Synthesis and emission properties of 1,6-methano[10]annulene-3,4- dicarboximides

Article abstract of DOI:10.3987/COM-11-12135

A mixture of 1,6-methano[10]annulene-3,4-dicarboximide (1e) and 1,6-methano[10]annulene-3,4-dicarboxylic anhydride (3) was obtained through a two-step sequence involving cyanation and subsequent hydrolysis from ethyl 4-bromo-1,6-methano[10]annulene-3-carb

Full text of DOI:10.3987/COM-11-12135

HETEROCYCLES, Vol. 83, No. 4, 2011
789
HETEROCYCLES, Vol. 83, No. 4, 2011, pp. 789 - 796. © The Japan Institute of Heterocyclic Chemistry
Received, 5th January, 2011, Accepted, 21st February, 2011, Published online, 22nd February, 2011
DOI: 10.3987/COM-11-12135
SYNTHESIS AND EMISSION PROPERTIES OF
1,6-METHANO[10]ANNULENE-3,4-DICARBOXIMIDES
Shigeyasu Kuroda,a,* Naoko Tamura,a Ryuta Miyatake,a Naoko Matsumoto,a
Yoshikazu Horino,a Daisuke Miyawaki,b and Mitsunori Odab,*
aGraduate School of Science and Engineering, Faculty of Nano and Functional
Materials Science, University of Toyama, Gofuku 3190, Toyama, 930-8555 Japan
bDepartment of Chemistry, Faculty of Science, Shinshu University, Asahi 3-1-1,
Matsumoto, Nagano, 390-8621 Japan, e-mail: kuro@eng.u-toyama.ac.jp
Abstract – A mixture of 1,6-methano[10]annulene-3,4-dicarboximide (1e) and
1,6-methano[10]annulene-3,4-dicarboxylic anhydride (3) was obtained through a
two-step sequence involving cyanation and subsequent hydrolysis from ethyl
4-bromo-1,6-methano[10]annulene-3-carboxylate (5). Alkylations of 1e provided
1f and 1g, and the nucleophilic substitution of p-fluoronitrobenzene with 1e
yielded 1i. Copper-catalyzed arylations of 1e with arylhalides gave 1a and 1h.
Reactions of 3 with anilines afforded 1a and 1h. Emission properties of the imides
obtained are also reported.
INTRODUCTION
Spectroscopic properties and photochemistry of 2,3-naphtalimides have long received much attention,
especially their luminescent behavior,1 photocycloadditions2 and photoreductions.3 Quite recently Heagy
O
1e R = H
1f R = Me
1g R = Et
1h R = p-MeO-C6H4
1i R = p-NO2-C6H4
O
1a R = C6H5
1b R = p-Me-C6H4
1c R = p-Et-C6H4
1d R = n-Bu
N
R
NR
O
O
2,3-naphtalimides
et al. reported that dual fluorescent 2,3-naphtalimides could be used in ratiometric DNA detection and
white organic light-emitting devices.4 During the course of our continuing research on 1,6- methano[10]-
annulenes,5
we
have
been
interested
in
physical
and
chemical
properties
of

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HETEROCYCLES, Vol. 83, No. 4, 2011
1,6-methano[10]annulene-3,4-dicarboximides 1, which are structurally related to 2,3-naphtalimides.
Recently Zuo et al. reported synthesis of 1a–d from diethyl 1,6-methano[10]annulene-3,4-dicarboxylate
(2) as shown in Scheme 1.6 Their papers prompt us to report our independent synthetic efforts for the
imides7 and also emission properties thereof.8
O
O
R–NH2
1. NaOH
2. HCl
CO2Et
CO2Et
O
NR
O
O
2
3
1a–1d
Scheme 1
RESULTS AND DISCUSSION
Our synthesis started with ethyl 4-bromo-1,6-methano[10]annulene-3-carboxylate (5), which was
prepared in three steps from 1,3,5-cycloheptatriene-1,6-dicarbaldehyde (4)9 by the Neidlein’s method.10
Cyanation of 5 with CuCN in DMF11 gave 6 in 91% yield. Hydrolysis of 6 with NaOH in refluxing
dioxane and subsequent acidification provided a mixture of 3 and 1e in 51 and 29% yields, respectively
(Scheme 2).
3 steps
CuCN
DMF
CHO
CHO
Br
CN
CO2Et
CO2Et
4
5
6
O
O
NaOH
+
O
NH
dioxane
O
O
1e
3
Cu2O
X
R–I, NaH
NO2
H2N
Y
or
F
Y
Y= H or OMe
X=I, Y= H
X=Br, Y= OMe
NaH
1a, 1h
1f, 1g, 1i
Scheme 2
Reactions of 3 with aniline and p-anisidine in refluxing xylene afforded 1a and 1h in 32 and 49% yields,
respectively. These results confirm the data reported by Zuo et al.6 On the other hand, alkylations of 1e
with methyl- and ethyliodides under basic conditions gave 1f and 1g in 90 and 88% yields, respectively,
and the nucleophilic substitution of p-fluoronitrobenzene with 1e in DMF provided 1i in 94% yield.

HETEROCYCLES, Vol. 83, No. 4, 2011
791
Copper-catalyzed couplings12 of 1e with arylhalides were also examined. Iodobenzene and
p-bromoanisole react with 1e in the presence of copper(I) oxide in refluxing quinoline to give 1a and 1h
in 63 and 91% yields, respectively, which are better than those from 3.
Structures of all new compounds were characterized by spectroscopic and elemental or high-resolution
1
mass spectrometric analyses. Hydrogens at the methylene bridge of the carboximides in their H NMR
spectra are deshielded by the [10]annulene ring to appear at a range between ! 0.2 and –0.2. Their IR
spectra show typical carbonyl stretching bands of a carboximide group at 1750–1760 and 1680–1690 cm–1.
The carboximides exhibited four absorption bands in UV-Vis spectra (Figure 1). Among them, the bands
around 290 nm are very strong. All carboximides except 1h exhibited emission upon excitation at the
longest-wavelength absorptions. Figure 2 shows emission spectra of 1e in methanol for example. Their
photophysical data are shown in Table 1. Kossanyi et al. reported that the quantum yield of N-phenyl-2,3-
Figure 1. UV-Vis absorption spectra of 1a,1e, 1f, 1g, 1h, and 1i.
Inset is expanded spectra at a region of 370–470 nm. Methanol was
used as a solvent for 1a,1e, 1f, 1g, and 1h, and acetonitrile for 1i.
Figure 2. UV-Vis absorption and nomalized emission spectra
of 1e.
Table 1. Photophysical data of 1a, 1e, 1f, 1g, 1h, and 1i
a
"
!
emi (nm)
Stokes shift (nm)
#
emi (%)
!
abs (nm)
1ab
1eb
421
418
0.13
0.13
472
468
51
50
8.5
0.13
1fb
1gb
1hb
1ic
419
419
421
421
0.13
0.13
0.12
0.12
470
470
–
51
51
–
9.7
9.6
–
467
46
5.5
a in 104 Lmol–1cm–1, b measured in MeOH, c measured in MeCN

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naphtalimide (2 x 10–2%) was far smaller than those of the corresponding N-methyl derivative (24%) and
the unsubstituted compound (26%).1 On the other hand, the quantum yield of 1a (8.5%) is comparable to
those of 1f (9.7%) and 1g (9.6%) as shown in Table 1. Besides, it should be noted that the emission
spectra of the carboximides 1 do not show dual emission as seen in 2,3-naphtalimides. These observations
clearly reveal different emission properties of 1,6-methano[10]annulene-3,4-dicarboximides from those of
2,3-naphtalimides. Further studies on photochemical reactivity of the carboximides are now in progress.
CONCLUSION
The title 1,6-methano[10]annulene-3,4-dicarboximides 1 were synthesized by the independent synthetic
method involving cyanation and subsequent functional transformations starting from ethyl
4-bromo-1,6-methano[10]annulene-3-carboxylate (5). Their emission spectra showed different properties
from those of structurally related 2,3-naphtalimides.
EXPERIMENTAL
Melting points were measured on a Yanaco MP-3. IR spectra were recorded on a Perkin-Elmer Spectrum
RX I spectrometer. UV-Vis spectra were measured on a Shimadzu UV-1600 spectrometer. Emission
spectra were recorded in a degassed solution at rt on a Shimadzu RF-5300PC spectrometer. 1H and
13C-NMR were recorded with tetramethylsilane as internal standard on a JEOL !400 NMR instrument.
Mass spectra were measured on a JMS-700 mass spectrometer. Column chromatography was done with
Kieselgel 60. DMF and quinoline were purified by distillation from CaH2. Ethyl
4-bromo-1,6-methano[10]annulene-3-carboxylate was prepared from 1,3,5-cycloheptatriene-1,6-
dicarbaldehyde9 according to a literature procedure.10 Emission quantum yields were determined by
comparison of a total emission area with that of anthracene (" = 0.27, upon excitation at 356 nm in
ethanol). The refractive indices, n = 1.33 (methanol), n = 1.37 (ethanol), and n = 1.35 (acetonitrile), were
used in correction.
Synthesis of ethyl 4-cyano-1,6-methano[10]annulene-3-carboxylate (6)
A suspension of 4.15 g (14.2 mM) of 5 and 5.08 g (56.7 mM) of cuprous cyanide in 40 mL of DMF was
refluxed on an oil bath for 3 h under nitrogen atmosphere. After the reaction mixture was cooled to room
temperature, solids formed were removed by filtration and the filtrate was evacuated under reduced
pressure. The residue was purified by column chromatography. Elution with 20%AcOEt-hexane gave
1
3.15 g of 6 as a yellow oil (93% yield). H NMR (CDCl3) ! = 8.33 (s, 1H), 7.90 (s, 1H), 7.40–7.65 (m,
4H), 4.49 (q, J = 7.2 Hz, 2H), 1.47 (t, J = 7.2 Hz, 3H), 0.04 (dt, J = 9.4, 0.1, 1H), –0.18 (dt, J = 9.4, 0.1
Hz, 1H) ppm; 13C NMR (CDCl3) ! = 166.9, 137.2, 134.2, 129.8, 129.3, 129.2, 128.5, 128.5, 120.1, 115.1,

HETEROCYCLES, Vol. 83, No. 4, 2011
793
114.2, 107.8, 62.3, 34.3, 14.1 ppm; IR (KBr) #max = 3035w, 2983w, 2217m, 1719s, 1100s, 1050s, 870w,
830s, 773s cm-1; MS m/z (rel int) 239 (M+, 67), 211 (10), 194 (78), 167 (49), 166 (100), 140 (48), 139
(34); UV-Vis (CH3OH) $max = 271 (log% = 4.88), 403 (3.04) nm. HRMS m/z Calcd for C15H13NO2 (M+)
239.0946, found 239.0924.
Hydrolysis of 6; Synthesis of 1,6-methano[10]annulene-3,4-dicarboximide (1e) and
1,6-methano[10]annulene-3,4-dicarboxylic anhydride (3)
A 15% NaOH aqueous solution (30 mL) was added nto a solution of 3.15 g (13.2 mM) of 6 in 25 mL of
dioxane. This mixture was refluxed on an oil bath for 2 h. The resulted reaction mixture was poured in
100 mL of a saturated NaCl solution and was extracted with AcOEt (50 mL x 3). The combined organic
layer was dried over MgSO4. The solvent was evaporated to give yellow solids, which were collected and
washed with ether to give 0.81 g (29% yield) of 1e. The water layer was acidified with 3M HCl and the
crystals formed were collected by filtration to give 1.41 g (51% yield) of 3.
1
1e: Light yellow microcrystals, mp 248–250 ºC. H NMR (CDCl3) ! = 8.27 (s, 2H), 7.74 (brt, 1H), 7.62
(m, 2H), 7.35 (m, 2H), 0.10 (d, J = 10.0 Hz, 1H), –0.20 (d, J = 10.0 Hz, 1H) ppm; 13C NMR (CDCl3) ! =
169.7, 130.7, 130.2, 129.3, 128.9, 119.4, 35.3 ppm; IR (KBr) #max = 3528m, 3047m, 2955m, 1757vs,
1690vs, 1521s, 1331s, 1165s, 781s, 745s, 634m, 610w, 585m cm–1; UV-Vis (CH3OH) $max = 242 (log% =
4.39), 285 (4.77), 324 (3.93), 419 (3.23) nm; MS m/z (rel int) 212 (M++1, 10), 211 (M+, 67), 210 (10), 168
(28), 167 (17), 165 (12), 141 (12), 140 (100), 139 (70). Anal. Calcd for C13H9NO2: C, 73.92; H, 4.29; N,
6.56%. Found C, 73.58; H, 4.44; N, 6.56%.
3: Creamy white prisms, mp 166–168 ˚C (lit.,6 165–166 ˚C). 1H-NMR (CDCl3) ! = 8.41 (s, 2H), 7.73 (m,
13
2H), 7.42 (m, 2H), –0.08 (d, J = 10.0 Hz, 1H), –0.14 (d, J = 10.0 Hz, 1H) ppm; C-NMR(CDCl3) ! =
165.5, 132.4, 131.1, 130.0, 126.5, 120.9, 34.5 ppm; MS m/z (rel int) 212 (M+, 35), 168 (32), 140 (100),
113 (12), 89 (15), 70 (19), 63 (23).
Synthesis of N-methyl-, N-ethyl-, and N-p-nitrophenyl-1,6-methano[10]annulene-3,4-dicarboximides
(1f, 1g, and 1i)
To a solution of 70.1 mg (0.332 mM) of 1e in DMF was added 15.9 mg (0.390 mM) of 60% NaH in
mineral oil. This mixture was stirred at rt under nitrogen atmosphere for 1h. Then, to this solution was
added 31.0 µL (0.498 mM) of iodomethane. The resulted mixture was stirred at rt for further 2h, and then
was poured into water. The solids formed were collected by filtration, washed with aqueous ethanol, and
dried to give 67.0 mg (90% yield) of 1f. An analytical sample was obtained by recrystallization from
hexane-dichloromehane. By the similar method with iodoethane (rt, 3 h) and p-fluoronitrobenzene (120
˚C, 2 h), 1g and 1i were obtained in 88 and 94% yields, respectively.

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1f: Yellow microcrystals, mp 168–170 ºC. 1H NMR (CDCl3) ! = 8.25 (s, 2H), 7.57 (m, 2H), 7.33 (m, 2H),
3.20 (s, 3H), 0.18 (d, J = 9.6 Hz, 1H), –0.22 (d, J = 9.6 Hz, 1H) ppm; 13C NMR (CDCl3) ! = 170.2, 130.3,
129.8, 129.1, 128.5, 119.3, 35.6, 24.3 ppm. IR (KBr) "max = 3037w, 2956w, 2927w, 1750s, 1687vs, 1436s,
1384m, 1256w, 757s, 745s, 648m, 610w, 582m cm–1; UV-Vis (CH3OH) $max = 246 (log% = 4.35), 286
(4.69), 325 (3.81), 420 (3.11) nm; MS m/z (rel int) 225 (M+, 100), 224 (50), 197 (25), 181 (69), 168 (100),
166 (30), 141 (72). HRMS m/z Calcd for C14H11NO2 (M+) 225.0790, found 225.0770.
1g: Yellow microcrystals, mp 163–165 ºC. 1H NMR (CDCl3) ! = 8.25 (s, 2H), 7.58 (m, 2H), 7.32 (m, 2H),
3.77 (q, J = 7.2 Hz, 2H), 1.28 (t, J = 7.2 Hz, 3H), 0.19 (d, J = 10.0 Hz, 1H), –0.22 (d, J = 10.0 Hz, 1H)
ppm;13C NMR (CDCl3) ! = 170.0, 130.2, 129.8, 129.0, 128.6, 119.3, 35.5, 33.2, 13.8 ppm; IR (KBr) "max
= 3036w, 2981w, 2947w, 1752s, 1689vs, 1402s, 1380m, 761m cm–1; UV-Vis (CH3OH) $max = 247 (log% =
4.42), 286 (4.77), 326 (3.87), 420 (3.14) nm; MS m/z (rel int) 239 (M+, 36), 224 (82), 168 (40), 167 (9),
140 (100), 139 (65), 115 (13). Anal. Calcd for C15H13NO2: C, 75.30; H, 5.48; N, 5.85%, found C, 75.43; H,
5.45; N, 5.87%.
1i: Yellow solids, mp 268–270 ºC. 1H NMR (CDCl3) ! = 8.41 (s, 2H), 8.37 (d, J = 8.6 Hz, 2H), 7.82 (d, J
= 8.6 Hz, 2H), 7.67 (m, 2H), 7.39 (m, 2H), 0.19 (d, J = 9.8 Hz, 1H), –0.10 (d, J = 9.8 Hz, 1H) ppm; 13C
NMR (CDCl3) ! = 168.3, 146.3, 137.9, 131.4, 130.3, 129.6, 127.5, 126.3, 124.3, 120.0, 35.4 ppm; IR
(KBr) #max = 3079w, 1759s, 1703vs, 1518m 1493m, 1371s, 1337s, 847m, 756m, 745m cm–1; UV-Vis
(CH3CN) $max = 251 (log% = 4.27), 295 (4.73), 332sh (4.21), 421 (3.07) nm; MS m/z (rel int) 332 (M+, 66),
302 (10), 288 (17), 286 (10), 242 (23), 168 (43), 140 (100), 139 (72). HRMS m/z Calcd for C19H12N2O4
(M+) 332.0797, found, 332.0773.
Synthesis of N-phenyl- and N-p-methoxyphenyl-1,6-methano[10]annulene-3,4-dicarboximides (1a
and 1h) from 3
A solution of 85.0 mg (0.401 mM) of 3 and 41.1 mg (0.441 mM) of aniline in 5 mL of xylene was
refluxed on an oil bath for 5 h under nitrogen atmosphere. The solvent was removed under reduced
pressure and the residue was purified by column chromatography (CHCl3/hexane = 1/4) to give 37.1 mg
(32% yield) of 1a. Compound 1h was obtained similarly with 3 and p-anisidine (49% yield).
1a: Yellow microcrystals, mp 158–159 ºC (lit.,6 170–171 ˚C).13 1H NMR (CDCl3) ! = 8.37 (s, 2H), 7.64
(m, 2H), 7.50 (m, 3H), 7.47 (m, 2H), 7.36 (m, 2H), 0.21 (d, J = 9.8 Hz, 1H), –0.14 (d, J = 9.8 Hz, 1H)
ppm; 13C NMR (CDCl3) ! = 169.1, 130.9, 130.1, 129.2, 129.1, 129.0, 128.1, 128.0, 126.5, 119.6, 35.5
ppm; UV-Vis (CH3OH) $max = 253 (log% = 3.27), 290 (4.71), 327 (2.91), 422 (3.12) nm.
1h: Yellow microcrystals, mp 217–218 ºC. 1H NMR (CDCl3) ! = 8.35 (s, 2H), 7.62 (m, 2H), 7.37 (d, J =
8.8 Hz, 2H), 7.35 (m, 2H), 7.02 (d, J = 8.8 Hz, 2H), 3.85 (s, 3H), 0.21 (d, J = 9.8 Hz, 1H), –0.16 (d, J =
9.8 Hz, 1H) ppm;13C NMR (CDCl3) ! = 169.3, 159.1, 130.8, 130.0, 129.2, 128.2, 127.8, 124.7, 119.6,

HETEROCYCLES, Vol. 83, No. 4, 2011
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114.4, 55.5, 35.5 ppm; IR (KBr) #max = 3034w, 1756s, 1705vs, 1508s, 1387s, 1246s, 1154m, 1028m,
827m, 774m, 751m cm–1; UV-Vis (CH3OH) $max = 229 (log% = 4.33), 289 (4.77), 338 (3.83), 421 (3.11)
nm; MS m/z (rel int) 317 (M+, 100), 302 (31), 168 (22), 140 (56), 139 (33). HRMS m/z Calcd for
C20H15NO3 (M+) 317.1052, found 317.1049.
Synthesis of N-phenyl- and N-p-methoxyphenyl-1,6-methano[10]annulene-3,4-dicarboximides (1a
and 1h) from 1e
A suspension of 106 mg (0.500 mM) of 1e, 112 mg (0.550 mM) of iodobenzene, and 36 mg (0.25 mM) of
copper(I) oxide in 5 mL of quinoline was refluxed on an oil bath for 5 h under nitrogen atmosphere.
Solids were removed by filtration. The solvent was removed under reduced pressure and the residue was
purified by column chromatography (CHCl3/hexane = 1/4) to give 90.4 mg (63% yield) of 1a. By the
similar way with p-bromoanisole and 1e, 1h was obtained in 91% yield.
ACKNOWLEDGEMENTS
This research was carried out in part under financial support from Kyowa Hakko Chemical Co. Inc (for S.
K). A financial support from the Faculty of Science at Shinshu University (for M.O.) is also
acknowledged. We also thank Ms Kanako Tsumuraya and Kimiko Kanayama at University of Toyama
for their preliminary research assistance for preparing compounds 1e and 3.
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