Liquid crystallinity of 2-fluorenyl 4-alkylbenzoates

Article abstract of DOI:10.1246/bcsj.78.523

The liquid crystallinity values of 2-fluorenyl 4-alkyl (pentadecyl, n-, or s-butyl)-benzoates were compared with those of biphenyl homologues. Cyano group or hydrogen was used as the end group at the 7-position of 2-fluorenol moiety. Methoxy and hydroxy groups in addition to hydrogen were examined as a lateral substituent at the 2-position of 4-alkylbenzoic acid unit. 7-Cyano-2-fluorenyl 2-hydroxy-4-pentadecylbenzoate shows very similar properties to those of 4′-cyanobiphenyl-4-yl 2-hydroxy-4-pentadecylbenzoate.

Full text of DOI:10.1246/bcsj.78.523

Ó 2005 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 78, 523–528 (2005)
523
Liquid Crystallinity of 2-Fluorenyl 4-Alkylbenzoates
Jun Yamamoto, Takao Kimura, Yutaka Takabayashi,1 Toru Oba,
ꢀ
Michinori Karikomi, and Masahiro Minabe
Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, Yoto 7-1-2, Utsunomiya 321-8585
1Research Institute of Scientific Crime Detection, Tochigi Police, Hanawada 1-1-20, Utsunomiya 320-8510
Received August 26, 2004; E-mail: minabe@cc.utsunomiya-u.ac.jp
The liquid crystallinity values of 2-fluorenyl 4-alkyl (pentadecyl, n-, or s-butyl)-benzoates were compared with
those of biphenyl homologues. Cyano group or hydrogen was used as the end group at the 7-position of 2-fluorenol moi-
ety. Methoxy and hydroxy groups in addition to hydrogen were examined as a lateral substituent at the 2-position of
4-alkylbenzoic acid unit. 7-Cyano-2-fluorenyl 2-hydroxy-4-pentadecylbenzoate shows very similar properties to those
of 40-cyanobiphenyl-4-yl 2-hydroxy-4-pentadecylbenzoate.
This paper compares the liquid crystallinity values of 2-fluo-
renyl 4-alkylbenzoates with those of biphenyl homologues.
Many fluorene derivatives have been studied in the field
of thermotropical liquid crystals.1–4 Study on a luminescent
mesogen is one of the recent developments of a functional de-
sign in this field.5 A liquid crystal that includes fluorene as a
mesogen unit has both merits and demerits, comparing to the
corresponding biphenyl derivatives which are widely used at
present.6 Fluorene is coplanar, but biphenyl is not. Therefore,
one of the merits of fluorene as a core is that thermal stability
of the liquid crystal phase is expected to be superior to biphen-
yl by increasing polarity due to the delocalization of ꢀ-elec-
trons over the biphenyl moiety. One of the demerits of fluorene
is that the methylene group increases the molecular width. In
addition, each substituent at the 2- and 7-positions deviates
by an angle of 12ꢁ from the axis of the central 4a–4b bond.
The molecule of 2,7-disubstituted fluorene that is easily ob-
tained by the electrophilic substitution thus has a banana
shape.7,8 These derivatives decrease the thermal stability of
the liquid crystal phase.
tadecyl group is examined as an alkyl end at the 4-alkylbenzo-
ic acid moiety. One of reactants is obtained from 3-pentadecyl-
phenol, a cardanol10 that is derived from nuts of Anacardium
occidentale L. This compound is used as one of starting mate-
rials of phenol resin and is expected to develop more valuable
usage of the biomass.11 The other terminal end, or the 7-posi-
tion of the 2-fluorenol moiety, is occupied by hydrogen or a
polar cyano group. In the case of hydrogen, fluorene itself is
a polar terminal cap in which the delocalized aromatic ring
should increase the polarity and the hardness of the molecule,
compared to those of biphenyl.
This paper deals with the influence of the cross effects due
to the molecular structure described above. The counteracting
of these opposing effects should result in the liquid crystallin-
ity of 2-fluorenyl 4-alkylbenzoates being similar and/or supe-
rior to that of biphenyl homologues. The findings should be
of help to design new liquid crystals or to modify authentic
biphenyl-type liquid crystals.
Results and Discussion
The connector examined in this paper is an ester group
formed by the combination of 2-fluorenol (or biphenyl-4-ol)
with 4-alkylbenzoic acid, as is shown in Scheme 1. The ester
group is easily formed and the polar ester scarcely affects the
temperature range and the clearing point in liquid crystallini-
ty.9
The target esters, 1–18, were obtained by the reactions of
the corresponding alcohol (19–22) with the acid chloride de-
rived from 4-alkylbenzoic acid (23–27), in the presence of tri-
ethylamine in chloroform (Scheme 2). The precursor, 7-cyano-
2-fluorenol (20), was synthesized from 7-bromo-2-fluorenol12
via acetylation of hydroxy group and substitution of bromine
atom by cyano group.13 Carboxylic acid 23 was derived from
20-hydroxy-40-pentadecylacetophenone14 by bromoform reac-
The terminal group of liquid crystals plays an important role
in the liquid crystallinity. In this study, n-butyl, s-butyl, or pen-
R2
R2
R1
COOH
R1
COO
R3
R1 = n-Bu, s-Bu, C15H31
R2 = H, OH, OCH3
R3 = H, CN
HO
R3
Scheme 1.
Published on the web March 11, 2005; DOI 10.1246/bcsj.78.523

524 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Liquid Crystals, 2-Fluorenyl 4-Alkylbenzoate
R2
R2
R1
COO
R3
R1
COO
R3
1 (R1 = C15H31, R2= OCH3, R3= H)
2 (R1 = C15H31, R2 = OH, R3= H)
3 (R1 = C15H31, R2 = R3= H)
11 (R1 = C15H31, R2 = OCH3, R3 = H)
12 (R1 = C15H31, R2= OH, R3= H)
13 (R1 = C15H31, R2= R3= H)
4 (R1 = n-C4H9, R2 = R3= H)
14 (R1 = C15H31, R2= OCH3, R3 = CN)
15 (R1 = C15H31, R2 = OH, R3= CN)
16 (R1 = C15H31, R2 = H, R3= CN)
17 (R1 = n-C4H9, R2 = H, R3= CN)
18 (R1 = s-C4H9, R2= H, R3=CN)
5 (R1 = s-C4H9, R2 = R3= H)
6 (R1 = C15H31, R2 = OCH3, R3 = CN)
7 (R1 = C15 H31, R2 = OH, R3= CN)
8 (R1 = C15H31, R2 = H, R3= CN)
9 (R1 = n-C4H9, R2 = H, R3= CN)
10 (R1 = s-C4H9, R2 = H, R3=CN)
HO
R3
R2
19 (R3 = H)
R1
COOH
20 (R3 = CN)
23 (R1 = C15H31, R2= OCH3)
24 (R1 = C15H31, R2= OH)
25 (R1 = C15H31, R2= H)
26 (R1 = n-C4H9, R2= H)
27 (R1 = s-C4H9, R2= H)
HO
R3
21 (R3 = H)
22 (R3 = CN)
Scheme 2.
tion after protection of hydroxy group by methylation. Com-
pound 23 was converted to 24 via demethylation. 4-Pentade-
cylbenzoic acid (25)15 was synthesized from pentadecylben-
zene through acetylation and successive bromoform reaction,
and 13, respectively.
The lateral substituent, R2 (OCH3, OH, or H), was examined
using the following three series: 1/2/3, 6/7/8, and 14/15/16.
The melting point (C–M) of these series increases in the order
of OH < OCH3 < H. On the other hand, the clearing point
(M–I) is higher in the order of OCH3 < OH < H. The order
of the clearing point fits with the melting points (C–I) of the
series, 11, 12, and 13, which do not show liquid crystallinity.
Figure 1 shows the optimum structural models of 6 and 15.
The widest part of 6 is between the methoxy group and the H5
of acid moiety (ca. 0.66 nm). The distance (ca. 0.53 nm) be-
tween the H9 and H4(5) of fluorene part is the widest part of
8. The intermolecular force maintaining the liquid crystal state
decreases with increasing width of molecule.17 The methoxy
derivatives 6 and 14 lowers the interaction between mesogen
units and hence lowers their clearing points.
ꢁ
and it shows a smectic phase between 98 and 107 C.
The structures of 1–18 were confirmed based on their spec-
tral analyses. The thermal behavior was determined at the sec-
ond heating and/or cooling process using a polarized micro-
scope and a DSC apparatus, as is summarized in Table 1. In
brief, a smectic phase was observed in the case of nitrile com-
pounds attached by pentadecyl group as the R1 of the acid moi-
ety. On the other hand, a nematic phase was confirmed in the
nitrile derivatives attached by n- or s-butyl group as the R1. A
nematic phase was also observed within a narrow temperature
range in the case of fluorene derivatives, 2 and 3, in which pen-
tadecyl group was attached as the R1.
Introduction of a cyano group as the R3 group results in in-
creasing thermal stability of liquid crystal. This finding is due
to larger dipole moment and stronger electron-withdrawing
property of the cyano group, compared to those of hydrogen.
These effects affect the molecules themselves to increase the
intermolecular attraction, and consequently to elevate the
clearing point (M–I).16 The melting points of 9 and 16 look
abnormal, being a little lower than those of the mother 43
The distance between the hydroxy group and the H5 of sal-
icylic moiety of 7 is estimated to be ca. 0.53 nm, similar to the
distance between the H9 and H4(5) of fluorene part. The IR
spectra of hydroxy compounds, or 2, 7, 12, and 15, show
strong intramolecular hydrogen bonds between the hydroxy
hydrogen and the carbonyl oxygen of salicylic moiety, as is
supported by ab initio calculations. This disturbs the rotation
between the phenyl carbon and the carbonyl carbon in salicylic

J. Yamamoto et al.
Table 1. Phase-Transition Temperature of Compounds 1–18
Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
525
Compd
CoreaÞ
R1
R2
R3
Phase-transition temp.bÞ/ꢁC
Yield/%
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Fluo
Fluo
Fluo
Fluo
Fluo
Fluo
Fluo
Fluo
Fluo
Fluo
Biph
Biph
Biph
Biph
Biph
Biph
Biph
Biph
C15H31
C15H31
C15H31
n-C4H9
s-C4H9
C15H31
C15H31
C15H31
n-C4H9
s-C4H9
C15H31
C15H31
C15H31
C15H31
C15H31
C15H31
n-C4H9
s-C4H9
OCH3
OH
H
H
H
OCH3
OH
H
H
H
OCH3
OH
H
OCH3
OH
H
H
H
H
H
H
CN
CN
CN
CN
CN
H
C–86–I
47
63
87
69
65
58
54
62
78
66
44
17
81
54
65
88
79
83
C–83 [35.5]–N–87 [0.4]–I
C–106 [36.9]–N–108 [0.5]–I
C–135–I
C–106–I
C–105 [48.9]–S–111 [2.6]–I
C–83 [34.0]–S–153 [3.0]–I
C–128 [33.0]–S–192 [4.1]–I
C–132 [22.0]–N–221 [0.3]–I
C–131 [21.0]–N–134cÞ–I
C–58–I
H
H
C–78–I
C–95–I
CN
CN
CN
CN
CN
C–87 [48.6]–S–126 [3.5]–I
C–84 [53.7]–S–153 [3.8]–I
C–92 [38.5]–S–194 [4.9]–I
C–95 [19.2]–N–244 [0.5]–I
C–117 [20.0]–N–171 [0.2]–I
H
H
a) Fluo: Fluorene; Biph: biphenyl. b) C: Crystal phase; I: isotropic phase; S: smectic phase; N: nematic
phase. Kind of smectic phases is uncertain at present. []: Enthalpy change at heating process
(kJ molꢂ1). c) No change was observed on the DSC curve.
0.66 nm
0.53 nm
0.53 nm
0.43 nm
Fig. 1. Optimum structural models of 6 (upper) and 15 (lower).
moiety. These result in lowering of the melting point and wid-
ening the thermal stability of liquid crystal phase in the cases
of 2 and 7, compared to the cases of 3 and 8, respectively. On
the other hand, the width at the biphenyl moiety in 15 and 16 is
only ca. 0.43 nm, narrower than that of salicylic part. There-
fore, the presence of hydroxy group in 15 seems to decrease
the thermal stability compared to that of 16, despite the lower
melting point.
temperature range of liquid crystal phase increases in the order
of s-butyl < pentadecyl < n-butyl. Lower clearing points of 8
and 16 compared to those of 9 and 17 are explained by the con-
sideration that longer alkyl chain increases the mobility of the
molecules and increases the overall entropy. The narrower
range of s-butyl compounds (10, 18) than that of n-butyl deriv-
atives (9, 17) is due to the fact that the s-butyl group is wider
than n-butyl group as a terminal substitent.
The terminal substitent at the R1 examined here is pentadec-
yl, n- or s-butyl group. In the case that the R3 was cyano group,
a smectic phase was observed when pentadecyl group was
used as the R1, and a nematic phase appeared when n- or s-bu-
tyl was attached. These findings have been generalized as the
relation between the length of the alkyl terminal chain and the
species of liquid crystal phase.18 The effect of the R1 is com-
pared in the following two series: 8/9/10 and 16/17/18. The
The endothermic peak at N–I transition could not observed
on the DSC curve of 10. The enthalpy change at N–I transition
is, in general, small because of the low order of molecules.
This tendency should be emphasized by the bent structure as
fluorene derivatives.5
A short range of nematic phase was detected in fluorene ser-
ies, 2 and 3, but was not observed in the corresponding biphen-
yl derivatives, 12 and 13. In these cases, fluorene (or biphenyl)

526 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Liquid Crystals, 2-Fluorenyl 4-Alkylbenzoate
pentadecylacetophenone: Mp 47–49 ꢁC (from ethanol): IR 1660
cmꢂ1 (CO). A solution of 20-methoxy-40-pentadecylacetophenone
(5.40 g, 15 mmol) in dioxane (100 mL) was added to a sodium hy-
pobromite solution obtained from bromine (4.61 mL, 90 mmol)
anꢁd sodium hydroxide (10.0 g, 250 mmol) in water (90 mL) at
0 C for 1 h. After stirring for 20 h at room temperature, 4.94 g
(91%) of 2-methoxy-4-pentadecylbenzoic acid (23) was isolated
by a usual treatment: Mp 77–79 ꢁC (from 80% ethanol): IR
3400–2400 (OH), 1710 cmꢂ1 (CO).
itself acts as a polar terminal end as well as a mesogen unit.
The polarity value of fluorene is higher than that of biphenyl;
this is due to the delocalization of ꢀ-electrons and results in
increasing of the intermolecular attraction.
The mesogen unit of cyanofluorene series, 6–10, is com-
pared with that of cyanobiphenyl series, 14–18. The 9-methyl-
ene group of fluorene elevates their melting points because of
increasing molecular weight and of wider coplanarity, com-
pared to the melting points of biphenyl. Also, the 9-methylene
group increases the width and the forced bent structure of the
mesogen unit. These decrease the range of liquid crystal phase,
compared to the case of biphenyl series.19,20
Compound 7 is very similar to 15 as a liquid crystal, though
the molecular arrangement of 7 may be a little more random
than that of 15, as observation of their enthalpy changes indi-
cates. These findings should be valuable for design of new
liquid crystals or modification of authentic liquid crystals by
transformation of substituents.
A mixture of 23 (2.17 g, 6.0 mmol) and phosphorus (red, 3.0 g)
in acetic anhydride (30 mL) was stirred with hydroiodic acid
ꢁ
(55%, 30 mL, 22.8 mmol) at 95 C for 5 h. Upon a usual treat-
ment, 1.76 g (85%) of 24 was isolated: Mp 95–97 ꢁC (from
80% ethanol); IR 3400–2400 (COOH), 3240 (OH), 1650 cmꢂ1
1
(CO); H NMR ꢁ 0.88 (3H, t, J ¼ 6:8 Hz, Me), 1.20–1.40 (24H,
m), 1.62 (2H, q, J ¼ 7:5 Hz), 2.61 (2H, t, J ¼ 7:5 Hz), 6.76
(1H, dd, J ¼ 8:4, 1.5 Hz, H5), 6.82 (1H, d, J ¼ 1:5 Hz, H3),
7.80 (1H, d, J ¼ 8:4 Hz, H6), 10.40 (1H, s, OH).
4-Pentadecylbenzoic Acid (25). 40-Pentadecylacetophenone
was obtained by the Friedel-Carfts reaction of pentadecylbenzene
with acetyl chloride and aluminum chloride in carbon disulfide in
Experimental
ꢁ
The melting points are uncorrected. The NMR (CDCl3) and IR
(KBr pellets) spectra were recorded with a Varian VXR-300 and
with a JASCO FT/IR-430, respectively. The DSC curves were ob-
tained with a DSC-3200S (Mac Science Co.) at scanning rate of 5
ꢁC/min under nitrogen atmosphere (100 mL/min). The elemental
analyses and mass spectra were measured with an EA 1108
CHNS-O (Fison Instruments) and with a JMX-AX 500 (JEOL,
70 eV), respectively.
The conformation of the molecules was estimated using a mo-
lecular-mechanics program in Chem 3D pro (CambridgeSoft
Corp.) on an iMac (Macintosh). The molecular structure of the
fluorenyl mesogen part was also examined by ab initio calculation
(HyperChem release 7.5, Hypercube Inc.). The octadecyl group of
7 was replaced with a methyl group in silico for simplicity, and
the molecular structure of this model compound, 7-cyano-2-fluo-
renyl 2-hydroxy-4-methylbenzoate, was energy-minimized by
molecular mechanics (MM+) and then by molecular orbital meth-
ods (PM3). Further optimization was carried out at the MP2/6-
31Gþ level starting from the PM3 geometry. The finally obtained
structure of the model molecule was found to be nearly the same
as those obtained by PM3 and MM+ calculations.
a 68% yield: Mp 41–43 C (from ethanol); IR 1680 cmꢂ1 (CO).
Compound 25 was derived from 40-pentadecylacetophenone by
a method similar to that used above in a 89% yield: Phase-transi-
ꢁ
tion temperature C–98 C [enthalpy change, 23.4 kJ/mol]–s–107
ꢁC [7.3 kJ/mol]–I (from 80% ethanol) (lit15 mp 97–98 ꢁC); IR
1
3160–2360 (OH), 1680 cmꢂ1 (CO); H NMR ꢁ 0.88 (3H, t, J ¼
6:6 Hz, Me), 1.20–1.40 (24H, m), 1.63 (2H, q, J ¼ 7:5 Hz),
2.67 (2H, t, J ¼ 7:5 Hz), 7.28 (2H, d, J ¼ 8:4 Hz, H3;5), 8.02
(2H, d, J ¼ 8:4 Hz, H2;6); MS m=z 332 (Mþ). Anal. Found: C,
79.40; H, 11.16%. Calcd for C22H36O2: C, 79.46; H, 10.92%.
2-Fluorenyl 2-Methoxy-4-pentadecylbenzoate (1). Typical
Procedure: Acid 23 (0.72 g, 2.0 mmol) in thionyl chloride
(20 mL) was stirred at 50–60 ꢁC for 1 h and then at 85 ꢁC for
3.5 h. Evaporation of the excess thionyl chloride in vacuo gave
the corresponding acid chloride: IR 1780 cmꢂ1
.
The acid chloride was added dropwise with stirring to a mixture
of 19 (0.54 g, 3.0 mmol) and triethylamine (0.42 g, 4.2 mmol) in
chloroform (40 mL) below 5 ꢁC, and the whole was stirred for 1 h.
After treatment with 3 M HCl and then water, the solution was
dried over anhydrous sodium sulfate, evaporated in vacuo, and
the residue was chromatographed on silica gel with cyclohex-
ane/benzene (1/4). The crude ester was recrystallized from etha-
nol, affording 0.50 g (47%) of 1: Mp 86–88 ꢁC; IR 1740 cmꢂ1
7-Cyano-2-fluorenol (20). Upon acetylation of 7-bromo-2-
fluorenol12 (yield 91%, mp 128–130 ꢁC), the ester (9.09 g, 30
mmol) was added to a freshly-prepared mixture of copper(I)
cyanide (4.03 g, 45 mmol) in N-methyl-2-pyrrolidone (130 mL),
and the whole was refluxed for 2.5 h according to the method
mentioned elsewhere.13 The resulting mixture was treated with
iron(III) chloride (7.29 g, 45 mmol) and 3 M HCl (180 mL) at
85 ꢁC for 1.5 h, and extracted with toluene, giving 5.11 g
(82%) of 20: Mp 222–225 ꢁC (from 50% ethanol); IR 3520–
1
(CO); H NMR ꢁ 0.88 (3H, t, J ¼ 6:6 Hz, Me), 1.20–1.40 (24H,
m), 1.66 (2H, q, J ¼ 7:8 Hz), 2.67 (2H, t, J ¼ 7:8 Hz), 3.92
0
(2H, s, H9 ), 3.95 (3H, s, OMe), 6.85 (1H, s, H3), 6.88 (1H, dd,
0
J ¼ 8:1, 1.5 Hz, H5), 7.22 (1H, dd, J ¼ 8:1, 2.1 Hz, H3 ), 7.30
0
0
(1H, td, J ¼ 7:5, 2.1 Hz, H7 ), 7.38 (1H, t, J ¼ 7:5 Hz, H6 ),
0
0
7.41 (1H, s, H1 ), 7.54 (1H, d, J ¼ 7:5 Hz, H8 ), 7.77 (1H, d, J ¼
0
0
7:5 Hz, H5 ), 7.79 (1H, d, J ¼ 8:1 Hz, H4 ), 7.99 (1H, d, J ¼ 7:8
3160 (OH), 2230 cmꢂ1 (CN); H NMR ꢁ 3.90 (2H, s, H9), 5.07
Hz, H6); 13C NMR ꢁ 14.1, 22.7, 29.3, 29.4, 29.5, 29.6, 29.7, 29.7,
1
0
31.1, 31.9, 36.4, 37.0 (C9 ), 56.0 (OMe), 112.4 (C3), 116.4 (C1),
(1H, s, OH), 6.91 (1H, dd, J ¼ 8:4, 2.1 Hz, H3), 7.06 (1H, s,
H1), 7.64 (1H, d, J ¼ 8:1 Hz, H6), 7.69 (1H, d, J ¼ 8:4 Hz,
H4), 7.73 (1H, d, J ¼ 8:1 Hz, H5), 7.76 (1H, s, H8); MS m=z
207 (Mþ). Anal. Found: C, 80.99; H, 3.96; N, 6.68%. Calcd for
C14H9NO: C, 81.14; H, 4.38; N, 6.76%.
2-Hydroxy-4-pentadecylbenzoic Acid (24). 20-Hydroxy-40-
pentadecylacetophenone14 (6.92 g, 20 mmol) was treated with di-
methylsulfate (6.57 mL, 52 mmol) and potassium hydroxide (3.76
g) in acetone (50 mL) for 7 h at room temperature. Upon filtration
of the mixture, the filtrate afforded 6.55 g (91%) of 20-methoxy-40-
0
118.9 (C1 ), 119.8 (C5 ), 120.3 (C4 ), 120.4 (C5), 120.5 (C3 ),
0
0
0
0
125.0 (C8 ), 126.5 (C7 ), 126.8 (C6 ), 132.4 (C6), 139.3 (C4 a),
0
0
0
0
0
0
0
141.1 (C4 b), 143.3 (C9 b), 144.5 (C9 a), 150.2 (C2 ), 150.6 (C4),
160.2 (C2), 164.6 (CO); MS m=z 526 (Mþ), 346, 181. Anal.
Found: C, 81.60; H, 9.22%. Calcd for C36H46O3: C, 82.08; H,
8.80%.
2-Fluorenyl 2-Hydroxy-4-pentadecylbenzoate (2). IR 3190
(OH), 1690 cmꢂ1 (CO); 1H NMR ꢁ 0.88, 1.20–1.40, 1.65, 2.64,
3.95, 6.81, 6.87, 7.20, 7.32, 7.39, 7.40, 7.56, 7.79, 7.83, 8.00,

J. Yamamoto et al.
Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
527
10.49 (OH); MS m=z 512 (Mþ), 331. Anal. Found: C, 81.85; H,
8.60%. Calcd for C35H44O3: C, 81.99; H, 8.65%.
Hz, H5), 6.87 (1H, s, H3), 7.28 (2H, d, J ¼ 8:4 Hz, H3 ;5 ), 7.37
0
0
00
00 00
(1H, t, J ¼ 7:2 Hz, H4 ), 7.46 (2H, t, J ¼ 7:2, Hz, H3 ;5 ), 7.60
2-Fluorenyl 4-Pentadecylbenzoate (3). IR 1730 cmꢂ1 (CO);
1H NMR ꢁ 0.88, 1.20–1.40, 1.66, 2.70, 3.93, 7.21, 7.30, 7.33, 7.39,
7.40, 7.55, 7.78, 7.81, 8.14; MS m=z 496 (Mþ), 315. Anal. Found:
C, 84.89; H, 8.99%. Calcd for C35H44O2: C, 84.63; H, 8.93%.
2-Fluorenyl 4-n-Butylbenzoate (4).3 Mp 135–137 ꢁC; IR
1730 cmꢂ1 (CO); 1H NMR ꢁ 0.95, 1.38, 1.65, 2.72, 3.93, 7.21,
7.30, 7.33, 7.39, 7.40, 7.55, 7.78, 7.81, 8.14; MS m=z 342 (Mþ),
181, 161. Anal. Found: C, 84.14; H, 6.43%. Calcd for C24H22O2:
C, 84.17; H, 6.47%.
(2H, d, J ¼ 7:2 Hz, H2 ;6 ), 7.64 (2H, d, J ¼ 8:4 Hz, H2 ;6 ),
7.98 (1H, d, J ¼ 8:4 Hz, H6), 10.46 (1H, s, OH); 13C NMR ꢁ
14.1, 22.7, 29.2, 29.4, 29.5, 29.6, 29.7, 29.7, 30.7, 31.9, 36.2,
00 00
0
0
0
109.3 (C1), 117.3 (C3), 120.2 (C5), 122.0 (C3 ;5 ), 127.2 (C2 ;6 ),
00
127.5 (C4 ), 128.3 (C2 ;6 ), 128.8 (C3 ;5 ), 130.2 (C6), 139.5
0
00 00
0
0
00 00
0
00
0
(C1 ), 140.2 (C1 ), 149.5 (C4 ), 153.1 (C4), 162.3 (C2), 169.0
(CO); MS m=z 500 (Mþ), 331. Anal. Found: C, 81.81; H,
8.89%. Calcd for C34H44O3: C, 81.56; H, 8.86%.
Biphenyl-4-yl 4-Pentadecylbenzoate (13). Mp 95–97 ꢁC; IR
1730 cmꢂ1 (CO); 1H NMR ꢁ 0.88, 1.20–1.40, 1.66, 2.67, 7.28,
7.33, 7.36, 7.45, 7.60, 7.64, 8.13; MS m=z 484 (Mþ), 315. Anal.
Found: C, 84.49; H, 9.36%. Calcd for C34H44O2: C, 84.25; H,
9.15%.
2-Fluorenyl 4-s-Butylbenzoate (5). Mp 106–108 ꢁC; IR 1730
cmꢂ1 (CO); 1H NMR ꢁ 0.85, 1.29, 1.66, 2.72, 3.94, 7.21, 7.30,
7.34, 7.39, 7.40, 7.55, 7.78, 7.81, 8.16; MS m=z 342 (Mþ), 181,
161. Anal. Found: C, 84.20; H, 6.50%. Calcd for C24H22O2: C,
84.17; H, 6.47%.
40 -Cyanobiphenyl-4-yl 2-Methoxy-4-pentadecylbenzoate
(14). IR 2230 (CN), 1740 cmꢂ1 (CO); H NMR ꢁ 0.88 (3H, t,
1
7-Cyano-2-fluorenyl 2-Methoxy-4-pentadecylbenzoate (6).
IR 2220 (CN), 1730 cmꢂ1 (CO); 1H NMR ꢁ 0.88, 1.20–1.40,
1.66, 2.68, 3.96, 3.98, 6.86, 6.89, 7.28, 7.47, 7.69, 7.81–7.87,
7.99; MS m=z 551 (Mþ), 345. Anal. Found: C, 80.77; H, 8.19;
N, 2.67%. Calcd for C37H45NO3: C, 80.54; H, 8.22; N, 2.54%.
7-Cyano-2-fluorenyl 2-Hydroxy-4-pentadecylbenzoate (7).
IR 3220 (OH), 2220 (CN), 1680 cmꢂ1 (CO); 1H NMR ꢁ 0.88
(3H, t, J ¼ 6:6 Hz, Me), 1.20–1.40 (24H, m), 1.65 (2H, q, J ¼
J ¼ 6:6 Hz, Me), 1.20–1.40 (24H, m), 1.66 (2H, q, J ¼ 7:2 Hz),
2.68 (2H, t, J ¼ 7:8 Hz), 3.95 (3H, s, OMe), 6.86 (1H, s, H3),
0
0
6.89 (1H, d, J ¼ 7:8 Hz, H5), 7.33 (2H, d, J ¼ 8:4 Hz, H3 ;5 ),
0
0
00 00 00 00
7.63 (2H, d, J ¼ 8:4 Hz, H2 ;6 ), 7.66–7.75 (4H, m, H2 ;3 ;5 ;6 ),
7.99 (1H, d, J ¼ 7:8 Hz, H6); 13C NMR ꢁ 14.1, 22.7, 29.3, 29.4,
00
29.5, 29.6, 29.6, 29.7, 31.1, 31.9, 36.4, 56.0 (OMe), 110.9 (C4 ),
0
112.3 (C3), 115.7 (C1), 118.9 (CN), 120.4 (C5), 122.7 (C3 ;5 ),
00 00 0 0 00 00
127.7 (C2 ;6 ), 128.2 (C2 ;6 ), 132.4 (C6), 132.6 (C3 ;5 ), 136.5
0
0
7:5 Hz), 2.64 (2H, t, J ¼ 7:5 Hz), 4.00 (2H, s, H9 ), 6.82 (1H,
0
00
0
dd, J ¼ 8:1, 1.5 Hz, H5), 6.87 (1H, d, J =1.5 Hz, H3), 7.27
(C1 ), 144.9 (C1 ), 151.0 (C4), 151.5 (C4 ), 160.3 (C2), 164.0
(CO); MS m=z 345. Anal. Found: C, 80.22; H, 8.34; N, 2.70%.
Calcd for C36H45NO3: C, 80.11; H, 8.40; N, 2.60%.
0
0
(1H, dd, J ¼ 8:4, 1.5 Hz, H3 ), 7.45 (1H, d, J ¼ 1:5 Hz, H1 ),
0
7.70 (1H, dd, J ¼ 8:1, 1.5 Hz, H6 ), 7.83 (1H, d, J ¼ 1:5 Hz,
H8 ), 7.85 (1H, d, J ¼ 8:1 Hz, H5 ), 7.88 (1H, d, J ¼ 8:4 Hz,
40-Cyanobiphenyl-4-yl
2-Hydroxy-4-pentadecylbenzoate
0
0
H4 ), 7.99 (1H, d, J ¼ 8:1 Hz, H6), 10.39 (1H, s, OH); 13C NMR
(15). IR 3300 (OH), 2220 (CN), 1690 cmꢂ1 (CO); H NMR ꢁ
0.88, 1.20–1.40, 1.64, 2.64, 6.82, 6.87, 7.33, 7.66, 7.68–7.77,
7.98, 10.39; MS m=z 525 (Mþ), 331. Anal. Found: C, 79.80; H,
8.19; N, 2.75%. Calcd for C35H43NO3: C, 79.96; H, 8.26; N,
2.66%.
1
0
ꢁ 14.1, 22.7, 29.2, 29.4, 29.4, 29.5, 29.7, 30.7, 31.9, 36.2, 36.8
0
0
(C9 ), 109.2 (C1), 109.8 (CN), 117.3 (C3), 119.0 (C1 ), 119.5
0
(C7 ), 120.3 (C5), 120.4 (C5 ), 121.1 (C3 ), 121.8 (C4 ), 128.6
0
0
0
0
(C8 ), 130.1 (C6), 131.4 (C6 ), 138.1 (C4 a), 143.6 (C9 b), 145.2
0
0
0
40-Cyanobiphenyl-4-yl 4-Pentadecylbenzoate (16). IR 2220
(CN), 1740 cmꢂ1 (CO); 1H NMR ꢁ 0.88, 1.20–1.40, 1.66, 2.71,
7.31–7.35, 7.64, 7.66–7.76, 8.13; MS m=z 509 (Mþ), 315. Anal.
Found: C, 82.39; H, 8.41; N, 2.89%. Calcd for C35H43NO2: C,
82.47; H, 8.50; N, 2.75%.
0
0
0
(C4 b), 145.4 (C9 a), 150.5 (C2 ), 153.3 (C4), 162.3 (C2), 169.0
(CO); MS m=z 537 (Mþ), 331, 207. Anal. Found: C, 80.35; H,
7.99; N, 2.72%. Calcd for C36H43NO3: C, 80.41; H, 8.06; N,
2.60%.
7-Cyano-2-fluorenyl 4-Pentadecylbenzoate (8).
IR 2230
(CN), 1740 cmꢂ1 (CO); 1H NMR ꢁ 0.88, 1.20–1.40, 1.66, 2.71,
3.99, 7.28, 7.34, 7.46, 7.69, 7.81–7.89, 8.13; MS m=z 521 (Mþ),
315, 207. Anal. Found: C, 82.88; H, 8.35; N, 2.69%. Calcd for
C36H43NO2: C, 82.87; H, 8.31; N, 2.68%.
40-Cyanobiphenyl-4-yl 4-n-Butylbenzoate (17).
IR 2230
(CN), 1740 cmꢂ1 (CO); H NMR ꢁ 0.95, 1.38, 1.65, 2.72, 7.31–
7.36, 7.64, 7.67–7.76, 8.14; MS m=z 355 (Mþ), 161. Anal. Found:
C, 80.76; H, 5.91; N, 4.07%. Calcd for C24H21NO2: C, 81.10; H,
5.96; N, 3.94%.
1
7-Cyano-2-fluorenyl 4-n-Butylbenzoate (9). IR 2230 (CN),
1740 cmꢂ1 (CO); 1H NMR ꢁ 0.95, 1.39, 1.66, 2.72, 3.93, 7.27,
7.34, 7.46, 7.68, 7.80–7.88, 8.13; MS m=z 367 (Mþ), 206, 161.
Anal. Found: C, 81.61; H, 5.51; N, 3.80%. Calcd for C25H21NO2:
C, 81.72; H, 5.76; N, 3.81%.
7-Cyano-2-fluorenyl 4-s-Butylbenzoate (10). IR 2230 (CN),
1740 cmꢂ1 (CO); 1H NMR ꢁ 0.85, 1.29, 1.67, 2.72, 3.99, 7.28,
7.34, 7.46, 7.69, 7.81–7.88, 8.13; MS m=z 367 (Mþ), 206, 161.
Anal. Found: C, 81.57; H, 5.59; N, 3.82%. Calcd for C25H21NO2:
C, 81.72; H, 5.76; N, 3.81%.
40-Cyanobiphenyl-4-yl 4-s-Butylbenzoate (18).
IR 2230
(CN), 1730 cmꢂ1 (CO); H NMR ꢁ 0.85, 1.28, 1.65, 2.72, 7.31–
7.36, 7.64, 7.67–7.76, 8.15; MS m=z 355 (Mþ), 161. Anal. Found:
C, 80.89; H, 5.90; N, 4.07%. Calcd for C24H21NO2: C, 81.10; H,
5.96; N, 3.94%.
1
References
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W. Kast, ‘‘Landolt-Bornstein,’’ 6th ed, Springer-Verlag,
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Biphenyl-4-yl 2-Methoxy-4-pentadecylbenzoate (11). Mp
58–59 ꢁC; IR 1740 cmꢂ1 (CO); 1H NMR ꢁ 0.88, 1.20–1.40,
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