Synthesis, structure, and mesomorphic properties of liquid crystals with a bitropone core

Article abstract of DOI:10.1246/bcsj.75.1353

New troponoid liquid crystals (1-4) with a bitropone core were prepared. The ester derivatives (1) had enantiotropic smectic A and/or C phases with higher thermal stabilities than the corresponding benzenoid derivatives (5), which had a smectic B phase. T

Full text of DOI:10.1246/bcsj.75.1353

c. Jpn.
© 2002 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 75, 1353–1358 (2002) 1353
e Chemical
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Synthesis, Structure, and Mesomorphic Properties of Liquid Crystals
with a Bitropone Core
Liquid Crystals with a Bitropone Core
K. Kubo et al.
Kanji Kubo,* Takanori Sutoh,† Akira Mori,* and Seiji Ujiie††
02
53
58
SJA8
09-2673
408
Institute of Advanced Material Study, 86, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580
†Graduate School of Engineering Sciences, 39, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580
††Department of Material Science, Interdisciplinary Faculty of Science and Engineering, Shimane University,
Nishikawatsu, Matue 690-8504
(Received November 12, 2001)
01
02
New troponoid liquid crystals (1–4) with a bitropone core were prepared. The ester derivatives (1) had enantiotro-
pic smectic A and/or C phases with higher thermal stabilities than the corresponding benzenoid derivatives (5), which
had a smectic B phase. The amide derivatives (3) had an enantiotropic smectic A phase, but the ether (2) and alkylamine
(4) derivatives were not mesomorphic. The crystals of 1c had a layer structure with an intermolecular π–π interaction
between the bitropone cores. X-ray diffraction studies revealed that the layer spacings of the smectic A and C phases of
1i were not very much different.
.2
.3
The typical structural units of rod-like liquid crystals pos-
sess a fairly rigid core, which generally consists of six-mem-
bered ring systems.1 The preparation of new types of liquid-
crystal materials with rings other than six-membered rings had
received less attention. However, it is important to extend the
molecular design of liquid crystals to involve other ring sys-
tems from not only theoretical, but also the practical, points of
view. Recently we reported that monocyclic 2-alkanoyloxy-5-
alkoxytropones showed a monotropic smectic A phase.2 Fur-
thermore, we prepared troponoid liquid crystals with a seven-
membered core, such as 5-hydroxytropolone,2 5-ami-
notropolone,3 2-amino-5-hydroxytropone,4 5-cyanotropolo-
ne,5 and 2-amino-5-phenyltropone.6 The tropolone core has a
large dipole moment (3.5 D),7 which would help to form a lay-
er structure. The cores enhanced the formation of smectic
phases when compared with the corresponding benzenoids. In
benzenoid liquid crystals, a biphenyl unit has been widely used
as one of the most useful cores.1 However, liquid crystals with
a bitropone core have not been reported. In this paper, the
crystal structures and mesomorphic properties of bitropone
compounds are compared with those of the corresponding ben-
zenoids.
5,5ꢀ-bitropone with alkanoyl chlorides. On the other hand, the
methylation of 5,5ꢀ-bitropolone with excess of diazomethane
gave 2,2ꢀ-dimethoxy-5,5ꢀ-bitropone quantitatively. Finally,
2,2ꢀ-dimethoxy-5,5ꢀ-bitropone was reacted with various alkyl-
amines to give 2-alkylaminotropone derivatives (4) in 15–43%
yield. The low yields of 1–4 are attributed to the poor solubili-
ty of the starting materials, such as 5,5ꢀ-bitropolone, 2,2ꢀ-
dimethoxy-5,5ꢀ-bitropone, and 2,2ꢀ-diamino-5,5ꢀ-bitropone.
The starting materials could not be recovered. The benzenoid
derivatives (5,6)9 were prepared by the esterification and alky-
lation of 4,4ꢀ-biphenol with alkanoyl chlorides and alkyl bro-
mides (Scheme 1). The structure and purity of 1 and 2 were
ascertained by NMR spectroscopy and elemental analysis.
The transition temperatures and thermal behaviors of the tex-
tures were determined using a differential scanning calorime-
ter and a polarizing microscope equipped with a hot stage as
well as by an X-ray diffraction study.
Mesomorphic Properties. The thermal behaviors of
bitropones (1–4) and the corresponding benzenoids (5,6) are
summarized in Table 1. Troponoids (1) and benzenoids (5)
have different mesomorphic sequences. The former series had
a phase sequence of crystals–smectic A–isotropic for n = 7
and crystals–smectic C–smectic A–isotropic for n = 8–15,
while the latter series have a phase sequence of crystals–smec-
tic B–isotropic. The smectic phases were determined from a
following observation as well as from X-ray diffraction stud-
ies, i.e., bâtonnets, focal-conic fan, and homeotropic textures
for the smectic A phase; broken-fan and schlieren textures for
the smectic C phase; homeotropic and mosaic textures for the
smectic B phase. As shown in Table 1, troponoids (1) showed
smectic phases with higher thermal stabilities than the corre-
sponding benzenoids (5). This is due to the presence of the
carbonyl group of a tropone core. The ether and amine deriva-
Results and Discussion
5,5ꢀ-Bitropolone was obtained by homocoupling reactions
of 5-iodotropolone in the presence of [Pd(PPh3)4].8 The reac-
tion of 5,5ꢀ-bitropolone with alkanoyl chlorides or alkyl bro-
mides in a triethylamine-HMPA (hexamethylphosphoric tria-
mide) solution afforded the ester and ether derivatives (1 and
2) in 13–40% and 11–22%, respectively, while 2,2ꢀ-diamino-
5,5ꢀ-bitropone was prepared by the amination of 5,5ꢀ-
bitropolone with aqueous NH3. The amide derivatives (3)
were obtained in 7–13% yield by the reaction of 2,2ꢀ-diamino-

1354 Bull. Chem. Soc. Jpn., 75, No. 6 (2002)
Liquid Crystals with a Bitropone Core
Scheme 1.
Table 1. Transition Temperatures of 1–6
Transition temp/°C
Cr•143.0•I
n
n
Transition temp/°C
Cr•144.3•I
1a
1b
1c
1d
1e
1f
5
4b
4f
4i
6
6
7
8
9
Cr•138.0•I
Cr•129.6•SA•132.2•I
Cr•117.2•SC•119.8•SA•148.3•I
Cr•120.9•SC•126.6•SA•155.2•I
10 Cr•145.3•I
14 Cr•140.1•I
5a
5b
5c
5d
5e
5f
5g
5h
5i
5
6
7
8
9
Cr•117.0•SB•118.0•I
Cr•105.0•SB•118.0•I
Cr•95.0•SB•122.0•I
Cr•95.0•SB•121.0•I
Cr•98.0•SB•122.0•I
10 Cr•119.2•SC•129.8•SA•156.7•I
11 Cr•124.3•SC•128.2•SA•157.2•I
12 Cr•110.0•SC•123.3•SA•152.5•I
13 Cr•110.2•SC•125.2•SA•146.1•I
14 Cr•115.0•SC•131.8•SA•151.6•I
15 Cr•118.2•SC•131.6•SA•153.4•I
1g
1h
1i
10 Cr•100.0•SB•121.4•I
11 Cr•101.1•SB•120.8•I
12 Cr•102.1•SB•120.4•I
13 Cr•102.0•SB•118.2•I
14 Cr•105.3•SB•118.9•I
15 Cr•119.0•I
1j
1k
2b
2f
6
Cr•141.3•I
10 Cr•141.4•I
14 Cr•138.5•I
5j
2i
5k
6b
6f
3a
3e
3i
5
9
Cr•160.0•I
Cr•149.6•(SA•142.7•) I
6
Cr•124.0•N•130.0•I
10 Cr•113.0•I
14 Cr•115.1•I
13 Cr•138.3•SA•144.5•I
6i
Cr: crystals, SA: smectic A phase, SC: smectic C phase, SB: smectic B phase, N: nematic
phase, I: isotropic liquid.
tives (2 and 4), however, were not mesomorphic. Compared
X-ray Crystal-Structure Analysis of 1c and 5a.
Two
with the melting points of compounds 1 and 2, it was con-
firmed that the ester groups at C-2 and C-2ꢀ of 1 assisted in the
appearance of the mesophase through a sigmatropic rearrange-
ment.2 The amide derivatives (3) had a monotropic and an
enantiotropic SA phase, respectively, when the alkyl chains
were n = 9 and 13, though the melting points of the com-
pounds 3 were higher than those of 1. This means that the hy-
drogen bonds between a NH and tropone carbonyl group make
the intermolecular interaction stronger.
single crystals of 1c and 5a were obtained by recrystallization
from chloroform. The molecular structure of 1c is shown in
Fig. 1. The planarity of the seven-membered ring of 1c is fair-
ly good. The C–C bond lengths of the seven-membered ring of
1c are similar to those of tropone10 and distinct from 2-butoxy-
5-nitrotropone.11
The intersection angle between two tropolone rings, A [de-
fined by C1/C2/C3/C4/C5/C6/C7/O1/O2] and B [defined by
C8/C9/C10/C11/C12/C13/C14/O3/O4], is 51.0°, which is dis-

K. Kubo et al.
Bull. Chem. Soc. Jpn., 75, No. 6 (2002) 1355
tinct from that [0°] of biphenyl.12 While the intersection an-
gles between the tropolone ring A and the ester plane [defined
by O2/O5/C15] and between the tropolone ring B and the ester
plane [defined by O4/O6/C23] are 76.9° and 79.5°, respective-
ly, which are similar to those [71.5° and 71.8°] of tropolonyl p-
chlorobenzoate13 and 2-butanoyl-5-nitrotropone.11 The paraf-
fin chains all have trans conformations, except for one gauche
conformation (C25–C26–C27–C28).
Intermolecular π–π interactions between the bitropone cores
(head-to-tail) of 1c were observed, as shown in Fig. 2. The
distance between the intermolecular tropolone planes is
3.46(3) Å for C8–C10i (symmetry codes i: 2−x, −y, 1−z),
which is similar to that [3.399 Å] for C1–C5ii (ii: −x, 1−y,
1−z) of 2-butoxy-5-nitrotropone.11
C12], is 18.8°, which is distinct from that [0°] of biphenyl.12
On the other hand, the intersection angles between plane A and
the ester plane [defined by O1/O2/C13] and between plane B
and the ester plane [defined by O3/O4/C19] are 57.1° and
28.9°. The paraffin chains all have trans conformations.
Intermolecular π–π interactions between the phenyl planes
of 5a were observed (Fig. 4). The distance between the inter-
molecular phenyl planes is 3.42 Å for C2–C5iii (iii: x, y, 1+z),
which is within the range of the intermolecular π–π interac-
tion.14 The crystals of 1c and 5a have distinct layer structures,
such as smectic phases (Fig. 5). The troponoids (1) showed
smectic phases with higher thermal stabilities than the corre-
sponding benzenoids (5). This suggests that the intermolecular
π–π interaction between the bitropone cores is stronger than
that between the biphenyl cores.
The molecular structure of 5a is shown in Fig. 3. The inter-
section angle between two benzene rings, Aꢀ [defined by C1/
C2/C3/C4/C5/C6] and Bꢀ [defined by C7/C8/C9/C10/C11/
X-ray Diffraction Study. We measured the X-ray diffrac-
tion pattern of the mesophases. The smectic layer spacings (d)
Fig. 1. ORTEP drawing of 1c with the numbering. Thermal ellipsoids are drawn with 50% probabilities.
Fig. 2. π–π interaction of head-to-tail dimer of 1c.
Fig. 3. ORTEP drawing of 5a with the numbering. Thermal ellipsoids are drawn with 50% probabilities.
Fig. 4. π–π interaction of 5a showing benzene–benzene stacking arrangement.

1356 Bull. Chem. Soc. Jpn., 75, No. 6 (2002)
Liquid Crystals with a Bitropone Core
with a bitropone core were investigated. The ester derivatives
(1) had enantiotropic smectic A and C phases. From a compar-
ison of the transition temperatures of compounds 1 and 5, a
bitropone core should be more useful to enhance the thermal
stabilities of the liquid–crystalline states than a biphenyl core.
The molecules of 1c and 5a form layer structures with inter-
molecular π–π interactions. Packing models of compounds 1
and 5 in the smectic phases were consistent with the observa-
tion of single crystallographic analyses. Thus, a bitropone
core should be useful to form a tilted layer structure.
Experimental
Elemental analyses were performed at the elemental analysis
laboratory of Kyushu University. The melting points were ob-
tained using a Yanagimoto micro-melting-point apparatus and are
uncorrected. The NMR spectra were recorded using JEOL Lamb-
da 400 and 600 spectrometers and solutions in CDCl3 at room
temperature; the chemical shifts are expressed in δ units. The
mass spectra were measured with JEOL 01SG-2 and JMS-700
spectrometers. The stationary phase used in column chromatogra-
phy was Wakogel C-300. The transition temperatures were mea-
sured by differential scanning calorimetry (Seiko DSC 200) and
the mesomorphic phases were observed by polarizing optical mi-
croscopy (Olympus BHSP BH-2 equipped with a Linkam TH-
600MS hot stage). X-ray diffraction measurements were carried
out with a Rigaku Rint 2100 system using Ni-filtered Cu-Kα radi-
ation at various temperatures. The measuring temperatures were
controlled with a Linkam HFS-91 hot stage.
Preparation of Bitropolone. A mixture of 5-iodotropolone
(300 mg, 1.21 mmol), [Pd(PPh3)4] (71 mg, 0.061 mmol), and tri-
ethylamine (0.48 cm3) in THF (6 cm3) was heated at 80 °C under
nitrogen. Acidification of the alkaline solution with 6 M HCl
yielded brownish-yellow precipitates, which were collected by fil-
tration, and washed with ethyl acetate (30 cm3) to give yellow
powders (91 mg, 69%) of 5,5ꢀ-bitropolone; mp 260 °C (decomp)
[lit.,8 260 °C (decomp)], 1H NMR (DMSO-d6) δ 7.25 (4H, d, J =
11.5 Hz) and 7.56 (4H, d, J = 11.5 Hz); 13C NMR (DMSO-d6) δ
124.7 (4C), 136.9 (4C), 141.6 (4C), and 171.1 (2C).
Fig. 5. Crystal structures of (a) 1c viewed down the b axis
and (b) 5a viewd down the c axis.
of 1i were observed to be 35.6 Å (140 °C) for the smectic A
phase and 36.5 Å (120, 125, and 130 °C) for the smectic C
phase, respectively. The d of 5d was observed to be 28.3 Å
(105 and 110 °C) for the smectic B phase. The calculated mo-
lecular lengths (l) of 1i and 5d by the MM2 method were
found to be 43.6 Å and 31.4 Å, respectively. The d/l ratios of
the smectic A and C phases of 1i are 0.82 and 0.84, respective-
ly. Although it seems to be unusual that both are almost the
same and the former smectic A has rather a smaller d/l ratio
than the latter, the d/l value (0.82) is typical for smectic A
phases,14 where terminal chains deform and the cores random-
ly tilt to make molecules orthogonal to the layer planes, as
shown in Fig. 6. In the case of the smectic C phase, the mole-
cules had an organized tilt direction to the normal of the layer
planes, where the mobility of the terminal chains would be re-
duced. As a result, the layer spacings between the smectic A
and C phases were not very different from each other. On the
other hand, the layer spacing of the smectic B phase is almost
identical with the calculated molecular length.
Preparation of Ester Derivatives (1).
Decanoyl chloride
(626 mg, 3.28 mmol) was added to an HMPA (2 cm3) solution of
5,5ꢀ-bitropolone (100 mg, 0.41 mmol) and triethylamine (1 cm3).
The reaction mixture was stirred at room temperature for 3 h. The
mixture was poured into a 2 M HCl solution and extracted with
ethyl acetate. The organic layer was washed with a saturated
NaCl solution and dried over Na2SO4. The organic layer was
evaporated in vacuo to leave a residue which was chromato-
graphed in hexane–ethyl acetate or hexane–chloroform mixture on
a silica-gel column to give crystals. The crystals were recrystal-
lized with hexane–benzene (1:1 v/v) to give colorless crystals (1e,
91 mg, 40%). 1a (18%); 1H NMR (CDCl3) δ 0.93 (6H, t, J = 7.5
Hz), 1.34–1.47 (8H, m), 1.79 (4H, quit, J = 7.5 Hz), 2.64 (4H, t, J
= 7.5 Hz), 7.20 (4H, d, J = 11.4 Hz), and 7.27 (4H, d, J = 11.4
Hz); FAB-MS m/z 439 (M + H+); Found: C, 70.99; H, 6.87%.
Calcd for C26H30O6: C, 71.21; H, 6.90%. 1b (28%); Found: C,
71.87; H, 7.33%. Calcd for C28H34O6: C, 72.08; H, 7.35%. 1c
(35%); Found: C, 72.65; H, 7.65%. Calcd for C30H38O6: C, 72.85;
H, 7.74%. 1d (21%); Found: C, 73.42; H, 8.05%. Calcd for
C32H42O6: C, 73.53; H, 8.10%. 1e (40%); Found: C, 74.12; H,
8.35%. Calcd for C34H46O6: C, 74.15; H, 8.42%. 1f (17%);
Found: C, 74.52; H, 8.67%. Calcd for C36H50O6: C, 74.71; H,
8.71%. 1g (22%); Found: C, 75.11; H, 8.90%. Calcd for
Fig. 6. Packing model of 1i in the smectic A phase. Terminal
alkyl chains deformed and bitropolone cores randomly tilt-
ed.
The X-ray diffraction pattern of 3i was taken at 137 °C (on
cooling), when a SA phase appeared obtained from a powder
sample of 3i. The layer spacing of 3i was 35.8 Å, whereas the
calculated molecular length from MM2 calculations is 45.1Å.
The d/l ratio of the smectic A phase of 3i is 0.79, which is sim-
ilar to that of 1i.
In conclusion, the mesogenic properties of liquid crystals

K. Kubo et al.
Bull. Chem. Soc. Jpn., 75, No. 6 (2002) 1357
C38H54O6: C, 75.21; H, 8.97%. 1h (25%); Found: C, 75.68; H,
9.22%. Calcd for C40H58O6: C, 75.67; H, 9.21%. 1i (24%);
Found: C, 75.92; H, 9.37%. Calcd for C42H62O6: C, 76.09; H,
9.43%. 1j (18%); Found: C, 76.44; H, 9.65%. Calcd for
C44H66O6: C, 76.48; H, 9.63%. 1k (13%); Found: C, 76.68; H,
9.79%. Calcd for C46H70O6: C, 76.84; H, 9.81%.
8.82; N, 5.10%. 3i (13%); Found: C, 76.09; H, 9.72; N, 4.18%.
Calcd for C42H64N2O4: C, 76.32; H, 9.76; N, 4.24%.
Preparation of Amine Derivatives (4).
2,2ꢀ-Dimethoxy-
5,5ꢀ-bitropone was prepared by the methylation of 5,5ꢀ-bitropolo-
ne with diazomethane, as reported before. A mixture of 2,2ꢀ-
dimethoxy-5,5ꢀ-bitropone (50 mg, 0.21 mmol) and 1-hexylamine
(4 cm3) was stirred at 120 °C for 24 h. The mixture was evaporat-
ed in vacuo to leave a residue, which was chromatographed in
hexane-ethyl acetate or hexane-chloroform mixture on a silica-gel
column to give crystals. The crystals were recrystallized with
hexane–benzene (1:1 v/v) to give yellow crystals (4b, 36 mg,
43%).
Preparation of Ether Derivatives (2). 1-Bromodecane (626
mg, 3.28 mmol) was added to a HMPA (1 cm3) solution of 5,5ꢀ-
bitropolone (50 mg, 0.21 mmol) and triethylamine (1 cm3). The
reaction mixture was stirred at 60 °C for 7 h. The mixture was
poured into 2 M HCl, and organic matter was extracted with ethyl
acetate. The organic layer was washed with a saturated NaCl so-
lution and dried over Na2SO4. The organic layer was evaporated
in vacuo to leave a residue, which was chromatographed in hex-
ane–ethyl acetate or hexane–chloroform mixture on a silica-gel
column to give crystals. The crystals were recrystallized with
hexane–benzene (1:1 v/v) to give pale-yellow crystals (18 mg,
4b (43%); 1H NMR (CDCl3) δ 0.91 (6H, t, J = 7.3 Hz), 1.24–
1.42 (8H, m), 1.46 (4H, quit, J = 7.3 Hz), 1.77 (4H, quit, J = 7.3
Hz), 3.34 (4H, q, J = 7.3 Hz), 6.60 (2H, d, J = 11.1 Hz), 7.19
(2H, d, J = 12.0 Hz), 7.25 (2H, brs), 7.35 (2H, dd, J = 11.1, 2.0
Hz), and 7.34 (2H, dd, J = 12.0, 2.0 Hz); 13C NMR (CDCl3) δ
14.4 (2C), 22.2 (2C), 27.2 (2C), 28.8 (2C), 31.8 (2C), 43.2 (2C),
109.1 (2C), 128.6 (2C), 136.1 (2C), 138.1 (2C), 154.9 (2C), and
176.1 (2C); Found: C, 76.46; H, 8.83; N, 6.79%. Calcd for
C26H36N2O2: C, 76.43; H, 8.88; N, 6.86%. 4f (34%); Found: C,
78.23; H, 10.11; N, 5.45%. Calcd for C34H52N2O2: C, 78.41; H,
10.06; N, 5.38%. 4i (15%); Found: C, 79.42; H, 10.82; N, 4.42%.
Calcd for C42H68N2O2: C, 79.69; H, 10.83; N, 4.43%.
1
20%). 2b (19%); H NMR (CDCl3) δ 0.91 (6H, t, J = 7.0 Hz),
1.28–1.53 (12H, m), 1.94 (4H, quit, J = 7.0 Hz), 4.09 (4H, t, J =
7.0 Hz), 6.79 (2H, d, J = 10.5 Hz), 7.12 (2H, dd, J = 12.3, 1.9
Hz), 7.27 (2H, d, J = 10.5 Hz), and 7.34 (2H, dd, J = 12.3, 1.9
Hz) ; 13C NMR (CDCl3) δ 14.0 (2C), 22.5 (2C), 25.6 (2C), 28.6
(2C), 31.5 (2C), 69.7 (2C), 112.9 (2C), 131.7 (2C), 136.8 (2C),
137.0 (2C), 141.9 (2C), 164.5 (2C), and 179.7 (2C); FAB-MS m/z
411 (M+H+); Found: C, 75.98; H, 8.34%. Calcd for C26H34O4: C,
76.06; H, 8.35%. 2f (20%); Found: C, 77.89; H, 9.65%. Calcd for
C34H50O4: C, 78.12; H, 9.64%. 2i (11%); Found: C, 79.26; H,
10.40%. Calcd for C42H66O4: C, 79.44; H, 10.48%.
Preparation of Benzenoid Derivatives (5,6).
The ben-
zenoid derivatives (5,6) were prepared by the esterification and
etherification of 4,4ꢀ-biphenol with alkanoyl chloride or alkyl bro-
mide, as reported in a previous paper.9
1
Preparation of 2,2ꢀ-Diamino-5,5ꢀ-bitropone. A mixture of
5,5ꢀ-bitropolone (693 mg, 2.87 mmol), NH3 aq (50 cm3), and
methanol (50 cm3) was heated at 150 °C in a sealed tube for 12 h.
The yellow precipitates were collected by filtration and recrystal-
lized with methanol to give yellow crystals (425 mg, 63%); mp >
5i; H NMR (CDCl3) δ 0.88 (6H, t, J = 7.4 Hz), 1.20–1.47
(40H, m), 1.77 (4H, quit, J = 7.4 Hz), 2.58 (4H, t, J = 7.4 Hz),
7.14 (4H, d, J = 8.7 Hz), and 7.55 (4H, d, J = 8.7 Hz); 13C NMR
(CDCl3) δ 14.1 (2C), 22.7 (2C), 25.0 (2C), 29.1 (2C), 29.3 (2C),
29.4 (2C), 29.5 (2C), 29.61 (4C), 29.66 (2C), 29.69 (2C), 31.9
(2C), 34.4 (2C), 121.9 (4C), 128.1 (4C), 138.1 (2C), 150.2 (2C),
and 172.4 (2C); FAB-MS m/z 607 (M+H+); Found: C, 79.21; H,
10.30%. Calcd for C40H62O4: C, 79.16; H, 10.30%. 5j; Found: C,
79.46; H, 10.45%. Calcd for C42H66O4: C, 79.44; H, 10.48%.
1
300 °C, H NMR (DMSO-d6) δ 6.97 (2H, d, J = 12.1 Hz), 7.00
(2H, d, J = 11.1 Hz), 7,34 (2H, d, J = 11.1 Hz), and 7.41 (2H, d,
J = 12.1 Hz); 13C NMR (DMSO-d6) δ 111.7 (2C), 128.5 (2C),
135.5 (2C), 136.4 (2C), 136.8 (2C), 157.3 (2C), and 174.5 (2C);
HR EI-MS Found: m/z 240.0900. Calcd for C14H12N2O2:
240.0899.
1
6i; H NMR (CDCl3) δ 0.88 (6H, t, J = 6.9 Hz), 1.20–1.41
(40H, m), 1.46 (4H, quit, J = 6.9 Hz), 1.80 (4H, quit, J = 6.9 Hz),
3.98 (4H, t, J = 6.9 Hz), 6.94 (4H, d, J = 8.7 Hz), and 7.46 (4H,
d, J = 8.7 Hz); 13C NMR (CDCl3) δ 14.1 (2C), 22.7 (2C), 26.1
(2C), 29.31 (2C), 29.37 (2C), 29.42 (2C), 29.59 (2C), 29.61 (2C),
29.66 (2C), 29.67 (2C), 29.68 (2C), 29.70 (2C), 31.9 (2C), 68.1
(2C), 114.7 (4C), 127.6 (4C), 133.3 (2C), and 158.2 (2C); FAB-
MS m/z 579 (M+H+); Found: C, 83.02; H, 11.50%. Calcd for
C40H66O2: C, 82.98; H, 11.49%.
Preparation of Amide Derivatives (3). Tetradecanoyl chlo-
ride (0.40 mL, 1.47 mmol) was added to a HMPA (1 cm3) solution
of 2,2ꢀ-diamino-5,5ꢀ-bitropone (50 mg, 0.21 mmol) and triethyl-
amine (0.5 cm3). The reaction mixture was stirred at room tem-
perature for 8 h. The mixture was poured into 2 M HCl, and or-
ganic matter was extracted with ethyl acetate. The organic layer
was washed with a saturated NaCl solution and dried over
Na2SO4. The organic layer was evaporated in vacuo to leave a res-
idue, which was chromatographed in hexane-ethyl acetate or a
hexane–chloroform mixture on a silica-gel column to give crys-
tals. The crystals were recrystallized with hexane–benzene (1:1
v/v) to give pale-yellow crystals (19 mg, 13%). 3a (7%); 1H NMR
(CDCl3) δ 0.92 (6H, t, J = 7.2 Hz), 1.30–1.46 (8H, m), 1.76 (4H,
quit, J = 7.2 Hz), 2.56 (4H, t, J = 7.2 Hz), 7.34 (2H, dd, J = 10.7,
2.0 Hz), 7.41 (2H, d, J = 12.6 Hz), 7.50 (2H, dd, J = 12.6, 2.0
Hz), 9.10 (2H, d, J = 10.7 Hz), and 9.39 (2H, s); 13C NMR
(CDCl3) δ 13.9 (2C), 22.3 (2C), 25.0 (2C), 31.3 (2C), 38.7 (2C),
120.5 (2C), 135.2 (2C), 136.1 (2C), 138.3 (2C), 144.6 (2C), 146.5
(2C), 173.5 (2C), and 178.3 (2C); EI MS: m/z 436 (M+), 240 (base
peak); Found: C, 71.61; H, 7.40; N, 6.46%. Calcd for
C26H32N2O4: C, 71.53; H, 7.39; N, 6.42%. 3e (19%); Found: C,
74.21; H, 8.77; N, 5.07%. Calcd for C34H48N2O4: C, 74.42; H,
X-ray Crystallographic Analyses of 1c and 5a.
Single
crystals of 1c and 5a for X-ray analysis were grown in a chloro-
form solution at room temperature. Two colorless crystals of 1c
and 5a having approximate dimensions of 0.10 × 0.10 × 0.05
mm and 0.35 × 0.30 × 0.06 mm were mounted on a glass fiber in
a random orientation, respectively. A preliminary examination
and data collection were performed with Mo Kα radiation (λ =
0.71069 Å) on a Rigaku RAXIS-RAPID equipped with an imag-
ing plate. Data collection and cell refinement: MSC/AFC diffrac-
tometer control. Data reduction: teXsan for windows version
1.06.16 Structure solution: SIR92.17 Refinement: SHELXL97.18
Molecular graphics: ORTEP-III.19 All H atoms were fixed at ideal
positions and restrained with Uiso held fixed to 1.2Ueq of the parent
atoms. Crystallographic data have been deposited at the CCDC,
12 Union Road, Cambridge CB2 1EZ, UK and copies can be ob-

1358 Bull. Chem. Soc. Jpn., 75, No. 6 (2002)
Liquid Crystals with a Bitropone Core
tained on request, free of charge, by quoting the publication cita-
tion and deposition numbers 180991 and 180992. The data also
were deposited as Document No. 75029 at the Office of the Editor
of Bull. Chem. Soc. Jpn.
9
H. Kawakuda and S. Yano, 14th Jpn. Symp. Liquid Crys-
tals, Sendai, September, 1988, Abstr., No. 2D312; F. K. Beilstein,
“Handbuch der Organischen Chemie,” J. Springer, Berlin (1987).
10 M. J. Barrow, O. S. Mills, and G. Filippini, J. Chem. Soc.,
Chem. Commun., 1973, 66.
11 K. Kubo, T. Tsuruta, and A. Mori, Acta Crystallogr., Sect.
E, 57, o326 (2001).
12 G.-P. Charbonneau and Y. Delugeard, Acta Crystallogr.,
Sect. B, 33, 1586 (1977).
13 J. P. Shaefer and L. L. Reed, J. Am. Chem. Soc., 93, 3902
(1971).
14 C. K. Prout, T. M. Orley, I. J. Tickle, and J. D. Wright, J.
Chem. Soc., Perkin Trans., 1973, 523; K. Nakasuji, H. Kubota, T.
Kotani, I. Murata, G. Saito, T. Enoki, K. Imaeda, H. Inokuchi, M.
Honda, A. Kawamoto, and J. Tanaka, J. Am. Chem. Soc., 108,
3460 (1986); K. Nakasuji, M. Sasaki, T. Kotani, I. Murata, T.
Enoki, K. Imaeda, H. Inokuchi, A. Kawamoto, and J. Tanaka, J.
Am. Chem. Soc., 109, 6970 (1987); C. A. Hunter, and J. K. M.
Sanders, J. Am. Chem. Soc., 112, 5525 (1990); M. Munakata, J.
Dai, M. Maekawa, K.-S. Takayoshi, and J. Fukui, J. Chem. Soc.,
Chem. Commun., 1994, 2331; A. Mori, K. Kubo, T. Nishimura, N.
Kato, and H. Takeshita, Chem. Lett., 2000, 180.
Crystal data for 1c: C30H38O6, monoclinic, P21/a, a =
13.770(1) Å, b = 8.2007(6) Å, c = 25.362(2) Å, β = 103.688(3)°,
V = 2782.6(4) Å3, Z = 4, Mr = 494.63, Dx = 1.181 Mg m−3, µ =
0.081 mm−1, T = 223(2) K, refinement on F2 (SHELXL97),18
R[F2 > 2σ(F2)] = 0.1011, wR(F2) = 0.2820, S = 1.025.
Crystal data for 5a: C24H30O4, triclinic, P1, a = 8.085 (2) Å, b
= 24.996(5) Å, c = 5.5008(9)Å, α = 93.80(1)°, β = 107.634(5)°,
γ = 87.325(2)°, V = 1056.6(3) Å3, Z = 2, Mr = 382.50, Dx =
1.202 Mg m−3, µ = 0.080 mm−1, T = 223(2) K, refinement on F2
(SHELXL97),18 R[F2 > 2σ(F2)] = 0.0938, wR (F2) = 0.2920, S
= 1.038.
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