Novel synthesis of 1,4-dialkoxy-5,6,7,8-multisubstituted-2,3- dicyanonaphthalenes through electron transfer from Mg metal and efficient development of new naphthalocyanines

Article abstract of DOI:10.1055/s-0030-1259910

Novel methods for efficient synthesis of 1,4-diamyloxy-5,6,7,8- multisubstituted-2,3-dicyanonaphthalenes were successfully developed, starting from easily available 2,3-dicyanohydroquinone as a common single compound through only three steps, the first di

Full text of DOI:10.1055/s-0030-1259910

862
LETTER
Novel Synthesis of 1,4-Dialkoxy-5,6,7,8-multisubstituted-2,3-dicyanonaphtha-
lenes through Electron Transfer from Mg Metal and Efficient Development of
New Naphthalocyanines
S
ynthesis of 1,4
a
-Dialkoxy-
k
5,6, 7,8-mult
e
isubstituted
s
-2,3-dicya
h
nonaphthale
i
nes Miyazaki, Aiko Harada, Hirofumi Maekawa,* Yoshimasa Yamamoto, Ikuzo Nishiguchi*
Department of Chemistry, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka, Niigata 940-2188, Japan
Fax +81(258)479300; E-mail: nishiiku@vos.nagaokaut.ac.jp
Received 28 December 2010
tive manner. However, the hitherto known methods3a–c,4,5
Abstract: Novel methods for efficient synthesis of 1,4-diamyloxy-
of 2,3-dicyanonaphthalene derivatives through bromina-
5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes were successful-
tion of the benzylic positions of xylene derivatives by N-
bromosuccimide may possess many of unfavorite demer-
ly developed, starting from easily available 2,3-dicyanohydro-
quinone as a common single compound through only three steps,
the first dibromination of 2,3-dicyanohydroquinone, the second its such as multistep synthesis, low overall yields, much
Mitsunobu dialkylation of 2,3-dicyano-5,6-diboromo-1,4-hydro-
limitation for introduction of substituents into 2,3-dicy-
quinone, and the last Diels–Alder-type of cycloaddition between
anonaphthalene molecules, especially much difficulty in
1,4-alkoxy-2,3-dicyano-5,6-diboromobenzenes and multisubstitut-
the case of alkyl and aryl groups as those introduced sub-
ed furans, followed by reductive deoxygenation with Mg turning.
stituents.
The obtained 1,4-diamyloxy-5,6,7,8-multisubstituted-2,3-dicy-
anonaphthalenes were easily transformed into the corresponding
naphthalocyanines in 20–45% yields which showed their lmax at
(R)n
(R)n
867–892 nm.
N
M
N
Key words: multisubstituted-2,3-dicyanonaphthalenes, Mg metal
naphthalocyanines, benzyne, nmax at 867–892 nm
N
N
N
N
N
N
Although phthalocyanines have been so far well-known
as useful color and dye stuffs1a–d and employed for many
actual purposes because of high stability for sunlight,
heat, chemicals, water, and so on, naphthalocyanines have
been recently expected as much better functional materi-
als for optical memory, semiconductivity, and electro-
chromic display.2a–c
(R)n
(R)n
phthalocyanines
max = ca. 700–800 nm
λ
(R)n
(R)n
(R)n
(R)n
N
Approximately two important properties have been re-
quired for those remarkable optically highly functional
materials. The first one is high solubility to usual organic
solvents and for this purpose, introduction of substituents
with long alkyl chains to the naphthalocyanine molecular
is needed (Figure 1). As the second necessary property,
N
N
N
N
M
N
N
N
(R)n
(R)n
(R)n
(R)n
l
max of the absorption band of those color materials should
be present between 800 and 900 nm. Since introduction of
conjugate systems such as aryl or vinyl groups to a naph-
thalocyanine skeleton is expected to show lmax of the
absorption band at longer than 800 nm, the naphthalocy-
anines having those conjugated systems could be re-
quired.
naphthalocyanines
max = ca. 800–900 nm
λ
Figure 1
Therefore, facile and general novel synthesis of 2,3-dicy-
anonaphthalenes should be quite important and strongly
required for development of new naphthalocyanines
which are easily soluble to usual organic solvents and also
have their lmax absorption at the area of 800–900 nm at the
same time.
On the other hand, since direct regioselective introduction
of those organic conjugate substituents into a naphthalo-
cyanine skeletone should be very difficult, it is probably
much more reasonable and realistic to introduce many
kinds of organic conjugate substituents in the course of
synthesis of 2,3-dicyanonaphthalenes in the regioselec-
In this study, we would like to present the successful
development of an efficient, facile, general, and novel
synthesis of 1,4-dialkoxy-2,3-dicyano-5,6,7,8-multisub-
stituted naphthalenes and the successful development of
the corresponding new naphthalocyanines, which are not
SYNLETT 2011, No. 6, pp 0862–0868
x
x.
x
x.
2
0
1
1
Advanced online publication: 15.03.2011
DOI: 10.1055/s-0030-1259910; Art ID: U11710ST
© Georg Thieme Verlag Stuttgart · New York

LETTER
Synthesis of 1,4-Dialkoxy-5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes
863
Table 1 Isolated Yields of 4a–k Starting from the Reaction of 3
with Various Furans 5a–k (continued)
only easily soluble to usual organic solvents, but also
show their absorption of lmax at 800–900 nm.
According to the reaction scheme developed by this study,
dibromonation of 2,3-dicyanohydroquinone (1) by NBS
followed by Mitsunobu reaction6a–c of the resulting 5,6-di-
bromo-1,4-dicyanohydroquinone (2)7 using n-pentanol,
diisopropyl azodicarboxylate, and triphenylphosphine in
tetrahydrofuran (THF) brought about effective formation
of 1,4-diamyloxy-2,3-dibromo-5,6-dicyanobenzene (3) in
a 63% overall yield. The subsequent treatment of 3 with
Mg turnings used for Grignard reaction in the presence of
a variety of substituted furans 6a–k8 in THF at room tem-
perature for 3 hours resulted in an efficient formation of
the desired corresponding 1,4-diamyloxy-5,6,7,8-multi-
substituted-2,3-dicyanonaphthalenes 4a–k in 82–33%
yields, as shown in Scheme 1.
Entry
Product
Yield (%)
Ph
OC5H11
CN
4
37
CN
OC5H11
Ph
4d
OC5H11
CN
Ph
Ph
5
6
68
52
37
36
36
37
CN
OC5H11
4e
OC5H11
CN
4-FC6H4
4-FC6H4
OH
OH
n-C5H11OH
DIAD, Ph3P
CN
CN
Br
Br
CN
CN
NBS
CN
OC5H11
t-BuOH
50 °C, 4 h
65%
THF, r.t., 3 h
97%
OH
OH
4f
1
2
OC5H11
CN
R1
O
R2
R3
4-MeOC6H4
4-MeOC6H4
7
R1
OC5H11
CN
OC5H11
CN
OC5H11
R4, Mg
R2
Br
CN
6
THF, r.t., 3 h
33–82%
4g
R3
CN
Br
CN
OC5H11
R4
OC5H11
OC5H11
Naph
Naph
CN
3
4
8
CN
Scheme 1 Novel synthesis of 1,4-diamyloxy-5,6,7,8-multisubstitu-
ted-2,3-dicyano-naphthalenes 4a–k
OC5H11
4h
Ph
Ph
Table 1 Isolated Yields of 4a–k Starting from the Reaction of 3
with Various Furans 5a–k
OC5H11
CN
9
Entry
Product
Yield (%)
Ph
Ph
CN
OC5H11
CN
OC5H11
4i
1
82
4-FC6H4
OC5H11
CN
CN
OC5H11
4-FC6H4
4-FC6H4
10
4a
4b
4c
CN
OC5H11
OC5H11
CN
4-FC6H4
4j
2
3
61
75
Ph
OC5H11
CN
OC5H11
CN
11
33
CN
OC5H11
CN
Ph
OC5H11
4k
CN
OC5H11
This three-step reaction scheme may be highly successful
from the viewpoint of safety and easy availability of re-
agents, good total yields, and easy availability of substi-
tuted furans. Isolated yields for each of 1,4-diamyloxy-
Synlett 2011, No. 6, 862–868 © Thieme Stuttgart · New York

864
T. Miyazaki et al.
LETTER
5,6,7,8-multisubstututed-2,3-dicyanonaphthalenes 4a–k
are summarized in Table 1.
OC5H11
CN
OC5H11
CN
OC5H11
CN
Br
Br
Br
Br
Mg
Interestingly, shortening of reaction time from 4 hours to
1 hour in the reactions of 3 with some of multisubstituted
furans (6a,e–g) resulted in formation of the mixtures (ca.
1:1) of the corresponding 1,4-diamyloxy-5,6,7,8-multi-
substituted-2,3-dicyanonaphthalenes 4a,e–g and the cor-
responding epoxy adducts 5a,e–g, as shown in Table 2.
This experimental fact clearly indicates that those substi-
tuted 1,4-diamyloxy-5,6,7,8-multisubstituted-2,3-dicy-
anonaphthalenes 4 are formed through Diels–Alder-type
of [4+2] cycloaddition between various substituted furans
with the corresponding benzyne intermediate,9 generated
from the reaction of Mg metal with 1,4-diamyloxy-2,3-di-
bromo-5,6-dicyanobenzene (3), to give the corresponding
epoxy adducts 5. Furthermore, cationic participation10 of
the generated MgBr2 to the epoxy adduct 5 was excluded
because of no reaction on treatment of 5 with an equiva-
lent molecular amount of MgBr2.
Mg
– MgBr2
CN
OC5H11
CN
CN
OC5H11
3
OC5H11
R1
R2
R3
O
R1
O
R1
O
OC5H11
CN
OC5H11
CN
R2
R3
R2
R3
R4
6
+ e (Mg)
CN
OC5H11
CN
R4
R4
OC5H11
5
R1
XO
R1
OC5H11
OC5H11
CN
R2
R3
R2
R3
CN
X+
+ e (Mg)
– XO–
CN
OC5H11
CN
R4
R4
OC5H11
On the other hand, treatment of the epoxy adduct 5 with
Mg turnings for Grignard reaction and MgBr2 (or
TMSCl), indicating subsequent electron transfer from Mg
metal11 may produce the corresponding anion radicals,
which gave the corresponding ring-opened products. And
finally, the desired 1,4-di(amyloxy)-5,6,7,8-multisubsti-
tuted-2,3-dicyanonaphthalenes 4 were obtained smoothly,
as shown in Scheme 2.
4
X = MgBr or TMS
Scheme 2 Proposed reaction scheme for the conversion of 1,4-di-
amyloxy-2,3-dibromo-6,7-dicyanobenzene (3) to 1,4-diamyloxy-
substituted-2,3-dicyanonaphthalenes 4 through the epoxy adducts 5
As a conclusion, in this study we have successfully devel-
oped a new efficient synthetic method of 1,4-diamyloxy-
5,6,7,8-multisubstituted-2,3-dicyano-naphthalenes 4, and
some of their derived new naphthalocyanines 7 (Table 3),
which are not only easily soluble to many of organic sol-
vents but also show their absorption of lmax at 800–900
nm. Those new organic functional materials are expected
to show much potentiality and possibility as new promis-
ing functional materials for optical memory, semiconduc-
tivity, electrochromic display, and infrared light
absorption.
From these obtained 1,4-diamyloxy-5,6,7,8-multisubsti-
tuted-2,3-dicyanonaphthalenes 4a,e–g, the corresponding
naphthalocyanines 7a,e–g were easily synthesized using
Li metal in n-pentanol in 20–45% yields according to the
usual procedure,12 which showed their lmax at 867–892
nm (e = 2.51–3.31·105 M–1cm–1). Furthermore, these new
organic color stuffs were found to be easily soluble to or-
ganic solvents such as chloroform, toluene, ethanol, etc.,
indicating that they can have much potentiality for semi-
conductors, electrochromic display, optical and electronic
materials, and absorption materials of infrared light.
Table 2 Trapping of the Epoxides 5a,e–g as Intermediates of the Cycloaddition of 3 with Furans 6a,e–ga
R1
OC5H11
CN
R1
OC5H11
CN
OC5H11
CN
R1
O
R2
R2
R2
R2
R2
R2
Br
Br
Mg
O
+
+
THF, r.t.
CN
OC5H11
CN
OC5H11
CN
OC5H11
4a,e–g
R1
R1
R1
6a,e–g
3
5a,e–g
R1
H
H
H
H
R2
Furan
Yield of 5a,e–g (%)b
Yield of 4a,e–g (%)b
H
6a
6e
6f
5a 36
5e 35
5f 42
5g 35
4a 20
4e 26
4f 33
4g 24
Ph
4-FC6H4
4-MeOC6H4
6g
a 3,6-Dialkoxy-4,5-dibromophthalonitrile (2.0 mol equiv), Mg (4.0 mol equiv), THF (4 mL), r.t., under N2 atmosphere, 1 h (after starting ma-
terial was consumed).
b Isolated yield.
Synlett 2011, No. 6, 862–868 © Thieme Stuttgart · New York

LETTER
Synthesis of 1,4-Dialkoxy-5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes
865
Table 3 Synthesis of New Naphthalocyanines Soluble in Organic Solvents
R
R
C5H11
O
C5H11
O
R
R
N
OC5H11
CN
C5H11O
OC5H11
OC5H11
N
HN
R
R
Li
N
N
n-C5H11OH
120 °C, 1 h
20–45%
NH
N
CN
OC5H11
C5H11O
N
4
O
O
R
R
C5H11
C5H11
R
R
7
R
Yield (%)
l
max (CHCl3)
e (M–1cm–1)
2.51·105
2.95·105
3.31·105
3.24·105
4a H
4e Ph
7a 34
7e 30
7f 45
7g 20
867 nm
888 nm
886 nm
892 nm
4f 4-F(C6H4)
4g 4-MeO(C6H4)
Preparation of 3,6-Dihydroxy-4,5-dibromophthalonitrile (2)
der N2 atmosphere. Then 4,5-dibromo-3,6-di(amyloxy)-4,5-dibro-
mophthalonitrile (3, 9.01 g, 20 mmol) and one of multisubstituted
furans 6a–k (10 mmol) was added to the solution with stirring, and
the resulting solution was continuously stirred at r.t. until all the
starting furans consumed.
Into the solution of 2,3-dicyanohydroquinone (1, 30.0 g, 187 mmol)
in t-BuOH (200 mL), NBS (135.2 g, 720 mmol) were carefully add-
ed in a small portion for 15 min at 45 °C, then the reaction mixture
was continued to stir for another 2 h. After the reaction, the reaction
mixture was poured into an aq NaHSO3 solution with vigorous stir-
ring. The resulting precipitate was filtered under reduced pressure
to wash adequately with H2O, and then was dried further under vac-
uum. The product was identified by comparison with its authentic
sample (65% yield).
After the reaction of 4 h, the product mixture was poured into aq
NH4Cl solution, and was extracted with three portions of CH2Cl2
(3 × 50 mL). The combined CH2Cl2 solution was washed with H2O,
and then dried over anhyd MgSO4. After evaporation of the solvent,
the organic layer was subjected to column chromatograph (elution:
CH2Cl2–hexane = 1:2) to give the desired product, each of 1,4-di-
amyloxy-5,6,7,8-multisubstituted-2,3-dicyanonapthalenes 4a–k.
Preparation of 3,6-Diamyloxy-4,5-dibromophthalonitrile (3)
Into the solution of n-amyl alcohol (12.5 g, 142 mmol), 4,5-dibro-
mo-3,6-dihydroxyphthalonitrile (2, 18.0 g, 56.6 mmol), Ph3P (35.9
g, 136 mmol) in anhyd THF (80 mL), a solution of diisopropyl
azodicarboxylate (28.8 g, 142 mmol) dissolved in THF (120 mL)
was added dropwise at 0 °C during 45 min, and then the mixture was
continued to be stirred for 5 h. After the reaction, evaporation of the
reaction solvent followed by addition of Et2O gave Ph3P, which was
removed by filtration and then washed with the solvent. Evapora-
tion of Et2O from the filtrate under reduced pressure gave the de-
sired product, which was purified by column chromatography and
recrystallization, and was characterized by spectroscopic methods
and elemental analysis.
Shortening the reaction time from 4 h to 1 h for the reaction of the
starting multisubstituted furans 6a,e–g with 3 brought about forma-
tion of almost the same ratio (1:1) of two products 4a,e–g and 5a,e–
g, which were found by isolation, chromatographic and spectro-
scopic analyses.
1,4-Diamyloxy-2,3-dicyanonaphthalene (4a)
Mp 52.6–53.1 °C. 1H NMR (400 MHz, CDCl3): d = 8.23 (dd, 2 H,
J = 3.0, 6.2 Hz), 7.79 (dd, 2 H, J = 3.0, 6.2 Hz), 4.42 (t, 4 H, J = 6.8
Hz), 1.97 (quint, 4 H, J = 6.8 Hz), 1.60–1.40 (m, 8 H), 0.97 (t, 6 H,
J = 6.8 Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 157.23, 130.45,
130.15, 123.53, 114.41, 98.7 ppm. MS (APCI): m/z = 351 [M + H]+.
Anal. Calcd for C22H26N2O2: C, 75.40; H, 7.48; N, 7.99. Found: C,
75.69; H, 7.60; N, 7.90.
3,6-Diamyloxy-4,5-dibromophthalonitrile (3)
1
Mp 68.8–69.9 °C. H NMR (400 MHz, CDCl3): d = 4.20 (t, 4 H,
J = 6.4 Hz), 1.94–1.87 (m, 4 H), 1.56–1.36 (m, 8 H), 0.95 (t, 6 H,
J = 7.2 Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 156.38, 129.62,
112.36, 109.21, 76.69, 29.63, 27.73, 22.34, 13.93 ppm. IR (KBr):
2959, 2858, 2234, 1548, 1466, 1423, 1361, 1231, 1072, 1044, 1006,
936, 889, 835, 729, 536, 499 cm–1. MS (APCI): m/z = 459 [M + H]+.
Anal. Calcd for C18H22Br2N2O2: C, 47.18; H, 4.84; N, 6.11. Found:
C, 47.29; H, 4.80; N, 6.06.
1,4-Diamyloxy-2,3-dicyano-5-methylnaphthalene (4b)
Mp 62.0–63.8 °C. H NMR (400 MHz, CDCl3): d = 8.08 (1 H, d,
1
J = 7.2 Hz), 7.62 (t, 1 H, J = 7.2 Hz), 7.53 (d, 1 H, J = 7.2 Hz), 4.35
(t, 2 H, J = 6.9 Hz), 4.22 (t, 2 H, J = 6.9 Hz), 2.88 (s, 3 H), 2.02–
1.92 (m, 4 H), 1.59–1.40 (m, 8 H), 0.97 (t, 6 H, J = 6.9 Hz) ppm.
13C NMR (100 MHz, CDCl3): d = 159.35, 157.42, 136.30, 133.94,
131.68, 129.75, 121.69, 114.44, 114.07, 101.29, 98.92, 77.00,
29.68, 27.72, 23.46, 22.28, 13.78 ppm. IR (KBr): 2939, 2872, 2228,
1571, 1496, 1459, 1409, 1350, 1330, 1208, 1044, 1021, 972, 888,
810, 782 cm–1. MS (APCI): m/z = 365 [M + H]+. Anal. Calcd for
C23H28N2O2: C, 75.79; H, 7.74; N, 7.69. Found: C, 76.00; H, 7.70;
N, 7.63.
General Method for the Synthesis of 1,4-Diamyloxy-5,6,7,8-
multisubstituted-2,3-dicyanonaphthalenes 4a–k and 1,4-Di-
amyloxy-5,8-epoxy-5,8-dihydro-2,3-dicyanonaphthalene 5a,e–g
Into anhyd THF (40 mL) of Mg turning for Gnignard reaction (1.0
g, 41 mmol) was introduced, and the solution was stirred at r.t. un-
Synlett 2011, No. 6, 862–868 © Thieme Stuttgart · New York

866
T. Miyazaki et al.
LETTER
1,4-Diamyloxy-2,3-dicyano-5,8-dimethylnaphthalene (4c)
Mp 95.0–95.3 °C. H NMR (400 MHz, CDCl3): d = 7.37 (s, 2 H),
1.49–1.26 (m, 8 H), 0.83 (t, 3 H, J = 7.4 Hz), 0.80 (t, 3 H, J = 7.3
Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 157.41, 143.79, 143.60,
137.15, 137.13, 133.31, 133.20, 132.00, 131.18, 129.38, 129.24,
128.38, 128.33, 128.12, 128.07, 127.99, 127.05, 126.58, 126.52,
126.27, 125.78, 125.62, 125.59, 125.41, 124.66, 124.46, 114.65,
99.11, 99.05, 76.63, 76.61, 29.78, 29.75, 27.84, 27.80, 22.30, 22.27,
13.85, 13.82 ppm. IR (KBr): 3047, 2955, 2871, 2224, 1592, 1560,
1509, 1426, 1340, 1177, 1011, 802, 775 cm–1. MS (APCI): m/z =
603 [M]+. Anal. Calcd for C42H38N2O2: C, 83.69; H, 6.35; N, 4.65.
Found: C, 83.70; H, 6.55; N, 4.45.
1
4.14 (t, 4 H, J = 6.8 Hz), 2.83 (s, 6 H), 1.97 (quint, 4 H, J = 6.8 Hz),
1.56–1.38 (m, 8 H), 0.96 (t, 6 H, J = 7.4 Hz) ppm. 13C NMR (100
MHz, CDCl3): d = 159.70, 134.12, 133.71, 131.39, 114.22, 101.66,
77.64, 29.37, 27.68, 23.80, 22.33, 13.76 ppm. IR (KBr): 2938, 2872,
2226, 1459, 1338, 1214, 1042, 1015, 962, 850, 729, 566 cm–1. MS
(APCI): m/z = 379 [M + H]+. Anal. Calcd for C24H30N2O2: C, 76.16;
H, 7.99; N, 7.40. Found: C, 76.45; H, 7.88; N, 7.19
1,4-Diamyloxy-2,3-dicyano-5,8-diphenylnaphthalene (4d)
Mp 192.5–194.4 °C. 1H NMR (400 MHz, CDCl3): d = 7.54 (s, 2 H),
7.44–7.35 (m, 10 H), 3.61 (t, 4 H, J = 6.8 Hz), 1.16 (quint, 4 H,
J = 6.8 Hz), 1.06 (quint, 4 H, J = 6.8 Hz), 0.93 (quint, 4 H, J = 6.8
Hz), 0.82 (t, 6 H, J = 6.8 Hz) ppm. 13C NMR (100 MHz, CDCl3):
d = 158.80, 141.99, 139.74, 133.64, 129.50, 128.84, 127.38,
127.13, 113.92, 102.95, 77.05, 28.21, 27.28, 22.18, 13.75 ppm. IR
(KBr): 3057, 2956, 2870, 2230, 1599, 1573, 1489, 1411, 1353,
1280, 1233, 1074, 1027, 960, 855, 758, 699 cm–1. MS (APCI): m/z
= 503 [M + H]+. Anal. Calcd for C34H34N2O2: C, 81.24; H, 6.82; N,
5.57. Found: C, 81.42; H, 6.83; N, 5.30.
1,4-Diamyloxy-2,3-dicyano-5,6,7,8-tetraphenylnaphthalene (4i)
Mp 201.4–203.1 °C. H NMR (400 MHz, CDCl3): d = 7.10–7.02
(m, 10 H), 6.82–6.77 (m, 6 H), 6.61–6.58 (m, 4 H), 3.66 (t, 4 H,
1
J = 6.9 Hz), 1.15 (sext, 4 H, J = 6.9 Hz), 1.05 (quint, 4 H, J = 6.9
Hz), 0.95 (quint, 4 H, J = 6.9 Hz), 0.79 (t, 6 H, J = 6.9 Hz) ppm. 13
C
NMR (100 MHz, CDCl3): d = 159.03, 145.52, 140.49, 138.88,
137.86, 130.60, 129.90, 129.88, 126.70, 126.47, 126.11, 125.60,
114.19, 103.41, 76.68, 28.37, 27.28, 22.27, 13.81 ppm. IR (KBr):
3056, 3025, 2957, 2228, 1601, 1567, 1542, 1493, 1442, 1358, 1279,
1027, 963, 759, 697 cm–1. MS (APCI): m/z = 673 [M + H2O]+. Anal.
Calcd for C46H42N2O2: C, 84.37; H, 6.46; N, 4.28. Found: C, 84.22;
H, 6.64; N, 4.13.
1,4-Diamyloxy-2,3-dicyano-6,7-diphenylnaphthalene (4e)
Mp 119.5–121.3 °C. 1H NMR (400 MHz, CDCl3): d = 8.12 (s, 2 H),
7.18–7.09 (m, 10 H), 4.33 (t, 4 H, J = 6.6 Hz), 1.83 (quint, 4 H,
1,4-Diamyloxy-2,3-dicyano-5,6,7,8-tetrakis(4¢-fluorophenyl)-
naphthalene (4j)
J = 6.6 Hz), 1.47–1.25 (m, 8 H), 0.82 (t, 6 H, J = 7.2 Hz) ppm. 13
C
NMR (100 MHz, CDCl3): d = 157.08, 143.66, 139.75, 129.64,
129.22, 128.10, 127.48, 125.12, 114.44, 98.78, 76.31, 29.73, 27.87,
22.27, 13.86 ppm. IR (KBr): 3061, 2956, 2870, 2223, 1565, 1495,
1340, 1041, 1025, 965, 908, 781, 768, 702, 565, 532 cm–1. MS
(APCI): m/z = 503 [M + H]+. Anal. Calcd for C34H34N2O2: C, 81.24;
H, 6.82; N, 5.57. Found: C, 81.44; H, 6.85; N, 5.38.
Mp 199.8–201.8 °C. 1H NMR (400 MHz, CDCl3): d = 6.97 (dd, 4
H, J = 5.3, 8.6 Hz), 6.84 (t, 4 H, J = 8.6 Hz), 6.60–6.51 (m, 8 H),
3.67 (t, 4 H, J = 6.9 Hz), 1.21–1.03 (m, 12 H), 0.82 (t, 6 H, J = 6.9
Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 161.50 (d, 1JCF = 246.6
Hz), 160.65 (d, 1JCF = 246.6 Hz), 158.78, 144.75, 137.36, 136.23 (d,
4JCF = 3.6 Hz), 134.53 (d, 4JCF = 3.6 Hz), 132.01 (d, 3JCF = 8.1 Hz),
3
2
131.26 (d, JCF = 8.1 Hz), 130.03, 114.13 (d, JCF = 20.7 Hz),
2
1,4-Diamyloxy-2,3-dicyano-6,7-bis(4¢-fluorophenyl)naphtha-
lene (4f)
114.04 (d, JCF = 21.6 Hz), 113.96, 103.95, 77.26, 28.60, 27.34,
22.29, 13.76 ppm. IR (KBr): 3052, 1900, 1599, 1514, 1498, 1238,
1160, 840, 818, 647, 622, 511 cm–1. MS (APCI): m/z = 727 [M]+.
Anal. Calcd for C46H38F4N2O2: C, 76.02; H, 5.27; N, 3.85. Found:
C, 76.27; H, 5.26; N, 3.62.
Mp 228.5–230.2 °C. 1H NMR (400 MHz, CDCl3): d = 8.21 (s, 2 H),
7.17–7.13 (m, 4 H), 7.01 (t, 4 H, J = 8.7 Hz), 4.47 (t, 4 H, J = 7.0
Hz), 1.95 (quint, 4 H, J = 7.0 Hz), 1.54 (quint, 4 H, J = 7.0 Hz), 1.41
(sext, 4 H, J = 7.0 Hz), 0.93 (t, 6 H, J = 7.0 Hz) ppm. 13C NMR (100
1
MHz, CDCl3): d = 162.40 (d, JCF = 247.7 Hz), 157.14, 142.58,
1,4-Diamyloxy-2,3-dicyano-5,10-diphenylanthracene (4k)
135.71 (d, 4JCF = 4.0 Hz), 131.36 (d, 3JCF = 8.0 Hz), 129.47, 125.25,
Mp 213.6–214.8 °C. H NMR (400 MHz, CDCl3): d = 7.55–7.35
1
2
115.36 (d, JCF = 20.0 Hz), 114.51, 99.12, 76.45, 29.83, 27.98,
(m, 14 H), 3.75 (t, 4 H, J = 7.4 Hz), 1.22 (quint, 4 H, J = 7.4 Hz),
1.15 (m, 8 H), 0.85 (t, 6 H, J = 7.4 Hz) ppm. 13C NMR (100 MHz,
CDCl3): d = 160.37, 140.55, 138.48, 133.60, 129.57, 127.71,
127.63, 127.54, 127.19, 125.70, 114.59, 99.78, 76.86, 28.52, 27.37,
22.36, 13.89 ppm. IR (KBr): 3056, 2954, 2925, 2869, 2227, 1575,
1471, 1401, 1380, 1335, 1274, 1033, 956, 948, 771, 759, 701, 517
cm–1. MS (APCI): m/z = 571 [M + H2O]+. Anal. Calcd for
C38H36N2O2: C, 82.58; H, 6.57, N, 5.07. Found: C, 82.85; H, 6.65;
N, 4.77.
22.36, 13.95 ppm. IR (KBr): 3070, 2960, 2874, 2226, 1905, 1603,
1509, 1339, 1220, 1161, 1015, 966, 842, 817, 546 cm–1. MS
(APCI): m/z = 538 [M]+. Anal. Calcd for C34H32F2N2O2: C, 75.82;
H, 5.99; N, 5.20. Found: C, 75.74; H, 6.07; N, 5.16.
1,4-Diamyloxy-2,3-dicyano-6,7-bis(4¢-methoxyphenyl)naphtha-
lene (4g)
Mp 128.0–130.0 °C. 1H NMR (400 MHz, CDCl3): d = 8.18 (s, 2 H),
7.13 (d, 4 H, J = 8.6 Hz), 6.84 (d, 4 H, J = 8.6 Hz), 4.45 (t, 4 H,
J = 7.2 Hz), 3.82 (s, 6 H), 1.95 (quint, 4 H, J = 7.2 Hz), 1.54 (quint,
4 H, J = 7.2 Hz), 1.42 (sext, 4 H, J = 7.2 Hz), 0.94 (t, 6 H, J = 7.2
Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 159.15, 157.30, 143.43,
132.36, 130.87, 129.28, 124.95, 114.66, 113.75, 98.80, 76.43,
55.23, 29.85, 27.98, 22.38, 13.96 ppm. IR (KBr): 3070, 2956, 2871,
2224, 1608, 1515, 1338, 1295, 1251, 1179, 1029, 835, 560 cm–1.
MS (APCI): m/z = 562 [M]+. Anal. Calcd for C36H38N2O4: C, 76.84;
H, 6.81; N, 4.98. Found: C, 76.99; H, 6.83; N, 4.79.
2,3-Dicyano-5,8-epoxy-5,8-dihydro-1,4-diamyloxynaphthalene
(5a)
1
Mp 77.6–78.5 °C. H NMR (400 MHz, CDCl3): d = 7.10 (s, 2 H),
6.02 (s, 2 H), 4.21 (dt, 2 H, J = 9.2, 6.0 Hz), 4.06 (dt, 2 H, J = 9.2,
6.0 Hz), 1.82 (quint, 4 H, J = 6.0 Hz), 1.52–1.35 (m, 8 H), 0.95 (t, 6
H, J = 6.0 Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 149.81,
145.79, 142.48, 113.24, 108.47, 81.06, 74.94, 29.44, 27.80, 22.30,
13.91 ppm. IR (KBr): 2955, 2871, 2231, 1578, 1447, 1376, 1288,
1062, 1034, 983, 892, 862, 710, 520 cm–1. MS (APCI): m/z = 385
[M + H2O]+. Anal. Calcd for C22H26N2O3: C, 72.11; H, 7.15; N,
7.64. Found: C, 71.81; H, 7.20; N, 7.62.
1,4-Diamyloxy-2,3-dicyano-6,7-bis(1¢-naphthyl)naphthalene
(4h)
Mp 142.1–142.6 °C. 1H NMR (400 MHz, CDCl3): d = 8.49 (s, 1 H),
8.44 (s, 1 H), 7.80 (dd, 1 H, J = 2.0, 7.6 Hz), 7.71 (dd, 1 H, J = 1.6,
7.3 Hz), 7.67–7.61 (m, 4 H), 7.49–7.42 (m, 2 H), 7.29–7.24 (m, 3
H), 7.09 (t, 1 H, J = 7.9 Hz), 7.04 (t, 1 H, J = 7.9 Hz), 6.95 (dd, 1 H,
J = 1.2, 7.1 Hz), 4.54–4.44 (m, 4 H), 1.88 (sext, 4 H, J = 6.6 Hz),
2,3-Dicyano-5,8-epoxy-5,8-dihydro-1,4-diamyloxy-6,7-diphe-
nylnaphthalene (5e)
1
Mp 101.2–101.5 °C. H NMR (400 MHz, CDCl3): d = 7.34–7.25
(m, 10 H), 6.23 (s, 2 H), 4.10 (dt, 2 H, J = 8.8, 6.6 Hz), 3.94 (dt, 2
Synlett 2011, No. 6, 862–868 © Thieme Stuttgart · New York

LETTER
Synthesis of 1,4-Dialkoxy-5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes
867
H, J = 8.8, 6.6 Hz), 1.77–1.68 (m, 4 H), 1.38–1.25 (m, 8 H), 0.90 (t,
6 H, J = 7.2 Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 149.95,
146.53, 146.22, 132.23, 128.89, 128.81, 126.92, 113.36, 108.84,
85.79, 75.35, 29.35, 27.62, 22.17, 13.87 ppm. IR (KBr): 3081,
3056, 3022, 2931, 2870, 2233, 1597, 1574, 1498, 1442, 1377, 1340,
1279, 984, 920, 863, 761, 695 cm–1. MS (APCI): m/z = 536 [M +
H2O]+, Anal. Calcd for C34H34N2O3: C, 78.74; H, 6.61; N, 5.40.
Found: C, 78.59; H, 6.83; N, 5.43.
16 H, J = 8.0 Hz), 0.92 (t, 24 H, J = 8.0 Hz) ppm. 13C NMR (100
MHz, CDCl3): d = 150.11, 141,80, 140.21, 130.25, 130.06, 128.09,
126.83, 126.47, 123.08, 77.05, 30.47, 28.78, 22.86, 14.18 ppm. IR
(KBr): 3297, 3059, 2953, 2669, 1599, 1573, 1495, 1427, 1334,
1278, 1203, 1178, 1110, 1075, 982, 903, 768, 700, 588 cm–1. MS–
FAB: m/z = 2013 [M]+. UV/vis (CHCl3): 888, 781, 491, 342, 277,
244 nm; lmax (e) = 2.95·105 M–1cm–1. Anal. Calcd for C136H138N8O8:
C, 81.16; H, 6.91; N, 5.57. Found: C, 81.46; H, 7.04; N, 5.28.
2,3-Dicyano-5,8-epoxy-5,8-dihydro-6,7-bis(4¢-fluorophenyl)-
3,4,12,13,21,22,30,31-Octakis(4¢-fluorophenyl)-
1,4-diaoxynamyloxyphthalene (5f)
1,6,10,15,19,24,28,33-octaamyloxy-37H,39H-naphthalocyanine
(7f)
1
Mp 160.5–161.2 °C. H NMR (400 MHz, CDCl3): d = 7.28–7.23
(m, 4 H), 7.02 (t, 4 H, J = 8.4 Hz), 6.17 (s, 2 H), 4.13 (dt, 2 H,
J = 8.9, 6.6 Hz), 3.95 (dt, 2 H, J = 8.9, 6.6 Hz), 1.83–1.68 (m, 4 H),
1.40–1.27 (m, 8 H), 0.91 (t, 6 H, J = 6.9 Hz) ppm. 13C NMR (100
Mp 286.5–287.3 °C. 1H NMR (400 MHz, CDCl3): d = 8.98 (s, 8 H),
7.43–7.40 (m, 16 H), 7.12 (t, 16 H, J = 8.0 Hz), 5.22 (t, 16 H, J = 8.0
Hz), 2.57 (br, 2 H), 2.23 (quint, 16 H, J = 8.0 Hz), 1.66 (quint, 16
H, J = 8.0 Hz), 1.44 (sext, 16 H, J = 8.0 Hz), 0.91 (t, 24 H, J = 8.0
Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 162.14 (d, 1JCF = 246.7
Hz), 150.01, 139.08, 137.53 (d, 4JCF = 3.0 Hz), 131.68 (d, 3JCF = 8.0
1
MHz, CDCl3): d = 162.82 (d, JCF = 250.4 Hz), 149.98, 145.98,
145.63, 128.85 (d, 3JCF = 8.1 Hz), 128.18 (d, 4JCF = 3.6 Hz), 116.26
2
(d, JCF = 21.6 Hz), 113.29, 109.11, 85.74, 75.45, 29.42, 27.70,
2
22.20, 13.90 ppm. IR (KBr): 3072, 2932, 2873, 2228, 1599, 1513,
1503, 1443, 1377, 1338, 1280, 1221, 1162, 983, 920, 865, 839, 685,
567, 538 cm–1. MS (APCI): m/z = 572 [M + H2O]+.
Hz), 130.02, 126.38, 125.75, 123.19, 115.23 (d, JCF = 21.0 Hz),
77.05, 30.42, 28.73, 22.80, 14.14 ppm. IR (KBr): 3300, 3069, 2954,
2867, 1604, 1510, 1333, 1226, 1178, 1111, 1039, 836, 583 cm–1.
MS–FAB: m/z = 2157 [M]+. UV/vis (CHCl3): 886, 780, 491, 344,
278, 242, 217 nm; lmax (e) = 3.31·105 M–1cm–1. Anal. Calcd for
2,3-Dicyano-5,8-epoxy-5,8-dihydro-6,7-bis(4¢-methoxyphenyl)-
1,4-dipentyloxynaphthalene (5g)
C136H130F8N8O8: C, 75.74; H, 6.08; N, 5.20. Found: C, 75.57; H,
Mp 105.8–106.4 °C. 1H NMR (400 MHz, CDCl3): d = 7.24 (d, 4 H,
J = 8.6 Hz), 6.84 (d, 4 H, J = 8.6 Hz), 6.16 (s, 2 H), 4.10 (dt, 2 H,
J = 8.9, 6.6 Hz), 3.95 (dt, 2 H, J = 8.9, 6.6 Hz), 3.81 (s, 6 H), 1.79–
1.71 (m, 4 H), 1.39–1.29 (m, 8 H), 0.91 (t, 6 H, J = 6.9 Hz) ppm.
13C NMR (100 MHz, CDCl3): d = 159.86, 149.91, 146.56, 144.31,
128.33, 124.86, 114.34, 113.45, 108.79, 85.76, 75.41, 55.26, 29.44,
27.71, 22.24, 13.93 ppm. IR (KBr): 2977, 2934, 2871, 2229, 1604,
1573, 1517, 1505, 1439, 1376, 1341, 1292, 1248, 1179, 982, 924,
863, 834, 679, 577, 547 cm–1. MS (APCI): m/z = 596 [M + H2O]+.
6.12; N, 5.05.
1,6,10,15,19,24,28,33-Octaamyloxy-3,4,12,13,21,22,30,31-
octakis(4¢-methoxyphenyl)-37H,39H-naphthalocyanine (7g)
Mp 289.9–291.5 °C. 1H NMR (400 MHz, CDCl3): d = 7.93 (s, 8 H),
7.40 (d, 16 H, J = 8.0 Hz), 6.96 (d, 16 H, J = 8.0 Hz), 5.19 (t, 16 H,
J = 8.0 Hz), 3.91 (s, 24 H), 2.61 (br, 2 H), 2.23 (quint, 16 H, J = 8.0
Hz), 1.65 (quint, 16 H, J = 8.0 Hz), 1.44 (sext, 16 H, J = 8.0 Hz),
0.92 (t, 24 H, J = 8.0 Hz) ppm. 13C NMR (100 MHz, CDCl3):
d = 158.63, 149.98, 139.78, 134.36, 131.27, 129.90, 126.10,
122.89, 113.60, 76.91, 55.30, 30.41, 28.74, 22.83, 14.19 ppm. IR
(KBr): 3302, 2953, 2869, 2835, 1607, 1573, 1514, 1465, 1333,
1246, 1176, 1108, 1042, 832, 585 cm–1. MS–FAB: m/z = 2153 [M]+.
UV/vis (CHCl3): 892, 784, 493, 462, 336, 287, 249 nm; lmax (e) =
3.24·105 M–1cm–1. Anal. Calcd for C144H154N8O16: C, 76.77; H,
6.89; N, 4.97. Found: C, 76.86; H, 7.00; N, 4.68.
General Method for the Synthesis of Metal-Free Multisubstitut-
ed Naphthalocyanines (7a,e–g)
Into a solution of one of 1,4-diamyloxy-6,7-disubstituted-2,3-dicy-
anonaphthalenes (4a,e–g, 1.5 mmol) dissolved in 1-pentanol (5.0
mL), was added Li metal (20 mol equiv) in a small portion with stir-
ring, and then the solution was heated at 100–120 °C for 1.0 h. After
cooling to r.t., the solution was poured into diluted aq AcOH (100
mL), and then the solution was extracted with CH2Cl2 (3 × 50 mL).
After the CH2Cl2 solution was dried over anhyd MgSO4, the drying
agent was filtered, and the filtrate was concentrated under reduced
pressure to give a black solid product, which was subjected to col-
umn chromatography (silica gel–CH2Cl2) to give the corresponding
naphthalocyanines (7a,e–g) in 20–45% yield.
Acknowledgment
The authors wish to express sincere gratitude for partial support of
this research through a Grant-in-Aid for Scientific Research (No.
19020018) on Priority Areas ‘Advanced Molecular Transformation
of Carbon Resources’ from the Ministry of Education, Sports, Cul-
ture, Science and Technology, Japan.
1,6,10,15,19,24,28,33-Octaamyloxy-37H,39H-naphthalocya-
nine (7a)
Mp 285.0–287.0 °C. 1H NMR (400 MHz, CDCl3): d = 9.00 (dd, 8
H, J = 3.2, 6.4 Hz), 7.89 (dd, 8 H, J = 3.2, 6.4 Hz), 5.17 (t, 16 H,
J = 6.8 Hz), 2.48 (s, 2 H), 2.28 (quint, 16 H, J = 6.8 Hz), 1.62 (quint,
16 H, J = 6.8 Hz), 1.49 (sext, 16 H, J = 6.8 Hz), 0.97 (t, 24 H,
J = 6.8 Hz) ppm. 13C NMR (100 MHz, CDCl3): d = 149.97, 130.82,
126.99, 124.50, 122.79, 76.96, 30.37, 28.52, 22.78, 14.18 ppm.
IR (KBr): 3298, 3069, 2957, 2929, 2859, 1583, 1349, 1249, 1155,
1127, 1095, 1049, 766, 730 cm–1. MS–FAB: m/z = 1403 [M]+.
UV/vis (CHCl3): 867, 765, 475, 448, 412, 328, 260, 242 nm;
lmax (e) = 2.51·105 M–1cm–1. Anal. Calcd for C88H108N8O8: C,
75.29; H, 7.601; N, 7.98. Found: C, 75.08; H, 7.35; N, 8.15.
Reference and Notes
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1982, 17, 2281. (b) Moser, F. H.; Thomas, A. L. The
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dichloronaphthalene to cyano groups by sodium cyanide
was reported,5 although the yield was inadequate (46%) and
1,6,10,15,19,24,28,33-Octaamyloxy-3,4,12,13,21,22,30,31-octa-
phenyl-37H,39H-naphthalocyanine (7e)
Mp 266.8–267.2 °C. 1H NMR (400 MHz, CDCl3): d = 9.05 (s, 8 H),
7.50–7.20 (m, 40 H), 5.24 (t, 16 H, J = 8.0 Hz), 2.63 (br, 2 H), 2.26
(quint, 16 H, J = 8.0 Hz), 1.68 (quint, 16 H, J = 8.0 Hz), 1.50 (sext,
Synlett 2011, No. 6, 862–868 © Thieme Stuttgart · New York

868
T. Miyazaki et al.
LETTER
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(5) Nakamori, T.; Chiba, T.; Kasai, T. Nippon Kagaku Zasshi
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