (compare 3a/3c ratio, Entries 3 and 1, Table 2).
Obviously it is caused by a shift of TS to the reagent-like state
owing to the considerable reaction acceleration in going from
neutral (NH3) to charged (NH2À) nucleophile (compare
temperatures, Entries 1 and 3, Table 2). According to these
data the pathway to the less reactive substrate – 4 versus 2a –
affects the reaction rate to a lesser degree.
The interaction of 2-acetamidoheptafluoronaphthalene (2c)
with liquid ammonia affords four isomeric amines with 2-
acetamido-6-aminohexafluoronaphthalene (5) being predomi-
nant. After hydrolysis of the reaction mixture, b,b-diamines 3a
and 3b have been obtained as the main products (Scheme 2,
Entry 4, Table 2). Their ratio (3a/3b = 1/5) testifies to the
preference of pseudo-para-replacement in 2c amination as
against pseudo-meta in 2a amination (3a/3b = 7/1, Entry 1,
Table 2). Besides the ratio of b/a-replacement products has
been enlarged in going from 2a to 2c ((3a + 3b)/(3c + 3d) is 9
and 23, Entries 1 and 4 respectively, Table 2). It can be provided
by increase of the substrate electrophilicity following by
enhancement of ortho-fluorines activating effect.
Thus, orientation of amination of 2a can be governed by the
reversible modification of amino group strengthening or
weakening its p-donating effect.
2.3. Isolation and structure determination of mono- and
diamines
Utilization of direct amination of fluorinated arenes is
limited by the complexity of isomeric mono- and/or diamine
separation by means of traditional methods. We have elaborated
an effective technique of individual polyfluorophenylenedia-
mine isolation from their mixtures [10]. This technique is based
on selective complexation of polyfluoroaromatic amines with
crown ether, and subsequent decomposition of the complexes
obtained by water.
In order to explore the possibility of sodium amide
utilization for the synthesis of 2a and one-pot synthesis of
3a, the interaction of 1 with NaNH2 has been investigated.
Complete conversion of 1 is achieved by the action of 2.1
equivalent of NaNH2 (Entry 8, Table 1), but in addition to 2a the
product mixture contains N,N-bis(heptafluoro-2-naphthyl)a-
Using this approach, some products of mono- and
diamination of 1 have been isolated effectively (ꢁ80% upon
their proportion in the mixture) and with rather high purity.
Thus, 2a has been isolated by complexation with 18-crown-6
from the product mixture of unselective amination of 1 by
aqueous ammonia (Entry 4, Table 1). Similarly diamine 3a has
been purified from 3c (Entry 3, Table 2). Using crown ether in
deficiency to the total amount of diamines 3a–d (Entry 4,
mine
and
2-amino-7-(N-heptafluoro-2-naphthylamino)-
naphthalene, as well as nonvolatile compounds. This result
is evidence for the reaction of 1 with NaNH2 to afford 2a,
followed by its ionization to amide 4, which competes with
NaNH2 in the interaction with highly electrophilic 1. The
formation of considerable amount of by-products in the
reaction of 1 with NaNH2 makes it less effective for 2a
Scheme 2.

T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
257
Table 4
19F NMR spectroscopic data for diamines 3a–3d
Diamine
Solvent
19F NMR chemical shifts, CFCl3, d (ppm)
Coupling constants, J (Hz)
3a
Chloroform-d
J(1,3) = J(6,8) = 4.0
J(1,4) = J(5,8) = 17.2
J(1,5) = J(4,8) ꢀ 0
J(1,6) = J(3,8) = À7.2
J(1,8) = 55.0
J(3,4) = J(5,6) = À17.2
J(3,5) = J(4,6) = 4.2
J(3,6) ꢀ 0
J(4,5) = 54.8
3b
Chloroform-d
J(1,3) = J(5,7) = 4.1
J(1,4) = J(5,8) = 15.7
J(1,5) = 1.9
J(1,7) = J(3,5) = 8.6
J(1,8) = J(4,5) = 56.0
J(3,4) = J(7,8) = À17.0
J(3,7) = 7.3
J(3,8) = J(4,7) = À3.6
J(4,8) = 1.6
3c
Chloroform-d
J(2,3) = À20.0
J(2,4) = 4.3
J(2,5) = À4.2
J(2,7) = À2.3
J(2,8) = 3.5
J(3,4) = À19.1
J(3,5) = 3.8
J(3,7) = 7.7
J(3,8) = À3.4
J(4,5) = 61.6
J(4,7) = À4.2
J(4,8) = 0.7
J(5,7) = 7.8
J(5,8) = 14.8
J(7,8) = À17.2
3d
Acetone-d6
J(2,3) = À19.6
J(2,4) = 3.8
J(2,5) = À3.8
J(2,6) = 6.9
J(2,8) = 3.8
J(3,4) = À19.3
J(3,5) = 3.9
J(3,6) = À5.0
J(3,8) ꢀ À2.5
J(4,5) = 59.5
J(4,6) = 5.0
J(4,8) ꢀ 0.7
J(5,6) = À17.0
J(5,8) = 14.5
J(6,8) = 6.7
Table 2) allows the isolation of the main component of the
mixture—diamine 3b. Complexation of the diamine mixtures
obtained in Entries 2 and 5, Table 1, Entries 1 and 2, Table 2,
was used for isolation of the mixtures of b,b-diamines
(3a + 3b) and a,b-diamines (3c + 3d).
some 2,6-disubstituted hexafluoronaphthalenes, 2,7-isomers
have been characterized in mixtures with 2,6 isomers by 19F
NMR spectroscopy; 1,6- and 1,7-disubstituted hexafluoro-
naphthalenes have been unknown. For novel individual
diamines 3a–3d comprehensive physical and spectroscopic
data were obtained. Location of the substituents was
determined by 19F NMR spectra simulation; the spectral
As was noted above data about 1 derivatives containing the
substituents in both rings are limited to characteristics of

258
T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
parameters of diamines 3a–3d are given in Table 4. Assign-
ments and numeric values of the chemical shifts and spin–
spin coupling constants are in agreement with the known data
for 1 derivatives [3–7].
3.3. Synthetic procedures
3.3.1. 2-Acetamidoheptafluoronaphthalene (2c)
It was obtained in 87% yield through acylation of 2a by
acetic anhydride in benzene. Mp 210-211 8C. IR (KBr): n 3210
(NHAc), 1690 cmÀ1 (Ac); 1H NMR (acetone-d6): d 2.22 (s, 3H,
Me), 9.36 (br.s, 1H, NH); 19F NMR (188.28 MHz, acetone-d6):
d À156.7 (t, 1F, J = 17, F7), À155.4 (t, 1F, J = 17, F6), À149.3
(dt, 1F, J = 57, J = 17, F4), À147.0 (dt, 1F, J = 57, J = 17, F5),
À145.5 (dt, 1F, J = 66, J = 17, F8), À139.3 (d, 1F, J = 17, F3),
À125.5 (dt, 1F, J = 66, J = 17, F1); HRMS calcd. for
C12H4OF7N: 311.0181, found: 311.0180.
3. Experimental
3.1. Materials
The following commercial products were used, octafluor-
onaphthalene (99%), aqueous NH3 28% (d 0.9 g LÀ1),
18-crown-6, tert-butyl methyl ether (t-BuMeO), plates
Kieselgel 60 F254 (Merck). Liquid NH3 was used without
purification for the reaction in autoclave, and was purified by
distillation from NaNH2 suspension for the reaction in the
open vessel.
3.3.2. Typical procedure for the reaction of 1, 2a and 2c
with liquid or aqueous NH3
A steel autoclave was charged with substrate and the
necessary quantity of liquid or aqueous NH3, reaction mixture
was heated up to the given temperature upon stirring by rotation
of autoclave and kept under these conditions for the necessary
time. On completion, the autoclave was cooled, NH3 was
evaporated and products were extracted with t-BuMeO. The
extract was dried with MgSO4, the solvent was evaporated. The
product mixture was purified by sublimation in vacuum and
analyzed by NMR, GC, GC–MS. Reactant amounts, reaction
conditions, yields and compositions of product mixtures are
listed in Tables 1–3. Methods of isolation of compounds
obtained for the first time are given in Sections 3.3.5 and 3.3.6.
By amination of 2c (Entry 4, Table 2) mixture of isomeric
acetamidoaminohexafluoronaphthalenes (96%, GC–MS and
NMR 19F) was obtained. The major component is 2-acetamido-
6-aminohexafluoronaphthalene (5), which has the followed
signals in 19F NMR spectrum of the mixture (188.28 MHz,
acetone-d6): d À152.8 (dm, 1F, J = 56, F5), À152.6 (m, 1F, F7),
À150.0 (dm, 1F, J = 64, F8), À147.1 (dm, 1F, J = 56, F4),
À143.0 (m, 1F, F3), À127.4 (dm, 1F, J = 64, F1).
3.2. General
1H and 19F NMR spectra were recorded on NMR
spectrometers Bruker AC-200 (200.13 and 188.28 MHz for
1H and 19F correspondingly) and AV-300 (300.13 and
282.36 MHz for 1H and 19F correspondingly) using TMS
and C6F6 (d = À163 ppm from CCl3F) as internal standards; d
are given in ppm relative to CCl3F, J are given in Hz. The 2D
phase sensitive 19F-19F COSY spectra were recorded for the
unambiguous assignment of the multiplet splittings. For
spectra simulation the program package Xsim/NUMMRIT
[20] and the data on the coupling constants in spectrum of
octafluoronaphthalene [21] were used. The numeric values of
the chemical shifts dF and spin-spin coupling constants JF-F
were determined via iterative simulation procedure to fit the
data to the experimental spectra. IR spectra were recorded on
Bruker Vector-22 instrument. UV spectra were recorded on
Fourier spectrometer HP 8453. The precise molecular
weights of ions were determined by high resolution mass
spectrometry on Finnigan MAT-8200 instrument. GC-MS
identification of mixture components was performed using
Hewlett Packard G1081A equipment comprising an HP 5890
Series II gas chromatograph and an HP5971 mass selective
detector; electron ionization energy of 70 eV; HP5 column
(5% of biphenyl and 95% of dimethylsiloxane),
30 m  0.25 mm  0.25 mm; with helium as carrier gas,
flow rate 1 mL minÀ1; column temperature programming
from 50 8C (2 min) at an increment of 10 8C minÀ1 to 280 8C
(5 min); injector temperature 280 8C; ion source temperature
173 8C; data acquisition rate 1.2 scan sÀ1 in the mass range
30–650 amu. Analyses of product mixtures and purity of
products were performed on HP 5890 Series II gas
chromatograph (thermo conductivity detector); HP5 column
(5% of biphenyl and 95% of dimethylsiloxane),
30 m  0.22 mm  2.6 mm; with helium as carrier gas, flow
rate 1 mL minÀ1; column temperature programming from
90 8C (2 min) at an increment of 10 8C minÀ1 to 330 8C
(5 min); injector temperature 300 8C; detector temperature
320 8C.
3.3.3. Typical procedure for the reaction of 1 and 2a with
NaNH2 in liquid NH3
To liquid NH3 in open glass vessel at À60 8C upon stirring
was added Na and, after a dark blue solution was formed, FeCl3
(catalytic amount); the mixture was stirred until discoloration.
To a suspension of NaNH2 thus obtained, substrate was added
and the mixture was stirred at the given temperature for the
necessary time. NH4Cl (2 g) was added to the reaction mixture
and NH3 was evaporated. Products were extracted from the
solid residue with t-BuMeO and solvent was evaporated.
Product mixture was analyzed as described above. Reactant
amounts, reaction conditions, yields and compositions of
product mixtures are listed in Tables 1 and 2.
3.3.4. Hydrolysis of 2c amination products
To the product mixture (4.9 g, Entry 4, Table 2) water (6 ml)
and 35% aqueous solution of NaOH (20 ml) were added, and
the reaction mixture was stirred under reflux for 3 h. The
reaction mixture was diluted with water; the precipitate was
filtered, washed with water and dried. The mixture of
diaminohexafluoronaphthalenes (3.9 g) was obtained.

T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
259
3.3.5. Mono- and diamine isolation by complexation with
18-crown-6
evaporated. The mixture of diamines 3c and 3d thus obtained
was separated by thin-layer chromatography, eluent hexane–
ethyl acetate (4:1 by volume).
3.3.5.1. 2-Aminoheptafluoronaphthalene (2a). Product mix-
ture (4.7 g, 17 mmol) (Entry 3, Table 1) was refluxed in pentane
(100 mL) for 0.5 h and the undissolved residue was filtered
(0.3 g, diaminohexafluoronaphthalenes 3a–3d). To the filtrate a
solution of 18-crown-6 (2.1 g, 8 mmol) in pentane (15 mL) was
added and the mixture was stirred for 1 h. The precipitate
formed was filtered, washed with pentane and dried. Complex
of amine 2a with 18-crown-6 (4.5 g) was obtained. The
complex was shaken with a mixture of t-BuMeO (25 mL) and
water (25 mL). The organic layer was washed with water (4Â
20 mL), dried with MgSO4 and the solvent was evaporated.
Amine 2a (3.0 g, 11 mmol, GC purity 98%) was obtained. Yield
61%, mp 73–74 8C; literature [22]; mp 70–71 8C.
1,6-Diaminohexafluoronaphthalene (3c) (Rf 0.49). GC
purity: 94%, mp 195–200 8C (decompos.). UV (EtOH): lmax
(log e) 230 (2.9), 254 (2.6), 304 (0.6), 349 (0.4) nm; IR (KBr): n
1
3509 and 3397 cmÀ1 (NH2); H NMR (chloroform-d): d 4.09
(br.s, C6NH2), 4.53 (br.s, C1NH2); 19F NMR see Table 4;
HRMS calcd. for C10H4F6N2: 266.0279, found: 266.0277.
1,7-Diaminohexafluoronaphthalene (3d) (Rf 0.31). GC
purity: 98%, mp 200–202.5 8C. UV (EtOH): lmax (log e)
224 (2.0), 249 (1.8), 316 (0.6) nm; IR (KBr): n 3498 and
3428 cmÀ1 (NH2); 1H NMR (chloroform-d): d 4.02 (br.s,
C7NH2), 4.50 (br.s, C1NH2); 19F NMR see Table 4; HRMS
calcd. for C10H4F6N2: 266.0279, found: 266.0285.
3.3.5.2. 2,7-Diaminohexafluoronaphthalene (3a). To a solu-
tion of diamines 3a and 3c (Entry 3, Table 2) (1.9 g, 7 mmol) in
t-BuMeO (10 mL) a solution of 18-crown-6 (1.8 g, 6.8 mmol)
in t-BuMeO (10 mL) was added. The mixture was stirred at
room temperature for 1 h. The precipitate formed was filtered,
washed with t-BuMeO and dried. A complex of diamine 3a
with 18-crown-6 (3.2 g) was obtained. The complex was
shaken up with a mixture of t-BuMeO (30 mL) and water
(30 mL). The organic layer was washed with water (4Â
20 mL), dried with MgSO4, and solvent was evaporated.
2,7-Diaminohexafluoronaphthalene (3a) (1.6 g, 6 mmol, GC
purity 99%). Yield 82%, mp 235–238 8C (decompos.). UV
(EtOH): lmax (log e) 223 (0.6), 253 (2.5) nm; IR (KBr): n 3520
References
[1] G.M. Brooke, J. Fluorine Chem. 86 (1997) 1–76.
[2] V.M. Vlasov, G.G. Yakobson, J. Org. Chem. USSR (Engl. Transl.) 12
(1976) 2345–2352;
V.M. Vlasov, G.G. Yakobson, J. Org. Chem. USSR (Engl. Transl.) 17
(1981) 1955–1963;
T.N. Gerasimova, E.F. Kolchina, I.Yu. Kargapolova, E.P. Fokin, Russ. J.
Org. Chem. (Engl. Transl.) 33 (1997) 735–740;
V.E. Platonov, A. Haas, M. Schelvis, M. Lieb, K.V. Dvornikova, O.I.
Osina, Yu.V. Gatilov, J. Fluorine Chem. 109 (2001) 131–140;
V.M. Vlasov, V.V. Aksenov, P.P. Rodionov, I.V. Beregovaya, L.N. Shche-
goleva, Russ. J. Org. Chem. (Engl. Transl.) 38 (2002) 115–125.
[3] G.M. Brooke, J. Fluorine Chem. 43 (1989) 393–404.
[4] D. Price, H. Suschitzky, J.I. Hollies, J. Chem. Soc. C (1969) 1967–1973.
[5] R.D. Chambers, M.J. Seabury, D.H.L. Williams, N. Hughes, J. Chem.
Soc., Perkin Trans. 1 (1988) 251–254.
1
and 3422 cmÀ1 (NH2); H NMR (chloroform-d): d 4.07 (br.s,
NH2); 19F NMR see Table 4; HRMS calcd. for C10H4F6N2:
266.0279, found: 266.0283.
[6] A.A. Shtark, T.V. Chuikova, V.D. Shteingarts, J. Org. Chem. USSR (Engl.
Transl.) 20 (1984) 960–967.
[7] C.L. Cheong, B.J. Wakefield, J. Chem. Soc., Perkin Trans. I (1988) 3301–
3306.
3.3.5.3. 2,6-Diaminohexafluoronaphthalene (3b). 2,6-Diami-
nohexafluoronaphthalene was obtained from a mixture of
diaminohexafluoronaphthalenes 3a–3d (Entry 4, Table 2)
(3.9 g, 15 mmol) by complexation with 18-crown-6 (2.0 g,
7.6 mmol) according to the procedure described in Section
3.3.5.2.
[8] R. Bolton, J.P.B. Sandall, J. Chem. Soc., Perkin Trans. 2 (1978) 746–750;
J. Burdon, H.S. Gill, I.W. Parsons, J. Chem. Soc., Perkin Trans. 1 (1980)
2494–2496;
V.I. Sorokin, V.A. Ozeryanskii, A.F. Pozharskii, Eur. J. Org. Chem. (2004)
766–769.
[9] Yu.N. Sazanov, Russ. J. Appl. Chem. (Engl. Transl.) 74 (2001) 1253–
1269;
2,6-Diaminohexafluoronaphthalene (3b) (2.0 g, 7.6 mmol,
GC purity 97%). Yield 47%, mp 234–235 8C (decompos.). UV
(EtOH): lmax (log e) 234 (3.0), 289 (1.1), 301 (1.3) nm; IR
(KBr): n 3509 and 3414 cmÀ1 (NH2); 1H NMR (chloroform-d):
d 3.97 (br.s, NH2); 19F NMR see Table 4; HRMS calcd. for
C10H4F6N2: 266.0279, found: 266.0275.
S. Ando, T. Matsuura, S. Sasaki, in: G. Hougham (Ed.), Fluoropolymers 2:
Properties, Kluwer Academic/Plenum Publishers, New York, 1999, pp.
277–303.
[10] T.A. Vaganova, S.Z. Kusov, V.I. Rodionov, I.K. Shundrina, E.V. Malykhin,
Russ. Chem. Bull., Int. Ed. 56 (2007) in press.
[11] E.W. Washburn (Ed.), International Critical Tables, McGraw-Hill Book
Company, London, 1928, p. 248.
3.3.6. Separation of diaminohexafluoronaphthalene 3a-d
mixture
[12] E.V. Malykhin, V.D. Shteingarts, Mendeleev Chem. J. (Engl. Transl.) 43
(1999) 37–47.
[13] G.A. Selivanova, L.M. Pokrovskii, V.D. Shteingarts, Russ. J. Org. Chem.
(Engl. Transl.) 37 (2001) 404–409.
A solution of diaminohexafluoronaphthalenes 3a–3d (9.0 g,
34 mmol, Entry 4, Table 1) was treated with a solution of 18-
crown-6 (9.0 g, 34 mmol) according to the procedure described
in Section 3.3.5.2. The precipitate was decomposed by water
and the mixture of diamines 3a and 3b (ꢀ9:1) was obtained
(6.6 g, 24 mmol, yield 60%). Anal. Calcd. for C10H4F6N2: C,
45.7; H, 1.57; N, 10.6. Found: C, 45.1; H, 1.50; N, 10.5.
The filtrate was shaken up with water (40 mL). The organic
layer was washed with water, dried with MgSO4, t-BuMeO was
[14] R.D. Chambers, M.J. Seabury, J.S. Waterhouse, D.L.H. Williams, J.
Chem. Soc., Perkin Trans. 2 (1977) 585–588.
[15] R.D. Chambers, D. Close, D.L.H. Williams, J. Chem. Soc., Perkin Trans. 2
(1980) 778–780;
R.D. Chambers, D. Close, W.K.R. Musgrave, J.S. Waterhouse, D.L.H.
Williams, J. Chem. Soc., Perkin Trans. 2 (1977) 1774–1778;
R.D. Chambers, M.J. Seabury, D.L.H. Williams, N. Hughes, J. Chem.
Soc., Perkin Trans. 1 (1988) 255–257.
[16] J.G. Allen, J. Burdon, J.C. Tatlow, J. Chem. Soc. (1965) 6329–6334.

260
T.A. Vaganova et al. / Journal of Fluorine Chemistry 129 (2008) 253–260
[17] J. Burdon, W.B. Hollyhead, J.C. Tatlow, J. Chem. Soc. (1965) 5152–
5156.
[21] L. Cassidei, O. Sciacovelli, L. Forlani, Spectrochim. Acta A 38 (1982)
755–758.
[18] R.H. Mobbs, J. Fluorine Chem. 1 (1971/1972) 365–368.
[19] R.B. Gosnell, US Patent 3,461,135, 1969.
[20] A.R. Quirt, J.S. Martin, J. Magn. Reson. 5 (1971) 318–327.
[22] F.I. Abezgauz, S.V. Sokolov, S.N. Eserskij, Zh. Vses. Khim. Ob. Im. D.I.
Mendeleeva 10 (1965) 113–114;
F.I. Abezgauz, S.V. Sokolov, S.N. Eserskij, Chem. Abs. 62 (1965) 16152h.