Isolation of potassium salt of oxadiazole-2-thione and in vitro anticancer activities of its Cu(II) and Zn(II) complexes against MDA-MB-231 human breast carcinoma cells.

A potassium 4-(pyridyl)-1,3,4-oxadiazole-2-thione was isolated in a basic medium, and its complexes [Cu(en)2(pot)2] (1) and [Zn(en)2(pot)2]HBr·CH3OH (2) containing ethylenediamine (en) as secondary ligand were synthesized and fully characterized. Upon changing the reaction conditions, the Cu(II) complex (1) adopts an octahedral geometry around the metal center. The cytotoxic activity of ligand (Kpot·H2O) along with complexes 1 and 2 was tested, and their anticancer activity against MDA-MB-231 human breast cancer cells was demonstrated, with complex 1 exhibiting superior cytotoxicity against these cells as compared to Kpot·H2O and complex 2. According to the DNA nicking assay, the ligand (Kpot·H2O) was found to be more potent to scavenge hydroxyl radicals even at a lower concentration (50 µg mL-1) than that of both complexes. The wound healing assay revealed that ligand Kpot·H2O and its complexes 1 and 2 attenuated the migration of the above-mentioned cell line. The loss of cellular and nuclear integrity and induction in the activity of Caspase-3 suggest the anticancer potential of ligand Kpot·H2O and its complexes 1 and 2 against MDA-MB-231 cells.

Synthesis and absolute structure of (R)-2-(benzyl-selan-yl)-1-phenyl-ethanaminium hydrogen sulfate monohydrate: crystal structure and Hirshfeld surface analyses.

A hydrogen sulfate salt, C15H18NSe+·HSO4 -·H2O or [BnSeCH2CH(Ph)NH3 +](HSO4 -), of a chiral selenated amine (R)-2-(benzyl-selan-yl)-1-phenyl-ethan-amine (BnSeCH2CH(Ph)NH2) has been synthesized and characterized by elemental analysis,1H and 13C{1H} NMR, FT-IR analysis, and single-crystal X-ray diffraction studies. The title salt crystallizes in the monohydrate form in the non-centrosymmetric monoclinic P21 space group. The cation is somewhat W shaped with the dihedral angle between the two aromatic rings being 60.9 (4)°. The carbon atom attached to the amine nitro-gen atom is chiral and in the R configuration, and, the -C-C- bond of the -CH2-CH- fragment has a staggered conformation. In the crystal structure, two HSO4 - anions and two water mol-ecules form an R 4 4(12) tetra-meric type of assembly comprised of alternating HSO4 - anions and water mol-ecules via discrete D(2) O-H⋯O hydrogen bonds. This tetra-meric assembly aggregates along the b-axis direction as an infinite one-dimensional tape. Adjacent tapes are inter-connected via discrete D(2) N-H⋯O hydrogen bonds between the three amino hydrogen atoms of the cation sandwiched between the two tapes and the three HSO4 - anions of the nearest asymmetric units, resulting in a complex two-dimensional sheet along the ab plane. The pendant arrangement of the cations is stabilized by C-H⋯π inter-actions between adjacent cations running as chains down the [010] axis. Secondary Se⋯O [3.1474 (4) Å] inter-actions are also observed in the crystal structure. A Hirshfeld surface analysis, including d norm, shape-index and fingerprint plots of the cation, anion and solvent mol-ecule, was carried out to confirm the presence of various inter-actions in the crystal structure.

Dual sensing of methionine and aspartic acid in aqueous medium by a quinoline-based fluorescent probe.

A quinoline-based Schiff base sensor, 6-methyl-2-oxo-1,2-dihydro-quinoline-3-carboxaldehyde-4(N)-phenylsemicarbazone (6MPS), has been developed for selective sensing of methionine and aspartic acid in aqueous medium through "on-off-on" type selective detection of copper ion. Fluorescence imaging of 6MPS, 6MPSC, 6MPSCN, 6MPSC-met, 6MPSCN-met, 6MPSC-asp and 6MPSCN-asp has been successfully demonstrated, in which the sensing probes 6MPSC-met, 6MPSCN-met, 6MPSC-asp and 6MPSCN-asp displayed bright green fluorescence in both in vitro and in vivo live cells.

Synthesis, antimicrobial and chitinase inhibitory activities of 3-amidocoumarins.

A series of 3-amidocoumarins has been synthesized and tested in vitro for their anitimicrobial and chitinase inhibitory activities. Among these, compounds 5k, 5l, 8b-8d, 8f and 8g exhibited good antibacterial activity with MIC values in the range of 6.25-25 µg/mL against some of the tested strains while compounds 5l, 8b, 8c and 8f showed good activity against at least one or two fungal strains. Some of the assayed compounds 5d, 5k, 5l, 8b and 8c displayed significant chitinase inhibitory activity with IC50 values in the range of 3.74-5.6 µM. Among them, 5l proved to be potent chitinase inhibitor with IC50 value of 3.74 µM. To better understand the enzyme-inhibitor interactions molecular docking study of all the synthesized compounds was carried out on Aspergillus fumigatus chitinase 1W9U. The compound 5l showed high binding affinity with the receptor with binding energy value of -8.44 Kcal/mol. This study also provides structure activity relationship (SAR) of synthesized compounds.

Classical hydrogen bonding and stacking of chelate rings in new copper(ii) complexes.

Three new copper(ii) complexes, viz., [Cu(L)(NO3)(H2O)]H2O 1, [Cu(L)(H2O)2]NO32 and [Cu2(L)2(pyrazine)](ClO4)2·4H2O 3, were prepared using a biomimetic synthesis strategy [HL = 4-chloro-2-{(E)-[2-(pyridin-2-yl)hydrazinylidene]methyl}phenol]. Structural characterization revealed very different local geometries around copper(ii) ions, being square pyramidal for mononuclear complexes (τ5 = 0.021 for 1 and τ5 = 0.13 for 2) and square planar for homobinuclear pyrazine bridged complex 3 (τ4 = 0.06). In complex 3, stacking of chelate rings was observed. This insight was thought to provide new structural evidence for the stacking of the planar chelate rings. These π-interactions provide stability to the crystal structure of homobinuclear complex 3. Magnetic measurements of bulk materials 1, 2 and 3 revealed weak antiferromagnetic coupling in all complexes. The EPR spectra of complexes 1, 2 and 3 in polycrystalline state exhibited broad signals at g ≅ 2.15 owing to spin-spin interactions between two copper ions. The cyclic voltammograms of mononuclear complexes (1 and 2) in DMSO gave one CuII/CuI irreversible wave. On the other hand, pyrazine bridged binuclear complex 3 exhibited two waves, which correspond to CuIICuII/CuIICuI and CuIICuI/CuICuI redox processes. Differential pulse voltammetry (DPV) experiments also exhibited the same reduction behavior. These complexes displayed effective antioxidant SOD activity and exhibit the outlines of a structure-based cyclic mechanism. On the basis of experimental and theoretical DFT studies, the structure-activity relationships of these complexes have also been discussed.

1,3,5-Tri-p-tolyl-pentane-1,5-diol.

In the title compound, C26H30O2, the central benzene ring forms dihedral angles of 14.85 (15) and 28.17 (14)° with the terminal benzene rings. The dihedral angle between the terminal benzene rings is 32.14 (13)°. The crystal packing exhibits two strong inter-molecular O-H⋯O hydrogen bonds, forming directed four-membered co-operative rings. A region of disordered electron density, most probably disordered ethyl acetate solvent mol-ecules, occupying voids of ca 519 Å(3) for an electron count of 59, was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]. Their formula mass and unit-cell characteristics were not taken into account during refinement. The structure was refined as an inversion twin [absolute structure parameter = -0.3 (4)].

2-(Naphthalen-1-yl)-1-phenyl-1H-benzimid-azole benzene hemisolvate.

In the title compound, C23H16N2·0.5C6H6, the benzimidazole unit [maximum deviation = 0.0258 (6) Å] and the naphthalene ring system [maximum deviation = 0.0254 (6) Å] are both essentially planar and make a dihedral angle of 61.955 (17)°. The imidazole ring makes dihedral angle of 61.73 (4)° with the phenyl ring. An intra-molecular C-H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, seven weak C-H⋯π inter-actions involving the fused ring system, the benzene solvent mol-ecule, the imidazole phenyl rings are observed, leading to a three-dimensional architecture.

1,5-Bis(4-chloro-phen-yl)-3-(4-methyl-phen-yl)pentane-1,5-dione.

In the title mol-ecule, C24H20Cl2O2, the central methyl-benzene ring forms dihedral angles of 42.47 (10) and 34.34 (10)° with the terminal 4-chloro-phenyl fragments. The dihedral angle between the chloro-benzene rings is 34.45 (11)°. A weak intra-molecular C-H⋯O inter-action generates an S(6) ring motif. The crystal packing exhibits weak C-H⋯O hydrogen bonds and C-H⋯π inter-actions.

10-Methyl-2-oxo-4-phenyl-2,11-di-hydro-pyrano[2,3-a]carbazole-3-carbo-nitrile.

In the title mol-ecule, C23H14N2O2, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1018 (8) Å]. The pyrrole ring makes dihedral angles of 4.44 (5), 3.84 (5), 2.18 (5) and 56.44 (5)° with the pyran, fused benzene rings and phenyl ring, respectively. In the crystal, pairs of N-H⋯O hydrogen bonds generate R 2 (2)(14) loops and a C-H⋯N inter-action is also found. Mol-ecules are further linked by a number of π-π interactions [centroid-centroid distances vary from 3.5702 (5) to 3.7068 (6) Å], forming a three-dimensional network.

Microwave-assisted synthesis and spasmolytic activity of 4-indolylhexahydroquinoline derivatives.

In the present study a microwave-assisted one-pot method was applied for the synthesis of 18 novel condensed 1,4-dihydropyridines carrying the indole moiety. The compounds were achieved by the reaction of appropriate 1,3-cyclohexanedione, substituted indole carboxaldehyde derivative, alkyl acetoacetate and ammonium acetate in methanol, according to a modified Hantzsch reaction. The structure elucidation of the compounds was carried out by spectral methods including X-ray studies. Their spasmolytic activities through calcium channel blockade were assayed on isolated rat ileum. The obtained results indicated that the introduction of the brom atom on the indole ring altered the mentioned activity positively.

7-Methyl-1-phenyl-1,10-di-hydro-pyrazolo-[3,4-a]carbazole.

In the title mol-ecule, C20H15N3, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1082 (15) Å]. The pyrrole ring makes dihedral angles of 3.17 (8)/4.10 (9), 7.20 (9) and 44.62 (9)° with the fused benzene, pyrazole and phenyl rings, respectively. In the crystal, mol-ecules are linked via N-H⋯N hydrogen bonds, forming an infinite chain along [010]. Mol-ecules are further linked by nine π-π [centroid-centroid distances vary from 3.6864 (11) to 3.9802 (11) Å] and one C-H⋯π inter-action, forming a three-dimensional network.

2-(1-Phenyl-1H-benzimidazol-2-yl)phenol.

In the title mol-ecule, C19H14N2O, the benzimidazole unit is close to being planar [maximum deviation = 0.0253 (11) Å] and forms dihedral angles of 68.98 (6) and 20.38 (7)° with the adjacent phenyl and benzene rings; the dihedral angle between the latter two planes is 64.30 (7)°. An intra-molecular O-H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked by C-H⋯N and C-H⋯O hydrogen bonds, and consolidated into a three-dimensional architecture by π-π stacking inter-actions, with a centroid-centroid distance of 3.8428 (12) Å.

(E)-2-[(Furan-2-yl)methyl-idene]-7-methyl-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

In the title mol-ecule, C(18)H(15)NO(2), the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1317 (12) Å]. The pyrrole ring makes dihedral angles of 1.01 (8) and 18.56 (10)° with the benzene and furan rings, respectively. The cyclo-hexene ring adopts a half-chair conformation. In the crystal, pairs of N-H⋯O hydrogen bonds form an R(2) (2)(10) ring. Mol-ecules are further linked by C-H⋯O and C-H⋯π inter-actions, forming a three-dimensional network.

2-(4-Fluoro-phen-yl)-1-(4-methyl-phen-yl)-1H-phenanthro[9,10-d]imidazole.

The phenanthrene tricyclic ring system in the title mol-ecule, C(28)H(19)FN(2), is slightly skewed with a dihedral angle of 7.50 (6)° between the outer benzene rings. The p-tolyl and fluoro-benzene rings are twisted from the attached imidazole ring by 70.40 (7) and 28.33 (7)°, respectively. In the crystal, C-H⋯F hydrogen bonds link the mol-ecules into zigzag chains in [001], and weak C-H⋯π inter-actions further consolidate the crystal packing.

2-Ethyl-3,5,6-triphenyl-pyrazine.

In the title mol-ecule, C(24)H(20)N(2), the pyrazine ring is significantly distorted from planarity, presumably due to steric crowding, and its conformation is well described as a flattened twist-boat. The benzene ring adjacent to the ethyl group forms dihedral angles of 53.79 (13) and 85.47 (12)° with the other benzene rings; the dihedral angle between adjacent benzene rings is 57.90 (12)°. The ethyl group is disordered over two positions; the site-occupancy factor of the major component is 0.546 (4). No hydrogen bonds are found in the crystal structure.

1-[4-(4-Fluoro-phen-yl)-6-methyl-2-sulfanyl-idene-1,2,3,4-tetra-hydro-pyrimidin-5-yl]ethanone.

In the title mol-ecule, C(13)H(13)FN(2)OS, the heterocyclic ring adopts a slightly distorted flattened boat conformation, and the plane through the four coplanar atoms makes a dihedral angle of 87.45 (14)° with the benzene ring. The thione, acetyl and methyl groups lie on the opposite side of the heterocyclic mean plane to the fluorophenyl group, which has an axial orientation. N-H⋯O, N-H⋯S, C-H⋯F and C-H⋯O inter-molecular hydrogen bonds and a weak C-H⋯π inter-action involving the benzene ring are found in the crystal structure.

1-[4-(4-Isopropyl-phen-yl)-6-methyl-2-sulfanyl-idene-1,2,3,4-tetra-hydro-pyrimidin-5-yl]ethanone.

In the title mol-ecule, C(16)H(20)N(2)OS, the heterocyclic ring adopts a slightly distorted flattened boat conformation, and the plane through the four coplanar atoms makes a dihedral angle of 86.98 (6)° with the benzene ring. The thione, acetyl and methyl groups lie on the opposite side of the heterocyclic mean plane to the isopropylphenyl group which has an axial orientation. A weak intra-molecular C-H⋯O hydrogen bond is observed. In the crystal, molecules are linked via N-H⋯O, N-H⋯S and C-H⋯S hydrogen bonds.

2-(4-Fluoro-phen-yl)-1-phenyl-1H-benzimidazole.

In the title mol-ecule, C(19)H(13)FN(2), the benzimidazole unit is close to planar [maximum deviation = 0.0342 (9) Å] and forms dihedral angles of 58.94 (3) and 51.43 (3)° with the phenyl and fluoro-benzene rings, respectively; the dihedral angle between the phenyl and fluoro-benzene rings is 60.17 (6)°. In the crystal, three C-H⋯F hydrogen bonds and two weak C-H⋯π inter-actions involving the fused benzene ring lead to a three-dimensional architecture.

2-Chloro-7,8,9,10-tetra-hydro-cyclo-hepta-[b]indol-6(5H)-one.

In the title mol-ecule, C(13)H(12)ClNO, the dihedral angle between the benzene and pyrrole rings is 1.38 (9)°. The cyclo-heptene ring adopts a distorted twist chair and sofa conformation. Inter-molecular N-H⋯O hydrogen bonds form an R(2) (2)(10) loop in the crystal packing. Further, weak C-H⋯O and C-H⋯π (involving the benzene ring) inter-actions are found in the crystal structure.

1,2-Diphenyl-1H-benzimidazole.

In the title mol-ecule, C19H14N2, the benzimidazole unit is close to being planar [maximum deviation = 0.0102 (6) Å] and forms dihedral angles of 55.80 (2) and 40.67 (3)° with the adjacent phenyl rings; the dihedral angle between the phenyl rings is 62.37 (3)°. In the crystal, one C-H⋯N hydrogen bond and three weak C-H⋯π inter-actions involving the fused benzene ring and the imidazole ring are observed, leading to a three-dimensional architecture.