Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів
Preparative method for the preparation of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles is presented. Alkylation of 1-alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with 2-(2-bromomethyl)-1H-isoindole-1,3(2H)-dione and chloroacetonitrile was carried out. In all cases, mixtures of isomeric...
Збережено в:
| Дата: | 2024 |
|---|---|
| Автори: | , |
| Формат: | Стаття |
| Мова: | Англійська |
| Опубліковано: |
V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine
2024
|
| Теми: | |
| Онлайн доступ: | https://bioorganica.com.ua/index.php/journal/article/view/87 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Ukrainica Bioorganica Acta |
| Завантажити файл: |  |
Репозитарії
Ukrainica Bioorganica Acta| _version_ | 1871193612920815616 |
|---|---|
| author | Vydzhak, Roman N. Panchishin, Svitlana Yа. |
| author_facet | Vydzhak, Roman N. Panchishin, Svitlana Yа. |
| author_institution_txt_mv | [
{
"author": "Roman N. Vydzhak",
"institution": "V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the NAS of Ukraine, Kyiv, Ukraine"
},
{
"author": "Svitlana Yа. Panchishin",
"institution": "V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the NAS of Ukraine, Kyiv, Ukraine"
}
] |
| author_sort | Vydzhak, Roman N. |
| baseUrl_str | https://bioorganica.com.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-19T14:56:55Z |
| description | Preparative method for the preparation of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles is presented. Alkylation of 1-alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with 2-(2-bromomethyl)-1H-isoindole-1,3(2H)-dione and chloroacetonitrile was carried out. In all cases, mixtures of isomeric products of 1- and 2-alkylation with isomer ratios of 1 : 0.8 were obtained. The mixtures of isomers were separated by chromatography and the target compounds did not contain impurities of another isomer. All phthalimide derivatives of pyrazolo[4,3-c]pyrazoles were converted into the corresponding 2-heterylethylamines, which were isolated as dihydrochlorides. The reduction of the nitrile group of (4,6-dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)acetonitrile and (4,6-dimethylpyrazolo[4,3-c]pyrazol-2(4H)-yl)acetonitrile under the action of various reagents was investigated: hydrogen at 20 atm on Raney nickel, lithium aluminum hydride in diethyl ether, and borane-dimethyl sulfide complex in tetrahydrofuran. The best results were obtained when reducing cyanomethyl derivatives with borane-dimethyl sulfide complex. In this case, the yields of the target amines are more than 90 percent. This is a preparative, convenient, and well-reproducible method and has been successfully applied to the synthesis of a number of 2-aminoethyl derivatives. The structure of the synthesized compounds was confirmed by 1H and 13C NMR spectroscopy. In vitro screening studies of antitumor activity were conducted on 60 cancer cell lines for the four synthesized compounds |
| doi_str_mv | 10.15407/bioorganica2024.02.010 |
| first_indexed | 2025-07-17T12:20:02Z |
| format | Article |
| fulltext |
ISSN 1814-9758. Ukr. Bioorg. Acta, 2024, Vol. 19, N 2
UDC 547.779
DOI: https://doi.org/10.15407/bioorganica2024.02.010
10
Ukrainica Bioorganica Acta
www.bi oorgan ica .org .ua
RESEARCH ARTICLE
Synthesis of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles
Roman N. Vydzhak*, Svitlana Ya. Panchishin
V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the NAS of Ukraine, Kyiv, Ukraine
Abstract: A preparative method to obtain 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles is presented. Alkylation of 1-alkyl-3-
methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with 2-(2-bromomethyl)-1H-isoindole-1,3(2H)-dione and chloroacetonitrile was carried out.
Mixtures of isomeric products of 1- and 2-alkylation with isomer ratios of 1:0.8 were obtained in all cases. The mixtures of isomers were
separated by chromatography, and the target compounds did not contain impurities from another isomer. All phthalimide derivat ives of
pyrazolo[4,3-c]pyrazoles were converted into the corresponding 2-heterylethylamines, which were isolated as dihydrochlorides. The
reduction of the nitrile group of (4,6-dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)acetonitrile and (4,6-dimethylpyrazolo[4,3-c]pyrazol-
2(4H)-yl)acetonitrile under the action of various reagents was investigated such as hydrogen at 20 atm on Raney nickel, lithium aluminum
hydride in diethyl ether, and borane-dimethyl sulfide complex in tetrahydrofuran. The best results were obtained when reducing
cyanomethyl derivatives with a borane-dimethyl sulfide complex. In this case, the yields of the target amines were more than 90 percent.
This is a preparative, convenient, and well-reproducible method and has been successfully applied to synthesizing a number of
2-aminoethyl derivatives. The structure of the synthesized compounds was confirmed by 1H and 13C NMR spectroscopy. In vitro screening
studies of antitumor activity were conducted on 60 cancer cell lines for the four synthesized compounds.
Keywords: pyrazolo[4,3-c]pyrazoles; alkylation of pyrazole derivatives; heteryl acetonitriles; reduction of the cyanomethyl group.
Introduction
Fragment-based drug discovery (FBDD) has recently
become an increasingly popular approach in medicinal
chemistry to generate lead compounds [1-4]. Over the past
two decades, searching for active compounds based on
FBDD has allowed more than fifty new molecules to enter
clinical trials [1]. To date, seven drugs obtained by
modifying fragments have been approved [1, 5-11]. It
demonstrates that FBDD is a powerful method for
developing new drugs that significantly reduce the time to
research. In this approach, it is important to search for new
hit fragments that do not show too high activity but have
significant potential for further modification. Examples of
such modifications are shown in Figure 1 [4, 12, 13].
In the field of FBDD, pyrazolo[4,3-c]pyrazoles are
practically not represented since few such derivatives are
Received:
Revised:
Accepted:
Published online:
25.09.2024
18.10.2024
19.11.2024
30.12.2024
Corresponding author. Tel.: +380-44-573-2596;
e-mail: vydzhak@bpci.kiev.ua (R.M. Vydzhak)
ORCID: 0000-0001-7942-169X
described in the literature [14-17]. These compounds are
attractive as fragments and are characterized by high
stability, the presence of multidirectional acceptors of
hydrogen atoms, and good solubility in water. Therefore,
compounds with a pyrazolopyrazole fragment have
significant potential for application in medicinal chemistry.
N-(2-aminoethyl) derivatives of pyrazolo[4,3-c]pyrazoles
are not described in the literature, therefore, the
development of methods for their synthesis is an important
task since similar derivatives of pyrazole [18-21], indazole
[22-26] and hetero-condensed derivatives of pyrazole [27-
29] are often used to search for active compounds.
Results and Discussion
The purpose of this work is to find a convenient
approach to the synthesis of 2-aminoethyl-substituted
pyrazolo[4,3-c]pyrazoles. A detailed analysis of literary
sources showed that for the synthesis of similar compounds,
two principle approaches are mainly used: alkylation of
nitrogen-containing heterocycles with N-protected
derivatives of 2-bromomethylamine followed by removal of
the protective group [18, 19, 30] and recovery of
© Vydzhak R.N. et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and source are credited.
R.N. Vydzhak, S.Ya. Panchishin
11
Figure 1. Examples of converting active hits to clinical candidates [4, 12, 13].
Scheme 1. Synthesis of phthalimide derivatives of pyrazolopyrazoles and their conversion into 2-aminoethyl substituted pyrazolo[4,3-
c]pyrazoles.
cyanomethyl derivatives [31]. We tried to use both
approaches to evaluate their advantages and disadvantages.
We carried out alkylation of 1-alkyl-3-methylpyrazolo[4,3-
c]pyrazoles 1 with 2-(2-bromethyl)-1H-isoindole-1,3(2H)-
dione (Scheme 1) and chloroacetonitrile (Scheme 2 ) in
acetonitrile. Cesium carbonate was used as a basis. Similar
alkylation of compound 1 with esters of halogen carboxylic
acids was studied earlier [15], and the specified reaction
conditions are optimal for this class of condensed pyrazoles.
The total yield of compounds 2a-c and 3a-c and the pair of
isomers 6a-c and 7a-c is moderate or high, and the ratio of
isomers is close to 1:0.8. The target compounds 2a-c, 3a-c,
6a-c and 7a-c were separated by chromatography and did
not contain impurities of the other isomer. Their
composition was confirmed by elemental analysis data, and
1H and 13C NMR spectroscopy confirmed their structure.
All signals of hydrogen atoms are present in the 1H NMR
spectra of compounds 2a-c and 3a-c, and their chemical
shifts do not differ significantly. In the 1H NMR spectra
recorded in DMSO-d6, there is a slight difference in the
position of the C-H signal of the pyrazolopyrazole
fragment. In compounds 2a-c, it is in the 7.35-7.40 ppm
region, and in the molecules of compounds 3a-c at 7.70-
7.75 ppm. In the 1H NMR spectra of isomeric compounds
2a and 3a recorded in CDCl3, the position of the C-H signal
of the pyrazolopyrazole fragment is almost the same: 7.25
ISSN 1814-9758. Ukr. Bioorg. Acta, 2024, Vol. 19, N 2
12
ppm in the molecule of compound 2a and 7.23 ppm for 3a.
In the 13C NMR spectra of isomeric compounds 2a-c and
3a-c, all signals of carbon atoms are present, and they differ
significantly from each other in terms of the position of
carbon atoms in the pyrazolopyrazole fragment. Thus, for
compounds 2a and 3a, we obtained the following results: 2a
(117.45, 125.44, 136.52, 139.67 ppm (CDCl3)); 3a (106.55,
132.72, 135.40, 148.16 ppm (CDCl3)). The positions of the
signals of the carbon atoms of the phthalimide fragment in
the molecules of compounds 2a-c and 3a-c practically did
not differ.
According to NOESY data, the molecule of compound
2a shows a spatial interaction between the hydrogen atoms
of the NCH2 and C-CH3 groups, as well as between the
hydrogen atoms of NCH3 and C6-H, which unequivocally
confirms the structure of 2-[2-(4,6-dimethylpyrazolo[4,3-
c]pyrazol-1(4H)-yl)ethyl]-1H-isoindole-1,3(2H)-dione 2a.
A similar interaction between hydrogen atoms is also
manifested in compounds 2b,c. The molecules of
compounds 3a-c show a spatial interaction between the
hydrogen atoms of the NCH2 and C3-H groups, which
unambiguously confirms their structure. Molecular ion
peaks [M+H]+ are usually detected in LC-MS spectra of the
compounds 2a-c and 3a-c. All signals of hydrogen atoms
are present in the 1H NMR spectra of compounds 6a-c and
7a-c, their chemical shifts do not differ significantly for
each pair of isomers and depend on the solvent in which the
spectra were recorded. For compound 6a, we obtained the
following results: C-CH3 (2.39 ppm (DMSO-d6), 2.48 ppm
(CDCl3)); NCH2CN (5.54 ppm (DMSO-d6), 5.08 ppm
(CDCl3)); C-H (7.58 ppm (DMSO-d6), 7.34 ppm (CDCl3)).
For isomer 7a, the positions of the corresponding signals
were as follows: C-CH3 (2.36 ppm (DMSO-d6), 2.46 ppm
(CDCl3)), NCH2CN (5.67 ppm (DMSO-d6), 5.22 ppm
(CDCl3)), C-H (7.84 ppm (DMSO-d6), 7.36 ppm (CDCl3)).
There is a slight difference in the position of the C-H signal
of the pyrazolopyrazole fragment for compounds 6 and 7 in
the 1H NMR spectra recorded in DMSO-d6, which can serve
as additional confirmation of the structure only in
combination with other methods. In the 13C NMR spectra of
isomeric compounds 6a-c and 7a-c, all signals of carbon
atoms are present, and they differ significantly from each
other in the position of the signals of carbon atoms in the
pyrazolopyrazole fragment for each pair of isomers. The
influence of the solvent on the position of these signals is
insignificant for a particular compound. Thus, for
compounds 6a and 7a, we obtained the following results: 6a
(116.68, 126.23, 139.69, 140.81 ppm (DMSO-d6)), (114.23,
126.51, 136.57, 140.87 ppm (CDCl3)); 7a (109.56, 131.50,
135.59, 148.37 ppm (DMSO-d6)), (106.84, 132.86, 135.62,
148.98 ppm (CDCl3)). The study's results correlate well
with the literature data obtained during the alkylation of
pyrazolopyrazoles with bromoacetic acid methyl ether [15].
According to the NOESY data, the molecule of compound
6a exhibits a spatial interaction between the hydrogen
atoms of the NCH2CN and C-CH3 groups, as well as
between the hydrogen atoms of the N-CH3 and C6-H
groups. Similar interactions between hydrogen atoms are
also present in compounds 6b and 6c. The molecules of
compounds 7a-c show a spatial interaction between the
hydrogen atoms of the NCH2CN and C3-H groups, which
confirms their structure. With the help of 13C NMR spectra,
the structure of a specific compound can be established, but
for reliable evidence of the structure of each isomer, a full
spectral study should be carried out and not limited to one
of the methods. Molecular ion peaks [M+H]+ are detected in
LC-MS spectra of the compounds 6a-c and 7a-c.
The synthesized phthalimido derivatives 2a-c and 3a-c
were converted into the corresponding target amines 4a-c
and 5a-c with high yields (Scheme 1). These compounds
were isolated as dihydrochlorides (Scheme 1). During
recrystallization, they do not lose hydrogen chloride,
indicating a relatively high basicity of the pyrazolopyrazole
fragment. Elemental analysis data confirmed their
composition and structure, which 1H NMR and 13C
spectroscopy confirmed. In the 1H NMR spectra of
compounds 4 and 5, all C-H signals and the signal of the
NH3
+ group are present, and in the 13C NMR spectra, all
signals of carbon atoms are present. Thus, for compounds
4a and 5a, the signal positions of the pyrazole fragment
were as follows: 4a (112.40, 125.55, 136.60, 139.78 ppm
(DMSO-d6)); 5a (110.84, 130.69, 134.81, 148.27 ppm
(DMSO-d6)). It correlated well with the data obtained for
the starting compounds 2a and 3a.
Amines 4a-c and 5a-c were obtained by reducing the
corresponding cyanomethyl derivatives of
pyrazolopyrazoles 6a-c and 7a-c (Scheme 2). First, we
attempted the catalytic hydrogenation of compounds 6a and
7a to obtain the target amines 4a and 5a since similar
transformations for pyrazole derivatives are well-studied.
Thus, during the hydrogenation of compound 6a on a nickel
catalyst, the target amine 4a was obtained with a low yield.
At the same time, partial recovery of the pyrazolopyrazole
fragment occurred and various impurities of amine nature
were formed. To purify amine 4a, we further converted it
into oxalate, poorly soluble in acetone. This manipulation
made it possible to get rid of these impurities but
significantly reduced the yield of the target product. Under
similar conditions, we failed to convert 7a to 5a. At the
same time, compound 5a was absent in the reaction
mixture. A mixture of amine compounds was obtained. This
indicates complete or partial hydrogenation of the
pyrazolopyrazole fragment. Changing the reaction
conditions makes it possible to achieve a higher yield of
amine 4a and carry out the transformation of 7a to 5a. Such
research requires a lot of effort, and the conditions for
reducing each specific compound may differ, so we decided
to use other approaches.
Reduction of the nitrile group in compound 6a with
lithium aluminum hydride gave the target amine 4a yielding
42.8%. Reduction of compound 7a under similar conditions
gave amine 5a with a yield of 46% and a purity of 75%.
Compound 5a contained various impurities of an amine
nature, and we could not purify it. Therefore, we continued
the search for more convenient methods of reducing the
nitrile group in compounds 6 and 7. By reducing the cyano
group in compound 6a with a borane-dimethylsulfide
complex in high yield, we obtained the target amine 4a.
Under similar conditions, compound 7a was also converted
R.N. Vydzhak, S.Ya. Panchishin
13
to amine 5a with a yield of 93%. Amines 4b,c and 5b,c
were obtained by this method from the corresponding
nitriles 6b,c and 7d,c. This method of obtaining amines is
more convenient than via the corresponding phthalimide
derivatives since the pairs of the corresponding isomeric
nitriles 6 and 7 are much easier to separate by
chromatography than the pairs of compounds 2 and 3.
Another method for reducing nitriles that we applied was
using sodium borohydride in methanol in the presence of
cobalt chloride. In this case, nitriles 6a and 7a were
converted into the corresponding 2-aminoethyl derivatives
4a and 5a, but the yields of the target amines were lower
than when reduced with the borane-dimethylsulfide
complex (Table 1). Compound 4a, synthesized by this
method, did not contain impurities, while amine 5a was
obtained with a 94-95% purity. The best method for
reducing cyanomethyl derivatives of pyrazolo[4,3-
c]pyrazoles is using the borane-dimethylsulfide complex in
tetrahydrofuran. We do not exclude using other methods to
reduce the nitrile group, but we did not conduct such
studies.
The 1H and 13C NMR spectra of amines 4a-c and 5a-c
obtained by reduction of the corresponding nitriles are
identical to the spectra of these compounds obtained from
the corresponding phthalimide derivatives 2a-c and 3a-c.
Although amines 4a-c and 5a-c were isolated as
dihydrochlorides, the molecular ion peaks [M+H]+ are
detected in the LC-MS spectra.
Compounds 6a-c and 7a-c are typical aliphatic amines
that can be used to create biologically active compounds
using conventional synthetic transformations. Using 6a as
an example, we prepared amide 8 and urea 9 by
conventional methods (Scheme 3). The composition of
compounds 8 and 9 was confirmed by elemental analysis
data and the structure by 1H NMR and 13C NMR
spectroscopy.
Scheme 2. Synthesis of pyrazolopyrazoles with a cyanomethyl group and their reduction in 2-aminoethyl derivatives of pyrazolo[4,3-
c]pyrazoles.
Table 1. Reduction of (4,6-dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)acetonitrile (6a) and (4,6-dimethylpyrazolo[4,3-c]py-
razol-2(4H)-yl)acetonitrile (7a).
Reaction conditions Yield 4a Yield 5a
1 H2/Ni, 40 ºC, 20 atm. 24.2% 0%
2 LiAlH4, Et2O 42.8% 0%
3 NaBH4, CoCl2 × 6H2O, MeOH 78.6% 68.7%
4 BH3·S(CH3)2, THF 91.7% 92.9%
N
N
N
N
HN
O
N
N
N
N
HN
HN
O
4a
PhC(O)Cl PhNCO
DIPEA DIPEA
8 9
Scheme 3. Synthetic application of 2-aminoethylpyrazolo[4,3-c]pyrazole 4a.
ISSN 1814-9758. Ukr. Bioorg. Acta, 2024, Vol. 19, N 2
14
The compounds presented in the work meet all the
FBDD criteria. All of them characterized by the originality
of the structure, high solubility in water, and contain donors
and acceptors of hydrogen atoms.
Four synthesized compounds, 4a (D-759369), 4c (D-
759370), 8 (D-759371), and 9 (D-759372), were tested for
antitumor activity within the framework of the international
scientific program of the US National Institutes of Health.
Screening studies were carried out in vitro on 60 cancer cell
lines covering relevant types of human oncological diseases
(lung, kidney, CNS, ovarian, prostate, breast, epithelial
cancer, as well as leukemia and melanoma cancer lines)
under the influence of the substance at a concentration of
1.10-5 M, as a result of which the percentage of growth (GP)
of cancer cell lines compared to the control (control –
100%) was determined [32-35].
Compounds 4a and 4c contain pyrazolo[4,3-c]pyrazole
and 2-aminoethyl fragments. These compounds showed a
similar percentage of growth of cancer cells of the MOLT-4
(leukemia) line GP=92.67% and GP=93.76%, respectively.
However, these compounds are characterized by different
lipophilicity. Therefore, they exhibit different activity on
other cancer cell lines. Thus, compound 4a showed a slight
inhibition of the growth of cells of the K-562 (leukemia)
line GP=92.96% and EKVX (Non-small cell lung cancer)
line GP=92.49%. Compound 4c, which has a higher
lipophilicity, showed a slight inhibition of the growth of
two Non-small cell lung cancer lines (A549/ATCC)
GP=94.63% and (HOP-92) GP=87.06%. Compound 8
contains dimethylpyrazolo[4,3-c]pyrazole and benzamide
moieties linked by a linker. It showed slight inhibition of
cell growth of U-251 (CNS Cancer) cell line GP=95.23%
and NCI-H226 (Non-small cell lung cancer) cell line
GP=94.65%. It should be noted that compound 4a, which
also includes a dimethylpyrazolo[4,3-c]pyrazole moiety,
showed inhibition of cell growth of NCI-H226 (Non-small
cell lung cancer) cell line GP=96.39%. Compound 9
combines dimethylpyrazolo[4,3-c]pyrazole and N-
phenylurea moieties. Like compound 4a, it inhibited the
growth of two leukemia cell lines (K-562) GP=96.11% and
(MOLT-4) GP=92.02%. Compound 9 also showed slight
inhibition of the growth of two Non-small cell lung cancer
lines (A549/ATCC) GP=94.33% and (NCI-H522)
GP=94.90%. Urea 9 showed the highest activity in
inhibiting the UACC-257 (melanoma) cell line GP=79.92%,
which may be due to the presence of the N-phenylurea
fragment in the molecule.
Conclusions
Thus, we have developed a preparative method for
obtaining 2-aminoethyl derivatives of pyrazolopyrazoles.
We carried out the alkylation of 1-alkyl-3-methyl-1,4-
dihydropyrazolo[4,3-c]pyrazoles with 2-(2-bromethyl)-1H-
isoindole-1,3(2H)-dione and chloroacetonitrile. In all cases,
mixtures of isomeric compounds were separated by
chromatography, and all 1- and 2-alkylation products were
isolated individually. In all cases, they did not contain
impurities of another isomer. The obtained phthalimide
hybrids were converted into the corresponding 1- and 2-(2-
aminoethyl) derivatives of dihydropyrazolo[4,3-c]pyrazoles
with high yield. The reduction of the cyanomethyl group of
(4,6-dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)acetonitrile
and (4,6-dimethylpyrazolo[4,3-c]pyrazol-2(4H)-yl)aceto-
nitrile was studied. It was shown that the best reduction
method is using the borane-dimethyl sulfide complex in
tetrahydrofuran. Six 2-aminoethyl derivatives of
pyrazolo[4,3-c]pyrazoles were synthesized. A virtual library
of pyrazolo[4,3-c]pyrazoles was created based on the
synthesized amines, which meet the FBDD criteria.
Currently, the biological properties of these compounds are
being evaluated in various fragment-based screening assays.
Notes
The authors declare no conflict of interest.
Experimental section
Synthesis
All used solvents were of analytical grade. The 1H and
13C NMR spectra were recorded on a Bruker Avance DRX
500 spectrometer (at 500 MHz for 1H NMR, 126 MHz for
13C NMR), in DMSO-d6. NMR chemical shifts are reported
in ppm (δ scale) using residual solvent peaks
SO(CD3)(CD2H) (δH = 2.50 ppm) or SO(CD3)2 (δC =
39.52 ppm) as internal standard. Coupling constants (J)
are given in Hz. Spectra are reported as follows: chemical
shift (δ, ppm), multiplicity, integration, and coupling
constants (Hz). LC-MS spectra were recorded on an Agilent
1100 Series HPLC equipped with a diode array and Agilent
LC/MSD SL mass selective detector, ionization method –
chemical ionization at atmospheric pressure, m/z scan range
from 80 to 1000. Melting points were determined in a
Fischer-Johns melting point apparatus and were
uncorrected. Elemental analysis was carried out in the
Analytical Laboratory of the Institute of Bioorganic and
Petrochemistry of the National Academy of Sciences of
Ukraine by manual methods: the carbon and hydrogen
contents were determined using the Pregl gravimetric
method, nitrogen was determined using the Duma’s
gasometrical micro method. Column chromatography
was performed using Macherey-Nagel Silica 60, 0.04-
0.063 mm silica gel.
1-Alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles
(1) were obtained according to the method described in
[15].
Alkylation of 1,3-dimethyl-1,4-dihydropyrazolo[4,3-
c]pyrazole (1a) with 2-(2-bromethyl)-1H-isoindole-1,3(2H)-
dione.
To a solution of 2.72 g (0.02 mol) of compound 1а in 60
ml of acetonitrile was added 5.52 g (0.02 mol) of cesium
carbonate and 5.59 g (0.022 mol) of 2-(2-bromethyl)-1Н-
isoindole-1,3(2Н)-dione. The mixture was refluxed for 48 h
with stirring, cooled, the precipitate was filtered off, washed
with acetonitrile, the solvent was evaporated, 50 ml of
R.N. Vydzhak, S.Ya. Panchishin
15
water was added, the precipitate was filtered off, and the
resulting mixture of reaction products was separated by
column chromatography on silica gel (eluent was
chloroform with a gradient of methanol from 0.5 to 2%).
The following compounds were isolated: 2a 2.43 g (39.3%);
3a 2.16 g (34.9%).
2-[2-(4,6-dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)-
ethyl]-1H-isoindole-1,3(2H)-dione (2a).
Yield 2.43g (39.3%). Colorless crystals, mp 217-219 °C
(acetonitrile). 1H NMR (500 MHz, CDCl3, ppm) δ 2.38 (s,
3H, CCH3), 3.81 (s, 3H, NCH3), 4.11 (t, J = 6.1 Hz, 2H,
NCH2), 4.49 (t, J = 6.1 Hz, 2H, NCH2), 7.25 (s, 1H, CH),
7.67-7.72 (m, 2H, Ar), 7.78-7.83 (m, 2H, Ar). 13C NMR
(125 MHz, CDCl3, ppm) δ 11.41, 36.78, 37.72, 47.80,
117.45, 122.85, 125.44, 131.32, 133.60, 136.52, 139.67,
167.21. MS (APCI) m/z = 310.1 [M+H]+. Anal. calcd. for
C16H15N5O2 (%): C, 62.13; H, 4.89; N, 22.64. Found (%):
C, 62.04; H, 4.93; N, 22.75.
2-[2-(4,6-dimethylpyrazolo[4,3-c]pyrazol-2(4H)-yl)-
ethyl]-1H-isoindole-1,3(2H)-dione (3a).
Yield 2.16g (34.9%). Yellow crystals, mp 243-245 °C
(acetonitrile). 1H NMR (500 MHz, DMSO-d6, ppm) δ 2.18
(s, 3H, CCH3), 3.67 (s, 3H, NCH3), 4.03 (t, J = 5.6 Hz, 2H,
NCH2), 4.50 (t, J = 5.6 Hz, 2H, NCH2), 7.70 (s, 1H, CH),
7.80-7.86 (m, 4H, Ar). 1H NMR (500 MHz, CDCl3, ppm) δ
2.40 (s, 3H, CCH3), 3.77 (s, 3H, NCH3), 4.21 (t, J = 6.1 Hz,
2H, NCH2), 4.59 (t, J = 6.1 Hz, 2H, NCH2), 7.23 (s, 1H,
CH), 7.69-7.73 (m, 2H, Ar), 7.79-7.85 (m, 2H, Ar).
13C NMR (125 MHz, CDCl3, ppm) δ 11.50, 37.05, 37.93,
50.75, 106.55, 122.93, 131.41, 132.72, 133.59, 135.40,
148.16, 167.23. MS (APCI) m/z = 310.2 [M+H]+ Anal.
calcd. for C16H15N5O2 (%): C, 62.13; H, 4.89; N, 22.64.
Found (%): C, 61.92; H, 4.85; N, 22.79.
Compounds 2b, 2c, and 3b, 3c were prepared similarly
to compounds 2a and 3a.
2-[2-(4-Ethyl-6-methylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)ethyl]-1H-isoindole-1,3(2H)-dione (2b).
It was obtained similarly from 3.78 g (0.02 mol) of
compound 1b. Yield 2.76g (42.6%). Colorless crystals, mp
194-195 °C (acetonitrile). 1H NMR (500 MHz, DMSO-d6,
ppm) δ 1.47 (t, J = 7.6 Hz, 3H, NCH2CH3). 2.26 (s, 3H,
CCH3), 3.94 (t, J = 5.8 Hz, 2H, NCH2), 4.15 (q, J = 7.6 Hz,
2H, NCH2CH3), 4.49 (t, J = 5.8 Hz, 2H, NCH2), 7.38 (s, 1H,
CH), 7.80-7.84 (m, 4H, Ar). 13C NMR (125 MHz, DMSO-
d6, ppm) δ 12.01, 14.85, 38.50, 45.31, 48.02, 118.48,
123.49, 125.48, 131.87, 134.91, 136.98, 139.10, 167.81.
MS (APCI) m/z = 324.2 [M+H]+. Anal. calcd. for
C17H17N5O2 (%): C, 63.15; H, 5.30; N, 21.66. Found (%):
C, 63.27; H, 5.26; N, 21.82.
2-[2-(4-Isopropyl-6-methylpyrazolo[4,3-c]pyrazol-
1(4H)-yl)ethyl]-1H-isoindole-1,3(2H)-dione (2c).
It was obtained similarly from 4.06 g (0.02 mol) of
compound 1с. Yield 3.03g (44.9%). Colorless crystals, mp
166-167 °C (ethanol). 1H NMR (500 MHz, DMSO-d6, ppm)
δ 1.35 (d, J = 6.6 Hz, 6H, CH(CH3)2), 2.30 (s, 3H, CCH3),
3.89 (t, J = 5.8 Hz, 2H, NCH2), 4.35-4.41 (m, 3H,
NCH(CH3)2, NCH2), 7.36 (s, 1H, CH), 7.80-7.84 (m, 4H,
Ar). 13C NMR (125 MHz, DMSO-d6, ppm) δ 11.63, 21.77,
37.99, 47.46, 51.91, 118.49, 123.01, 124.83, 131.41,
134.25, 134.46, 136.64, 137.40, 167.34. MS (APCI) m/z =
338.1 [M+H]+. Anal. calcd. for C18H19N5O2 (%): C, 64.08;
H, 5.68; N, 20.76. Found (%): C, 63.97; H, 5.71; N, 20.90.
2-[2-(4-Ethyl-6-methylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)ethyl]-1H-isoindole-1,3(2H)-dione (3b).
It was obtained similarly from 2.78 g (0.02 mol) of
compound 1b. Yield 2.02g (31.2%). Light yellow crystals,
mp 183-185 °C (acetonitrile). 1H NMR (500 MHz, DMSO-
d6, ppm) δ 1.25 (t, J = 7.4 Hz, 3H, NCH2CH3). 2.17 (s, 3H,
CCH3), 3.92-4.04 (m, 4H, NCH2, NCH2CH3), 4.47 (t, J =
5.8 Hz, 2H, NCH2), 7.74 (s, 1H, CH), 7.80-7.84 (m, 4H,
Ar). 13C NMR (125 MHz, DMSO-d6, ppm) δ 11.79, 13.93,
38.31, 44.95, 50.53, 108.71,123.01, 131.03, 131.57, 134.09,
134.35, 147.69, 167.42. MS (APCI) m/z = 324.2 [M+H]+.
Anal. calcd. for C17H17N5O2 (%): C, 63.15; H, 5.30; N,
21.66. Found (%): C, 63.21; H, 5.34; N, 21.78.
2-[2-(4-Isopropyl-6-methylpyrazolo[4,3-c]pyrazol-
2(4H)-yl)ethyl]-1H-isoindole-1,3(2H)-dione (3c).
It was obtained similarly from 4.06 g (0.02 mol) of
compound 1c. Yield 2.42g (35.9%). Light yellow crystals,
mp 177-179 °C (acetonitrile). 1H NMR (500 MHz, DMSO-
d6, ppm) δ 1.30 (d, J = 6.6 Hz, 6H, CH(CH3)2), 2.20 (s, 3H,
CCH3), 3.54-3.66 (m, 2H, NCH2), 4.31 (septet, J = 6.6 Hz,
1H, NCH(CH3)2), 4.47-4.54 (m, 2H, NCH2), 7.78 (s, 1H,
CH), 7.80-7.85 (m, 4H, Ar). 13C NMR (125 MHz, DMSO-
d6, ppm) δ 11.59, 20.93, 37.85, 46.52, 52.80, 109.11,
123.12, 130.86, 131.52, 134.02, 134.35, 147.54, 167.39.
MS (APCI) m/z = 338.2 [M+H]+. Anal. calcd. for
C18H19N5O2 (%): C, 64.08; H, 5.68; N, 20.76. Found (%):
C, 64.21; H, 5.62; N, 20.64.
[2-(4,6-Dimethylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)ethyl]amine dihydrochloride (4a).
a. 1.75 g (0.035 mol) of hydrazine hydrate was added to
a solution of 2.15 g (0.007 mol) of compound (2a) in 20 ml
of ethanol. The mixture was boiled for 12 h with stirring,
cooled to 20 °C, and 10 ml of concentrated hydrochloric
acid was added and boiled for 12 h. The solvent was
evaporated in vacuo, 25 ml of water was added to the
residue, and the precipitate was filtered and washed with
water (2×10 ml). The aqueous solution was evaporated in
vacuo to the minimum volume, and 10% sodium hydroxide
solution was added to pH > 10 and extracted with
methylene chloride (6×40 ml). The organic layer was
washed with 20 ml of 15% potassium carbonate solution
and dried with sodium sulfate; the solvent was evaporated
in a vacuum to a volume of 15-20 ml and saturated with dry
hydrogen chloride. The precipitate was filtered and washed
with acetone-diethyl ether (1:2) and diethyl ether. The yield
of compound 4a was 1.37 g (78.2%), with a purity of 95%.
ISSN 1814-9758. Ukr. Bioorg. Acta, 2024, Vol. 19, N 2
16
For analysis, 0.2 g of the product was solidified by heating
in a minimum volume of absolute ethanol, the same volume
of dry acetone and three times the volume of dry diethyl
ether were added. The mixture was left for 12 h at –15 °C.
The precipitate was filtered and washed with dry diethyl
ether, dried in vacuo, and obtained 4a. Colorless crystals,
mp 197-198 °C. 1H NMR (500 MHz, DMSO-d6, ppm) δ:
2.40 (s, 3H, CCH3), 3.13-3.27 (m, 2H, NCH2CH2NH3
+),
3.77 (s, 3H, NCH3), 4.46 (t, J = 6.6 Hz, 2H,
NCH2CH2NH3
+), 7.50 (s, 1H, CH), 8.40 (br. s, 3H, NH3
+).
13C NMR (125 MHz, DMSO-d6, ppm) δ 11.73, 36.89,
38.58, 46.70, 112.40, 125.55, 136.60, 139.78. MS (APCI)
m/z = 180.2 [M+H]+. Anal. calcd. for C8H15Cl2N5 (%): C,
38.11; H, 6.00; Cl, 28.12; N, 27.77. Found (%): C, 37.85;
H, 6.14; Cl, 27.94; N, 27.59.
Reduction of (4,6-dimethylpyrazolo[4,3-c]pyrazol-
1(4H)-yl)acetonitrile (6a).
b. To mixture 1.75 g (0.01 mol) of 6a and Reney-Nickel
(1g) in 40 ml methanol was added 20% NH3 solution (7 ml,
aqueous). The above reaction mixture was hydrogenated
under a pressure of 20 (at) of H2 for a period of 12h at
40 °C. The catalyst was then filtered off, and the filtrate was
evaporated under reduced pressure. 15 ml of 5% sodium
hydroxide solution was added to the residue and extracted
with methylene chloride (6×40 ml). The solvent was
evaporated under reduced pressure, the residue was
dissolved in 20 ml of acetone, and 25 ml of a saturated
acetone solution of oxalic acid was added. The precipitate
was filtered, washed with 20 ml of acetone, dried, and
mixed with 15 ml of water; 10% sodium hydroxide solution
was added to PH>10 and extracted with methylene chloride
(6×40 ml). The organic layer was washed with 20 ml of
15% potassium carbonate solution and dried with sodium
sulfate; the solvent was evaporated under reduced pressure
to a volume of 15-20 ml and saturated with dry hydrogen
chloride. The precipitate was filtered and washed with
acetone-diethyl ether (1:2) and diethyl ether. The yield of
compound 4a was 0.61 g (24.2%).
c. To a suspension of 1.14 g (0.03 mol) of lithium
aluminum hydride in 50 ml of diethyl ether in an inert
atmosphere, while stirring, a solution of 1.75 g (0.01 mol)
of compound 6a in 20 ml of diethyl ether was added
dropwise for 50 min at –5 °C. The mixture was stirred for 4
hours at 20 °C and boiled for 12 h. The mixture was cooled
to 0 °C, and 3.5 ml of 40% sodium hydroxide solution was
added dropwise and stirred for 2 hours. The precipitate was
filtered off, washed with diethyl ether (2×30 ml), the filtrate
was evaporated under reduced pressure, the residue was
dissolved in 15 ml of water, 1 ml of 10% sodium hydroxide
solution was added and extracted with methylene chloride
(6×40 ml). Compound 4a was isolated as the
dihydrochloride as described in the method a. The yield of
compound 4a was 1.08 g (42.8%).
d. To a solution of 10.5 g (0.06 mol) of compound 6a in
200 ml of tetrahydrofuran in an inert atmosphere at –10 °C,
9.88 g (0.13 mol) of the borane-dimethyl sulfide complex
was added for 2 h. The mixture was stirred for 4 h at 0 °C,
12 h at 20 °C and 24 h at 45 °C. The mixture was cooled to
–10 °C, 80 ml of methanol was added over two hours,
stirred for 4 h at 0 °C, and 30 ml of water was added. The
solvent was distilled off at normal pressure to a 120-130 ml
volume; 150 ml of methanol was added and distilled off
again. The last procedure was repeated twice. 40 ml of 20%
hydrochloric acid was added to the residue, and the mixture
was stirred for 2 h at 50 °C. The solution was evaporated to
half under reduced pressure and cooled to 0 °C, and 20%
sodium hydroxide solution was added to PH > 10 and
extracted with methylene chloride (6×80 ml). Compound 4a
was isolated as the dihydrochloride as described in the
method a. The yield of compound 4a was 13.86 g (91.7%).
e. To a solution of 1.75 g (0.01 mol) of compound 6a in
50 ml of methanol in an inert atmosphere at –10 °C was
added 0.2 g cobalt chloride hexahydrate and, over 1 h, 1.52
g (0.04 mol) of sodium borohydride in small portions. The
mixture was stirred for 2 h at 0 °C, 2 h at 20 °C, and 1 h at
40 °C. The mixture was cooled to 0 °C, and 20 ml of water
was added. 10 ml of 20% hydrochloric acid was added to
the residue, and the mixture was stirred for 2 h at 50 °C.
The solution was evaporated under reduced pressure and
cooled to 0 °C, and 20% sodium hydroxide solution was
added to PH>10 and extracted with methylene chloride
(6×30 ml). Compound 4a was isolated as the
dihydrochloride as described in the method a. The yield of
compound 4a was 1.98 g (78.6%).
Compounds 4b,c, and 5b-c were prepared similarly to
compound 4a according to methods a and d. Compound 5a
was prepared using methods a, d, and e.
[2-(4-Ethyl-6-methylpyrazolo[4,3-c]pyrazol-1(4H)-yl)-
ethyl]amine dihydrochloride (4b).
It was obtained from 2.45 g of compound 2b (method a).
Yield 1.71g (84.7%). By reducing 13.25 g of substituted
nitrile 6b, 17.21 g of compound 4b was obtained (method
d). Yield 92.3%. Colorless crystals, mp 195-197 °C. 1H
NMR (500 MHz, DMSO-d6, ppm) δ 1.51 (t, J = 7.6 Hz, 3H,
NCH2CH3). 2.51 (s, 3H, CCH3), 3.14-3.26 (m, 2H,
NCH2CH2NH3
+), 4.18 (q, J = 7.6 Hz, 2H, NCH2CH3), 4.46
(t, J = 6.5 Hz, 2H, NCH2CH2NH3
+), 7.52 (s, 1H, CH), 8.42
(br. s, 3H, NH3
+). 13C NMR (125 MHz, DMSO-d6, ppm) δ
11.82, 21.77, 38.56, 45.92, 46.71, 114.10, 125.38, 136.71,
138.19. MS (APCI) m/z = 194.1 [M+H]+. Anal. calcd. for
C9H17Cl2N5 (%): C, 40.61; H, 6.44; Cl, 26.64; N, 26.31.
Found (%): C, 40.47; H, 6.25; Cl, 26.43; N, 26.17.
[2-(4-Isopropyl-6-meth ylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)ethyl]amine dihydrochloride (4c).
It was obtained from 2.75g of compound 2c (method a).
Yield 1.92g (84.2%). By reducing 12.2 g of substituted
nitrile 6c, 15.86 g of compound 4c was obtained (method
d). Yield 94.2%. Colorless crystals, mp 203-205 °C. 1H
NMR (500 MHz, DMSO-d6, ppm) δ 1.42 (d, J = 6.6 Hz,
6H, CH(CH3)2), 2.41 (s, 3H, CCH3), 3.16-327 (m, 2H,
NCH2CH2NH3
+), 4.37-4.54 (m, 3H, NCH2CH2NH3
+, N
CH(CH3)2), 7.57 (s, 1H, CH), 8.39 (br. s, 3H, NH3
+). 13C
NMR (125 MHz, DMSO-d6, ppm) 11.86, 21.91, 38.55,
R.N. Vydzhak, S.Ya. Panchishin
17
46.65, 52.02, 118.80, 125.12, 136.82, 137.18. MS (APCI)
m/z = 208.2 [M+H]+. Anal. calcd. for C10H19Cl2N5 (%): C,
42.87; H, 6.83; Cl, 25.31; N, 24.99. Found (%): C, 42.64;
H, 6.95; Cl, 25.12; N, 24.76.
[2-(4,6-Dimethylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)ethyl]amine dihydrochloride (5a).
It was obtained from 1.9g of compound 3a (method a).
Yield 1.09g (70.4%). By reducing 8.76 g of substituted
nitrile 7a, 11.61 g (92.9%) of compound 5a was obtained
(method d). By reducing 1.75 g of substituted nitrile 7a,
1.73 g (68.7%) of compound 5a was obtained (method e).
Colorless crystals, mp 201-203 °C. 1H NMR (500 MHz,
DMSO-d6, ppm) δ 2.37 (s, 3H, CCH3), 3.26-3.34 (m, 2H,
NCH2CH2NH3
+), 3.68 (s, 3H, NCH3), 4.21 (t, J = 6.7 Hz,
2H, NCH2CH2NH3
+), 7.86 (s, 1H, CH), 8.35 (br. s, 3H,
NH3
+). 13C NMR (125 MHz, DMSO-d6, ppm) δ 12.21,
36.89, 44.68, 49.70, 110.84, 130.69, 134.81, 148.27. MS
(APCI) m/ z= 180.2 [M+H]+. Anal. calcd. for C8H15Cl2N5
(%): C, 38.11; H, 6.00; Cl, 28.12; N, 27.77. Found (%): C,
37.87; H, 6.13; Cl, 27.91; N, 27.58.
[2-(4-Ethyl-6-methylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)ethyl]amine dihydrochloride (5b).
It was obtained from 2.62g of compound 3b (method a).
Yield 1.83g (84.9%). By reducing 11.35 g of substituted
nitrile 7b, 14.73 g of compound 5b was obtained (method
d). Yield 92.2%. Colorless crystals, mp 191-192 °C. 1H
NMR (500 MHz, DMSO-d6, ppm) δ 1.36 (t, J = 7.4 Hz, 3H,
NCH2CH3). 2.35 (s, 3H, CCH3), 3.29-3.37 (m, 2H,
NCH2CH2NH3
+), 4.09 (q, J = 7.4 Hz, 2H, NCH2CH3), 4.56
(t, J = 6.7 Hz, 2H, NCH2CH2NH3
+), 7.84 (s, 1H, CH), 8.27
(br.s, 3H, NH3
+). 13C NMR (125 MHz, DMSO-d6, ppm) δ
12.49, 14.64, 39.41, 45.57, 50.45, 109.95, 131.58, 134.58,
148.15. MS (APCI) m/z = 194.2 [M+H]+. Anal. calcd. for
C9H17Cl2N5 (%): C, 40.61; H, 6.44; Cl, 26.64; N, 26.31.
Found (%): C, 40.36; H, 6.52; Cl, 26.40; N, 26.09.
[2-(4-Isopropyl-6-methylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)ethyl]amine dihydrochloride (5c).
It was obtained from 2.25g of compound 3c (method a).
Yield 1.63g (87.2%). By reducing 10.16 g of substituted
nitrile 7c, 13.05 g of compound 4c was obtained (method
d). Yield 93.1%. Colorless crystals, mp 196-197 °C. 1H
NMR (500 MHz, DMSO-d6, ppm) δ 1.44 (d, J = 6.5 Hz,
6H, CH(CH3)2), 2.37 (s, 3H, CCH3), 3.15-3.26 (m, 2H,
NCH2CH2NH3
+), 4.39-4.57 (m, 3H, NCH2CH2NH3
+, N
CH(CH3)2), 7.82 (s, 1H, CH), 8.43 (br.s, 3H, NH3
+). 13C
NMR (125 MHz, DMSO-d6, ppm) δ 11.82, 21.93, 38.70,
45.68, 51.89, 109.92, 131.38, 133.47, 148.02. MS (APCI)
m/z = 208.2 [M+H]+. Anal. calcd. for C10H19Cl2N5 (%): C,
42.87; H, 6.83; Cl, 25.31; N, 24.99. Found (%): C, 42.59;
H, 6.91; Cl, 25.19; N, 24.89.
Alkylation of 1,3-dimethyl-1,4-dihydropyrazolo[4,3-
c]pyrazole 1a with chloroacetonitrile.
65.2 g (0.2 mol) Of cesium carbonate and 22.65 g (0.3
mol) of chloroacetonitrile were added to a solution of 40.85
g (0.3 mol) of compound (1a) in 400 ml of acetonitrile. The
mixture was stirred for 18 h at 65 °C, after that it was
cooled, 4.52 g (0.06 mol) of chloroacetonitrile was added,
and stirred for 24 h at 65 °C. The precipitate was filtered off
and washed with acetonitrile. The solvent was evaporated,
and the resulting mixture of reaction products was separated
by column chromatography on silica gel (gradient elution
with chloroform and methanol from 1 to 3%). The
following compounds were isolated: 6a 23.97 g (45.6%), 7a
21.65 g (41.2%).
(4,6-Dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)aceto-
nitrile (6a).
Colorless crystals, mp 120-122 °C (hexane). 1H NMR
(500 MHz, DMSO-d6, ppm) δ 2.39 (s, 3H, CCH3), 3.78(s,
3H, NCH3), 5.54 (s, 2H, CH2CN), 7.58 (s, 1H, CH). 1H
NMR (500 MHz, CDCl3, ppm) δ 2.48 (s, 3H, CCH3), 3.83
(s, 3H, NCH3), 5.08 (s, 2H, CH2CN), 7.34(s, 1H, CH). 13C
NMR (125 MHz, DMSO-d6, ppm) δ 11.93, 37.42, 38.63,
116.68, 120.75, 126.23, 136.69, 140.81. 13C NMR (125
MHz, CDCl3, ppm) δ 12.09, 37.42, 38.63, 114.23, 120.31,
126.51, 136.57, 140.87. MS (APCI) m/z = 176.1 [M+H]+.
Anal. calcd. for C8H9N5 (%): C, 54.85; H, 5.18; N, 39.97.
Found (%): C, 54.71; H, 5.26; N, 40.19.
(4,6-Dimethylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)acetonitrile (7a).
Light yellow crystals, mp 94-95 °C (hexane). 1H NMR
(500 MHz, DMSO-d6, ppm) δ 2.36 (s, 3H, CCH3), 3.75 (s,
3H, NCH3), 5.67 (s, 2H, CH2CN), 7.84 (s, 1H, CH). 1H
NMR (500 MHz, CDCl3, ppm) δ 2.46 (s, 3H, CCH3), 3.78
(s, 3H, NCH3), 5.22 (s, 2H, CH2CN), 7.36 (s, 1H, CH).13C
NMR (125 MHz, DMSO-d6, ppm) δ 11.81, 37.24, 40.79,
109.56, 115.92, 131.50, 135.59, 148.37. 13C NMR (125
MHz, CDCl3, ppm) 11.52, 37.09, 40.57, 106.84, 113.27,
132.86, 135.62, 148.98. MS (APCI) m/z = 176.2 [M+H]+.
Anal. calcd. for C8H9N5 (%): C, 54.85; H, 5.18; N, 39.97.
Found (%): C, 55.02; H, 5.27; N, 40.21.
Compounds 6b,c, and 7b,c were prepared similarly to
compounds 6a and 7a.
(4-Ethyl-6-methylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)acetonitrile (6b).
By alkylation of 30.16 g (0.2mol) of 1-ethyl-3-methyl-
1,4-dihydropyrazolo[4,3-c]pyrazole (1b), 17.97 g (47.3%)
of compound (6b) was obtained. Colorless crystals, mp 92-
94 °C (hexane). 1H NMR (500 MHz, CDCl3, ppm) δ 1.49 (t,
J = 7.6 Hz, 3H, CH3). 2.51 (s, 3H, CCH3), 4.17 (q, J = 7.6
Hz, 2H, NCH2), 5.12 (s, 2H, CH2CN), 7.38 (s, 1H, CH). 13C
NMR (125 MHz, CDCl3, ppm) δ 12.06, 14.62, 38.55, 45.86,
114.25, 120.44, 126.18, 136.62, 139.54. MS (APCI) m/z =
190.2 [M+H]+. Anal. calcd. for C9H11N5 (%): C, 57.13; H,
5.86; N, 37.01. Found (%): C, 57.24; H, 5.78; N, 37.29.
(4-Isopropyl-6-methylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)acetonitrile (6c).
ISSN 1814-9758. Ukr. Bioorg. Acta, 2024, Vol. 19, N 2
18
By alkylation of 32.85 g (0.2mol) of 1-isopropyl-3-
methyl-1,4-dihydropyrazolo[4,3-c]pyrazole (1c), 19.56 g
(48.1%) of compound (6c) was obtained. Colorless crystals,
mp 84-85 °C (hexane). 1H NMR (500 MHz, CDCl3, ppm) δ
1.53 (d, J = 6.6 Hz, 6H, 2CH3). 2.52 (s, 3H, CCH3), 4.51
(septet, J = 6.6 Hz, 1H, NCH), 5.13 (s, 2H, CH2CN), 7.41
(s, 1H, CH). 13C NMR (125 MHz, CDCl3, ppm) δ 11.63,
21.74, 38.04, 52.71, 113.77, 120.48, 125.36, 136.20,
137.80. MS (APCI) m/z = 204.1 [M+H]+. Anal. calcd. for
C10H13N5 (%): C, 59.10; H, 6.45; N, 34.46. Found (%): C,
59.26; H, 6.37; N, 34.63.
(4-Ethyl-6-methylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)acetonitrile (7b).
By alkylation of 30.16 g (0.2 mol) of 1-ethyl-3-methyl-
1,4-dihydropyrazolo[4,3-c]pyrazole (1b), 16.15 g (42.5%)
of compound (7b) was obtained. Light yellow crystals, mp
86-87 °C (hexane). 1H NMR (500 MHz, CDCl3, ppm) δ
1.40 (t, J = 7.3 Hz, 3H, CH3). 2.46 (s, 3H, CCH3), 4.10 (q, J
= 7.3 Hz, 2H, NCH2), 5.20 (s, 2H, CH2CN), 7.36 (s, 1H,
CH). 13C NMR (125 MHz, CDCl3, ppm) δ 12.06, 14.21,
41.05, 45.87, 107.37, 113.68, 133.21, 134.72, 149.64. MS
(APCI) m/z = 190.2 [M+H]+.. Anal. calcd. for C9H11N5 (%):
C, 57.13; H, 5.86; N, 37.01. Found (%): C, 57.05; H, 5.88;
N, 37.19.
(4-Isopropyl-6-methylpyrazolo[4,3-c]pyrazol-2(4H)-
yl)acetonitrile (7c).
By alkylation of 32.85 g (0.2mol) of 1-isopropyl-3-
methyl-1,4-dihydropyrazolo[4,3-c]pyrazole (1c), 16.91 g
(41.6%) of compound (6c) was obtained. Yellow oil. 1H
NMR (500 MHz, CDCl3, ppm) δ 1.29 (d, J = 6.6 Hz, 6H,
CH(CH3)2), 2.43 (s, 3H, CCH3), 4.31 (septet, J = 6.6 Hz,
1H, NCH(CH3)2), 5.19 (s, 2H, CH2CN), 7.34 (s, 1H, CH).
MS (APCI) m/z = 204.1 [M+H]+. Anal. calcd. for C10H13N5
(%): C, 59.10; H, 6.45; N, 34.46. Found (%): C, 58.87; H,
6.53; N, 34.69.
N-[2-(4,6-Dimethylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)ethyl]benzamide (8).
0.52 g (0.004 mol) Of ethyldiisopropylamine was added
to a suspension of 0.25 g (0.001 mol) of compound 4a in 10
ml of dry acetonitrile, the mixture was stirred at 50 °C until
the precipitate was completely dissolved, cooled to 0 °C,
0.14 g (0.001 mol) of benzoyl chloride was added and
stirred for 2 h at 20-25 °C. The solvent was evaporated in
vacuo, 40 ml of water was added to the residue and
extracted with ethyl acetate (2×50 ml). The organic layer
was washed with water and salt solution, dried with sodium
sulfate, the solvent was evaporated, and compound 8 was
purified by crystallization from a mixture of ethyl acetate-
hexane (1:3). Yield 0.23g (81.3%). Colorless crystals, mp
132-133 °C. 1H NMR (500 MHz, DMSO-d6, ppm) δ 2.31
(s, 3H, CCH3), 3.61-3.75 (m, 2H, NHCH2), 3.75 (s, 3H,
NCH3), 4.35 (t, J = 6.3 Hz, 2H, NCH2), 7.38-7.55 (m, 4H,
Ar, CH), 7.76 (d, J = 7.6 Hz, 2H, Ar), 8.56 (br.s, 1H, NH).
13C NMR (125 MHz, DMSO-d6, ppm) δ 11.54, 36.84,
40.25, 49.12, 117.38, 125.30, 127.05, 128.25, 131.21,
134.18, 136.71, 139.73, 166.45. MS (APCI) m/z = 284.2
[M+H]+. Anal. calcd. for C15H17N5O (%): C, 63.59; H, 6.05;
N, 24.72. Found (%): C, 63.28; H, 6.19; N, 24.97.
N-[2-(4,6-Dimethylpyrazolo[4,3-c]pyrazol-1(4H)-
yl)ethyl]-N'-phenylurea (9).
0.39 g (0.003 mol) Of ethyldiisopropylamine was added
to a suspension of 0.25 g (0.001 mol) of compound 4a in 10
ml of dry acetonitrile; the mixture was stirred at 50 °C until
the precipitate completely dissolved, cooled to 0 °C, 0.12 g
(0.001 mol) of phenyl isocyanate was added and stirred for
2 h at 20-25 °C. The solvent was evaporated in vacuo, 40
ml of water was added to the residue and extracted with
methylene chloride (2×50 ml). The organic layer was
washed with water and dried with sodium sulfate, the
solvent was evaporated, and compound 9 was purified by
crystallization from a mixture of ethyl acetate-hexane (1:2).
Yield 0.24g (80.5%). Colorless crystals, mp 172-174 °C. 1H
NMR (500 MHz, DMSO-d6, ppm) δ 2.34 (s, 3H, CCH3),
3.42-3.51 (m, 2H, NHCH2), 3.77 (s, 3H, NCH3), 4.25 (t, J =
6.2 Hz, 2H, NCH2), 6.13 (t, J = 5.4 Hz, 1H, NH), 6.89 (t, J
= 7.8 Hz, 1H, Ar), 7.17-7.26 (m, 2H, Ar), 7.36 (d, J = 8.1
Hz, 2H, Ar), 7.43 (s, 1H, CH), 8.49 (s, 1H, NH). 13C NMR
(125 MHz, DMSO-d6, ppm) δ 11.51, 36.84, 40.00, 49.96,
117.35, 117.66, 121.11, 125.47, 128.61, 136.85, 139.68,
140.28, 155.13. MS (APCI) m/z = 299.1 [M+H]+. Anal.
calcd. for C15H18N6O (%): C, 60.39; H, 6.08; N, 28.17.
Found (%): C, 60.12; H, 6.19; N, 28.44.
Study of anticancer activity
The methodology of in vitro anticancer screening and
the rules for data interpretation are described in detail on the
NCI Development Therapeutics Program website [36].
References
1. Woodhead, A.J.; Erlanson, D.A.; de Esch, I.J.P.; Holvey, R.S.;
Jahnke, W.; Pathuri, P. Fragment-to-Lead Medicinal Chemistry
Publications in 2022. J. Med. Chem. 2024, 67, 2287-2304.
2. Walsh, L.; Erlanson, D.A.; de Esch, I.J.P.; Jahnke, W.; Woodhead,
A.; Wren, E. Fragment-to-Lead Medicinal Chemistry Publications in
2021. J. Med. Chem. 2023, 66, 1137-1156.
3. de Esch, I.J.P.; Erlanson, D.A.; Jahnke, W.; Johnson, C.N.; Walsh,
L. Fragment-to-Lead Medicinal Chemistry Publications in 2020. J.
Med. Chem. 2022, 65, 84-99.
4. Kirsch, P.; Jakob, V.; Oberhausen, K.; Stein, S.C.; Cucarro, I.;
Schulz, T.F.; Empting, M. Fragment-Based Discovery of a Qualified
Hit Targeting the Latency-Associated Nuclear Antigen of the
Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human
Herpesvirus 8. J. Med. Chem. 2019, 62, 3924-3939.
5. Deeks, E.D.; Venetoclax: First Global Approval. Drugs 2016, 76,
979-987.
6. Murray, J.B.; Davidson, J.; Chen, I.; Davis, B.; Dokurno, P.;
Graham, C.J.; Harris, R.; Jordan, A.; Matassova, N.; Pedder, C.;
Ray, S.; Roughley, S.D.; Smith, J.; Walmsley, C.; Wang, Y.;
Whitehead, N.; Williamson, D.S.; Casara, P.; Le Diguarher, T.;
Hickman, J.; Stark, J.; Kotschy, A.; Geneste, O.; Hubbard, R.E.
Establishing Drug Discovery and Identification of Hit Series for the
Anti-apoptotic Proteins, Bcl-2 and Mcl-1. ACS Omega 2019, 4,
8892-8906.
7. Schoepfer, J.; Jahnke, W.; Berellini, G.; Buonamici, S.; Cotesta, S.;
Cowan-Jacob, S.W.; Dodd, S.; Drueckes, P.; Fabbro, D.; Gabriel,
T.; Groell, J.-M.; Grotzfeld, R.M.; Hassan, A.Q.; Henry, C.; Iyer,
V.; Jones, D.; Lombardo, F.; Loo, A.; Manley, P.W.; Pellé, X.;
Rummel, G.; Salem, B.; Warmuth, M.; Wylie, A.A.; Zoller, T.;
R.N. Vydzhak, S.Ya. Panchishin
19
Marzinzik, A.L.; Furet, P. Discovery of Asciminib (ABL001), an
Allosteric Inhibitor of the Tyrosine Kinase Activity of BCR-ABL1.
J. Med. Chem. 2018, 61, 8120-8135.
8. Lanman, B.A.; Allen, J.R.; Allen, J.G.; Amegadzie, A.K.; Ashton,
K.S.; Booker, S.K.; Chen, J.J.; Chen, N.; Frohn, M.J.; Goodman, G.;
Kopecky, D.J.; Liu, L.; Lopez, P.; Low, J.D.; Ma, V.; Minatti, A.E.;
Nguyen, T.T.; Nishimura, N.; Pickrell, A.J.; Reed, A.B.; Shin, Y.;
Siegmund, A.C.; Tamayo, N.A.; Tegley, C.M.; Walton, M.C.;
Wang, H.-L.; Wurz, R.P.; Xue, M.; Yang, K.C.; Achanta, P.;
Bartberger, M.D.; Canon, J.; Hollis, L.S.; McCarter, J.D.; Mohr, C.;
Rex, K.; Saiki, A.Y.; San Miguel, T.; Volak, L.P.; Wang, K.H.;
Whittington, D.A.; Zech, S.G.; Lipford, J.R.; Cee, V.J. Discovery of
a Covalent Inhibitor of KRASG12C (AMG 510) for the Treatment
of Solid Tumors. J. Med. Chem. 2020, 63, 52-65.
9. Chapman, P.B.; Hauschild, A.; Robert, C.; Haanen, J.B.; Ascierto,
P.; Larkin, J.; Dummer, R.; Garbe, C.; Testori, A.; Maio, M.; Hogg,
D.; Lorigan, P.; Lebbe, C.; Jouary, T.; Schadendorf, D.; Ribas, A.;
O'Day, S.J.; Sosman, J.A.; Kirkwood, J.M.; Eggermont, A.M.;
Dreno, B.; Nolop, K.; Li, J.; Nelson, B.; Hou, J.; Lee, R.J.; Flaherty,
K.T.; McArthur, G.A. Improved survival with vemurafenib in
melanoma with BRAF V600E mutation. N. Engl. J. Med. 2011, 364,
2507-2516.
10. Turner, N.C.; Oliveira, M.; Howell, S.J.; Dalenc, F.; Cortes, J.;
Moreno, H.L.G.; Hu, X.; Jhaveri, K.; Krivorotko, P.; Loibl, S.;
Murillo, S.M.; Okera, M.; Park, Y.H.; Sohn, J.; Toi, M.; Tokunaga,
E.; Yousef, S. et al. Capivasertib in Hormone Receptor-Positive
Advanced Breast Cancer. N. Engl. J. Med. 2023, 388, 2058-2070.
11. Benner, B.; Good, L.; Quiroga, D.; Schultz, T.E.; Kassem, M.;
Carson, W.E.; Cherian, M.A.; Sardesai, S.; Wesolowski, R.
Pexidartinib, a Novel Small Molecule CSF-1R Inhibitor in Use for
Tenosynovial Giant Cell Tumor: A Systematic Review of Pre-
Clinical and Clinical Development. Drug. Des. Ther. 2020, 14,
1693-1704.
12. Kwiatkowski, J.; Liu, B.; Pang, S.; Ahmad, N.H.B.; Wang, G.;
Poulsen, A.; Yang, H.; Poh, Y.R.; Tee, D.H.Y.; Ong, E.; Retna, P.;
Dinie, N.; Kwek, P.; Wee, J.L.K.; Manoharan, V.; Low, C.B.; Seah,
P.G.; Pendharkar, V.; Sangthongpitag, K.; Joy, J.; Baburajendran,
N.; Jansson, A.E.; Nacro, K.; Hill, J.; Keller, T.H.; Hung, A.W.
Stepwise Evolution of Fragment Hits against MAPK Interacting
Kinases 1 and 2. J. Med. Chem. 2020, 63, 621-637.
13. Smith, C.R.; Aranda, R.; Bobinski, T.P.; Briere, D.M.; Burns, A.C.;
Christensen, J.G.; Clarine, J.; Engstrom, L.D.; Gunn, R.J.; Ivetac,
A.; Jean-Baptiste, R.; Ketcham, J.M.; Kobayashi, M.; Kuehler, J.;
Kulyk, S.; Lawson, J.D.; Moya, K.; Olson, P.; Rahbaek, L.; Thomas,
N.C.; Wang, X.; Waters, L.M.; Marx, M.A. Fragment-Based
Discovery of MRTX1719, a Synthetic Lethal Inhibitor of the
PRMT5•MTA Complex for the Treatment of MTAP-Deleted
Cancers. J. Med. Chem. 2022, 65, 1749-1766.
14. Vydzhak, R.N.; Panchishin, S.Y.; Kislyi, V.V.; Brovarets, V.S. A
facile synthesis of 1,3-dimethyl-1,4-dihydropyrazolo[4,3-c]pyrazole.
Russ. J. Gen. Chem. 2016, 86, 1967-1968.
15. Vydzhak, R.N.; Panchishin, S.Y.; Brovarets, V.S. Alkylation of 1-
Alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with
Halocarboxylic Acids Esters. Russ. J. Gen. Chem. 2018, 88, 221-
233.
16. Li, Y.; Shu, Y.; Wang, B.; Zhang, S.; Zhai, L. Synthesis, structure
and properties of neutral energetic materials based on N-
functionalization of 3,6-dinitropyrazolo[4,3-c]pyrazole. RSC
Advances 2016, 6, 84760-84768.
17. Kadam, S.S.; Maier, L.; Kostakis, I.; Pouli, N.; Toušek, J.; Nečas,
M.; Marakos, P.; Marek, R. Synthesis and Tautomerism of
Substituted Pyrazolo[4,3-c]pyrazoles. European Journal of Organic
Chemistry 2013, 2013, 6811-6822.
18. Purohit, M.K.; Chakka, S.K.; Scovell, I.; Neschadim, A.; Bello,
A.M.; Salum, N.; Katsman, Y.; Bareau, M.C.; Branch, D.R.; Kotra,
L.P. Structure-activity relationships of pyrazole derivatives as
potential therapeutics for immune thrombocytopenias. Bioorg. Med.
Chem. 2014, 22, 2739-2752.
19. Sturbaut, M.; Bailly, F.; Coevoet, M.; Sileo, P.; Pugniere, M.;
Liberelle, M.; Magnez, R.; Thuru, X.; Chartier-Harlin, M.-C.;
Melnyk, P.; Gelin, M.; Allemand, F.; Guichou, J.-F.; Cotelle, P.
Discovery of a cryptic site at the interface 2 of TEAD - Towards a
new family of YAP/TAZ-TEAD inhibitors. Eur. J. Med. Chem.
2021, 226, 113835.
20. Takahashi, H.; Riether, D.; Bartolozzi, A.; Bosanac, T.; Berger, V.;
Binetti, R.; Broadwater, J.; Chen, Z.; Crux, R.; De Lombaert, S.;
Dave, R.; Dines, J.A.; Fadra-Khan, T.; Flegg, A.; Garrigou, M.;
Hao, M.-H.; Huber, J.; Hutzler, J.M.; Kerr, S.; Kotey, A.; Liu, W.;
Lo, H.Y.; Loke, P.L.; Mahaney, P.E.; Morwick, T.M.; Napier, S.;
Olague, A.; Pack, E.; Padyana, A.K.; Thomson, D.S.; Tye, H.; Wu,
L.; Zindell, R.M.; Abeywardane, A.; Simpson, T. Synthesis, SAR,
and Series Evolution of Novel Oxadiazole-Containing 5-
Lipoxygenase Activating Protein Inhibitors: Discovery of 2-[4-(3-
{(R)-1-[4-(2-Amino-pyrimidin-5-yl)-phenyl]-1-cyclopropyl-ethyl}-
[1,2,4]oxadiazol-5-yl)-pyrazol-1-yl]-N,N-dimethyl-acetamide (BI
665915). J. Med. Chem. 2015, 58, 1669-1690.
21. Hu, Z.; Zhang, Q.; Li, Z.; Yang, H.; Chen, X.; Zhang, Q.; Yang, T.;
He, X.; Feng, Q.; He, J.; Yu, L. Design, synthesis and antitumor
activity of a novel FGFR2-selective degrader to overcome resistance
of the FGFR2V564F gatekeeper mutation based on a pan-FGFR
inhibitor. Eur. J. Med. Chem. 2024, 275, 116612.
22. May, J.A.; Sharif, N.A.; McLaughlin, M.A.; Chen, H.H.; Severns,
B.S.; Kelly, C.R.; Holt, W.F.; Young, R.; Glennon, R.A.; Hellberg,
M.R.; Dean, T.R. Ocular Hypotensive Response in Nonhuman
Primates of (8R)-1-[(2S)-2-Aminopropyl]-8,9-dihydro-7H-
pyrano[2,3-g]indazol-8-ol a Selective 5-HT2 Receptor Agonist. J.
Med. Chem. 2015, 58, 8818-8833.
23. May, J.A.; Dantanarayana, A.P.; Zinke, P.W.; McLaughlin, M.A.;
Sharif, N.A. 1-((S)-2-Aminopropyl)-1H-indazol-6-ol: A Potent
Peripherally Acting 5-HT2 Receptor Agonist with Ocular
Hypotensive Activity. J. Med. Chem. 2006, 49, 318-328.
24. May, J.A.; Dantanarayana, A.P.; Zinke, P.W.; McLaughlin, M.A.;
Sharif, N.A. 1-((S)-2-Aminopropyl)-1H-indazol-6-ol: A Potent
Peripherally Acting 5-HT2 Receptor Agonist with Ocular
Hypotensive Activity. J. Med. Chem. 2006, 49, 318-328.
25. Guo, S.; Jia, T.; Xu, X.; Yang, F.; Xiao, S.; Hou, Z.; Xu, H.; Ma, S.;
Liu, X.; Luo, C.; Jiang, H.; Chen, H.; Chen, S. Design, synthesis of
novel benzimidazole derivatives as ENL inhibitors suppressing
leukemia cells viability via downregulating the expression of MYC.
Eur. J. Med. Chem. 2023, 248, 115093.
26. Huo, C.; Luo, Z.; Ning, X.; Kang, X.; Yan, Q.; Guo, Y.; Li, G.;
Wang, Z.; Li, Y.; Qian, S. 4,6-Disubstituted-1H-Indazole-4-Amine
derivatives with immune-chemotherapy effect and in vivo antitumor
activity. Eur. J. Med. Chem. 2022, 241, 114625.
27. Owens, T.D.; Brameld, K.A.; Verner, E.J.; Ton, T.; Li, X.; Zhu, J.;
Masjedizadeh, M.R.; Bradshaw, J.M.; Hill, R.J.; Tam, D.; Bisconte,
A.; Kim, E.O.; Francesco, M.; Xing, Y.; Shu, J.; Karr, D.; LaStant,
J.; Finkle, D.; Loewenstein, N.; Haberstock-Debic, H.; Taylor, M.J.;
Nunn, P.; Langrish, C.L.; Goldstein, D.M. Discovery of Reversible
Covalent Bruton’s Tyrosine Kinase Inhibitors PRN473 and
PRN1008 (Rilzabrutinib). J. Med. Chem. 2022, 65, 5300-5316.
28. Zheng, N.; Hao, Q.; Lin, K.; Pan, J.; Li, Y.; Zhou, W. Synthesis and
biological evaluation of novel 1-substituted 3-(3-phenoxyprop-1-yn-
1-yl)-1H-pyrazolo[3,4-d]pyrimidin-4-amines as potent Bruton's
tyrosine kinase (BTK) inhibitors. Bioorg. Med. Chem. Lett. 2019,
29, 225-229.
29. Krapcho, A.P.; Menta, E.; Oliva, A.; Di Domenico, R.; Fiocchi, L.;
Maresch, M.E.; Gallagher, C.E.; Hacker, M.P.; Beggiolin, G.;
Giuliani, F.C.; Pezzoni, G.; Spinelli, S. Synthesis and Antitumor
Evaluation of 2,5-Disubstituted- Indazolo[4,3-gh]isoquinolin-6(2H)-
ones (9-Aza-anthrapyrazoles). J. Med. Chem. 1998, 41, 5429-5444.
30. Varghese, S.; Rahmani, R.; Russell, S.; Deora, G.S.; Ferrins, L.;
Toynton, A.; Jones, A.; Sykes, M.; Kessler, A.; Eufrásio, A.;
Cordeiro, A.T.; Sherman, J.; Rodriguez, A.; Avery, V.M.; Piggott,
M.J.; Baell, J.B. Discovery of Potent N-Ethylurea Pyrazole
Derivatives as Dual Inhibitors of Trypanosoma brucei and
Trypanosoma cruzi. ACS Med. Chem. Lett. 2020, 11, 278-285.
31. Hirose, W.; Kato, Y.; Yamamoto, T.; Kassai, M.; Takata, M.;
Hayashi, S.; Arai, Y.; Imai, S.; Yoshida, K. Synthesis, structure-
activity relationships and biological evaluation of 4,5,6,7-
tetrahydropyrazolopyrazines as metabotropic glutamate receptor 5
negative allosteric modulators. Bioorg. Med. Chem. Lett. 2016, 26,
3866-3869.
32. Boyd, M.R.; Paull, K.D. Some practical considerations and
applications of the national cancer institute in vitro anticancer drug
discovery screen. Drug Develop. Res. 1995, 34, 91-109.
33. Shoemaker, R.H. The NCI60 human tumour cell line anticancer
drug screen. Nature Rev. Cancer 2006, 6, 813-823.
34. Alley, M.C.; Scudiero, D.A.; Monks, A.; Hursey, M.L.; Czerwinski,
M.J.; Fine, D.L.; Abbott, B.J.; Mayo, J.G.; Shoemaker, R.H.; Boyd,
M.R. Feasibility of drug screening with panels of human tumor cell
lines using a microculture tetrazolium assay. Cancer Res. 1988, 48,
589-601.
35. Grever, M.R.; Schepartz, S.A.; Chabner, B.A. The National Cancer
Institute: cancer drug discovery and development program. Semin.
Oncol. 1992, 19, 622-638.
36. NCI-60 Human Tumor Cell Lines Screen. DTP Developmental
Therapeutics Program, NIH website [Internet]. Available from:
ISSN 1814-9758. Ukr. Bioorg. Acta, 2024, Vol. 19, N 2
20
https://dtp.cancer.gov/discovery_development/nci-60/default.htm
(accessed on March 20, 2020).
Синтез 2-аміноетильних похідних піразоло[4,3-c]піразолів
Р.М. Виджак*, С.Я. Панчишин
Інститут біоорганічної хімії та нафтохімії ім. В.П. Кухаря НАН України, Київ, Україна
Резюме: Представлено препаративний метод одержання 2-аміноетильних похідних піразоло[4,3-c]піразолів. Здійснено алкілювання 1-алкіл-3-
метил-1,4-дигідропіразоло[4,3-c]піразолів 2-(2-брометил)-1Н-ізоіндол-1,3(2Н)-діоном та хлорацетонітрилом. У всіх випадках одержано суміші
ізомерних продуктів 1- та 2-алкілування з співвідношеннями ізомерів 1:0.8. Суміші ізомерів розділено за допомогою хроматографії і цільові
сполуки не містили домішки іншого ізомеру. Всі фталімідні похідні піразоло[4,3-c]піразолів перетворено у відповідні 2-гетерилетиламіни, які
виділено у вигляді дигідрохлоридів. Досліджено відновлення нітрильної групи (4,6-диметилпіразоло[4,3-c]піразол-1(4Н)-іл)ацетонітрилу та
(4,6-диметилпіразоло[4,3-c]піразол-2(4Н)-іл)ацетонітрилу при дії різних реагентів: воднем при 20 атм на нікелі Ренея, алюмогідридом літію в
діетиловому ефірі та комплексом боран-диметилсульфід в тетрагідрофурані. Найкращі результати одержано при відновленні ціанометильних
похідних комплексом боран-диметилсульфід. При цьому виходи цільових амінів складають більше 90 процентів. Це препаративний, зручний та
добре відтворюваний метод і його з успіхом застосовано для синтезу цілого ряду 2-аміноетильних похідних. Будову синтезованих сполук
підтверджено методами 1Н та 13С ЯМР спектроскопії. Для чотирьох синтезованих сполук було проведено скрінінгові дослідження
протипухлинної активності in vitro на 60 лініях ракових клітин.
Ключові слова: піразоло[4,3-c]піразоли; алкілювання похідних піразолу; гетерилацетонітрили; відновлення ціанометильної групи.
https://dtp.cancer.gov/discovery_development/nci-60/default.htm
|
| id | oai:ojs2.bioorganica.com.ua:article-87 |
| institution | Ukrainica Bioorganica Acta |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-20T01:01:29Z |
| publishDate | 2024 |
| publisher | V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | bioorganicacomua/13/02ea6d3297b4362a00f50635a3e37013.pdf |
| spelling | oai:ojs2.bioorganica.com.ua:article-872026-07-19T14:56:55Z Synthesis of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів Vydzhak, Roman N. Panchishin, Svitlana Yа. pyrazolo[4,3-c]pyrazoles alkylation of pyrazole derivatives heteryl acetonitriles reduction of the cyanomethyl group піразоло[4,3-c]піразоли алкілювання похідних піразолу гетерилацетонітрили відновлення ціанометильної групи Preparative method for the preparation of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles is presented. Alkylation of 1-alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with 2-(2-bromomethyl)-1H-isoindole-1,3(2H)-dione and chloroacetonitrile was carried out. In all cases, mixtures of isomeric products of 1- and 2-alkylation with isomer ratios of 1 : 0.8 were obtained. The mixtures of isomers were separated by chromatography and the target compounds did not contain impurities of another isomer. All phthalimide derivatives of pyrazolo[4,3-c]pyrazoles were converted into the corresponding 2-heterylethylamines, which were isolated as dihydrochlorides. The reduction of the nitrile group of (4,6-dimethylpyrazolo[4,3-c]pyrazol-1(4H)-yl)acetonitrile and (4,6-dimethylpyrazolo[4,3-c]pyrazol-2(4H)-yl)acetonitrile under the action of various reagents was investigated: hydrogen at 20 atm on Raney nickel, lithium aluminum hydride in diethyl ether, and borane-dimethyl sulfide complex in tetrahydrofuran. The best results were obtained when reducing cyanomethyl derivatives with borane-dimethyl sulfide complex. In this case, the yields of the target amines are more than 90 percent. This is a preparative, convenient, and well-reproducible method and has been successfully applied to the synthesis of a number of 2-aminoethyl derivatives. The structure of the synthesized compounds was confirmed by 1H and 13C NMR spectroscopy. In vitro screening studies of antitumor activity were conducted on 60 cancer cell lines for the four synthesized compounds Представлено препаративний спосіб одержання 2-аміноетилпохідних піразоло[4,3-с]піразолів. Проведено алкілування 1-алкіл-3-метил-1,4-дигідропіразоло[4,3-с]піразолів 2-(2-бромметил)-1Н-ізоіндол-1,3(2Н)-діоном та хлорацетонітрилом. У всіх випадках отримано суміші ізомерних продуктів 1- і 2-алкілування із співвідношенням ізомерів 1 : 0,8. Суміші ізомерів розділяли хроматографією, і цільові сполуки не містили домішок іншого ізомеру. Усі фталімідні похідні піразоло[4,3-с]піразолів переведено у відповідні 2-гетерилетиламіни, які виділено у вигляді дигідрохлоридів. Відновлення нітрильної групи (4,6-диметилпіразоло[4,3-c]піразол-1(4H)-іл)ацетонітрилу та (4,6-диметилпіразоло[4,3-c]піразол-2(4H)) -іл)ацетонітрилу під дією різних реагентів: водню при 20 атм на нікелі Ренея, літію. гідрид алюмінію в діетиловому ефірі та комплекс боран-диметилсульфід у тетрагідрофурані. Найкращі результати отримано при відновленні ціанометильних похідних боран-диметилсульфідним комплексом. При цьому виходи цільових амінів становлять більше 90 відсотків. Це препаративний, зручний і добре відтворюваний метод, який успішно застосовувався для синтезу низки 2-аміноетилових похідних. Структуру синтезованих сполук підтверджено методами ЯМР 1Н та 13С. Скринінгові дослідження протипухлинної активності in vitro були проведені на 60 лініях ракових клітин для чотирьох синтезованих сполук V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine 2024-12-30 Article Article application/pdf https://bioorganica.com.ua/index.php/journal/article/view/87 10.15407/bioorganica2024.02.010 Ukrainica Bioorganica Acta; Vol. 19 No. 2 (2024): Ukrainica Bioorganica Acta; 10-20 Ukrainica Bioorganica Acta; Том 19 № 2 (2024): Ukrainica Bioorganica Acta; 10-20 1814-9766 1814-9758 10.15407/bioorganica2024.02 en https://bioorganica.com.ua/index.php/journal/article/view/87/86 Copyright (c) 2024 Roman N. Vydzhak, Svitlana Yа. Panchishin https://creativecommons.org/licenses/by/4.0 |
| spellingShingle | піразоло[4,3-c]піразоли алкілювання похідних піразолу гетерилацетонітрили відновлення ціанометильної групи Vydzhak, Roman N. Panchishin, Svitlana Yа. Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| title | Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| title_alt | Synthesis of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles |
| title_full | Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| title_fullStr | Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| title_full_unstemmed | Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| title_short | Синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| title_sort | синтез 2-аміноетилпохідних піразоло[4,3-c]піразолів |
| topic | піразоло[4,3-c]піразоли алкілювання похідних піразолу гетерилацетонітрили відновлення ціанометильної групи |
| topic_facet | pyrazolo[4,3-c]pyrazoles alkylation of pyrazole derivatives heteryl acetonitriles reduction of the cyanomethyl group піразоло[4,3-c]піразоли алкілювання похідних піразолу гетерилацетонітрили відновлення ціанометильної групи |
| url | https://bioorganica.com.ua/index.php/journal/article/view/87 |
| work_keys_str_mv | AT vydzhakromann synthesisof2aminoethylderivativesofpyrazolo43cpyrazoles AT panchishinsvitlanaya synthesisof2aminoethylderivativesofpyrazolo43cpyrazoles AT vydzhakromann sintez2amínoetilpohídnihpírazolo43cpírazolív AT panchishinsvitlanaya sintez2amínoetilpohídnihpírazolo43cpírazolív |