Synthesis of new mesogens of the 3-arylisoxazolone and 3-arylpyrazolone series

Article abstract of DOI:10.1134/S1070428010120067

Acylation of ethyl acetoacetate with mesogenic para-substituted benzoyl chlorides, followed by cleavage of ethyl aroylacetoacetates thus obtained under basic conditions, gave the corresponding ethyl 3-aryl-3-oxopropanoates which were brought into condensations with hydroxylamine and hydrazine to obtain mesogenic 3-arylisoxazolones and 3-arylpyrazolones, respectively. Pleiades Publishing, Ltd., 2010.

Full text of DOI:10.1134/S1070428010120067

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 12, pp. 1812–1816. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © V.N. Kovganko, N.N. Kovganko, M.A. Polovkov, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 12,
pp. 1803–1807.
Synthesis of New Mesogens of the 3-Arylisoxazolone
and 3-Arylpyrazolone Series
V. N. Kovgankoa, N. N. Kovgankob, and M. A. Polovkova
a Byelorussian State Technological University, ul. Sverdlova 13a, Minsk, 220050 Belarus
e-mail: umkauhanka@tut.by
b Byelorussian State Medical University, Minsk, Belarus
Received March 22, 2010
Abstract—Acylation of ethyl acetoacetate with mesogenic para-substituted benzoyl chlorides, followed by
cleavage of ethyl aroylacetoacetates thus obtained under basic conditions, gave the corresponding ethyl 3-aryl-
3-oxopropanoates which were brought into condensations with hydroxylamine and hydrazine to obtain
mesogenic 3-arylisoxazolones and 3-arylpyrazolones, respectively.
DOI: 10.1134/S1070428010120067
Liquid crystalline compounds possessing five-
membered heterorings occupy a specific place among
known classes of mesomorphic materials [1–7]. Such
compounds can be used as components of smectic and
nematic liquid crystalline systems characterized by
good mesomorphic and electrooptical properties [1–7].
Liquid crystalline compounds containing various five-
membered heterorings have been reported up to now
[1–7]. In particular, we have synthesized a series of
new mesogenic 4,5-dihydroisoxazole [7], isoxazole
[8], and pyrazole derivatives [9]. Substituted isoxazol-
5-ones and pyrazol-5-ones are structurally related to
the above five-membered heterocyclic compounds.
Isoxazol-5-one and pyrazolo-5-one derivatives are
well known as drugs, pesticides, materials for elec-
tronics, and analytical reagents [10–14]. Many sub-
stituted isoxazolones and pyrazolones were found to
exhibit various kinds of biological activity [15, 16].
Scheme 1.
O
O
O
O
O
O
Me
OEt
III
OH
Cl
OEt
R
R
R
O
Me
Ia–Id
IIa–IId
IVa–IVd
O
N
O
O
O
R
R
OEt
VIa–VId
NH
R
N
O
Va–Vd
VIIa–VIId
R = C3H7O (a), C7H15O (b), C8H17O (c), 4-C5H11C6H4 (d).
1812

SYNTHESIS OF NEW MESOGENS
1813
However, despite broad spectrum of practical applica-
tions of isoxazolones and pyrazolones, liquid crystal-
line compounds containing these five-membered het-
erocyclic fragments have not been reported so far.
Taking the above stated into account, the goal of the
present work was to synthesize mesogenic isoxazol-5-
ones and pyrazol-5-ones and examine their mesomor-
phic properties. As first subjects for study we selected
3-arylisoxazolone and 3-arylpyrazolone derivatives.
corresponding β-keto esters Va–Vd with hydroxyl-
amine hydrochloride in the presence of sodium acetate
(Scheme 1). Their structure was confirmed by IR, UV,
and NMR spectroscopy. In the UV spectrum of isoxa-
zolone VIb we observed an absorption maximum at
λ 280 nm. A small blue shift of the absorption maxi-
mum of compound VIb relative to that in the spectrum
of β-keto ester Vb is likely to indicate that the corre-
sponding electron transition occurs in the substituted
benzene ring conjugated with the imino group. The IR
spectra of isoxazolones Va–Vd contain strong absorp-
tion bands at 1819 and 1790 cm–1 due to stretching
vibrations of the C=O and C=N bonds. In the 1H NMR
spectra of VIa–VId, methylene protons in the dihydro-
isoxazole ring resonated as a singlet at δ 3.90 ppm
(2H), whereas no signals typical of ester ethoxy group
(triplet and quartet) were present. These data con-
firmed the cyclization with formation of dihydroisoxa-
zole ring and elimination of ethanol molecule.
The key intermediate products in the synthesis of
isoxazolones and pyrazolones are substituted β-keto
esters. The required ethyl 3-aryl-3-oxopropanoates Va–
Vd were prepared by acylation of ethyl acetoacetate
and subsequent cleavage according to Hunsdiecker
[17] (Scheme 1). In the first step, 4-alkoxybenzoic
acids Ia–Ic and 4′-pentylbiphenyl-4-carboxylic acid
(Id) were converted into the corresponding benzoyl
chlorides IIa–IId by treatment with thionyl chloride.
Chlorides IIa–IId were used to acylate ethyl aceto-
acetate (III) in the presence of magnesium ethoxide.
According to the TLC data, the reaction mixtures at
that step contained β-oxo esters Va–Vd in addition to
tricarbonyl compounds IVa–IVd. To avoid laborious
separation of compounds IV and V, the product mix-
tures were subjected to cleavage under basic condi-
tions without purification. This reaction was carried
out using either aqueous ammonia in the presence of
ammonium chloride or potassium hydroxide. The
yields of target β-dicarbonyl compounds V attained
56% calculated on the initial benzoic acids.
The structure of isoxazolones VIc and VId was
additionally confirmed by the 13C NMR data. The 13C
NMR spectrum of VIc contained 15 signals, which is
consistent with the formula C17H23NO3 with account
taken of magnetically equivalent carbon atoms in the
benzene ring. The C=O and C=N signals appeared at
δC 177.1 and 164.8 ppm, respectively, and the C4 atom
in the isoxazole ring resonated at δC 35.4 ppm.
Mesogenic 3-aryl-1H-pyrazol-5(4H)-ones VIIa–
VIId were synthesized by reaction of β-keto esters
Va–Vd with hydrazine hydrate, and their yields ranged
from 66 to 95%. The structure of compounds VIIa–
VIId unambiguously followed from their spectral data.
The UV spectrum of VIIb contained an absorption
maximum at λ 265 nm, whose position considerably
differed from the position of the absorption maximum
in the spectrum of initial β-keto ester Vb. All pyrazo-
lones VIIa–VIId characteristically showed in the IR
spectra broadened absorption bands in the regions
2000–2800 and 3300–3600 cm–1 due to stretching
vibrations of the O–H and N–H groups involved in
intermolecular hydrogen bonds. Stretching vibrations
of the carbonyl group gave rise to a strong absorption
band at 1619 cm–1.
The structure of β-keto esters Va–Vd was proved
1
by their UV, IR, and H NMR spectra. Compound Vb
displayed in the UV spectrum an absorption maximum
at λ 284 nm, which is typical of substituted benzene
ring. The IR spectra of all compounds Va–Vd con-
tained two strong carbonyl absorption bands (1634 and
1612 cm–1 for homologous compounds Vb and Vc). In
1
the H NMR spectra of Va–Vd we observed signals
from protons in all structural fragments of their mole-
cules (β-keto ester moiety, para-substituted benzene
ring, and alkyl substituent). For instance, the ketone
1
tautomer of Va showed in the H NMR spectrum
(CD3OD) a multiplet signal at δ 3.31 ppm from the
methylene protons in the 1,3-dicarbonyl fragment. In
keeping with the H NMR data, ester Vb in DMSO-d6
exists exclusively in the enol form: the spectrum con-
tained a singlet at δ 4.11 ppm due to the =CH proton in
the enol fragment.
1
The H NMR spectra of compounds VIIa–VIId
1
were recorded from solutions in pyridine-d5. Judging
by the spectral data, pyrazolones VIIa–VIId in that
solvent exist as 5-hydroxypyrazole or 2,5-dihydro-1H-
pyrazol-5-one tautomers [10]. The spectra contained
a one-proton signal at δ 6.33 ppm, which belongs to
the vinylic 4-H proton; no signals assignable to meth-
Mesogenic 3-arylisoxazol-5(4H)ones VIa–VId
were synthesized in 90–95% yield by reaction of the
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 12 2010

KOVGANKO et al.
1814
ylene protons (C4H2) in the pyrazole ring and ethoxy
group were present. The structure of compounds VIIa–
VIId was also confirmed by their 13C NMR spectra.
combined with the organic phase, washed with a satu-
rated solution of sodium chloride, and evaporated
under reduced pressure. The residue containing ethyl
aroylacetoacetate IVa was dissolved in 50 ml of
ethanol, a solution of 15.08 g (269.3 mmol) of potas-
sium hydroxide was added, and the mixture was stirred
for 24 h at room temperature, treated in succession
with water and dilute hydrochloric acid (10:3), and
extracted with benzene. The benzene extracts were
washed with a saturated solution of sodium chloride
and treated with neutral aluminum oxide over a period
of 3 days. The sorbent was filtered off, the solvent was
removed, and the residue was distilled under reduced
pressure. A fraction of β-keto ester Va with bp 175–
189°C (1 mm), 28.16 g, was additionally purified via
conversion into the corresponding chelate with cop-
Study on mesomorphic properties of the obtained
isoxazole and pyrazole derivatives showed that only
compounds VId and VIId possessing a biphenyl frag-
ment give rise to a mesophase. Isoxazolone VId was
found to form monotropic nematic liquid crystalline
phase with the following phase transition temperatures:
heating: Cr→I (160°C); cooling: I→N (155°C)→Cr
(147°C). Pyrazolone VIId produced smectic A phase
in the temperature range from 270 to 292°C. Most
probably, the lack of liquid crystalline properties of
compounds VIa–VIc and VIIa–VIIc is related to
small number of rings (2) in the rigid skeleton of their
molecules.
per(II) acetate. Yield of Va 20.43 g (45%), nD18
=
1.5330. IR spectrum, ν, cm–1 (film): 3077, 3045, 2970,
EXPERIMENTAL
2939, 2879 (C–H); 1742, 1678 (C=O); 1601, 1574,
1511 (C=Carom). H NMR spectrum (CD3OD), δ, ppm,
1
The melting points and phase transition tempera-
tures were determined on a hot stage coupled with
a polarizing microscope. Mesophases were identified
by comparing the observed texture with reference
samples given in [18]. The IR spectra (400–4000 cm–1)
were recorded in KBr (unless otherwise stated) on
a Nicolet Nexus IR spectrometer with Fourier trans-
form. The UV spectra were measured on a Specord
M500 spectrophotometer. The NMR spectra were
obtained on a Bruker Avance 500 instrument at
ketone tautomer: 1.05 t (3H, CH3, J = 7 Hz), 1.82 sext
(2H, CH2, J = 7 Hz), 4.02 t (2H, OCH2, J = 7 Hz)
{OC3H7}; 1.24 t (3H, CH3, J = 7 Hz), 4.17 q (2H,
OCH2, J = 7 Hz) {OC2H5}; 3.31 m (2H, 2-H), 7.00 d
(2H, Harom, J = 9 Hz), 7.94 d (2H, Harom, J = 9 Hz);
enol tautomer: 1.30 t (3H, CH3, J = 7 Hz), 3.98 t (2H,
OCH2, J = 7 Hz), 4.23 q (2H, OCH2, J = 7 Hz), 6.95 d
(2H, Harom, J = 9 Hz), 7.75 d (2H, Harom, J = 9 Hz).
Compounds Vb–Vd were synthesized in a similar
way. In the synthesis of keto esters Vc and Vd, cleav-
age of ethyl aroylacetoacetates IVc and VId was per-
formed using excess aqueous ammonia in the presence
of ammonium chloride.
1
500.13 MHz for H and 125.75 MHz for 13C. The
progress of reactions and the purity of products were
monitored by thin-layer chromatography on Kieselgel
60 F254 plates (Merck).
Ethyl 3-oxo-3-(4-propoxyphenyl)propionate
(Va). A solution of magnesium ethoxide prepared from
4.35 g (181.2 mmol) of magnesium and 50 ml of anhy-
drous ethanol containing 5 ml of carbon tetrachloride
was heated to the boiling point, and a solution of
22.9 ml (180.4 mmol) of ethyl acetoacetate in 40 ml of
tetrahydrofuran was added dropwise under stirring.
The mixture was cooled to 0°C, a solution of
4-propoxybenzoyl chloride [prepared from 32.46 g
(180.3 mmol) of 4-propoxybenzoic acid and excess
thionyl chloride] in 50 ml of tetrahydrofuran was
added dropwise over a period of 30 min under stirring,
and the mixture was stirred for 3 h on cooling with an
ice bath and left overnight at room temperature. The
mixture was then diluted in succession with 100 ml of
water, 113 ml of dilute hydrochloric acid (10:1.3), and
100 ml of benzene. The aqueous phase was separated
and extracted with benzene. The benzene extract was
Ethyl 3-(4-heptyloxyphenyl)-3-oxopropionate
(Vb). Yield 53%, mp 47–48°C (from propan-2-ol–
petroleum ether). UV spectrum: λmax 284 nm. IR spec-
trum, ν, cm–1: 3048, 2956, 2940, 2866 (C–H); 1634,
1612 (C=O); 1573, 1516 (C=Carom). 1H NMR spectrum
(DMSO-d6), δ, ppm: enol tautomer (100%): 0.87 t (3H,
CH3, J = 7 Hz), 1.23–1.36 m (6H), 1.41 quint (2H, J =
7 Hz), 1.73 quint (2H, J = 7 Hz), 4.07 t (2H, OCH2, J =
7 Hz) {OC7H15}; 1.18 t (3H, CH3, J = 7 Hz), 4.11 q
(2H, OCH2, J = 7 Hz) {OC2H5}; 3.34 s (1H, OH,
enol), 4.11 s (1H, 2-H), 7.05 d (2H, Harom, J = 9 Hz),
7.92 d (2H, Harom, J = 9 Hz).
Ethyl 3-(4-octyloxyphenyl)-3-oxopropionate
(Vc). Yield 56%, mp 49–50°C (from propan-2-ol–
petroleum ether). IR spectrum, ν, cm–1: 3110, 3047,
2959, 2942, 2926, 2865, 2851 (C–H); 1634, 1612
1
(C=O); 1573, 1515 (C=Carom). H NMR spectrum
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 12 2010

SYNTHESIS OF NEW MESOGENS
1815
(CD3OD), δ, ppm: ketone tautomer: 0.90 t (3H, CH3,
J = 7 Hz), 1.26–1.42 m (8H), 1.48 quint (2H, J =
7 Hz), 1.79 quint (2H, J = 7 Hz), 4.06 t (2H, OCH2, J =
7 Hz) {OC8H17}; 1.24 t (3H, CH3, J = 7 Hz), 4.17 q
(2H, OCH2, J = 7 Hz) {OC2H5}; 3.31 s (2H, 2-H),
6.99 d (2H, Harom, J = 9 Hz), 7.94 d (2H, Harom, J =
9 Hz); enol tautomer: 4.01 t (2H, OCH2, J = 7 Hz),
4.23 q (2H, OCH2, J = 7 Hz), 6.95 d (2H, Harom, J =
9 Hz), 7.75 d (2H, Harom, J = 9 Hz).
(3H, CH3, J = 7 Hz), 1.28–1.40 m (6H, CH2),
1.45 quint (2H, CH2, J = 7 Hz), 1.77 quint (2H, CH2,
J = 7 Hz), 3.90 s (2H, 4-H), 4.03 t (2H, OCH2, J =
7 Hz), 7.01 d (2H, Harom, J = 9 Hz), 7.64 d (2H, Harom
,
J = 9 Hz).
3-(4-Octyloxyphenyl)isoxazol-5(4H)-one (VIc).
Yield 96%, mp 108°C (from propan-2-ol). UV spec-
trum: λmax 281 nm. IR spectrum, ν, cm–1: 3079
(C–Harom); 2923, 2854 (C–Haliph); 1819, 1790 (C=O,
C=N); 1609, 1592, 1558, 1519 (C=Carom); 1252, 1177
Ethyl 3-oxo-3-(4′-pentylbiphenyl-4-yl)propionate
(Vd). Yield 22%, mp 105°C (from propan-2-ol–petro-
leum ether). UV spectrum: λmax 309 nm. IR spectrum,
ν, cm–1: 3113, 2954, 2929, 2867, 2857 (C–H); 1645,
1
(C–O). H NMR spectrum (CD3CN), δ, ppm: 0.89 t
(3H, CH3, J = 7 Hz), 1.24–1.40 m (8H, CH2),
1.45 quint (2H, CH2, J = 7 Hz), 1.76 quint (2H, CH2,
J = 7 Hz), 4.02 s (2H, 4-H), 4.03 t (2H, OCH2, J =
1
1615 (C=O); 1574, 1553, 1496 (C=Carom). H NMR
spectrum (acetone-d6), δ, ppm: ketone tautomer: 0.90 t
(3H, CH3, J = 7 Hz), 1.32–1.40 m (4H), 1.67 quint
(2H, J = 7.5 Hz), 2.68 t (2H, C6H4CH2, J = 7.5 Hz)
{C5H11}; 1.23 t (3H, CH3, J = 7 Hz), 4.19 q (2H,
OCH2, J = 7 Hz) {OC2H5}; 4.14 s (2H, 2-H), 7.36 d
(2H, Harom, J = 9 Hz), 7.68 d (2H, Harom, J = 9 Hz),
7.83 d (2H, Harom, J = 9 Hz), 8.09 d (2H, Harom, J =
9 Hz); enol tautomer: 4.28 q (2H, OCH2, J = 7 Hz),
7.36 d (2H, Harom, J = 9 Hz), 7.66 d (2H, Harom, J =
7 Hz), 7.00 d (2H, Harom, J = 9 Hz), 7.63 d (2H, Harom
,
J = 9 Hz). 13C NMR spectrum (CD3CN), δC, ppm:
14.43 (CH3); 23.40, 26.69, 29.83, 30.02, 30.06, 32.61,
69.25 (CH2); 35.40 (C4); 116.01, 121.29, 129.42,
163.08 (Carom); 164.82, 177.09 (C=N, C=O).
3-(4′-Pentylbiphenyl-4-yl)isoxazol-5(4H)-one
(VId). Yield 90%. Phase transition temperatures:
heating: Cr→I (160°C); cooling: I→N (155°C)→Cr
(147°C). UV spectrum: λmax 282 nm. IR spectrum, ν,
cm–1: 3085, 3049, 3024 (C–Harom); 2954, 2920, 2855
(C–Haliph); 1820, 1792 (C=O, C=N); 1607, 1588, 1502
9 Hz), 7.78 d (2H, Harom, J = 9 Hz), 7.96 d (2H, Harom
,
J = 9 Hz).
1
3-(4-Propoxyphenyl)isoxazol-5(4H)-one (VIa).
A solution of 2.78 g (11.12 mmol) of keto ester Va,
0.85 g (12.2 mmol) of hydroxylamine hydrochloride,
and 1.00 g (12.0 mmol) of sodium acetate in a mixture
of 40 ml of ethanol and 10 ml of water was heated for
3 h under reflux with stirring. The mixture was then
diluted with 50 ml of water, and the precipitate was
filtered off and washed with aqueous ethanol (12 ml)
and water (50 ml). Yield 1.94 g (92%), mp 118°C
(from ethanol). UV spectrum, λmax, nm: 266, 279. IR
spectrum, ν, cm–1: 3083 (C–Harom); 2967, 2936, 2879
(C–Haliph); 1818, 1790 (C=O, C=N); 1608, 1555, 1520
(C=Carom); 1176 (C–O). H NMR spectrum (CD3CN),
δ, ppm: 0.90 t (3H, CH3, J = 7 Hz), 1.29–1.40 m (4H,
CH2), 1.64 quint (2H, CH2, J = 7.5 Hz), 2.66 t (2H,
C6H4CH2, J = 7.5 Hz), 3.97 s (2H, 4-H), 7.32 d (2H,
H
arom, J = 8 Hz), 7.61 d (2H, Harom, J = 8 Hz), 7.78–
7.80 m (4H, Harom). 13C NMR spectrum (CD3CN), δC,
ppm: 14.39 (CH3); 23.28, 31.98, 32.29, 36.10 (CH2);
35.37 (C4); 127.79, 127.95, 128.22, 128.33, 130.15,
137.86, 144.49, 145.17 (Carom); 165.13, 176.93 (C=N,
C=O).
3-(4-Propoxyphenyl)-1H-pyrazol-5(4H)-one
(VIIa). β-Keto ester Va, 5.62 g (22.48 mmol), was
dissolved in 40 ml of ethanol, 1.2 ml of hydrazine
hydrate (containing 64% of hydrazine) was added, and
the mixture was heated for 2 h 45 min under reflux.
The mixture was cooled to room temperature and
diluted with 40 ml of water, and the precipitate was
filtered off and washed with 10 ml of aqueous ethanol
(1:1) and 60 ml of water. Yield 4.29 g (88%), mp 229–
230°C (from toluene–ethyl acetate). UV spectrum:
λmax 268 nm. IR spectrum, ν, cm–1: 3500–2000 br
(N–H); 3125 (C–Harom); 2966, 2939, 2875 (C–Haliph);
1619 (C=O); 1553, 1496 (C=Carom); 1250, 1180 (C–O).
1H NMR spectrum (C5D5N), δ, ppm: 0.83 t (3H, CH3,
J = 7 Hz), 1.59 sext (2H, CH2, J = 7 Hz), 3.75 t (2H,
1
(C=Carom); 1255, 1179 (C–O). H NMR spectrum
(CD3CN), δ, ppm: 1.02 t (3H, CH3, J = 7 Hz),
1.80 sext (2H, CH2, J = 7 Hz), 3.90 s (2H, 4-H), 4.01 t
(2H, OCH2, J = 7 Hz), 7.01 d (2H, Harom, J = 9 Hz),
7.64 d (2H, Harom, J = 9 Hz).
Compounds VIb–VId were synthesized in a similar
way.
3-(4-Heptyloxyphenyl)isoxazol-5(4H)-one (VIb).
Yield 89%, mp 102°C (from propan-2-ol). UV spec-
trum: λmax 280 nm. IR spectrum, ν, cm–1: 3080
(C–Harom); 2950, 2930, 2857 (C–Haliph); 1819, 1790
(C=O, C=N); 1609, 1557, 1519 (C=Carom); 1253, 1178
1
(C–O). H NMR spectrum (CD3CN), δ, ppm: 0.91 t
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 12 2010

KOVGANKO et al.
1816
OCH2, J = 7 Hz), 6.33 s (1H, 4-H), 7.00 d (2H, Harom
,
13C NMR spectrum (C5D5N), δC, ppm: 14.23 (CH3);
22.82, 31.47, 31.71, 35.73 (CH2); 126.25, 127.19,
127.65, 129.50 (Carom).
J = 9 Hz), 7.88 d (2H, Harom, J = 9 Hz). 13C NMR
spectrum (C5D5N), δC, ppm: 10.47 (CH3); 22.68, 69.49
(CH2); 87.07 (C4); 115.17, 126.95 (Carom); 159.26.
REFERENCES
Compounds VIIb–VIId were synthesized in a sim-
ilar way.
1. Petrov, V.F., Liq. Cryst., 2001, vol. 28, p. 217.
3-(4-Heptyloxyphenyl)-1H-pyrazol-5(4H)-one
(VIIb). Yield 95%, mp 223°C (from propan-2-ol).
UV spectrum: λmax 265 nm. IR spectrum, ν, cm–1:
2800–2000, 3600–3300 br (N–H); 3125 (C–Harom);
2955, 2928, 2856 (C–Haliph); 1619 (C=O); 1552, 1514,
1496 (C=Carom); 1248, 1180 (C–O). 1H NMR spectrum
(C5D5N), δ, ppm: 0.76 t (3H, CH3, J = 7 Hz), 1.06–
1.19 m (6H, CH2), 1.30 quint (2H, CH2, J = 7 Hz),
1.63 quint (2H, CH2, J = 7 Hz), 3.85 t (2H, OCH2, J =
7 Hz), 6.34 s (1H, 4-H), 7.05 d (2H, Harom, J = 9 Hz),
7.90 br.d (2H, Harom, J = 9 Hz), 12.4–13.4 br.m (OH,
NH). 13C NMR spectrum (C5D5N), δC, ppm: 14.30
(CH3); 22.90, 26.32, 29.33, 29.60, 32.03, 68.29 (CH2);
87.27 (C4); 115.40, 127.17 (Carom); 159.52.
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Chem., 2006, vol. 42, p. 243.
3-(4-Octyloxyphenyl)-1H-pyrazol-5(4H)-one
(VIIc). Yield 85%, mp 208°C (from propan-2-ol). UV
spectrum: λmax 265 nm. IR spectrum, ν, cm–1: 3600–
3300, 2800–2000 br (N–H); 3123 (C–Harom); 2924,
2855 (C–Haliph); 1619 (C=O); 1553, 1496 (C=Carom);
9. Kovganko, V.N. and Kovganko, N.N., Russ. J. Org.
Chem., 2006, vol. 42, p. 696.
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11. Aret, E., Meekes, H., Vlieg, E., and Deroover, G., Dyes
Pigm., 2007, vol. 72, p. 339.
1
1248, 1181 (C–O). H NMR spectrum (C5D5N), δ,
12. Marchetti, F., Pettinari, C., and Pettinari, R., Coord.
Chem. Rev., 2005, vol. 249, p. 2909.
13. Arichi, J., Goetz-Grandmont, G., and Brunette, J.P.,
ppm: 0.76 t (3H, CH3, J = 7 Hz), 1.04–1.20 m (8H,
CH2), 1.30 quint (2H, CH2, J = 7 Hz), 1.64 quint (2H,
CH2, J = 7 Hz), 3.85 t (2H, OCH2, J = 7 Hz), 6.32 s
(1H, 4-H), 7.04 d (2H, Harom, J = 9 Hz), 7.88 d (2H,
Hydrometallurgy, 2006, vol. 82, p. 100.
H
arom, J = 9 Hz). 13C NMR spectrum (C5D5N), δC,
14. Shen, L., Chen, Z., Zhao, Q., Li, F.-Y., Yi, T., Cao, Y.,
and Huang, C.-H., Inorg. Chem. Commun., 2006, vol. 9,
p. 620.
15. Braña, M.F., Gradillas, A., Ovalles, A.G., López, B.,
Acero, N., Llinares, F., and Muñoz Mingarro, D.,
Bioorg. Med. Chem. 2006, vol. 14, p. 9.
16. Laughlin, S.K., Clark, M.P., Djung, J.F., Golebiow-
ski, A., Brugel, T.A., Sabat, M., Bookland, R.G., Laufer-
sweiler, M.J., VanRens, J.C., Townes, J.A., De, B.,
Hsieh, L.C., Xu, S.C., Walter, R.L., Mekel, M.J., and
Janusz, M.J., Bioorg. Med. Chem. Lett., 2005, vol. 15,
p. 2399.
ppm: 14.31 (CH3); 22.93, 26.36, 29.52, 29.58, 29.63,
68.28 (CH2); 87.28 (C4); 115.38, 127.17 (Carom);
159.53.
3-(4′-Pentylbiphenyl-4-yl)-1H-pyrazol-5(4H)-one
(VIId). Yield 66%. Phase transition temperatures:
Cr→SmA (270°C)→I (292°C). IR spectrum, ν, cm–1:
3600–3250, 2800–2000 br (N–H); 3151, 3022
(C–Harom); 2955, 2926, 2855 (C–Haliph); 1616 (C=O);
1
1551, 1508 (C=Carom). H NMR spectrum (C5D5N), δ,
ppm: 0.74 t (3H, CH3, J = 7 Hz), 1.12–1.19 m (4H,
CH2), 1.49 quint (2H, CH2, J = 7 Hz), 2.50 t (2H,
C6H4CH2, J = 7 Hz), 6.43 s (1H, 4-H), 7.24 d (2H,
17. Benetti, S., Romagnoli, R., de Risi, C., Spalluto, G., and
Zanirato, V., Chem. Rev., 1995, vol. 95, p. 1065.
H
arom, J = 8 Hz), 7.61 d (2H, Harom, J = 8 Hz), 7.71 d
18. Demus, D. and Richter, L., The Texture of Liquid
Crystals, Leipzig: Grandstoffindustie, 1978, p. 219.
(2H, Harom, J = 8 Hz), 8.02 d (2H, Harom, J = 8 Hz).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 12 2010