Synthesis of new liquid crystalline compounds containing an α,β-unsaturated ketone and β-chloroketone groups in the side chain

Article abstract of DOI:10.1007/s11178-005-0044-y

A number of new liquid crystalline compounds containing an α,β-unsaturated ketone or β-chloro ketone moiety in the side chain were synthesized. The key intermediates in the synthesis were 1-(4-hydroxy-phenyl)-2-octen-1-one and 3-chloro-1-(4-hydroxyphenyl)

Full text of DOI:10.1007/s11178-005-0044-y

Russian Journal of Organic Chemistry, Vol. 40, No. 10, 2004, pp. 1477–1482. Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004,
pp. 1526–1531.
Original Russian Text Copyright © 2004 by V. Kovganko, N. Kovganko, Bezborodov.
Synthesis of New Liquid Crystalline Compounds
Containing an α,β-Unsaturated Ketone and β-Chloroketone
Groups in the Side Chain
V. N. Kovganko, N. N. Kovganko, and V. S. Bezborodov
Sevchenko Research Institute of Applied Physical Problems, Belarussian State Universitety,
ul. Kurchatova 7, Minsk, 220064 Belarus
e-mail: kauhanka@bsu.by
Received March 1, 2004
Abstract—A number of new liquid crystalline compounds containing an α,β-unsaturated ketone or β-chloro
ketone moiety in the side chain were synthesized. The key intermediates in the synthesis were 1-(4-hydroxy-
phenyl)-2-octen-1-one and 3-chloro-1-(4-hydroxyphenyl)octan-1-one which were prepared from 5-(4-hydroxy-
phenyl)-3-pentyl-4,5-dihydroisoxazole and 3-hydroxy-1-(4-hydroxyphenyl)octan-1-one, respectively.
We previously [1] synthesized a series of new
liquid crystalline compounds which contained a β-hy-
droxy ketone moiety in the side chain. The key inter-
mediate product in these syntheses was β-hydroxy
ketone IV which was prepared from 4-hydroxybenz-
aldehyde (I) through oxime II and 4,5-dihydroisoxa-
zole III (Scheme 1). It was presumed that compound
IV can also be used to prepare new liquid crystalline
compounds having an α,β-unsaturated ketone fragment
in the side chain. For this purpose we examined de-
hydration of compound IV.
was used for dehydration of β-hydroxy ketone IV,
α,β-unsaturated ketone V was isolated in 65% yield.
Compounds V and VI can be regarded as starting
materials for the synthesis of liquid crystalline sub-
stances. The structure of V and VI was proved by
1
analysis of their UV, IR, and H NMR spectra. The
IR spectrum of V contained an absorption band at
1662 cm–1 due to carbonyl stretching vibrations and
a band at 1618 cm–1 belonging to stretching vibrations
1
of the double bond. In the H NMR spectrum of V,
the vinyl proton on C3 gave a triplet of doublets at
δ 7.05 ppm with coupling constants J of 7 Hz (with
the methylene protons on C4) and 15 Hz (with the
vinyl proton on C2). The signal from 2-H was partially
overlapped by the multiplet signal from the hydroxy
proton at δ 6.82–6.98 ppm. The downfield position of
the 3-H signal relative to 2-H results from deshielding
effect of the carbonyl group, which is typical of con-
jugated enone systems. The coupling constant for the
vinyl protons 2-H and 3-H, J = 15 Hz, indicates trans
configuration of the double bond.
Various procedures for dehydration of compound
IV by the action of both acids and bases were studied.
Heating of compound IV in 2-propanol with excess
triethylamine gave 15% of α,β-unsaturated ketone V,
while the most part of initial β-hydroxy ketone IV was
recovered from the reaction mixture. By heating of
compound IV in toluene in the presence of alkaline
aluminum oxide, enone V was obtained in 20% yield.
Much better results were obtained by dehydration of
IV in the presence of acid catalysts. Treatment of IV
with concentrated hydrochloric acid afforded two
products in approximately equal amounts. According
to the spectral data, these products were assigned the
structures of α,β-unsaturated ketone V and β-chloro
ketone VI (Scheme 1). When the reaction of β-hy-
droxy ketone IV with hydrochloric acid was pro-
longed, the major product was β-chloro ketone VI
which was isolated in 70% yield. When perchloric acid
In the IR spectrum of β-chloro ketone VI,
stretching vibrations of the carbonyl group appeared at
1
1675 cm–1. The H NMR spectrum of VI is charac-
terized by downfield shifts of the multiplet signals
from 2-H and 3-H (∆δ = 0.23–0.39 ppm) relative to the
corresponding signals of initial ketone IV.
Liquid crystalline compounds having an α,β-un-
saturated and β-chloro ketone fragments in the side
1070-4280/04/4010-1477 © 2004 MAIK “Nauka/Interperiodica”

KOVGANKO et al.
1478
Scheme 1.
O
CHO
CH=NOH
N
(1) NCS
C5H11
(2) Et3N
NH2OH
(3) CH2=CHC5H11
HO
OH
OH
I
II
III
O
OH
O
O
Cl
H2, Raney Ni
HCl
C5H11
C5H11
+
C5H11
HO
HO
HO
IV
V
VI
O
OH
O
RCOOH, DCC
DMAP
MeSO2Cl
pyridine
O
C5H11
O
C5H11
IV
R
O
R
O
VIIf
VIIIe–VIIIh
O
Cl
RCOOH, DCC
DMAP
RCOOH, DCC
DMAP
O
C5H11
V
VIIIe–VIIIh
VI
R
O
IXa–IXd, IXh
R = 4-FC6H4 (a), 4-NCC6H4 (b), 4-C3H7OC6H4 (c), 4-C6H13OC6H4 (d), 4-C5H11OC6H4 (e), 4-C12H25OC6H4 (f),
C12H25O (g), C5H11 (h).
chain were synthesized by esterification of phenols V
and VI with various mesogenic carboxylic acids. Reac-
tions of compound V with carboxylic acids in the pres-
ence of N,N'-dicyclohexylcarbodiimide and a catalytic
amount of 4-dimethylaminopyridine gave 60–90% of
esters VIIIe, VIIIg, and VIIIh. Likewise, from phenol
VI we obtained esters IXa–IXd and IXh in 70–80%
yield. Esters VIII were also synthesized by an alter-
native procedure from β-hydroxy ketone IV, i.e., the
first stage in the synthesis was esterification, and
the second, dehydration. The reaction of IV with
4-dodecyloxybenzoic acid according to the procedure
reported in [1] afforded ester VIIf which was treated
with methanesulfonyl chloride in pyridine; as a result,
ester VIIIf was isolated in ~60% yield.
hydroxy group were absent. Compounds VIIIe–VIIIh
showed in the IR spectra absorption bands due to
stretching vibrations of the double bond at 1618–
1625 cm–1, as well as of the conjugated carbonyl group
at 1668 cm–1 for the s-cis conformers and 1648 cm–1
for the s-trans conformers. The carbonyl stretching
vibration frequency in the spectra of IXa–IXd and
1
IXh ranges from 1675 to 1690 cm–1. In the H NMR
spectra of esters VIIId–VIIIh, IXa–IXd, and IXh we
observed multiplet signals from the vinyl protons or
CHCl protons, which indicated conservation of the
enone and β-chloro ketone moieties in the esterifica-
tion of phenols V and VI, respectively.
Among the nine newly synthesized esters, five
compounds were found to exhibit mesomorphic pro-
perties. Comparison of the phase transition tempera-
tures for esters VIIIe–VIIIh, IXa–IXd, and IXh with
those of the previously reported liquid crystalline com-
pounds having a β-hydroxy ketone fragment in the side
chain [1] allowed us to estimate the effect of side-
The structure of esters VIIIe–VIIIh, IXa–IXd, and
1
IXh was confirmed by the UV, IR, and H NMR
spectra. The IR spectra of these compounds contained
strong absorption bands from the ester carbonyl group
at 1750–1735 cm–1, while bands assignable to phenolic
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 40 No. 10 2004

SYNTHESIS OF NEW LIQUID CRYSTALLINE COMPOUNDS
Phase transition temperatures of compounds VIIIe–VIIIh, IXa–IXd, and IXh
1479
Compound
no.
Smecic
phase C
Smectic
phase B
Transition
temperature, °C
Smectic
phase A
Nematic
phase
Clarification
temperature, °C
mp, °C
90.5–91.0
0.107–107.5
125
–
–
●
●
–
–
–
–
●
–
–
–
–
–
–
–
●
–
–
–
–
–
–
–
VIIIe
VIIIf
VIIIg
VIIIh
IXa
–
–
–
–
–
.0205.5
098
1830
–
●
–
–
191
93–94
95–94
085
–
–
–
–
–
–
–
0(77)
IXb
(74)
0.92.5
1710
●
●
●
IXc
086
–
094
IXd
156
174 ●
179 (decomp.)
IXh
temperature range and their melting points are lower.
This is likely to result from weakening of polar inter-
action in going from compounds possessing a β-hy-
droxy ketone fragment in the side chain to their
analogs having a β-chloro ketone moiety. Like esters
VII [1], compounds IXa and IXb, whose molecules
contain polar groups in the terminal part, exhibit no
liquid crystalline properties. Esters IXh gives rise to
both smectic mesophases C and A and nematic phase
in the range 5°C; the latter was not observed for
bi(cyclohexyl)carboxylic acid ester VIIIh having
a side-chain enone fragment.
chain functional groups on the formation and stabiliza-
tion of liquid crystalline state. Esters VIIIe and VIIIf
showed no mesomorphic properties, although pentyl-
oxybenzyl and dodecyloxybenzyl ether derived from
phenol IV gave rise to smectic mesophase in a fairly
wide temperature range [1]. Dehydration leading to
formation of an enone fragment in the side chain
weakens intermolecular polar interaction. Presumably,
this is the reason why alkoxybenzoates VIIIe and
VIIIf possessing two benzene rings do not form meso-
phase. Esterification of α,β-unsaturated ketone V with
substituted biphenyl- and bicyclohexylcarboxylic acids
leads to esters VIIIg and VIIIh which contain three
rings. Compound VIIIg gives a smectic liquid crystal-
line mesophase C in the range 80.5°C, whereas ester
VIIIh, apart from smectic phase C in the range 85°C,
gives rise to less ordered smectic phase A in the range
8°C. Thus, increase in the number of rings (from two
to three) in esters VIII having an enone fragment in
the side chain leads to appearance of a mesophase.
Stabilization of the mesophase and extension of the
corresponding temperature range are accompanied by
increase of the melting point, which is clearly seen
with compounds VIIIe–VIIIg as examples and is
consistent with published data [2, 3].
To conclude, it should be noted that compounds V
and VI may be used in further modifications of side
chains in liquid crystalline compounds with a view to
analyze their mesomorphic properties with regard to
the presence of different functional groups in the side
chains of their molecules. The results of our further
studies in this field will be reported elsewhere.
EXPERIMENTAL
The phase transition temperatures were determined
on a heating device coupled with a polarizing micro-
scope. The IR spectra were obtained from solutions in
chloroform on a Specord 75 IR spectrometer using
KBr cells. The UV spectra were measured from solu-
tions in methanol on a Specord M40 spectrophotom-
Propoxybenzoate IXc with a β-chloro ketone
moiety in the side chain produces a monotropic liquid
crystalline phase A in the range 3°C. For homologous
hexyloxybenzoate IXd, we observed stabilization of
thermotropic smectic mesophases C (in the range
6.5°C) and A (in the range 1.5°C). Thus β-chloro
ketones IXc and IXd, as welll as analogous esters
containing a β-hydroxy ketone fragment in the side
chain [1], are smectogenic substances, but smectic
phases produced by the former exist in a narrower
1
eter. The H NMR spectra were recorded on a Bruker
Avance 400 spectrometer (400 MHz) using CDCl3 as
solvent and HMDS as internal reference. The phase-
transition temperatures of compounds VIIIe–VIIIh,
IXa–IXd, and IXh are given in table.
3-(4-Hydroxyphenyl)-5-pentyl-4,5-dihydroiso-
xazole (III). Gaseous phase over concentrated hydro-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 40 No. 10 2004

KOVGANKO et al.
1480
chloric acid was withdrawn using a syringe and was
then passed through a solution of 1.6 g (11.7 mmol) of
4-hydroxybenzaldehyde oxime in 50 ml of dimethyl-
formamide. N-Chlorosuccinimide, 1.7 g (12.7 mmol),
was then added in portions under stirring over a period
of 2.5 h, the mixture was stirred for 1 h at room
temperature and cooled to 0°C, 3.3 ml (23.5 mmol) of
1-heptene was added, and a solution of 1.8 ml of tri-
ethylamine in 35 ml of dimethylformamide was added
dropwise over a period of 2.5 h. The mixture was
stirred for 12 h at room temperature, diluted with
50 ml of chloroform, and treated with dilute (1:5)
hydrochloric acid. The organic phase was separated,
the aqueous layer was extracted with chloroform, and
the combined extracts were washed with two portions
of a saturated solution of sodium chloride and dried
over sodium sulfate. The most part of the solvent was
removed under reduced pressure, and the residue was
diluted with a 5-fold volume of water. The crystals of
dihydroisoxazole III were filtered off and washed
with water and petroleum ether. Yield 1.9 g (70%),
mp 109.5–111°C (from toluene–ethyl acetate) [4]. IR
spectrum, ν, cm–1: 3595, 3530–3080 (O–H); 3010
(C–Harom); 2955, 2930, 2860 (C–Haliph); 1605, 1515
7.2 Hz), 1.20–1.40 m (4H, C6H2, C7H2), 1.50 quint
(2H, C5H2, J = 7 Hz), 2.28 distorted q (2H, C4H2, J =
7 Hz), 6.82–6.98 m (2H, 2-H, 4'-OH), 7.05 t.d (1H,
3-H, J1 = 7, J2 = 15 Hz), 6.90 d and 7.89 d (2H each,
Harom, J = 8.5 Hz).
b. A solution of 0.1 g (0.42 mmol) of hydroxy
ketone IV and 0.2 ml (1.44 mmol) of triethylamine in
5 ml of 2-propanol was heated for 24 h under reflux.
The solvent was distilled off under reduced pressure,
and the residue was subjected to column chromatog-
raphy on silica gel using ethyl acetate–cyclohexane
(1:3) as eluent. Yield of ketone V 0.014 g (15%). The
subsequent elution gave 0.084 g of initial β-hydroxy
ketone IV. The yield of enone V, calculated on the
reacted initial ketone IV, was 94%.
c. Alkaline aluminum oxide (according to Brock-
mann), 10 g, was added to a solution of 0.5 g of
β-hydroxy ketone IV in 50 ml of toluene. The mixture
was stirred for 1 h at the boiling point, the heating bath
was removed, and the mixture was stirred for an ad-
ditional 1 h. Aluminum oxide was filtered off and
washed on a filter first with 150 ml of toluene and then
with 150 ml of ethyl acetate. The ethyl acetate solution
was evaporated, and the residue was subjected to
column chromatography on silica gel using ethyl
acetate–petroleum ether (1:4) as eluent. Removal of
the solvent from the eluate gave 0.092 g (20%) of
ketone V.
1
(C=Carom); 1270 (C–O). H NMR spectrum, δ, ppm:
0.84 t (3H, CH3, J = 6.5 Hz), 1.14–1.82 m (8H, CH2,
alkyl), 2.90 d.d (1H, 4-H, J1 = 8.2, J2 = 16.5 Hz),
3.32 d.d (1H, 4-H, J1 = 10.2, J2 = 16.5 Hz), 4.54–
4.74 m (1H, 5-H), 6.92 d and 7.47 d (2H each, Harom
,
J = 8.5 Hz).
3-Chloro-1-(4-hydroxyphenyl)octan-1-one (VI).
Concentrated hydrochloric acid, 1 ml, was added to
a solution of 0.766 g of β-hydroxy ketone IV in 20 ml
of dioxane. The mixture was stirred for 22.5 h at 20°C,
and 40 ml of toluene and 50 ml of a saturated aqueous
solution of sodium chloride were added. The aqueous
phase was separated and extracted with toluene (2×
20 ml). The extracts were combined with the organic
phase, washed in succession with 30 ml of a saturated
solution of sodium hydrogen carbonate and 30 ml of
a saturated solution of sodium chloride, and dried over
sodium sulfate. The solvent was distilled off under
reduced pressure, and the residue was recrystallized
from toluene–petroleum ether. Yield 0.577 g (70%),
mp 56–57°C (decomp., from toluene–petroleum ether).
UV spectrum, λmax, nm: 221.1, 279.8. IR spectrum, ν,
cm–1: 3585, 3100–3500 (O–H); 3025, 3010 (C–Harom);
2960, 2930, 2875, 2865 (C–Haliph); 1675 (C=O); 1605,
1-(4-Hydroxyphenyl)-2-octen-1-one (V). a. To
a solution of 0.44 g of β-hydroxy ketone IV (prepared
from 4,5-dihydroisoxazole III according to the proce-
dure described in [1]) in 15 ml of dioxane we added
0.3 ml of a 70% solution of perchloric acid. The mix-
ture was stirred for 18 h at 15–17°C, and 40 ml of
ethyl acetate and 40 ml of a saturated aqueous solution
of sodium chloride were added. The aqueous phase
was separated and extracted with ethyl acetate (2×
15 ml). The extracts were combined with the organic
phase, washed in succession with 20 ml of a saturated
solution of sodium hydrogen carbonate and 20 ml of
a saturated solution of sodium chloride, and dried over
sodium sulfate. The solvent was distilled off under
reduced pressure, and the residue was recrystallized
from toluene–petroleum ether. Yield 0.27 g (65%),
mp 67–68°C (from toluene–petroleum ether). IR spec-
trum, ν, cm–1: 3590, 3100–3500 (O–H); 3035, 3015
(C–Harom); 2965, 2935, 2875, 2865 (C–Haliph); 1662
(C=O); 1618 (C=C); 1605, 1585, 1513 (C=Carom).
1H NMR spectrum, δ, ppm: 0.88 t (3H, C8H3, J =
1
1585, 1510 (C=Carom). H NMR spectrum, δ, ppm:
0.88 t (3H, C8H3, J = 6.8 Hz), 1.20–1.38 m (4H, C6H2,
C7H2), 1.40–1.62 m (2H, C5H2), 1.69–1.89 m (2H,
C4H2), 3.18 d.d (1H, J1 = 5.6, J2 = 16.4 Hz) and
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 40 No. 10 2004

SYNTHESIS OF NEW LIQUID CRYSTALLINE COMPOUNDS
1481
3.50 d.d (1H, J1 = 8, J2 = 16.4 Hz) (C2H2); 4.48–
4.57 m (1H, C3H), 5.74 br.s (1H, 4'-OH), 6.88 d and
7.89 d (2H each, Harom, J = 8.8 Hz).
(22H), 1.45–1.59 m (3H), 1.66–1.79 m (4H), 1.80–
1.88 m (2H), and 2.10–2.22 m (2H) (CH2, alkyl, cyclo-
hexyl); 2.29 d.q (2H, C4'''H2, J1 = 1.2, J2 = 6.8 Hz);
2.46 t.t (1H, 4-H, J1 = 3.6, J2 = 12.4 Hz); 6.83 distorted
d (1H, 2'''-H, J = 15.6 Hz); 7.05 t.d (1H, 3'''-H, J1 =
4-(2-Octenoyl)phenyl 4-pentyloxybenzoate
(VIIIe). A catalytic amount of 4-(dimethylamino)pyr-
idine was added to a solution of 0.1 g (0.46 mmol)
of α,β-unsaturated ketone V, 0.1 g (0.48 mmol) of
4-pentyloxybenzoic acid, and 0.095 g (0.46 mmol) of
N,N'-dicyclohexylcarbodiimide in 15 ml of methylene
chloride. The mixture was stirred for 26 h at 20°C and
filtered through a layer of aluminum oxide, the sorbent
was washed with 40 ml of methylene chloride, the
solvent was removed from the filtrate under reduced
pressure, and the residue was recrystallized from
2-propanol. Yield 0.113 g (61%). IR spectrum, ν, cm–1:
3010 (C–Harom); 2965, 2925, 2870, 2855 (C–Haliph);
1732 (C=O, ester); 1668 (C=O, s-cis); 1648 (C=O,
6.8, J2 = 15.6 Hz); 7.15 d and 7.94 d (2H each, Harom
,
J = 8.8 Hz).
4-(2-Octenoyl)phenyl 4-dodecyloxybenzoate
(VIIIf). A solution of 0.056 g (0.11 mmol) of ester
VIIf (prepared from compound IV according to the
procedure described in [1]) in 10 ml of pyridine was
cooled to 0°C, and 0.03 ml of methanesulfonyl
chloride was added with stirring. The mixture was
stirred for 30 min, the cooling bath was removed, and
the mixture was stirred for 24 h at 20°C and for 1 h at
70°C. Ethyl acetate, 40 ml, and dilute (1:5) hydro-
chloric acid, 50 ml, were added, the aqueous phase was
separated, and the organic phase was treated in succes-
sion with 25 ml of water, 25 ml of a saturated aqueous
solution of sodium hydrogen carbonate, and 25 ml of
water again and dried over sodium sulfate. The solvent
was distilled off under reduced pressure, and the
residue was recrystallized from 2-propanol. Yield of
VIIIf 0.032 g (59%). UV spectrum: λmax 273.1 nm. IR
spectrum, ν, cm–1: 3025, 3010 (C–Harom); 2925, 2855
(C–Haliph); 1732 (C=O, ester); 1668 (C=O, s-cis); 1648
(C=O, s-trans); 1618 (C=C); 1606, 1600, 1581, 1511,
1
s-trans); 1599, 1580, 1511, 1506 (C=Carom). H NMR
spectrum, δ, ppm: 0.90 t (3H, J = 6.8 Hz) and 0.93 t
(3H, J = 7.2 Hz) (C5'H3 and C8''H3); 1.26–1.58 m (10H,
CH2 alkyl); 1.82 quint (2H, C2'H2, J = 7 Hz); 2.31 d.q
(2H, C4''H2, J1 = 1.2, J2 = 7.2 Hz); 4.04 t (2H, OC1'H2,
J = 7 Hz); 6.87 distorted d (1H, 2''-H, J = 15.2 Hz);
7.08 t.d (1H, 3''-H, J1 = 7.2, J2 = 15.2 Hz); 6.96 d
(2H, J = 8.8 Hz), 7.30 d (2H, J = 8.8 Hz), 8.00 d (2H,
J = 8.8 Hz), and 8.13 d (2H, J = 8.8 Hz) (Harom).
Compounds VIIIg and VIIIh were synthesized in
a similar way by esterification of phenol V.
1
1506 (C=Carom). H NMR spectrum, δ, ppm: 0.87 t
(3H, J = 7.2 Hz) and 0.90 t (3H, J = 7.2 Hz) (C12'H3
and C8''H3); 1.16–1.40 m (20H) and 1.41–1.58 m (4H)
(CH2, alkyl); 1.81 quint (2H, C2'H2, J = 7 Hz); 2.31 d.q
(2H, C4''H2, J1 = 1.2, J2 = 6.8 Hz); 4.03 t (2H, OC1'H2,
J = 7 Hz); 6.87 distorted d (1H, 2''-H, J = 15.6 Hz);
7.08 t.d (1H, 3''-H, J1 = 6.8, J2 = 15.6 Hz); 6.96 d (2H,
J = 8.8 Hz), 7.30 d (2H, J = 8.4 Hz), 8.00 d (2H, J =
8.4 Hz), and 8.13 d (2H, J = 8.8 Hz) (Harom).
4-(2-Octenoyl)phenyl 4'-decyloxy-1,1'-biphenyl-
4-carboxylate (VIIIg). Yield 80%. IR spectrum, ν,
cm–1: 3025, 3015 (C–Harom); 2955, 2930, 2855
(C–Haliph); 1734 (C=O, ester); 1668 (C=O, s-cis); 1647
(C=O, s-trans); 1618 (C=C); 1605, 1600, 1520, 1505,
1
1498 (C=Carom). H NMR spectrum, δ, ppm: 0.87 t
(3H, J = 6.8 Hz) and 0.90 t (3H, J = 7 Hz) (C10''H3 and
C8'''H3); 1.20–1.58 m (20H, CH2, alkyl); 1.80 quint
(2H, C3''H2, J = 7 Hz); 2.31 d.q (2H, C4'''H2, J1 = 1.2,
J2 = 6.8 Hz); 4.00 t (2H, OC1''H2, J = 7 Hz);
6.88 distorted d (1H, 2'''-H, J = 15.6 Hz); 7.09 t.d (1H,
3'''-H, J1 = 6.8, J2 = 15.6 Hz); 6.99 d (2H, J = 9 Hz),
7.33 d (2H, J = 9 Hz), 7.58 d (2H, J = 9 Hz), 7.69 d
(2H, J = 9 Hz), 8.02 d (2H, J = 9 Hz), and 8.22 d (2H,
J = 9 Hz) (Harom).
Compounds IXa–IXd and IXh were synthesized in
a similar way by esterification of phenol VI.
4-(3-Chlorooctanoyl)phenyl 4-fluorobenzoate
(IXa). Yield 70%. UV spectrum: λmax 250.4 nm. IR
spectrum, ν, cm–1: 3025, 3020 (C–Harom); 2955, 2925,
2875, 2855 (C–Haliph); 1740 (C=O, ester); 1690 (C=O);
1
1600, 1510 (C=Carom). H NMR spectrum, δ, ppm:
0.90 t (3H, C8'H3, J = 7 Hz); 1.20–1.40 m (4H, C6'H2,
C7'H2); 1.42–1.64 m (2H, C5'H2); 1.71–1.91 m (2H,
C4'H2); 3.25 d.d (1H, J1 = 5.6, J2 = 17.2 Hz) and
3.56 d.d (1H, J1 = 7.6, J2 = 17.2 Hz) (C2'H2); 4.50–
4.60 m (1H, 3'-H); 7.19 distorted t (2H, J = 8.8 Hz),
7.32 d (2H, J = 8.8 Hz), 8.04 d (2H, J = 8.8 Hz), and
8.22 distorted d.d (2H, J1 = 5.6, J2 = 8.8 Hz) (Harom).
4-(2-Octenoyl)phenyl 4'-pentyl-1,1'-bi(cyclo-
hexyl)-4-carboxylate (VIIIh). Yield 91%. IR spec-
trum, ν, cm–1: 3025, 3015 (C–Harom); 2930, 2860
(C–Haliph); 1750 (C=O, ester); 1668 (C=O, s-cis); 1648
(C=O, s-trans); 1618 (C=C); 1600, 1505 (C=Carom).
1H NMR spectrum, δ, ppm: 0.87 t (3H, J = 7 Hz) and
0.90 t (3H, J = 7 Hz) (C5''H3 and C8'''H3); 0.80–1.38 m
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KOVGANKO et al.
1482
C2'H2, J = 6.4 Hz); 1.71–1.91 m (2H, C4''H2); 3.24 d.d
(1H, J1 = 5.6, J2 = 17.2 Hz) and 3.56 d.d (1H, J1 = 7.6,
J2 = 17.2 Hz) (C2''H2); 4.04 t (2H, OCH2, J = 6.4 Hz);
4.50–4.60 m (1H, CHCl); 6.96 d (2H, J = 8.4 Hz),
7.32 d (2H, J = 8.4 Hz), 8.02 d (2H, J = 8.4 Hz), and
8.12 d (2H, J = 8.4 Hz) (Harom).
4-(3-Chlorooctanoyl)phenyl 4-cyanobenzoate
(IXb). Yield 76%. IR spectrum, ν, cm–1: 3025
(C–Harom); 2960, 2930, 2860 (C–Haliph); 2235 (C≡N);
1745 (C=O, ester); 1685 (C=O); 1600, 1500 (C=Carom).
1H NMR spectrum, δ, ppm: 0.90 t (3H, C8'H3, J =
6.8 Hz); 1.18–1.40 m (4H, C6'H2, C7'H2); 1.42–1.64 m
(2H, C5'H2); 1.71–1.92 m (2H, C4'H2); 3.24 d.d (1H,
J1 = 5.2, J2 = 17.2 Hz) and 3.57 d.d (1H, J1 = 7.6, J2 =
17.2 Hz) (C2'H2); 4.45–4.59 m (1H, 3'-H); 7.34 d
(2H, J = 8.4 Hz), 7.83 d (2H, J = 8.4 Hz), 8.06 d (2H,
J = 8.4 Hz), and 8.30 d (2H, J = 8.4 Hz) (Harom).
4-(3-Chlorooctanoyl)phenyl 4'-pentyl-1,1'-bi(cy-
clohexyl)-4-carboxylate (IXh). Yield 75%. UV spec-
trum: λmax 254.2 nm. IR spectrum, ν, cm–1: 3030, 3015
(C–Harom); 2930, 2855 (C–Haliph); 1755 (C=O, ester);
1
1690 (C=O); 1625, 1600, 1505 (C=Carom). H NMR
spectrum, δ, ppm: 0.87 t (3H, J = 7 Hz) and 0.89 t (3H,
J = 7 Hz) (C5''H3 and C8'''H3); 0.94–1.18 m, 1.18–
1.38 m, 1.40–1.63 m, and 1.66–1.90 m (33H, CH2,
alkyl, and CH2, CH, cyclohexyl); 2.11–2.19 m (2H,
C3H2, C5H2); 2.46 t.t (1H, 4-H, J1 = 3.6, J2 = 12.4 Hz);
3.22 d.d (1H, J1 = 5.6, J2 = 17 Hz) and 3.53 d.d (1H,
J1 = 7.6, J2 = 17 Hz) (C2'''H2); 4.48–4.58 m (1H,
CHCl); 7.16 d and 7.97 d (2H each, Harom, J = 8.6 Hz).
4-(3-Chlorooctanoyl)phenyl 4-propoxybenzoate
(IXc). Yield 81%. IR spectrum, ν, cm–1: 3030, 3010
(C–Harom); 2960, 2930, 2875, 2860 (C–Haliph); 1730
(C=O, ester); 1690 (C=O); 1600, 1580, 1510 (C=Carom).
1H NMR spectrum, δ, ppm: 0.89 t (3H, C8''H3, J =
7 Hz); 1.06 t (3H, C3'H3, J = 7 Hz); 1.18–1.38 m (4H,
C6''H2, C7''H2); 1.40–1.64 m (2H, C5''H2); 1.70–1.92 m
(2H, C4''H2); 1.84 sext (2H, C2'H2, J = 7 Hz); 3.25 d.d
(1H, J1 = 5.6, J2 = 17 Hz) and 3.56 d.d (1H, J1 = 7.6,
J2 = 17 Hz) (C2''H2); 4.00 t (2H, OC1'H2, J = 7 Hz);
4.50–4.60 m (1H, 3''-H); 6.97 d (2H, J = 8.8 Hz),
7.32 d (2H, J = 8.8 Hz), 8.03 d (2H, J = 8.8 Hz), and
8.12 d (2H, J = 8.8 Hz) (Harom).
REFERENCES
1. Bezborodov V.S., Kovganko V.N. Russ. J. Org. Chem.,
2004, vol. 40, p. 1295.
2. Liquid Crystals. Landolt-Börnstein. New Series. Group
IV, Madelung, O., Ed., Berlin: Springer, 1992, Vol. 7b.
3. Handbook of Liquid Crystals, Demus, D., Goodby, J.W.,
Gray, G.W., Spiess, H.-W., and Vill, V., Eds., Weinheim:
Wiley, 1998, vols. 1-3.
4. Bezborodov, V.S., Kovganko, N.N., and Lapanik, V.I.,
Vestsi Nats. Akad. Navuk Belarusi, Ser. Khim. Navuk,
2003, no. 1, p. 48.
4-(3-Chlorooctanoyl)phenyl 4-hexyloxybenzoate
(IXd). Yield 71%. UV spectrum, λmax, nm: 267.2,
305.1, 317.1, 332.1. IR spectrum, ν, cm–1: 3025, 3010
(C–Harom); 2955, 2930, 2875, 2860 (C–Haliph); 1730
(C=O, ester); 1680 (C=O); 1600, 1575, 1505 (C=Carom).
1H NMR spectrum, δ, ppm: 0.82–0.96 m (6H, C6'H3,
C8''H3); 1.20–1.64 m (12H, CH2, alkyl); 1.81 quint (2H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 40 No. 10 2004