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Leishmaniasis is a neglected parasitic disease caused by various Leishmania species. The discovery of new protozoa drugs makes it easier to treat the disease; but, conventional clinical issues like drug resistance, cumulative toxicity, and target selectivity are also getting attention. So, there is always a need for new therapeutics to treat Leishmaniasis. Here, we have reported 2,3-dihydroquinazolin-4(1H)-one derivative as a new class of anti-leishmanial agents. Two derivatives, 3a (6,8-dinitro-2,2-disubstituted-2,3-dihydroquinazolin-4(1H)-ones) and 3b (2-(4-chloro-3-nitro-phenyl)-2-methyl-6,8-dinitro-2,3-dihydro-1H-quinazolin-4-one) were prepared that show promising in silico anti-leishmanial activities. Molecular docking was performed against the Leishmanial key proteins including Pyridoxal Kinase and Trypanothione Reductase. The stability of the ligand-protein complexes was further studied by 100 ns MD simulations and MM/PBSA calculations for both compounds. 3b has been shown to be a better anti-leishmanial candidate. In vitro studies also agree with the in-silico results where IC50 for 3a and 3b was 1.61 and 0.05 µg/mL, respectively.

Alzheimer’s disease (AD) causes dementia and continuous damage to brain cells. Cholinesterase inhibitors can alleviate the condition by increasing communication between the nerve cells and reducing the risk of dementia. In an effort to treat Alzheimer’s disease, we synthesized flurbiprofen-based diamines (1,2 diaminoethane and 1,3 diaminopropane) Zn(II), Cu(II) metal complexes and characterized them by single-crystal X-ray analysis, NMR, (FT)-IR, UV-Vis, magnetic susceptibility, elemental analysis and conductivities measurements. Synthesized diamine metal complexes appeared in ionic forms and have distorted octahedral geometry based on conductivity studies, magnetic susceptibility and electronic studies. Single crystal X-ray diffraction analysis confirmed (2b) Cu(H2O)2(L1)2(L2)2 complex formation. Moreover, we tested all synthesized metal complexes against the cholinesterase enzyme that showed higher inhibition potential. In general, copper metal complexes showed higher inhibitory activities than simple metal complexes with flurbiprofen. These synthesized metal complexes may derive more effective and safe inhibitors for cholinesterases.

In the title molecule, C9H6Cl2N2S, the mean planes of the benzene and thiazole rings make a dihedral angle of 54.18 (8)°. In the crystal, molecules are joined into dimers with an R22(8) ring motif by pairs of N—H...N hydrogen bonds. These dimers are linked by C—H...Cl interactions into layers parallel to (011). The thiazole rings form columns along the c-axis direction, with a centroid–centroid separation of 3.8581 (9) Å, indicating π–π interactions. An intramolecular C—H...S contact also occurs.

In the title compound, C15H14BrNO, the dihedral angle between the aromatic rings is 4.10 (11)° and the molecule is close to planar (r.m.s. deviation for the non-H atoms = 0.053 Å). An intramolecular O—H...N hydrogen bond closes an S(6) ring. In the crystal, very weak C—H...π interactions are observed.

In the title compound, C12H14N2S, the dihedral angle between the 1,3,5-trimethylbenzene and 1,3-thiazol-2-amine groups is 73.15 (4)°. In the crystal, inversion dimers linked by pairs of N—H...N hydrogen bonds generate R22(8) loops.

The paper by Awan et al. [Acta Cryst. (2011), E67, m576–m577] is retracted. It has subsequently been shown that the crystal studied was an already known zinc compound, [Zn4Cl4(C2H6NS)4].

In the title compound, C14H10FNO3, the dihedral angle between the two benzene rings is 32.66 (14)°. An S(6) ring motif is formed due to an intramolecular O—H...O hydrogen bond between the hydroxy and carbonyl groups. In the crystal, molecules are consolidated into dimers with R22(8) ring motifs by pairs of O—H...O hydrogen bonds.

In the title compound, C17H19NO2, the aromatic rings are oriented at a dihedral angle of 59.27 (12)°. In the crystal, inversion dimers linked by pairs of weak C—H...O interactions generate R22(12) loops.

The asymmetric unit of the title compound, C13H11ClN2, contains two geometrically distinct molecules; one molecule is close to planar [dihedral angle between the aromatic rings = 2.44 (18)°] and the other is twisted about the linking hydrazide group [dihedral angle = 14.08 (19)°]. In the crystal, the N—H groups do not form hydrogen bonds and the molecules are linked by weak C—H...π interactions.

In the centrosymmetric title compound, [Co4Cl4(C3H6S)]4], the two independent CoIII ions are each coordinated in a distorted tetrahedral geometry by one C, one Cl and two S atoms. The molecules are stabilized by C—H...Cl hydrogen bonds. In the crystal, intermolecular C—H...Cl and C—H...S hydrogen bonds with R22(8), R42(8) and R22(6) ring motifs generate a polymeric network.

In the title compound, C15H10Cl2N4O8, the methylacetate and dichloroanilinic groups are oriented at dihedral angles of 57.73 (8) and 62.44 (4)°, respectively to the dinitro-sustituted benzene ring. S(5) and S(7) rings are formed due to intramolecular N—H...Cl and N—H...O hydrogen bonds, respectively. In the crystal, N—H...O hydrogen bonds link the molecules into C(8) chains along the a axis. Further C—H...O and N—H...O hydrogen bonds link these chains in pairs, forming a polymeric network.

There are two geometrically different molecules in the asymmetric unit of the title compound, C14H9Cl2NO3. The 5-amino-2-hydroxybenzoic acid units [r.m.s. deviations of 0.0323 and 0.0414 Å] and 2,6-dichlorobenzaldehyde groups [r.m.s. deviations of 0.0285 and 0.0226 Å] are roughly planar and oriented at dihedral angles of 11.69 (13) and 83.12 (6)° in the two molecules. An intramolecular O—H...O hydrogen bond completes an S(6) ring motif in each molecule. The two molecules form dimers with each other through intermolecular O—H...N and C—H...O hydrogen bonds, completing an R22(8) ring motif. The dimers are interlinked via intermolecular O—H...N and C—H...O hydrogen bonds, forming polymeric sheets.

In the title zwitterion, C15H13NO4, obtained from the condensation of 5-aminosalicylic acid and 4-methoxybenzaldehyde, the 4-hydoxyanilinic group of the 5-aminosalicylic acid moiety and the 4-methoxybenzaldehyde moiety are twisted with respect to one another, making a dihedral angle of 10.37 (7)°. The carboxylate group makes a dihedral angle of 5.7 (2)° with the parent 4-hydoxyanilinic group. An intramolecular O—H...O hydrogen bond forms an S(6) ring motif. In the crystal, intermolecular C—H...O and N—H...O hydrogen bonds with R21(7) ring motifs link the molecules into infinite chains extending along the c axis. The occurence of slipped π–π stacking between symmetry-related aromatic rings reinforces the packing.

In the title compound, C15H11NO4, the dihedral angle between the aromatic rings is 23.8 (2)° and an intramolecular O—H...N hydrogen bond generates an S(6) ring. In the crystal, C—H...O hydrogen bonds link the molecules into a three-dimensional network.

In the title compound, C14H11Cl2N, the dihedral angle between the 4-methylanilinic and 2,4-dichlorobenzaldehyde moieties is 7.37 (8)°. In the crystal, C—H...π interactions between the terminal methyl group and a symmetry-related ring of the anilinic group help to establish the packing.

In the title compound, C15H15NO, the almost planar 2,3-dimethylaniline unit and the salicylaldehyde group (r.m.s. deviations of 0.0156 and 0.0109 Å, respectively) are oriented at a dihedral angle of 43.69 (9)° with respect to each other. An S(6) ring motif is formed due to intramolecular O—H...N hydrogen bonding. In the crystal, C—H...π interactions occur between the 2,3-dimethylaniline unit and the salicylaldehyde group, where the CH is from the o-methyl group.

In the title compound, C16H13NO2, the 2,3-dimethylphenyl group and the 1H-isoindole-1,3(2H)-dione group are essentially planar, with r.m.s. deviations of 0.006 and 0.013 Å, respectively, and are oriented at an angle of 78.19 (3)° with respect to each other. In the crystal, weak C—H...O interactions link the molecules, forming a zigzag chain parallel to the b axis. Futhermore, C—H...π interactions are present between the C—H group of isoindole and the 2,3-dimethylphenyl benzene ring. The H atoms of the ortho-methyl group are statistically disordered over two positions. Such disorder might be related to the antagonism between intramolecular steric repulsions and intermolecular C—H...O interactions.

The asymmetric unit of the title compound, C15H14ClNO2, contains two molecules with significantly different conformations: the dihedral angles between the 4-chloroaniline and 3,4-dimethoxyphenyl (excluding C atoms) moieties are 19.68 (7) and 45.54 (4)°. In the crystal, the molecules are linked by C—H...O hydrogen bonds and weak C—H...π interactions.

In the title compound, C13H14N2, the dihedral angle between the aromatic rings is 69.73 (14)°. In the crystal, inversion dimers linked by pairs of N—H...N hydrogen bonds generate R22(10) loops. A weak C—H...π interaction also occurs.

In the title compound, C18H21NO3, the C=N bond has a trans conformation and the benzene rings are oriented at a dihedral angle of 61.32 (6)°. The C atoms of the three methoxy groups are all roughly coplanar with their attached ring [deviations = 0.219 (2), −0.097 (2) and −0.137 (2) Å]. In the crystal, a weak C—H...π interaction may help to establish the packing.

In the title compound, C14H14N2O, the dihedral angle between the aromatic rings is 9.30 (6)°. In the crystal, molecules are linked by C—H...π and N—H...π interactions.

The asymmetric unit of the title compound, C13H11N3O2, contains two molecules with slightly different conformations: the dihedral angle between the aromatic rings is 13.01 (10)° in one molecule and 14.05 (10)° in the other. Both molecules feature short intramolecular C—H...O contacts, which generate S(6) rings. In the crystal, both molecules form inversion dimers linked by pairs of N—H...O hydrogen bonds, thereby generating R22(16) rings.

In the title compound, C22H19NO, the 2,3-dimethylanilinic group is planar with an r.m.s. deviation of 0.0226 Å. The phenyl rings with the carbonyl and imine substituents are also planar with r.m.s. deviations of 0.0019 and 0.0048 Å, respectively. These phenyl rings are oriented at dihedral angles of 74.70 (5) and 79.43 (5)°, respectively, with the 2,3-dimethylanilinic group, whereas the dihedral angle between them is 88.28 (4)°. Weak intramolecular C—H...N hydrogen bonding occurs and completes an S(5) ring motif in the molecule. In the crystal, weak π–π interactions are present between the carbonyl-containing phenyl rings at a centroid–centroid distance of 3.5958 (12) Å. C—H...π interactions between the 2,3-dimethylanilinic and the carbonyl-containing phenyl rings are also present, where the C—H group is from the former.

There are two independent molecules in the asymmetric unit of the title compound, C17H20N2, in which the dihedral angles between the aromatic rings are 30.34 (11) and 41.44 (8)°. In the crystal, weak C—H...π interactions may help to establish the packing.

In the title compound, C15H14ClN, the conformation about the C=N bond is trans and the dihedral angle between the aromatic rings is 51.48 (4)°. In the crystal, some very weak C—H...π interactions may help to establish the packing.

In the title compound, C15H14N2O2, the aromatic rings are oriented at a dihedral angle of 24.52 (5)°. The dihedral angle between the nitro group and its parent benzene ring is 9.22 (16)°. In the crystal, molecules interact through aromatic π—π stacking interactions [centroid–centroid separations = 3.8158 (14) and 3.9139 (14) Å].

In the title compound, C15H14N2O2, the 2,3-dimethylanilinic and benzaldehyde groups are planar, with r.m.s. deviations of 0.0101 and 0.0241 Å, respectively, and are oriented at a dihedral angle of 11.69 (3)°. The nitro group is inclined to the benzaldehyde group by 34.02 (9)°. The molecule adopts an E configuration about the C=N bond. In the crystal, molecules are linked via C—H...O interactions, giving rise to the formation of zigzag polymeric chains extending along [010]. They are also linked by C—H...π, and π–π interactions [centroid–centroid distance of 3.7185 (11) Å] involving symmetry-related aniline and benzene rings. The H atoms of the ortho-methyl group are disordered over two sites with a refined occupancy ratio of 0.69 (2):0.31 (2).

In the title hydrated molecular salt, 2C7H8NO2+·SO42−·H2O, each cation in the asymmetric unit is stabilized by an intramolecular N—H...O hydrogen bond. The O atoms of the sulfate ion are disordered over two sets of sites with an occupancy ratio of 0.541 (13):0.459 (13), which possibly optimizes the acceptance of N—H...O hydrogen bonds from the cations. The crystal structure also features aromatic π–π stacking [centroid–centroid separation = 3.842 (2) Å] and a C—H...π interaction.

In the centrosymmetric title compound, [Ag4(C10H2O8)]n, the benzene ring has irregular bond lengths but remains planar (r.m.s. deviation 0.0002 Å). The Ag—O bond lengths are in the range 2.153 (3)–2.615 (4) Å. The carboxylate groups are oriented at dihedral angles of 26.4 (5) and 74.9 (4)° to the benzene ring. The coordination behaviour of each carboxylate O atom is different: in one carboxylate, the O atoms are coordinated to a single and two Ag atoms; in the other carboxylate, the O atoms are coordinated to two and three Ag atoms. Non-classical intermolecular C—H...O hydrogen bonding is present in the crystal structure. The title compound forms a three-dimensional polymeric network due to the coordination of the Ag atoms.

The title compound, C12H19O4P, has a distorted tetrahedral geometry around the P atom. The molecules form dimers with R22(10) ring motifs due to intermolecular O—H...O hydrogen bonds. The double-bonded O atom of the phosphonate group behaves as an acceptor and the hydroxy group acts as a donor. Both of the ethyl groups are disordered with occupancies of 0.55:0.45 and 0.725:0.275.

In the molecule of the title compound, 2C4H10N3O2+·SO4−, the cations are planar (r.m.s. deviations = 0.0144 and 0.0236 Å) and oriented at a dihedral angle of 62.30 (4)°. Intramolecular N—H...O hydrogen bonds result in the formation of two planar six-membered rings. The cations are linked to the sulfate ion through intermolecular C—H...O and N—H...O hydrogen bonds, forming an R22(8) ring motif. In the crystal structure, intermolecular N—H...O and C—H...O hydrogen bonds link the molecules into a three-dimensional network.

In the molecule of the title compound, C14H20N4O3, the five-membered ring adopts an envelope conformation with the O atom displaced by 0.207 (3) Å from the plane of the other ring atoms. Intramolecular C—H...O hydrogen bonds result in the formation of three five-membered rings having envelope conformations. In the crystal structure, intermolecular N—H...O hydrogen bonds link the molecules, forming R22(20) ring motifs, which produce two-dimensional polymeric sheets extending along the b axis. There are also two C—H...π interactions. The H atoms of one of the methyl groups are disordered over two positions and were refined with occupancies of 0.50.

In the molecule of the title compound, C11H14N2O2S, the five-membered ring adopts an envelope conformation and an intramolecular N—H...O hydrogen bond occurs. Intramolecular N—H...O, C—H...S and C—H...N hydrogen bonds result in the formation of two five- and one six-membered rings, having twisted conformations. In the crystal structure, intermolecular N—H...O, N—H...S and C—H...S hydrogen bonds link the molecules, forming polymeric sheets. The π–π contacts between the isoindole ring systems, [centroid–centroid distances = 3.5883 (8) and 4.0619 (8) Å] may further stabilize the structure. A C—H...π interactions also occur.

In the title molecule, C12H10Cl2, the torsion angles Cr—Cr—Cm—Cl around the Cm—Cr bonds have values of −104.1 (4) and −101.9 (4)°, where Cm is a methylene and Cr is a ring C atom. The molecules related by translation along the b axis are arranged into stacks by π–π interactions between unsubstituted and substituted aromatic rings of the naphthalene ring system (centroid–centroid distance = 3.940 Å).

The title compound, C10H10N2O2·H2O, is dimerized by inversion-related intermolecular N—H...O hydrogen bonding. There is an intramolecular N—H...O bond, resulting in a six-membered ring. Each dimer interacts with other dimers through hydrogen bonding with water molecules. The water molecules are linked to each other in a stair-like chain, thus generating two-dimensional polymeric strips. The dimers are also linked to each other through intermolecular C—H...O hydrogen bonding. There are π–π interactions between the aromatic and heterocyclic five-membered rings [centroid–centroid distance 3.8360 (12) Å]. C—H...π interactions also exist between CH2 groups and aromatic rings.

The title molecule, C9H8N2O2, is essentially planar. The crystal structure is stabilized by hydrogen bonding. An intramolecular N—H...O hydrogen bond results in a six-membered ring. Each molecule interacts with two others through N—H...O and C—H...O hydrogen bonding, resulting in the formation of nine-membered rings. These hydrogen bonds generate a two-dimensional polymeric network. There are also π–π interactions between the aromatic and heterocyclic rings [centroid–centroid distance 3.638 (2) Å].