5-Aryl-1-[pyrimidin-2(4)-yl]-3-phenyl-4,5-dihydro-1H-pyrazoles. Synthesis from substituted 2(4)-hydrazinopyrimidines and fragmentation under positive electrospray ionization

Article abstract of DOI:10.1134/S1070428016080133

Reaction of substituted 2(4)-hydrazinopyrimidines with 3-aryl-1-phenyl-2-propen-1-ones in the presence of a base results prevailingly in 5-aryl-1-[pyrimidin-2(4)-yl]-3-phenyl-4,5-dihydro-1H-pyrazoles. The fragmentation path of these compounds under positive electrospray ionization consists in simultaneous decomposition of their heterocyclic fragments.

Full text of DOI:10.1134/S1070428016080133

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2016, Vol. 52, No. 8, pp. 1173–1178. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © A.V. Erkin, O.S. Yuzikhin, V.I. Krutikov, 2016, published in Zhurnal Organicheskoi Khimii, 2016, Vol. 52, No. 8, pp. 1181–1185.
5-Aryl-1-[pyrimidin-2(4)-yl]-3-phenyl-4,5-dihydro-1H-pyrazoles.
Synthesis from Substituted 2(4)-Hydrazinopyrimidines and
Fragmentation under Positive Electrospray Ionization
A. V. Erkina*, O. S. Yuzikhinb, and V. I. Krutikova
a St. Petersburg State Technologic Institute (Technical University), Moskovskii pr. 26, St. Petersburg, 190013 Russia
*e-mail: anerkin@yandex.ru
b Kirov St. Petersburg State Forest University, St. Petersburg, Russia
Received April 22, 2016
Abstract—Reaction of substituted 2(4)-hydrazinopyrimidines with 3-aryl-1-phenyl-2-propen-1-ones in the
presence of a base results prevailingly in 5-aryl-1-[pyrimidin-2(4)-yl]-3-phenyl-4,5-dihydro-1H-pyrazoles. The
fragmentation path of these compounds under positive electrospray ionization consists in simultaneous
decomposition of their heterocyclic fragments.
DOI: 10.1134/S1070428016080133
The attention directed to 3,5-diaryl-1-(pyrimidin-2-
yl)-4,5-dihydro-1H-pyrazoles 1 is due to the wide
range of biologic actions they exhibit. Compounds
found in this series possess antioxidant, antiphlogistic,
analgesic [1], and antiproliferative [2] properties. The main
procedure of the synthesis of compounds 1 consists in
the cyclocondensation of 2-hydrazinopyrimidines [1, 2]
or aminoguanidine [3] with 1,3-diaryl-2-propen-1-ones.
The preparation of 1-(pyrimidin-2-yl)pyrazolines 1
from 1-carboxamidino-4,5-dihydro-1H-pyrazoles and
4-alkoxy-3-alken-2-ones was described in [4].
quantum chemical calculations by semiempirical
methods AM1 and PM3 the nitrogen atom of the ter-
minal amino group of this anion is characterized by a
larger excessive charge [–0.249 (AM1), –0.145 (PM3)]
than the same atom of the non-ionized form of the
initial compound [–0.219 (AM1), –0.038 (PM3)]. The
1H NMR spectra of pyrazolines 2a–2d contain typical
[1–3] doublets of doublets of protons from the spin
system ABX [δA 3.1–3.3 (JAX 3.8–5.3 Hz), δB 3.7–4.0
(JAB 17.3–17.8 Hz), δX 5.7–5.9 (JBX 11.8–12.0 Hz) ppm].
In the 13С NMR spectra of compounds 2a–2d signals
appeared belonging to atoms С4 and С5 of the five-
membered ring with characteristic [1–3] chemical
shifts δC 40–42 and 57–62 ppm respectively.
The aim of this study was the synthesis of
previously unknown 5-aryl-1-(4,6-dimethylpyrimidin-
2-yl)-3-phenyl-4,5-dihydro-1H-pyrazoles 2a–2d and 5-
aryl-1-[6-methyl-2-(methylsulfanyl)pyrimidin-4-yl]-3-
phenyl-4,5-dihydro-1H-pyrazoles 3a–3d from the corres-
ponding 2(4)-hydrazinopyrimidines and 3-aryl-1-phe-
nyl-2-propen-1-ones 4a–4d and establishing the frag-
mentation path of the target compounds under the con-
ditions of the positive electrospray ionization (HESI).
The attempt to increase the yield of pyrazolines 2a–
2d by isolation of potential [6] intermediate N-(4,6-
Scheme 1.
Ph
Ph
Ar
Me
N
O
4a_4d
Pyrazolines 2a–2d were prepared by cyclocon-
densation of 2-hydrazino-4,6-dimethylpyrimidine 5
with chalcones 4a–4d in the presence of an equimolar
amount of potassium hydroxide at heating in ethanol
(Scheme 1). The use of a base in this charge-controlled
1,2-addition reaction [5] was due to the requirement of
converting hydrazine 5 in the anion form. According to
N
Ar
N
N
NH2
N
N
N
Me
H
Me
Me
2a_2d
5
Ar = Ph (a), 2-HOC6H4 (b), 3-O2NC6H4 (c), 4-Me2NC6H4 (d).
1173

ERKIN et al.
1174
Scheme 2.
Ph
Ph
N
N
NH
N
Me
Me
Me
4a
AcOH
6
5
Ph
OH
Me
N
Ph
N
N
+
H
N
N
N
N
N
Me
H
O
Me
Me
7
8
dimethylpyrimidin-2-yl)-N'-(3-aryl-1-phenylallyli-
dene)hydrazines failed. Thus, at boiling compound 5
with chalcone 4a in anhydrous benzene for 1 h no
released water was collected in the Dean-Stark trap.
The mixed sample of the precipitate formed on cooling
the reaction mixture with hydrazine 5 showed no
depression of the melting point. The analysis of the
benzene filtrate by TLC also did not detect any
compounds different from initial hydrazine 5 and
chalcone 4a.
0.75 (А)] in a 1 : 1 ratio. The acylation of hetarylhyd-
razines with acetic acid was not described before [7].
To simplify the identification of the components of the
isolated mixture we determined the spectral cha-
racteristics of an authentic sample of acetylhydrazine 7
synthesized by reaction of compound 5 with glacial
acetic acid at 100°С (Scheme 2).
Along with the signals of compound 7 NMR
spectra of the mixture contained the signals of 4-
hydroxypyrazoline 8: 1Н NMR spectrum contained the
doublets of the spin system AX [δA 4.99, δX 6.40 (JAX
7.3 Hz) ppm] and a doublet of the hydroxy group
[δ 5.43 (4JHOH 1.2 Hz) ppm], in the 13С NMR spectrum
signals of atoms С4 and С5 of the five-membered ring
were present with characteristic chemical shifts [8]
δ 71.70 and 80.93 ppm respectively. In the high
frequency region of the IR spectrum beside the
absorption bands of the stretching vibrations of NH
groups of acetylhydrazine 7 a band was observed
corresponding to vibrations of the hydroxy group of
compound 8 at 3342 cm–1.
The replacement of benzene for glacial acetic acid
and raising the reaction temperature to 100°С did not
result in the formation either of N-(4,6-dimethyl-
pyrimidine-2-yl)-N'-(1,3-diphenylallylidene)hydrazine
6, or pyrazoline 2a. Treatment of the residue obtained
after complete removal of the acid with diethyl ether
gave a product that after recrystallization from ethanol
containing 25% of DMF consisted of a mixture of two
compounds, 2-(2-acetylhydrazino)-4,6-dimethylpyri-
midine 7 [Rf 0.41 (А)] and 1-(4,6-dimethylpyrimidin-
2-yl)-3,5-diphenyl-4,5-dihydro-1H-pyrazol-4-ol 8 [Rf
Scheme 3.
OH
O
Ph
Ph
Ph
Ph
Ph
Ph
[O]
4a
8
5
HN
_H2O
N
N
NH
NH
NH
R
R
R
A
B
C
R = 4,6-dimethylpyrimidin-2-yl.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 8 2016

5-ARYL-1-[PYRIMIDINE-2(4)-YL]-3-PHENYL-4,5-DIHYDRO-1H-PYRAZOLES. SYNTHESIS
1175
Scheme 4.
Ph
Ar
Ph
Ph
Ph
NH2
OH
Ar
HN
N
O
N
N
N
Ar
Ar
N
[O]
N
N
N
N
4a, 4c, 4d
4b
N
N
N
N
Me
S
Me
Me
Me
Me
S
N
Me
S
Me
S
Me
10
3b
3a, 3c, 3d
9
Ar = Ph (a), 2-HOC6H4 (b), 3-O2NC6H4 (c), 4-Me2NC6H4 (d).
The composition of the mixture was additionally
pyrazolines 3a, 3c, and 3d whose spectral parameters
coincided with those of compounds 2a–2d we isolated
3-(2-hydroxyphenyl)-2-(4,6-dimethylpyrimidin-2-yl)-
5-phenyl-3,4-dihydro-2Н-pyrazol-3-ol 10 originating
from the spontaneous oxidation of pyrazoline 3b with
proved by HPLC-MS measurements since in the spec-
trum two peaks of monoprotonated molecules [M + H]+
were observed corresponding to acetylhydrazine 7 (m/z
181) and compound 8 (m/z 345). The fragment peak
(m/z 327) formed by water elimination from the ion [M +
H]+ of 4-hydroxypyrazoline 8.
1
air oxygen (Scheme 4). Н NMR spectrum of com-
pound 10 contained characteristic [10] doublets of the
spin system AB [δA 3.60, δB 3.83 (JAB 18.8 Hz) ppm]
and a broadened singlet of the hydroxy group at the
atom C3 at ~6.6 ppm. In the 13С NMR spectrum of
pyrazol-3-ol 10 typical signals [10] were present of the
atoms С3 and C4 of the five-membered ring at δC 93
and 54 ppm respectively. Mass spectrum of compound
10 contained a peak of the monoprotonated molecule
[M + H]+ (m/z 393).
The formation of compound 8 may be caused by
successive transformations of intermediates A–C. The
primary 1,2-addition of hydrazine 5 to chalcone 4а
provided adduct A. At water elimination from
intermediate A α,β-unsaturated hydrazone B was
obtained which by the oxidation with air oxygen was
converted into epoxide С, the key intermediate [9] in
the synthesis of 4-hydroxypyrazolines 8. The final
closure of the five-membered ring at the intra-
molecular nucleophilic attack on atom C3 of the
propylidene fragment of intermediate С with the
secondary amino group led to the formation of
compound 8 (Scheme 3).
Among the fragmentation products of 1,3,5-triaryl-
4,5-dihydro-1H-pyrazoles under the HESI condi-
tions the prevalence of protonated molecules of 2,4-
diarylazets and 1,2-diarylaziridines was observed
[11]. We found that notwithstanding the significant
differrence in the structure of the diazine frag-
ments of pyrazolines 2a–2d, 3a, 3c, 3d, and
10 the fragmentation path of these compounds is
similar. This is demonstrated by the presence of a
fragment peak (m/z 83) of moderate (50%) and high
(90–100%) intensity in the mass spectra of all
mentioned pyrazolines. The assumed fragmentation
scheme of compounds 2a–2d, 3a, 3c, 3d, and 10
includes the simultaneous elimination of below
mentioned neutral molecules from [M + H]+ ions
with the formation of a protonated 2-amino-4-
methylazet. From ions [M + H]+ of pyrazolines
2a–2d the following compounds are eliminated:
benzonitrile, arylethynes, acetonitrile, from ions
[M + H]+ of compounds 3a, 3c, 3d, and 10 ben-
zonitrile, arylethynes [2-(ethynyloxy)phenol from
pyrazole-3-ol 10], and methyl thiocyanate are
released (Scheme 5).
In contrast to the cyclocondensation of hydrazine 5
with chalcones 4a–4d the analogous reaction of 4-
hydrazino-6-methyl-2-(methylsulfanyl)pyrimidine
9
with the same reagents afforded not only 1-(pyrimidin-
4-yl)-4,5-dihydro-1H-pyrazoles but their functional
derivatives as well. In particular, along with
Scheme 5.
_Ph
_R
N
+
Me
_R'
N
+ H
[M + H]+
N
NH2
m/z 83
R = Ar, R' = Me (2a–2d), MeS (3a, 3c, 3d);
R = 2-HOC6H4O, R' = MeS (10).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 8 2016

ERKIN et al.
1176
Thus, the substituted 2(4)-hydrazinopyrimidines
1-(4,6-Dimethylpyrimidin-2-yl)-3,5-diphenyl-4,5-
reacted with 3-aryl-1-phenyl-2-propen-1-ones
affording mainly 5-aryl-1-[pyrimidin-2(4)-yl]-3-phe-
nyl-4,5-dihydro-1H-pyrazoles which undergo fragmen-
tation under the conditions of positive electrospray
ionization through the decomposition of the
heterocyclic fragments of their molecules.
dihydro-1H-pyrazole (2a). Yield 0.62 g (52%), mp
187°С (ethanol), Rf 0.62 (B). Н NMR spectrum, δ,
1
ppm: 2.22 s (6H, Me), 3.13, 3.14, 3.18, 3.19 d.d (1H,
С4HA, JAX 4.5 Hz), 3.86, 3.88, 3.89, 3.92 d.d (1H,
C4HB, JAB 17.7 Hz), 5.73, 5.74, 5.76, 5.77 d.d (1H,
С5HX, JBX 11.9 Hz), 6.51 s (1H, CH), 7.17–7.81 m
(10H, Ph). 13С NMR spectrum, δ, ppm: 24.03 (Me),
42.17 (С4pyrazole), 62.01 (С5pyrazole), 111.5 (С5pyrimidine),
126.3, 126.7, 127.4, 128.9, 129.1, 129.8, 132.5, 143.9,
151.7, 158.4, 167.3. Mass spectrum, m/z (Irel, %):
329.14 (100) [M + H]+, 82.95 (50). Found, %: С 76.53;
H 5.79; N 16.75. C21H20N4. Calculated, %: С 76.80; H
6.14; N 17.06.
EXPERIMENTAL
1Н (400 MHz) and 13С (100 MHz) NMR spectra
were registered on a spectrometer Bruker Avance III in
DMSO-d6, the signals of residual protons of the
solvent served as internal reference. IR spectra were
recorded on a spectrophotometer Shimadzu FTIR-
8400S from pellets with KBr. The mixture of
compounds 7 and 8 was analyzed by the method
HPLC-MS on an instrument Thermo Scientific TSQ
Quantum Access (chromatography conditions: column
Zorbax CB-C18, 150 × 2.1 mm, 35°C, eluent 0.1%
water solution of trifluoroacetic acid–acetonitrile, 95 : 5;
mass detection conditions: solvent for initial sample
methanol, HESI mode). Mass spectra were recorded on
a tandem quadrupole mass spectrometer Waters XEVO
TQD (solvent for initial samples methanol, HESI
mode.). Elemental analysis was carried out on an
analyzer Flash EA 1112. The homogeneity of the
substances was checked by TLC on Sorbfil plates
PTSKh-AF-V-UV, eluents acetone–hexane, 2 : 1 (А)
and 1 : 1 (B), spots visualized under UV irradiation, λ
254 nm. Compounds 5 and 9 were prepared by
procedures [12, 13] respectively, chalcones 4a–4d,
according to recommendations of [5]. The properties
of compounds 4a–4d are in agreement with
characteristics published in [14–17]. Quantum
chemical calculations were carried out applying
software HyperChem Release 8.0.8 for Windows
Molecular Modeling System.
5-(2-Hydroxyphenyl)-1-(4,6-dimethylpyrimidin-
2-yl)-3-phenyl-4,5-dihydro-1H-pyrazole (2b). Yield
0.12 (10%), mp 264°С (ethanol–DMF, 8 : 1), Rf 0.61
(B). 1Н NMR spectrum, δ, ppm: 2.24 s (6H, Me), 3.23,
3.24, 3.28, 3.29 d.d (1H, С4HA, JAX 3.7 Hz), 3.92, 3.95,
3.97, 4.00 d.d (1H, C4HB, JAB 17.3 Hz), 5.86, 5.87,
5.89, 5.90 d.d (1H, С5HX, JBX 11.8 Hz), 6.52 s (1H,
CH), 7.41–8.14 m (9H, Ph + Ar). 13С NMR spectrum,
δ, ppm: 24.07 (Me), 40.96 (С4pyrazole), 57.68 (С5pyrazole),
111.3 (С5pyrimidine), 116.0, 119.2, 126.4, 126.6, 128.3,
129.0, 129.1, 129.7, 132.7, 152.5, 154.7, 158.4, 167.4.
Mass spectrum, m/z (Irel, %): 345.19 (100) [M + H]+,
82.96 (90). Found, %: С 72.81; H 5.91; N 16.03.
C21H20N4O. Calculated, %: С 73.23; H 5.85; N 16.27.
1-(4,6-Dimethylpyrimidin-2-yl)-5-(3-nitrophe-
nyl)-3-phenyl-4,5-dihydro-1H-pyrazole (2c). Yield
1
0.21 g (15%), mp 200°С (ethanol), Rf 0.68 (B). Н
NMR spectrum, δ, ppm: 2.24 s (6H, Me), 3.23, 3.24,
3.28, 3.29 d.d (1H, С4HA, JAX 5.3 Hz), 3.92, 3.95, 3.97,
4.00 d.d (1H, C4HB, JAB 17.7 Hz), 5.86, 5.87, 5.89,
5.90 d.d (1H, С5HX, JBX 11.9 Hz), 6.52 s (1H, CH),
7.41–8.14 m (9H, Ph + Ar). 13С NMR spectrum, δ,
ppm: 23.98 (Me), 41.77 (С4pyrazole), 61.58 (С5pyrazole),
111.9 (С5pyrimidine), 121.6, 122.5, 126.8, 129.1, 130.0,
130.6, 132.2, 133.3, 146.0, 148.2, 152.0, 158.2, 167.5.
Mass spectrum, m/z (Irel, %): 374.14 (100) [M + H]+,
83.00 (95). Found, %: С 66.72; H 4.85; N 18.62.
C21H19N5O2. Calculated, %: С 67.55; H 5.13; N 18.75.
Compounds 2a–2d. To a solution of 0.2 g (3.6 mmol)
of potassium hydroxide in 20 mL of ethanol was added
successively 0.5 g (3.6 mmol) of hydrazine 5 and
3.6 mmol of an appropriate 3-aryl-1-phenyl-2-propen-
1-one 4a–4d. The mixture was boiled for 2 h and
cooled to room temperature. The separated precipitate
was filtered off, washed with a minimal quantity of
ethanol cooled to 5°С, recrystallized from an
appropriate solvent or mixture of solvents, and dried to
a constant weight. Further physicochemical and
spectral characteristics are listed for the products
purified by crystallization.
5-(4-Dimethylaminophenyl)-1-(4,6-dimethyl-
pyrimidin-2-yl)-3-phenyl-4,5-dihydro-1H-pyrazole
(2d). Yield 0.53 g (39%), mp 222°С (ethanol–DMF,
1
3 : 1), Rf 0.68 (B). Н NMR spectrum, δ, ppm: 2.23 s
(6H, Me), 2.82 s (6H, MeN), 3.11, 3.12, 3.15, 3.16 d.d
(1H, С4HA, JAX 4.0 Hz), 3.77, 3.80, 3.81, 3.84 d.d (1H,
C4HB, JAB 17.5 Hz), 5.64, 5.65, 5.67, 5.68 d.d (1H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 8 2016

5-ARYL-1-[PYRIMIDINE-2(4)-YL]-3-PHENYL-4,5-DIHYDRO-1H-PYRAZOLES. SYNTHESIS
1177
С5HX, JBX 11.8 Hz), 6.51 s (1H, CH), 6.63, 6.65 d (2H,
Ar), 6.93–7.74 m (5H, Ph), 7.78, 7.80 d (2H, Ar). 13С
NMR spectrum, δ, ppm: 24.07 (Me), 42.02 (С4pyrazole),
61.46 (С5pyrazole), 111.3 (С5pyrimidine), 112.7, 126.6, 127.2,
129.1, 129.7, 131.2, 132.7, 149.9. 151.7, 158.4, 167.3.
Mass spectrum, m/z (Irel, %): 372.18 (40) [M + H]+,
186.60 (65) [M + 2H]2+, 82.97 (100). Found, %: С
74.22; H 6.54; N 18.53. C23H25N5. Calculated, %: С
74.36; H 6.78; N 18.85.
131.4, 132.9, 145.0, 148.3, 154.5, 158.9, 165.8, 170.1.
Mass spectrum, m/z (Irel, %): 406.07 (97) [M + H]+,
82.95 (100). Found, %: С 68.77; H 4.79; N 16.98.
C21H19N5O2S. Calculated, %: С 62.21; H 4.72; N
17.27.
5-(4-Dimethylaminophenyl)-1-[6-methyl-2-
(methylsulfanyl)pyrimidin-4-yl]-3-phenyl-4,5-
dihydro-1H-pyrazole (3d). Yield 0.20 g (17%), mp
1
173°С (water–ethanol, 1 : 4), Rf 0.73 (B). Н NMR
Compounds 3a, 3c, and 3d. To a solution of 0.16 g
(2.9 mmol) of potassium hydroxide in 20 mL of
ethanol was added successively 0.5 g (2.9 mmol) of
hydrazine 9 and 2.9 mmol of an appropriate 3-aryl-1-
phenyl-2-propen-1-one 4a, 4c, and 4d. At the use of
chalcone 4a the mixture was boiled for 2 h, with
chalcones 4c and 4d the mixture was heated for 2 h at
50°С and 40°С respectively. On cooling to room
temperature the separated precipitate was filtered off,
washed with a minimal quantity of ethanol cooled to
5°С, recrystallized from an appropriate solvent or
mixture of solvents, and dried to a constant weight.
Further physicochemical and spectral characteristics
are listed for the products purified by crystallization.
spectrum, δ, ppm: 2.25 s (3H, Me), 2.27 s (3H, MeS),
2.85 s (6H, MeN), 3.14, 3.15, 3.19, 3.20 d.d (1H,
С4HA, JAX 4.2 Hz), 3.85, 3.88, 3.89, 3.92 d.d (1H,
C4HB, JAB 17.8 Hz), 5.64, 5.65, 5.67, 5.68 d.d (1H,
С5HX, JBX 11.8 Hz), 6.62, 6.64 d (2H, Ar), 6.90 s (1H,
CH), 7.01, 7.03 d (2H, Ar), 7.46–7.84 m (5H, Ph). 13С
NMR spectrum, δ, ppm: 13.74 (MeS), 23.93 (Me),
42.59 (С4pyrazole), 61.14 (С5pyrazole), 99.46 (С5pyrimidine),
112.8, 126.8, 126.9, 129.2, 130.4, 130.6, 131.8, 150.1,
154.4, 158.9, 165.4, 169.9. Mass spectrum, m/z (Irel,
%): 404.15 (70) [M + H]+, 202.56 (60) [M + 2H]2+,
82.97 (100). Found, %: С 68.25; H 5.87; N 17.42.
C23H25N5S. Calculated, %: С 68.46; H 6.24; N 17.35.
2-(2-Acetylhydrazino)-4,6-dimethylpyrimidine
(7). A mixture of 0.5 g (3.6 mmol) of hydrazine 5 and
10 mL of glacial acetic acid was stirred at 100°С for 2 h.
Excess of the acid was distilled off in a vacuum, the
residue was treated with 6 mL of acetonitrile. The
obtained precipitate was filtered off, twice
recrystallized from ethanol, and dried to a constant
weight. Yield 0.28 g (43%), mp 258°С, Rf 0.41 (А). IR
spectrum, ν, cm–1: 3221 s (NH), 3040 s (NH), 1664 s
1-[6-Methyl-2-(methylsulfanyl)pyrimidin-4-yl]-
3,5-diphenyl-4,5-dihydro-1H-pyrazole (3a). Yield
0.56 g (53%), mp 138°С (water–ethanol, 1 : 3), Rf 0.74
(B). 1Н NMR spectrum, δ, ppm: 2.21 s (3H, Me), 2.27
s (3H, MeS), 3.16, 3.18, 3.21, 3.22 d.d (1H, С4HA, JAX
5.0 Hz), 3.91, 3.94, 3.96, 3.99 d.d (1H, C4HB, JAB
17.8 Hz), 5.72, 5.74, 5.76, 5.77 d.d (1H, С5HX, JBX
12.0 Hz), 6.92 s (1H, CH), 7.20–7.32 m (10H, Ph). 13С
NMR spectrum, δ, ppm: 13.59 (MeS), 23.95 (Me),
42.64 (С4pyrazole), 61.66 (С5pyrazole), 99.47 (С5pyrimidine),
126.0, 127.0, 127.6, 129.1, 129.2, 130.5, 131.6, 143.2,
154.3, 158.9, 165.6, 170.0. Mass spectrum, m/z (Irel,
%): 361.05 (97) [M + H]+, 82.90 (100). Found, %: С
69.71; H 5.39; N 15.18. C21H20N4S. Calculated, %: С
69.97; H 5.59; N 15.54.
1
(C=O). Н NMR spectrum, δ, ppm: 1.86 s (3H, Ac),
2.24 s (6H, Me), 6.51 s (1H, CH), 8.48 s (1H, NH),
9.62 s (1H, NH). 13С NMR spectrum, δ, ppm: 21.13
(Me, Ac), 23.91 (Me), 111.5, 163.4, 167.4, 169.2
(C=O). Found, %: С 52.86; H 6.51; N 30.74.
C8H12N4O. Calculated, %: С 53.32; H 6.71; N 31.09.
3-(2-Hydroxyphenyl)-2-(4,6-dimethylpyrimidin-
2-yl)-5-phenyl-3,4-dihydro-2Н-pyrazol-3-ol (10). To
a solution of 0.16 g (2.9 mmol) of potassium
hydroxide in 20 mL of ethanol was added successively
0.5 g (2.9 mmol) of hydrazine 9 and 0.65 g (2.9 mmol)
of 3-(2-hydroxyphenyl)-1-phenyl-2-propen-1-one 4b.
The mixture was heated at 50°С for 2 h and cooled to
room temperature. The separated precipitate was
filtered off, washed with ethanol cooled to 5°С,
recrystallized from water-ethanol mixture, 1 : 3, and
dried to a constant weight. Yield 0.19 g (18%), mp
1-[6-Methyl-2-(methylsulfanyl)pyrimidin-4-yl]-
5-(3-nitrophenyl)-3-phenyl-4,5-dihydro-1H-
pyrazole (3c). Yield 65 mg (7%), mp 194°С (ethanol–
1
DMF, 5 : 1), Rf 0.71 (B). Н NMR spectrum, δ, ppm:
2.10 s (3H, Me), 2.29 s (3H, MeS), 3.28, 3.29, 3.32,
3.33 d.d (1H, С4HA, JAX 5.8 Hz), 3.98, 4.01, 4.02, 4.05
d.d (1H, C4HB, JAB 18.0 Hz), 5.90, 5.91, 5.93, 5.94 d.d
(1H, С5HX, JBX 12.0 Hz), 6.96 s (1H, CH), 7.47–7.70
m (9H, Ph + Ar). 13С NMR spectrum, δ, ppm: 13.50
(MeS), 23.96 (Me), 42.30 (С4pyrazole), 61.07 (С5pyrazole),
99.61 (С5pyrimidine), 121.3, 122.7, 127.1, 129.2, 130.7, 130.9,
1
172°С, Rf 0.67 (B). Н NMR spectrum, δ, ppm: 1.85 s
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 8 2016

ERKIN et al.
1178
(3H, Me), 2.23 s (3H, MeS), 3.58 d, 3.62 d (1H, С4HA,
JAB 18.8 Hz), 3.81 d, 3.85 d (1H, С4HB, JAB 18.8 Hz),
6.64 br.s (1H, C3OH), 6.91–7.58 m (10H, СН + Ph + Ar),
10.42 br.s (1H, OH). 13С NMR spectrum, δ, ppm: 13.20
(MeS), 24.02 (Me), 54.14 (C4pyrazole), 93.16 (C3pyrazole),
100.1 (C5pyrimidine), 116.8, 117.0, 120.0, 125.3, 127.7,
128.7, 129.1, 131.9, 153.4, 157.1, 158.3, 166.2, 170.0.
Mass spectrum, m/z (Irel, %): 393.11 (98) [M + H]+, 82.99
(100). Found, %: С 63.74; H 4.88; N 14.03. C21H20N4O2S.
Calculated, %: С 64.27; H 5.14; N 14.27.
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