Synthesis, Crystal Structure, and Antiproliferative Activity of Novel 7-Arylaminopyrazolo[1,5-a]pyrimidine Derivatives Containing the Hydrazone Moiety

Article abstract of DOI:10.1134/S1070363219110252

A series of novel 7-arylaminopyrazolo[1,5-a]pyrimidine derivatives containing the hydrazone moiety has been synthesized by a five-step procedure including cyclization, chlorination, animation, hydrazinolysis, and condensation. Structures of the products have been characterized by IR, ¹H NMR and MS spectra, and single-crystal X-ray diffraction. The bioassay results indicate most of the compounds as potentially antiproliferation agents against A549 and HT-29 cell lines. Among those, compounds 6e and 6f exhibit remarkable inhibitory activity against HT-29 cell lines, that are comparable with that of the positive control sorafenib. Preliminary structure-activity relationship is considered.

Full text of DOI:10.1134/S1070363219110252

ISSN 1070-3632, Russian Journal of General Chemistry, 2019, Vol. 89, No. 11, pp. 2321–2327. © Pleiades Publishing, Ltd., 2019.
Synthesis, Crystal Structure, and Antiproliferative Activity
of Novel 7-Arylaminopyrazolo[1,5-a]pyrimidine Derivatives
Containing the Hydrazone Moiety
Jian-tao Shia, Ye Chena, Shengjun Jib, Shi Dinga, and Ju Liua,*
a College of Pharmacy of Liaoning University, Key Laboratory of New Drug Research and Development of Liaoning Province,
Shenyang, Liaoning, 110036 China
b Jilin Yimintang Pharmaceutical Co., LTD, Siping, Jilin, 136000 China
*e-mail: liuju1216@126.com
Received September 21, 2019; revised November 17, 2019; accepted November 21, 2019
Abstract—A series of novel 7-arylaminopyrazolo[1,5-a]pyrimidine derivatives containing the hydrazone moiety
has been synthesized by a five-step procedure including cyclization, chlorination, amination, hydrazinolysis, and
condensation. Structures of the products have been characterized by IR, 1H NMR and MS spectra, and single-crystal
X-ray diffraction. The bioassay results indicate most of the compounds as potentially antiproliferation agents against
A549 and HT-29 cell lines. Among those, compounds 6e and 6f exhibit remarkable inhibitory activity against
HT-29 cell lines, that are comparable with that of the positive control sorafenib. Preliminary structure–activity
relationship is considered.
Keywords: pyrazolo[1,5-a]pyrimidine, synthesis, X-ray diffraction, antiproliferation activity
DOI: 10.1134/S1070363219110252
INTRODUCTION
RESULTS AND DISCUSSION
Pyrazolo[1,5-a]pyrimidine derivatives constitute an
imperative class of compounds with diverse therapeu-
tic and pharmacological properties such as antitumor
[1–3], antifungal [4], antibacterial [5], analgesics [6],
anti-inflammatory [7]. Insomnia agent indiplon [8],
anticancer drug dinaciclib [9], Type 2 diabetes mellitus
agent anagliptin [10] are all the approved drugs contain-
ing the pyrazolo[1,5-a]pyrimidine moiety. On the other
hand, the hydrazone moiety has been widely applied in
drug design due to its ability to act as H-bond donator
and acceptor.Also it can impart some degree of flexibility
to chemical structures [11, 12]. Previous literatures have
not been fully considered to the compounds contain both
pyrazolo[1,5-a]pyrimidine and hydrazone units, which
may possess novel bio-activities for screening.
The synthetic methods for compounds 6a–6k were
outlined in Scheme 1. The commercially available 3-ami-
nopyrazole (1) was condensed with diethyl malonate in
the presence of sodium ethanolate to give pyrazolo[1,5-
a]pyrimidine-5,7-diol (2). Chlorination of compound 2
with phosphorus oxychloride proceeded smoothly with
formation of 5,7-dichloropyrazolo[1,5-a]pyrimidine
(3) as a yellow solid. A regioselective condensation
of 2-(isopropylsulfonyl)aniline with the 7-position of
5,7-dichloropyrazolo [1,5-a]pyrimidine (3) in the pres-
ence of NaH in N,N-dimethylformamide provided the
intermediate 4, chlorine of which was substituted with
hydrazine hydrate giving the key intermediate 5, conden-
sation of which with an appropriate aromatic aldehyde
afforded the target compounds 6a–6k with good yields.
Their structures were supported by IR, 1H NMR, and MS
spectra. For the deeper insight into the structure of the
products the crystal structure of 6j was determined by
X-ray single-crystal diffraction analysis.
In continuation of our research on novel anticancer
agents [13, 14], herein we report the synthesis of a series
of substituted pyrazolo[1,5-a]pyrimidine–hydrazone hy-
brids by the five-step synthesis and evaluation of their in
vitro antiproliferative activity against A549 and HT-29
cancer cell lines.
The molecular structure of compound 6j with atomic
numbering scheme as presented in Figs. 1 and 2 depicts
the molecular packing and hydrogen bonds in a unit cell.
2321

2322
JIAN-TAO SHI et al.
Scheme 1. Synthetic route to the target compounds 6a–6k.
O
O
OH
Cl
N
N
NH
NH2
EtO
EtONa, EtOH
POCl3
OEt
N
N
N
N
N
OH
Cl
1
2
3
O
O
O
O
O
O
S
O
S
S
S
O
O
Ar
EtOH
H2N
NH2NH2
EtOH
HN
HN
HN
N
NaH, DMF
N
N
N
N
N
N
Ar
NH2
N
N
N
N
H
N
Cl
H
6aꢀ6k
4
5
Ar = phenyl (6a), 2-fluorophenyl (6b), 4-fluorophenyl (6c), 4-nitrophenyl (6d), 4-methoxyphenyl (6e),
4-(dimethylamino)phenyl (6f), 3-methoxyphenyl (6g), 2,4-difluorophenyl (6h), 2-chloro-4-fluorophenyl (6i),
2,3,4-trimethoxyphenyl (6j), 1H-3-indolyl (6k).
Configuration of the imino double bonds in the target
compounds was confirmed to be the E isomer (Fig. 1).
Generally, the average bond lengths and bond angles of
pyrazole and phenyl rings were within normal ranges
[3, 15]. The N1–C1 (1.325 Å) and N3–C4 (1.319 Å) bonds
were longer than the general C=N double bond (1.27 Å),
which indicated significant electron delocalization in the
fused ring system. The bond C5–N7 (1.27 Å) belonged
to the typical C=N double bond. In the crystal struc-
ture of compound 6j the dihedral angles between the
pyrazolo[1,5-a]pyrimidine ring, benzene ring (C18, C19,
C20) and benzene ring (C8, C9, C10) were determined to
be 40.877(8)° and 7.062°, respectively, which indicated
the pyrazolo[1,5-a]pyrimidine ring to be almost coplanar
with the benzene ring (C8, C9, C10). The intermolecular
hydrogen bonds C7–H7···O5#1, C14–H14A···O2, and
C20–H20···O1#2 were formed (Table 1). The two adjacent
molecules were stabilized via π∙∙∙π stacking, van der
Waals and intermolecular hydrogen forces with formation
of complex accumulation space structures.
Antiproliferative activity and structure–activity
relationship. Antiproliferative activity of all the newly
synthesized compounds 6a–6k was evaluated against
human lung adenocarcinoma cell line A549 and human
colon cancer cell line HT-29 using the standard MTT-
based assay in vitro, with sorafenib used as the positive
control (Table 2). All the compounds were more potent
against HT-29 cell line than A549. Such results revealed
21
b
C
20
5
C
b
O
16
C
22
C
19
C
a
c
a
1
S
4
c
17
C
12
11
3
C
C
O
6
O
18
6
N
C
13
C
23
1
C
C
C
24
15
C
2
5
C
5
8
N
C
N
C
1
2
10
N
O
C
9
C
O
7
1
C
4
1
C
4
C
N
3
C
3
N
2
C
Fig. 1. The structure of C25H26N6O5S with all non H-atom
labeling scheme and ellipsoids drawn at the 30% probability
level.
Fig. 2. Packing diagram of C25H26N6O5S.
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SYNTHESIS, CRYSTAL STRUCTURE, AND ANTIPROLIFERATIVE ACTIVITY
2323
Table 1. Hydrogen bond lengths and bond angles in compound
that the compounds possessed selectivity against HT-29
cancer cell line, and demonstrated high potential as a
specific drug for colon cancer. Results presented in Table
1 indicated that the presence of the electron-donating
groups (EDGs) on the Ar had a positive effect on the
antiproliferative activity, particularly of compounds
6e (Ar = 4-OCH3Ph) and 6f [Ar = 4-N(CH3)2] that
were more active than compound 6a (Ar = Ph). How-
ever, attachment of the other groups to the Ar fragment
(Ar = 2-FPh, 4-FPh, 4-NO2Ph, 2,4-diFPh, and 2-Cl-4-
FPh) reduced the antiproliferative activity. The bulky
groups such as 2,3,4-trimethoxyphenyl (6j) or 1H-3-in-
dolyl (6k) bonded with theAr also reduced antiprolifera-
tive activity of the compounds.
6ja
DHA
angle,
deg
d(D–H), d(H···A), d(D···A),
D–H···A
Å
Å
Å
C7–H7···O5 #1
C14–H14A···O2
C20–H20···O1#2
0.93
0.96
0.93
2.63
2.42
2.47
3.434(3)
3.022(4)
3.159(3)
144
120
131
a Symmetry codes: (#1) x, y–1, z; (#2) x, y+1, z.
specified otherwise. Melting points were determined on
a Beijing Taike X-4 microscopy melting point apparatus
and are uncorrected. 1H NMR spectra were measured on
a Bruker Biospin 600 MHz or Bruker Biospin 300 MHz
spectrometers using TMS as the internal standard. IR
spectra were recorded as KBr pellets on a Perkin-Elmer
Spcetrum one FT-IR spectrophotometer. Mass spectra
EXPERIMENTAL
All starting materials and reagents were obtained from
commercial suppliers without further purification, unless
Table 2. Inhibitory effect of target compounds against tumor cell linesa
IC50±SD, μmol/L
IC50±SD, μmol/L
A549 HT-29
Compound
Ar
Compound
Ar
A549
HT-29
6a
6g
27.21±1.86 4.95±0.29
27.47±1.76 8.02±1.27
OCH3
6b
6c
6h
6i
30.68±2.11 8.32±0.98
29.32±1.45 10.41±1.10
25.44±2.03 6.75±0.56
22.35±1.38 7.86±0.62
F
F
F
F
F
Cl
6d
6e
6j
32.45±2.24 4.78±1.04
11.22±1.21 2.94±0.24
42.38±2.73 8.95±0.36
32.81±1.74 11.631±0.99
NO
OCH3
OCH3
2
H3CO
6k
NH
OCH
3
6f
8.83±0.54 4.29±0.35 Sorafenib
–
3.43±0.15 4.02±0.19
N
a Each experiment was carried out in triplicate.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 11 2019

2324
JIAN-TAO SHI et al.
were measured on a Waters Quattro micro API mass
spectrometer (ESI, direct injection). Elemental analysis
of the newly synthesized compounds was carried out on
a Carlo Erba 1108 analyzer.
NMR spectrum, δ, ppm: 10.10 s (1H), 8.14 d (1H, J =
1.8 Hz), 8.04 d (1H, J = 7.8 Hz), 7.78 d (2H, J = 5.0 Hz),
7.48–7.40 m (1H), 6.67–6.48 m (2H), 3.26–3.08 m (1H),
1.28 d, (6H, J = 6.8 Hz). MS (ESI): m/z: 373.0 [M + Na]+.
Synthesis of pyrazolo[1,5-a]pyrimidine-5,7-diol
(2). Metal sodium (7.62 g, 331.0 mmol) was reacted with
150 mL of ethanol at 0°C. 3-Aminopyrazole (11.00 g,
132.38 mmol) and diethyl malonate (21.20 g,
132.38 mmol) were added to the above solution of sodium
ethoxide in ethanol. The reaction mixture was refluxed
for 20 h, then cooled down to room temperature. The pre-
cipitate was filtered off and washed with EtOH. The dried
solid was dissolved in water (400 mL), and the solution
was acidified to pH 2 with 10 N HCl. The solid precipi-
tate was collected by filtration and washed with water to
give pyrazolo[1,5-a]pyrimidine-5,7-diol as a light yellow
solid, yield 63.5%. Thus obtained crude product was used
in the next step without further purification.
Synthesis of 5-hydrazinyl-N-(2-(isopropylsulfonyl)-
phenyl)pyrazolo[1,5-a]pyrimidin-7-amine (5). A
mixture of compound 4 (4.00 g, 0.012 mol) with 80%
hydrazine monohydrate (15 mL) in ethanol (40 mL)
was refluxed overnight upon vigorous agitation. Most of
the solvent was evaporated under reduced pressure and
white solid precipitated. After cooling down to 10°C,
the precipitate was filtered off, washed with water, and
dried under vacuum to afford the title compound 5 as a
pale solid, yield 81.0%. 1H NMR spectrum, δ, ppm: 9.79
s (1H), 8.00 d (1H, J = 7.9 Hz), 7.94 d (1H, J = 1.9 Hz),
7.75 d (1H, J = 8.1 Hz), 7.68 t (1H, J = 7.7 Hz), 7.32 t
(1H, J = 7.6 Hz), 6.17 d (1H, J = 2.0 Hz), 6.08 d (2H,
J = 6.8 Hz), 3.87 s (2H), 3.26–3.15 m (1H), 1.28 d (6H,
J = 6.8 Hz). MS (ESI): m/z: 474.2 [M + H]+.
Synthesis of 5,7-dichloropyrazolo[1,5-a]pyrimi-
dine (3). Solution of pyrazolo[1,5-a]pyrimidine-5,7-diol
(6.50 g, 43.0 mmol) in phosphorus oxychloride (80 mL)
was mixed with N N-dimethylaniline (5.0 mL), and the
mixture was refluxed for 24 h. Excess phosphorus oxy-
chloride was removed in vacuo. After cooling to room
temperature, the residue was poured into ice water and
extracted with EtOAc (3×100 mL). The combined organic
phases were washed with 1 N HCl several times, until
N,N-dimethylaniline was completely removed, and then
washed with water and brine. The organic phase was
dried over anhydrous Na2SO4 and concentrated in vacuo.
The resulting residue was purified by silica gel column
chromatography to afford the compound 3 as a yellow
General procedure for preparation of compounds
6a–6k. To a solution of compound 5 (0.20 g, 0.58 mmol)
in EtOH (5 mL), 1.2 equiv of the appropriate aldehyde
and acetic acid (1 drop) were added, and the mixture was
refluxed for 10–12 h to completion of the process accord-
ing to TLC. After cooling down to room temperature,
the resulting precipitate was filtered off and dried under
vacuum to afford the corresponding target compound
6a–6k as a light yellow solid.
5-(2-Benzylidenehydrazinyl)-N-[2-(isopropylsul-
fonyl)phenyl]pyrazolo[1,5-a]pyrimidin-7-amine (6a).
Yield 82%, mp 236–238°C. IR spectrum, ν, cm–1: 3434.6
(NH2), 1633.4 (C=N), 1553.2 (C=Carom), 1466.1, 1360.2
1
1
solid, yield 68.0%. H NMR spectrum, δ, ppm: 8.23 d
(O=S=O), 1143.3. H NMR spectrum, δ, ppm: 11.26 s
(1H, J = 3.0 Hz), 7.02 s (1H), 6.77 d (1H, J = 3.0 Hz).
MS (ESI): m/z: 181.1 [M + H]+.
(1H), 9.75 s (1H), 8.13–7.89 m (5H), 7.66–7.45 m (3H),
7.45–7.25 m (3H), 6.64 s (1H), 6.13 d (1H, J = 2.1 Hz),
3.53–3.37 m (1H), 1.13 d (6H, J = 6.8 Hz). MS (ESI): m/z:
435.1 [M + H]+, 457.1 [M + Na]+. Found, %: C 60.94;
H 5.14; N 19.45. C22H22N6O2S. Calculated, %: C 60.81;
H 5.10; N 19.34.
Synthesis of 5-chloro-N-(2-(isopropylsulfonyl)-
phenyl)pyrazolo[1,5-a] pyrimidin-7-amine (4). To
the suspension of 60% NaH (1.36 g, 34 mol) in N,N-di-
methylformamide (60 mL), 2-(isopropylsulfonyl)aniline
(4.10 g, 20.6 mmol) was added at 0°C. The mixture was
stirred for 30 min at 0°C, and then 5,7-dichloropyrazolo-
[1,5-a]pyrimidine (3.20 g, 17.0 mmol) diluted by N,N-
dimethylformamide (10 mL) was added slowly. The
mixture was warmed up to room temperature and heated
at 60°C for 8 h, then poured into water to give a dark
red precipitate which was collected by filtration. The
crude product was crystallized from isopropanol to af-
ford compound 4 as a dark yellow solid, yield 68.7%. 1H
5-[2-(2-Fluorobenzylidene)hydrazinyl]-N-[2-
(isopropylsulfonyl)phenyl]pyrazolo[1,5-a]pyrimidin-
7-amine (6b). Yield 84%, mp 228–230°C. IR spectrum,
ν, cm–1: 3440.5 (NH), 2976.2, 1634.6 (C=N), 1553.0
(C=Carom), 1448.9, 1420.8, 1319.8, 1275.5, 1242.9,
1
1201.7, 1088.2, 1051.8, 909.0. H NMR spectrum, δ,
ppm: 11.41 s (1H), 9.77 s (1H), 8.22 s (1H), 8.08–7.86
m (4H), 7.75 m (1H), 7.51 m (1H), 7.37 m (1H), 7.22 d
(2H, J = 7.4 Hz), 6.64 br (1H), 6.15 s (1H), 3.58–3.37 m
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SYNTHESIS, CRYSTAL STRUCTURE, AND ANTIPROLIFERATIVE ACTIVITY
2325
(1H), 1.23–0.99 m (6H). MS (ESI): m/z: 453.1 [M + H]+,
475.2 [M + Na]+. Found, %: C 58.47; H 4.74; N 18.64.
C22H21FN6O2S. Calculated, %: C 58.39; H 4.68; N 18.57.
6.07 d (1H, J = 2.1 Hz), 3.55–3.38 m (1H), 2.93 s (6H),
1.13 d (6H, J = 6.8 Hz). MS (ESI): m/z: 478.2 [M + H]+,
500.2 [M + Na]+. Found, %: C 60.48; H 5.76; N 20.61.
C24H27N7O2S. Calculated, %: C 60.36; H 5.70; N 20.53.
5-[2-(4-Fluorobenzylidene)hydrazinyl]-N-[2-
(isopropylsulfonyl)phenyl]pyrazolo[1,5-a]pyrimidin-
7-amine (6c). Yield 83%, mp 230–232°C. IR spectrum,
ν, cm–1: 3428.0 (NH), 1634.6 (C=N), 1555.0 (C=Carom),
N-[2-(Isopropylsulfonyl)phenyl]-5-[2-(3-methoxy-
benzylidene)hydrazinyl]pyrazolo[1,5-a]pyrimidin-
7-amine (6g). Yield 80%, mp 224–226°C. IR spectrum,
1
1495.0, 1466.0, 1275.9 (O=S=O), 1232.9, 1143.2. H
–1: 3444.3 (NH), 1635.8 (C=N), 1582.3 (C=Carom),
ν, cm
NMR spectrum, δ, ppm: 11.26 s (1H), 9.76 s (1H),
8.16–7.83 m (5H), 7.70–7.57 m (2H), 7.55–7.41 m
(1H), 7.24 t (2H, J = 8.9 Hz,), 6.63 s (1H), 6.13 d (1H,
J = 2.1 Hz), 3.52–3.39 m (1H), 1.13 d (6H, J = 6.8 Hz).
MS (ESI) m/z(%): 453.1 [M + H]+, 475.2 [M + Na]+.
Found, %: C 58.48; H 4.72; N 18.62. C22H21FN6O2S.
Calculated, % C 58.39; H 4.68; N 18.57.
1551.7, 1465.7, 1422.3, 1320.2 (O=S=O), 1273.8, 1141.1,
1046.6. H NMR spectrum, δ, ppm: 11.29 s (1H), 9.73
1
s (1H), 8.07–7.80 m (5H), 7.51 t (1H, J = 7.5 Hz), 7.29
t (1H, J = 7.8 Hz), 7.20–7.05 m (2H), 6.89 d (1H, J =
7.5 Hz), 6.62 s (1H), 6.13 s (1H), 3.74 s (3H), 3.57–3.38
m (1H), 1.12 d (6H, J = 6.7 Hz). MS (ESI): m/z: 465.1
[M + H]+, 487.1 [M + Na]+. Found, %: C 59.55; H 5.25;
N 18.16. C23H24N6O3S. Calculated, %: C 59.47; H 5.21;
N 18.09.
N-[2-(Isopropylsulfonyl)phenyl]-5-[2-(4-nitro-
benzylidene)-hydrazinyl]pyrazolo[1,5-a]pyrimi-
din-7-amine (6d). Yield 76%, mp 232–234°C. IR
spectrum, ν, cm–1: 3441.9 (NH), 1636.7 (C=N),
1551.8 (C=Carom), 1514.0, 1464.3, 1335.6 (O=S=O),
5-[2-(2,4-Difluorobenzylidene)hydrazinyl]-N-(2-
(isopropylsulfonyl)phenyl)pyrazolo[1,5-a]pyrimidin-
7-amine (6h). Yield 83%, mp 231–233°C. IR spectrum,
ν, cm–1: 3419.3 (NH), 1634.5 (C=N), 1685.8, 1585.8
(C=Carom), 1488.9, 1463.9, 1418.4, 1345.7 (O=S=O),
1277.0, 1142.4. 1H NMR spectrum, δ, ppm: 11.39 s (1H),
9.78 s (1H), 8.16 s (1H), 8.04–7.85 m (4H), 7.87–7.73
m (1H), 7.51 t (1H, J = 7.3 Hz), 7.31 t (1H, J = 9.3 Hz),
7.16 t (1H, J = 8.4 Hz), 6.63 s (1H), 6.15 d (1H, J =
1.8 Hz), 3.54–3.39 m (1H), 1.13 d (6H, J = 6.7 Hz). MS
(ESI): m/z: 471.1 [M + H]+, 493.1 [M + Na]+. Found, %:
C 56.28; H 4.31; N 17.93. C22H20F2N6O2S. Calculated,
%: C 56.16; H 4.28; N 17.86.
1
1312.2 (Carom–NO2), 1144.0. H NMR spectrum,
δ, ppm: 11.64 s (1H), 9.83 s (1H), 8.25 d (2H,
J = 8.9 Hz), 8.12 s (1H), 8.03 d (1H, J = 2.2 Hz), 8.00–7.93
m (3H), 7.83 d (2H, J = 8.9 Hz) , 7.53 s (1H), 6.67 s (1H),
6.20 d (1H, J = 2.1 Hz), 3.52–3.40 m (1H), 1.13 d (6H,
J = 6.8 Hz). MS (ESI): m/z: 480.1 [M + H]+, 502.1 [M +
Na]+. Found, %: C 55.22; H 4.47; N 20.53. C22H21N7O4S.
Calculated, %: C 55.11; H 4.41; N 20.45.
N-[2-(Isopropylsulfonyl)phenyl]-5-[2-(4-methoxy-
benzylidene)hydrazinyl]pyrazolo[1,5-a]pyrimidin-
7-amine (6e). Yield 81%, mp 223–225°C. IR spectrum,
ν, cm–1: 3435.7 (NH), 1634.6 (C=N), 1554.7 (C=Carom),
5-[2-(2-Chloro-4-fluorobenzylidene)hydrazinyl]-
N-[2-(isopropylsulfonyl)phenyl]pyrazolo[1,5-a]-
pyrimidin-7-amine (6i). Yield 79%, mp 234–236°C. IR
spectrum, ν, cm–1: 3431.4 (NH), 3280.2, 2978.0, 1633.9
(C=N), 1555.4 (C=Carom), 1465.0, 1316.9 (O=S=O),
1
1497.7, 1465.0, 1307.4 (O=S=O), 1253.8, 1142.8. H
NMR spectrum, δ, ppm: 11.11 s (1H), 9.73 s (1H),
7.96 m (5H), 7.52 d (3H, J = 8.5 Hz), 6.96 d (2H, J =
8.8 Hz), 6.62 s (1H), 6.10 d (1H, J = 2.0 Hz), 3.77 s (3H),
3.55–3.38 m (1H), 1.13 d (6H, J = 6.8 Hz). MS (ESI): m/z:
465.1 [M + H]+, 487.1 [M + Na]+. Found, %: C 59.59;
H 5.26; N 18.14. C23H24N6O3S. Calculated, %: C 59.47;
H 5.21; N 18.09.
1
1419.1, 1249.4, 1144.3. H NMR spectrum, δ, ppm:
11.48 s (1H), 9.78 s (1H), 8.34 s (1H), 8.07–7.76 m (5H),
7.61–7.42 m (2H), 7.29 m (1H), 6.63 s (1H), 6.17 d (1H,
J = 2.1 Hz), 3.51–3.38 m (1H), 1.20–1.04 m (6H). MS
(ESI): m/z: 487.1 [M + H]+, 509.1 [M + Na]+. Found, %:
C 54.34; H 4.17; N,17.33. C22H20ClFN6O2S. Calculated,
%: C 54.26; H 4.14; N 17.26.
5-{2-[4-(Dimethylamino)benzylidene]hydrazinyl}-
N-[2-(isopropylsulfonyl)phenyl]pyrazolo[1,5-a]-
pyrimidin-7-amine (6f). Yield 81%, mp 222–225°C. IR
spectrum, ν, cm–1: 3430.5 (NH), 1633.9 (C=N), 1555.7
(C=Carom), 1489.7, 1464.5, 1360.8 (O=S=O), 1198.9,
1124.8, 1050,8. 1H NMR spectrum, δ, ppm: 10.94 s (1H),
9.70 s (1H), 8.06–7.85 m (5H), 7.57–7.45 m (1H), 7.39
d (2H, J = 8.8 Hz), 6.70 d (2H, J = 8.8 Hz), 6.62 s (1H),
N-[2-(Isopropylsulfonyl)phenyl]-5-[2-(2,3,4-
trimethoxybenzylidene)hydrazinyl]pyrazolo[1,5-a]
pyrimidin-7-amine (6j). Yield 78%, mp 235–237°C. IR
spectrum, ν, cm–1: 3443.7 (NH), 1635.7 (C=N), 1554.3
(C=Carom), 1483.0, 1459.6, 1286.5 (O=S=O), 1143.2,
1094.8, 1028.0. 1H NMR spectrum, δ, ppm: 11.13 s (1H),
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 11 2019

2326
JIAN-TAO SHI et al.
Table 3. Crystal data for compound 6j
Parameter
Crystal size
Formula
Fw
Value
Parameter
α, deg
Value
102.739(2)
105.385(2)
104.187(2)
1277.4(2)
2
0.18×0.15×0.12
C25H26N6O5S
522.58
β, deg
γ, deg
T, K
273(2) K
V, Å 3
Crystal system
Space group
a, Å
Triclinic
Z
P1
Dc, g/cm3
F(000)
1.359
9.5142(11)
11.9857(13)
12.5854(14)
548
b, Å
GOF on F2
Reflection/unique
R1, wR2 [I >2(I)]
R1, wR2 (all data)
1.095
c, Å
6491/4459
0.0551, 0.1793
0.0697, 0.1950
9.71 s (1H), 8.20 s (1H), 8.02–7.88 m (4H), 7.51 t (1H,
J = 7.3 Hz), 7.40 d (1H, J = 8.8 Hz), 6.87 d (1H, J =
9.0 Hz), 6.60 s (1H), 6.11 d (1H, J = 2.1 Hz), 3.81 s (3H),
3.77 s (3H), 3.74 s (3H), 3.56–3.37 m (1H), 1.13 d (6H,
J = 6.8 Hz). MS (ESI): m/z: 525.2 [M + H]+, 547.1 [M +
Na]+. Found, %: C 57.37; H 5.42; N 16.11. C25H28N6O5S.
Calculated, %: C 57.24; H 5.38; N 16.02.
0.71073 Å) using multi-scan mode at 273(2) K. A to-
tal of 6491 reflections were collected in the range of
2.4° < θ < 25.0° (index ranges: –11 < h < 11, –13 < k <
14, –14 < l < 8) and 4459 were independent (Rint = 0.013),
of which 3515 observed reflections with I > 2σ(I) were
used in the structure determination and refinements. The
structure was solved by direct methods with SHELXS-97
program and expanded by Fourier technique. The non-
hydrogen atoms were refined anisotropically [16]. The
hydrogen atoms bound to carbon were determined with
theoretical calculations, and those attached to nitrogen
and oxygen were determined with successive difference
Fourier syntheses. The structure was refined by full-
matrix least-squares techniques on F2 with SHELXL-97
[17]. The final refinement gave the final R = 0.055 and
wR = 0.195 (w = 1/[σ2(Fo2) + (0.140P)2 + 0.0035P]),
where P = (Fo2 + 2Fc2)/3; S = 1.10, (Δσ)max < 0.001,
(Δρ)max = 0.78 and (Δρ)min = –0.43 e/Å–3.All calculations
were performed using the Crystal Structure crystallo-
graphic software package except for the refinement. Crys-
tallographic data and experimental details of structural
analyses for the compound are summarized in Table 3.
CCDC 1948432 contains the supplementary data for this
paper. The data can be obtained free of charge from the
Cambridge Crystallographic Data Centre via https://sum-
mary.ccdc.cam.ac.uk/structure-summary-form.
5-{2-[(1H-Indol-3-yl)methylene]hydrazinyl}-N-[2-
(isopropylsulfonyl)phenyl]pyrazolo[1,5-a]pyrimidin-
7-amine (6k). Yield 82%, mp 226–228°C. IR spectrum,
ν, cm–1: 3348.6 (NH), 1634.2 (C=N), 1584.8 (C=Carom),
1494.4, 1466.8, 1415.2, 1357.9 (O=S=O), 1274.0, 1131.7.
1H NMR spectrum, δ, ppm: 11.43 s (1H), 10.92 s (1H),
9.60 s (1H), 8.21 s (1H), 8.11–7.86 m (5H), 7.73–7.57
m (2H), 7.40 d (1H, J = 8.1 Hz), 7.25–7.12 m (1H),
7.04–6.90 m (1H), 6.68 s (1H), 6.06 s (1H), 3.54–3.38
m (1H), 1.11 d, (6H, J = 6.5 Hz). MS (ESI): m/z: 474.2
[M + H]+, 497.1 [M + Na]+. Found, %: C 60.97; H 4.94;
N 20.78. C24H23N7O2S. Calculated, %: C 60.87; H 4.90;
N 20.70.
Crystal data structure determination of compound
6j. The yellow powder of compound 6i was dissolved in
ethanol–ethyl acetate–tetrahydrofuran (5 : 2 : 2 by v : v : v).
Upon slow evaporation of the solvents for several days,
some single crystals suitable for X-ray analysis were ob-
tained.Ayellow crystal (C25H26N6O5S) with dimensions
of 0.18×0.15×0.12 mm was selected for data collection
on a Bruker APEX-II CCD automatic diffractometer
with graphite-monochromatized MoKα radiation (λ =
In vitro anticancer activity test of the compounds
6a–6j on HT-29 andA549 cell lines. The anti-prolifera-
tive activity of the title compounds was evaluated against
HT-29 and A549 cell lines using the standard MTT as-
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SYNTHESIS, CRYSTAL STRUCTURE, AND ANTIPROLIFERATIVE ACTIVITY
2327
5. Gouda, M.A., Berghot, M.A., Shoeib, A.I., and Kha-
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(FBS). Approximately 4×103 cells, suspended in MEM
medium, were plated onto each well of a 96-well plate
and incubated in 5% CO2 at 37°C for 24 h. The tested
compounds at the indicated final concentrations were
added to the culture medium and the cell cultures were
stored for 72 h. Fresh MTT was added to each well at a
terminal concentration of 5 μg/mL, and incubated with
cells at 37°C for 4 h. The formazan crystals were dis-
solved in 100 mLDMSO each well, and the absorbance at
492 nm (for absorbance of MTT formazan) and 630 nm
(for the reference wavelength) was measured with an
ELISA reader. All compounds were tested three times
for each cell line. The results expressed as IC50 were the
averages of three determinations and calculated by us-
ing the Bacus Laboratories Incorporated Slide Scanner
(Bliss) software.
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FUNDING
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The authors thank the financial support of Shenyang Sci-
ence and Technology project (project no. 18-013-0-03) and
Natural Science Foundation of Liaoning Province (project
no. 2019-ZD-0191).
CONFLICT OF INTEREST
No conflict of interest was declared by the authors.
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