We report synthesis of a novel 1,2,3,4-tetrahydroquinazoline derivative, named 2-(6,8-dibromo-3-(4-hydroxycyclohexyl)-1,2,3,4-tetrahydroquinazolin-2-yl)phenol (
), which was obtained from the ...hydrochloride of 4-((2-amino-3,5-dibromobenzyl)amino)cyclohexan-1-ol (ambroxol hydrochloride) and salicylaldehyde in EtOH. The resulting compound was produced in the form of colorless crystals of the composition
∙0.5EtOH. The formation of the single product was confirmed by the IR and
H spectroscopy, single-crystal and powder X-ray diffraction, and elemental analysis. The molecule of
contains a chiral tertiary carbon of the 1,2,3,4-tetrahydropyrimidine fragment and the crystal structure of
∙0.5EtOH is a racemate. Optical properties of
∙0.5EtOH were revealed by UV-vis spectroscopy in MeOH and it was established that the compound absorbs exclusively in the UV region up to about 350 nm.
∙0.5EtOH in MeOH exhibits dual emission and the emission spectra contains bands at about 340 and 446 nm upon excitation at 300 and 360 nm, respectively. The DFT calculations were performed to verify the structure as well as electronic and optical properties of
. ADMET properties of the
-isomer of
were evaluated using the SwissADME, BOILED-Egg, and ProTox-II tools. As evidenced from the blue dot position in the BOILED-Egg plot, both human blood-brain barrier penetration and gastrointestinal absorption properties are positive with the positive PGP effect on the molecule. Molecular docking was applied to examine the influence of the structures of both
-isomer and
-isomer of
on a series of the SARS-CoV-2 proteins. According to the docking analysis results, both isomers of
were found to be active against all the applied SARS-CoV-2 proteins with the best binding affinities with Papain-like protease (PLpro) and nonstructural protein 3 (Nsp3_range 207-379-AMP). Ligand efficiency scores for both isomers of
inside the binding sites of the applied proteins were also revealed and compared with the initial ligands. Molecular dynamics simulations were also applied to evaluate the stability of complexes of both isomers with Papain-like protease (PLpro) and nonstructural protein 3 (Nsp3_range 207-379-AMP). The complex of the
-isomer with Papain-like protease (PLpro) was found to be highly unstable, while the other complexes are stable.
A number of novel heteroligand Zn(II) complexes (
-
) of the general type (L
)Zn(NN) containing O,N,O'-, O,N,S-donor redox-active Schiff bases and neutral N,N'-chelating ligands (NN) were ...synthesized. The target Schiff bases L
H
were obtained as a result of the condensation of 3,5-di-
-butyl-2-hydroxybenzaldehyde with substituted
-aminophenols or
-aminothiophenol. These ligands with combination with 2,2'-bipyridine, 1,10-phenanthroline, and neocuproine are able to form stable complexes upon coordination with zinc(II) ion. The molecular structures of complexes
∙H
O,
, and
in crystal state were determined by means of single-crystal X-ray analysis. In the prepared complexes, the redox-active Schiff bases are in the form of doubly deprotonated dianions and act as chelating tridentate ligands. Complexes
and
possess a strongly distorted pentacoordinate geometry while
∙H
O is hexacoordinate and contains water molecule coordinated to the central zinc atom. The electrochemical properties of zinc(II) complexes were studied by the cyclic voltammetry. For the studied complexes, O,N,O'- or O,N,S-donor Schiff base ligands are predominantly involved in electrochemical transformations in the anodic region, while the N,N'-coordinated neutral nitrogen donor ligands demonstrate the electrochemical activity in the cathode potential range. A feature of complexes
and
with sterically hindered
-butyl groups is the possibility of the formation of relatively stable monocation and monoanion forms under electrochemical conditions. The values of the energy gap between the boundary redox orbitals were determined by electrochemical and spectral methods. The parameters obtained in the first case vary from 1.97 to 2.42 eV, while the optical bang gap reaches 2.87 eV.
Reported herein is the first example of a gold-catalyzed cyclization of bis(arylmethyl)ethynylphosphine oxides. This represents an original approach to bridgehead methanophosphocines 1, ...eight-membered heterocycles. Gold catalyst in combination with triflic acid activates alkyne and induces a double hydroarylation. Mechanistic studies suggest that the reaction proceeds stepwise, forming first the 1H-isophosphinoline 2-oxide 5. Reduction and protection of the corresponding phosphine oxides 1 described herein also highlight the effectiveness of our approach to this new class of electron-rich ligands.
We report two complexes Cu(L
)
(
) and Cu(L
)
(
) (HL
=
-cyclohexyl-3-methoxysalicylideneimine, HL
=
-cyclohexyl-3-ethoxysalicylideneimine). The ligands in both complexes are
-1,5-N,O-coordinated, ...yielding a square planar CuN
O
coordination core. The molecule of
is planar with two cyclohexyl groups oriented to the opposite sites of the planar part of a molecule, while the molecule of
is significantly bent with two cyclohexyl groups oriented to the same convex site of a molecule. It was established that both complexes in MeOH absorb in the UV region due to intraligand transitions and LMCT. Furthermore, the UV-vis spectra of both complexes revealed two low intense shoulders in the visible region at about 460 and 520 nm, which were attributed to d-d transitions. Both complexes were predicted to belong to a fourth class of toxicity with the negative BBB property and positive gastrointestinal absorption property. According to the molecular docking analysis results, both complexes are active against all the applied SARS-CoV-2 proteins with the best binding affinity with Nsp 14 (N7-MTase), PLpro and Mpro. The obtained docking scores of complexes are either comparable to or even higher than those of the initial ligands. Complex
was found to be more efficient upon interaction with the applied proteins in comparison to complex
. Ligand efficiency scores for the initial ligands,
and
were also revealed.
A new 1D-coordination polymer Co(Piv)
(NH
(CH
)
NH
)
(
, Piv is Me
CCO
anion) was obtained, the mononuclear fragments {Co(O
CR)
} within which are linked by μ-bridged molecules of ...hexamethylenediamine (NH
(CH
)
NH
). For this compound, two different monoclinic
2/
(α-
) and
2/
(β-
) phases were found at room temperature by single-crystal X-ray diffraction analysis, with a similar structure of chains and their packages in unit cells. The low-temperature phase (γ-
) of crystal
at 150 K corresponds to the triclinic space group
-1. As the temperature decreases, the structural phase transition (SPT) in the α-
and β-
crystals is accompanied by an increase in the crystal packing density caused by the rearrangements of both H-bonds and the nearest ligand environment of the cobalt atom ("octahedral CoN
O
around the metal center at room temperature" → "pseudo-tetrahedral CoN
O
at 150 K"). The SPT was confirmed by DSC in the temperature range 210-150 K; when heated above 220 K, anomalies in the behavior of the heat flow are observed, which may be associated with the reversibility of SPT; endo effects are observed up to 300 K. The SPT starts below 200 K. At 100 K, a mixture of phases was found in sample
: 27% α-
phase, 61% γ-
phase. In addition, at 100 K, 12% of the new δ-
phase was detected, which was identified from the diffraction pattern at 260 K upon subsequent heating: the
,
,
-parameters and unit cell volume are close to the structure parameters of γ-
, and the values of the α,β,γ-angles are significantly different. Further heating leads to a phase transition from δ-
to α-
, which both coexist at room temperature. According to the DC magnetometry data, during cooling and heating, the χ
(
) curves for
form a hysteresis loop with ~110 K, in which the difference in the χ
values reaches 9%. Ab initio calculations of the electronic structure of cobalt(II) in α-
and γ-
have been performed. Based on the EPR data at 10 K and the ab initio calculations, the behavior of the χ
(
) curve for
was simulated in the temperature range of 2-150 K. It was found that
exhibits slow magnetic relaxation in a field of 1000 Oe.
A series of novel 4-(het)arylimidazoldin-2-ones were obtained by the acid-catalyzed reaction of (2,2-diethoxyethyl)ureas with aromatic and heterocyclic C-nucleophiles. The proposed approach to ...substituted imidazolidinones benefits from excellent regioselectivity, readily available starting materials and a simple procedure. The regioselectivity of the reaction was rationalized by quantum chemistry calculations and control experiments. The anti-cancer activity of the obtained compounds was tested in vitro.
Herein, we report a highly regioselective one-pot synthesis of pyrazolo3,4-bpyridines via the reaction of 3-arylidene-1-pyrrolines with aminopyrazoles. The reaction proceeds through the sequential ...nucleophilic addition/electrophilic substitution/C–N bond cleavage and provides easy access to pyrazolo3,4-bpyridine derivatives featuring a primary amino group. Moreover, the reaction can be terminated at the electrophilic substitution stage, thus providing convenient entry to the hardly accessible pyrazolopyrrolopyridine scaffold.
Varying the temperature of the reaction of {Cd(pfb)(H2O)4}+n·n(pfb)−, Ln2(pfb)6(H2O)8·H2O (Hpfb = pentafluorobenzoic acid), and 1,10-phenanthroline (phen) in MeCN followed by crystallization resulted ...in the isolation of two type of products: 1D-polymers LnCd(pfb)5(phen)n·1.5nMeCN (Ln = Eu (I), Gd (II), Tb (III), Dy (IV)) which were isolated at 25 °C, and molecular compounds Tb2Cd2(pfb)10(phen)2 (V) formed at 75 °C. The transition from a molecular to a polymer structure becomes possible because of intra- and intermolecular interactions between the aromatic cycles of phen and pfb from neighboring tetranuclear Ln2Cd2 fragments. Replacement of cadmium with zinc in the reaction resulted in molecular compounds Ln2Zn2 Ln2Zn2(pfb)10(phen)2·4MeCN (Ln = Eu (VI), Tb (VIII), Dy (IX)) and Gd2Zn2(pfb)10(H2O)2(phen)2·4MeCN (VII). A new molecular EuCd complex Eu2Cd2(pfb)10(phen)4·4MeCN (X) was isolated from a mixture of cadmium, zinc, and europium pentafluorobenzoates (Cd:Zn:Ln = 1:1:2). Complexes II-IV, VII and IX exhibit magnetic relaxation at liquid helium temperatures in nonzero magnetic fields. Luminescent studies revealed a bright luminescence of complexes with europium(III) and terbium(III) ions.
Herein we present the regio- and diastereoselective synthesis of novel pyrrolidine-fused spiro-dihydrophosphacoumarins via intermolecular 3 + 2 cycloaddition reaction. The presented approach is ...complementary to existing ones and provides an easy entry to the otherwise inaccessible derivatives. Additionally, the unprecedented pathway of the reaction of 4-hydroxycoumarin with azomethine ylides is described. The anti-cancer activity of the obtained compounds was tested in vitro, the most potent compound being 2.6-fold more active against the HuTu 80 cell line than the reference 5-fluorouracil, with a selectivity index > 32.
A new carboxylate complex Co
2
Li
2
(Piv)
6
(L)
2
·CH
3
CN (
1
) (Piv is the anion of pivalic acid) has been synthesized and structurally characterized. According to ac magnetic measurements, ...compound
1
exhibits a field induced slow magnetic relaxation, which is approximated by a combination of Raman and direct mechanisms. These data are confirmed by
ab initio
calculations indicating easy-plane anisotropy of Co(
ii
) ions in the complex.
A new carboxylate complex Co
2
Li
2
(Piv)
6
(L)
2
·CH
3
CN (
1
) (Piv is the anion of pivalic acid) has been synthesized and structurally characterized. It exhibits a field induced slow magnetic relaxation.
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