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This work focuses on optimizing an efficient green synthesis of arylamidoximes from appropriate nitrile and hydroxylamine hydrochloride in water and triethylamine (1.6 mol equivalent) as a base at room temperature for 6 h. This new green synthetic methodology is compared with previously known methods. The main advantages of this new process reported are good yield, easier work-up and short reaction times. Moreover, some of the synthesized arylamidoximes converted to 1,2,4-oxadiazole derivatives 13a,b and 14 via the reaction with (4-acetylphenoxy)acetic acid 12.

This study reports the synthesis of two new hydrazide derivatives, namely, (E)-N'-(4- bromobenzylidene)-2-(4-isobutylphenyl)propanehydrazide (4a) and (E)-N'-benzylidene-2-(4-isobutylphenyl)propanehydrazide (4b), respectively. The compounds were synthesized by the reaction of benzaldehyde with Ibuprofen acid hydrazide. Their structures were confirmed by X-ray crystallography. To try to do a more detailed investigation, computational studies including Hirshfeld surface analyses, energy frameworks, density functional theory (DFT) optimizations, frontier orbital analyses, molecular electrostatic potential analyses, and natural bond orbital analyses of the studied compounds are performed. Moreover, molecular docking and dynamics simulations of complexes of the compounds with the cyclooxygenase-2 (COX-2) enzyme were performed to determine the anti-inflammatory potential of the compounds. These analyses predicted the compounds to show maximum chemical interactions and be dynamically stable during simulation time. Furthermore, estimation of binding free energies confirmed the high binding affinity of the compounds for the COX-2 enzyme.

An efficient procedure for the synthesis of a novel class of benzylidene-2-alkoxy-4-aryl-6,7-dihydro-5H-cyclopenta[b]pyridine-, -5,6,7,8-tetrahydroquinoline and/or -6,7,8,9-tetrahydro-5H-cyclohepta...

In the fall of 2019, a new type of coronavirus took place in Wuhan city, China, and rapidly spread across the world and urges the scientific community to develop antiviral therapeutic agents. In our effort we have synthesized a new hydrazide derivative, (

Mild steel corrosion in HCl solution is an example of corrosion in acidic mediums. The ongoing research efforts to develop novel environmentally friendly corrosion inhibitors raise questions regarding their ability to effectively protect steel from corrosion. Herein, a series of experimental studies were conducted to explain the scientific mechanism of adsorption of four hydrazone derivatives (HDZs) namely, 2-((2,3-dimethylphenyl)amino)-N′-((1E,2E)-3-phenylallylidene)benzohydrazide (HDZ1) (E)-2-((2,3-dimethylphenyl)amino)-N′-(4-hydroxybenzylidene)benzohydrazide (HDZ2) (E)-2-((2,3-dimethylphenyl)amino)-N′-(1-phenylethylidene)benzohydrazide (HDZ3) and N′-cyclohexylidene-2-((2,3-dimethylphenyl)amino)benzohydrazide (HDZ4) on mild steel (MS) in 1.0 M HCl using chemical, electrochemical and surface characterization techniques. All results show that the inhibitor molecules form a stable layer on steel surface through chemical and physical interactions. HDZs adsorption onto the steel surface was found to follow Langmuir model. Furthermore, electrochemical results demonstrated that our developed inhibitors act as mixed-type inhibitors, with HDZ1 showing the highest polarization resistance and lowest corrosion current density. X-ray diffraction and scanning electron microscope were used to study corrosion products phases and surface morphology of MS samples. Our findings provide deeper insights into understanding the interaction mechanisms of HDZs with a steel surface and can be helpful to explore novel approaches to mitigate the steel dissolution.

The mol­ecular and crystal structure of the title imidazole derivative is reported. The structure features an extensive O—H⋯N, C—H⋯O/N and C—H⋯π(ring) hydrogen-bonding network., The title compound, C24H21N3O3, crystallizes with two unique but closely r.m.s. overlay fit = 0.215 Å) comparable mol­ecules (1 and 2) in the asymmetric unit of the triclinic unit cell. In molecule 1, the dihedral angles between the central imidazlole ring and the benzene-ring substituents are 42.51 (9), 45.41 (9) and 56.92 (8)°, respectively. Comparable data for molecule 2 are 39.36 (10), 34.45 (11) and 60.34 (8)°, respectively. The rings at the 2-positions carry p-nitro substituents that subtend dihedral angles of 12.9 (4)° in mol­ecule 1 and 11.7 (4)° in mol­ecule 2 to their respective benzene ring planes. The imidazole rings also have propan-2-ol substituents on the 1-N atoms, which adopt extended conformations for the N—C—C—C chains. In the crystal, classical O—H⋯N hydrogen bonds combine with C—H⋯O, C—H⋯N and C—H⋯π(ring) hydrogen bonds and stack the molecules along the a-axis direction.

The title compound, C16H13N3OS, comprises an oxadiazolethione ring bound to the N atom of an almost planar carbazole ring system (r.m.s. deviation = 0.0088 Å) through an ethylene chain. The oxadiazole ring is inclined to the the carbazole ring system by 40.71 (6)°. In the crystal, N—H...O, N—H...S, C—H...N and C—H...S hydrogen bonds combine with C—H...π(ring) and π–π contacts to stack the molecules along theb-axis direction.

The current investigation seeks to explore the adsorption mechanism of newly synthesized Naproxen-based hydrazones on mild steel (MS) surface in 1.0 M HCl solution and their corrosion inhibition efficiencies. To this end, two hydrazone derivatives namely, (E)-N′-(1-(4-chlorophenyl)ethylidene)-2-(6-methoxynaphthalen-2-yl)propanehydrazide (PHD Cl) and (E)-N′-(1-(4-hydroxyphenyl)ethylidene)-2-(6-methoxynaphthalen-2-yl)propanehydrazide (PHD-OH) were synthesized, characterized and their corrosion inhibition effects were evaluated using a combined electrochemical and theoretical approach. It is evidently clear from the findings presented in this investigation that the two inhibitors exhibited excellent protection efficiency, and the best inhibition performance was shown by PHD-OH inhibitor (96% at 5 × 10−3 M). Weight loss measurements revealed that the optimum concentration of inhibitors is 5 × 10−3 mol/L. The experimental results obtained by electrochemical techniques (potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS)) indicated that the presence of PHD-Cl and PHD-OH compounds greatly increased the polarization resistance and affected both anodic and cathodic reactions, i.e. mixed-type inhibitors. Based on electrochemical results, the polarization resistance was greatly increased, from an initial value for the MS (in 1.0 mol/L HCl) of 29 up to 871 Ω cm2 for the inhibited solution (1.0 mol/L HCl with 5 × 10−3 mol/L of PHD-OH). Furthermore, the adsorption isotherm coincides well with the Langmuir isotherm model. The effect of temperature on PHD-OH adsorption was investigated, experimentally using weight loss tests, and theoretically using molecular dynamic simulations (MD). Moreover, the study found that a protective barrier was set up through the adsorption of the studied compounds on MS surface which is confirmed by scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX).Moreover, molecular proprieties of corrosion inhibitor molecules were explored from a theoretical viewpoint using Density Functional Theory (DFT), molecular dynamic (MD) simulation and radial distribution function (RDF) studies. Theoretical results that were in good agreement with experimental findings demonstrated strong interactions between inhibitor molecules and metal surface.

Hydrazone derivatives have drawn much attention because of their large pharmacological applications. In the present work, the compound (E)-2-((2,3-dimethylphenyl)amino)-N’-(furan-2-ylmethylene)benzohydrazide, noted C20H19N3O2 was synthesized, and its 3D structure was determined by X-ray crystallography. Structural characterization by X-ray crystallography was supported by Density Functional Theory (DFT) and Hartree Fock (HF) calculations. Intermolecular interactions in the crystal network were determined using Hirshfeld surface analyses. The optimized geometry, global reactivity descriptors, Natural Bond Orbital (NBO) analysis, and HOMO-LUMO of the molecule were computed using the DFT-B3LYP method and 6-311++G (d,p) basis set. The C20H19N3O2 has a monoclinic system and P21/c space group with parameters a = 13.8181 (10) Å, b = 16.1969 (10) Å, c = 8.1285 (7) Å, ? = 104.546 (6)° and Z = 4. It forms an S(6) ring motif with an intramolecular N—H?O hydrogen bond. Hirshfeld surface analysis and 2D fingerprint plots signify meaningful interactions in crystal packing [H?H (47.2%), C?H/H?C (29%), and O?H/H?O (13.3%) contacts]. Atomic charges were predicted using the Mulliken population and the NBO theory. The molecular electrostatic potential (MEP) picture was drawn using the same level of theory to visualize the chemical reactivity and charge distribution on the molecule. The local reactivity was examined by determining the Fukui functions and dual descriptor indices. © 2020 Elsevier B.V.

SALGHI, Rachid/0000-0003-4845-8849; Dege, Necmi/0000-0003-0660-4721; Marzouki, Riadh/0000-0002-2502-2164; LGAZ, Hassane/0000-0001-8506-5759; Kansiz, Sevgi/0000-0002-8433-7975 WOS: 000511287400072 Hydrazones are an important class of organic compounds, which exhibit large pharmacological applications. Hydrazones have long been used for the synthesis of a wide range of useful heterocyclic compounds due to their reactivity toward electrophiles and nucleophiles. Herein, a hydrazone derivative, 2-[(2,3-dimethylphenyl)amino]-N'-[(E)-thiophen-2-ylmethylidene]benzohydrazide, noted C20H19N3OS was synthesized and its three-dimensional structure was determined by X-ray crystallography. Structural characterization by X-ray crystallography was supported by Density Functional Theory (DFT) calculations. Intermolecular interactions in the crystal network were determined using Hirshfeld surface analyses. The optimized geometry, global reactivity descriptors, Natural Bond Orbital (NBO) analysis, and HOMO-LUMO orbitals of the molecule were computed using the DFT-B3LYP method and 6-311++G (d,p) basis set. C20H19N3OS has a monoclinic system and P2(1)/c space group with parameters a = 13.9774 (13) angstrom, b = 16.3851 (16) angstrom, c = 8.2101 (8) angstrom, beta = 105.429 (7)degrees and Z = 4. C20H19N3OS forms an S (6) ring motif with an intramolecular N-H center dot center dot center dot O hydrogen bond. In the crystal, the molecule chains along the c-axis direction are linked by C-H center dot center dot center dot O hydrogen bond. Atomic charges were predicted using the Mulliken population and the NBO theory. The molecular electrostatic potential (MEP) picture was drawn using the same level of theory to visualize the chemical reactivity and charge distribution on the molecule. The local reactivity was examined by determining the Fukui functions and dual descriptor indices. (c) 2019 Elsevier B.V. All rights reserved. Deanship of Scientific Research at King Khalid University [R.G.P.2/46/40]; Ondokuz Mayis UniversityOndokuz Mayis University [PYO.FEN.1906.19.001] "The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through research groups program under grant number R.G.P.2/46/40. This study was supported by Ondokuz Mayis University under project No. PYO.FEN.1906.19.001."

The molecule of the title compound, C15H15N3O3, is twisted, with the dihedral angle between the pyridyl and benzene rings being 58.34 (6)°. In the crystal, amide-N—H...O(amide) and imine-C—H...O(amide) hydrogen bonds lead to zigzag (glide symmetry) chains extending along the c axis which are joined into layers parallel to the [100] direction by offset π–π stacking interactions between inversion-related benzene rings [centroid–centroid distance = 3.7468 (7) Å] and by C—H...π(pyridyl) interactions. Pyridyl rings protrude from the surfaces of the layers and partially intercalate with those of adjacent layers.

In the title compound, C21H22N4O2S, the dihedral angle between the pyrazole ring and adjacent benzene ring is 6.4 (1)°. The molecular conformation is influenced by intramolecular N—H...O and C—H...O hydrogen bonds. In the crystal, N—H...O hydrogen bonds plus C—H...π and π–π stacking interactions form chains extending in thea-axis direction. The chains are linked by complementary pairs of C—H...π interactions.

In the title compound, C22H20ClN3O, the dihedral angle between the planes of the chlorophenyl and dimethylphenyl rings is 66.50 (9)°. These rings make dihedral angles 47.79 (8) and 69.24 (9)°, respectively, with the central benzene ring. In the crystal, molecules are linked into a three-dimensional supramolecular network by N—H...O, C—H...O hydrogen bonds and weak C—H...π interactions.

In the title compound, C23H22ClN3O, the dihedral angle between the planes of the chlorophenyl and dimethylphenyl rings is 62.49 (10)°. These rings make dihedral angles of 21.11 (9) and 59.85 (9)°, respectively, with the central benzene ring. In the crystal, molecules are linked into a three-dimensional supramolecular network by N—H...N, N—H...O and C—H...O hydrogen bonds, and weak C—H...π interactions.

In the title compound, C27H32BrNO5, the central 1,4-dihydropyridine ring adopts a shallow sofa conformation (with the C atom bearing the bromophenol ring as the flap), whereas the pendant cyclohexene rings both have twisted-boat conformations. The molecule features an intramolecular O—H...O hydrogen bond, which closes anS(8) ring. In the crystal, molecules are linked by C—H...O interactions, formingC(12) chains along thec-axis direction. The ethyl acetate grouping is disordered over two sets of sites in a 0.719 (11):0.281 (11) ratio.

In the title compound, C22H23ClN2O2S, the chlorophenyl ring is inclined to the pyridine ring of the isoquinoline ring system by 79.78 (4)°. The cyclohexane ring adopts a flattened boat conformation. In the crystal, dimers form through complementary sets of inversion-related O—H...O and C—H...O hydrogen bonds. These are connected into zigzag chains along the c-axis direction by pairwise C—H...N interactions that also form inversion dimers.

2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent, LR) reacted with pyrano[2,3-d]pyrimidine-2,4-(1H,3H)-dione derivatives in boiling acetonitrile to afford various pyrimido[5',4':5,6]pyrano[2,3-d][1,3,2]thiazaphosphinine derivatives. The structures of the target compounds were characterized by elemental analysis and spectral data. The biological activities of all synthesized compounds were tested against various microorganisms by the disk diffusion method. In general, the newly synthesized compounds showed good inhibitory effects against most of the applied microorganisms.

In the title compound, C14H17N3S, the cyclohexane ring adopts a chair conformation. The dihedral angle between the triazole and phenyl ring is 77.2 (3)°. In the crystal structure, C—H...S hydrogen link molecules intoC(7) chains along theb-axis direction. The crystal studied was refined as as an inversion twin.

In the crystal of the title molecule, C16H17NO6S, there are three sets of intermolecular C—H...O hydrogen bonds, as well as two sets of intermolecular C—H...π(ring) interactions. In addition, the thiazolidene rings participate in offset π–π stacking interactions [centroid–centroid distance = 3.685 (1) Å]. These generate small channels running parallel to theaaxis with approximate cross-sections of 3.7 × 8.1 Å.

The mol­ecular and crystal structure of the title imidazole derivative is reported. The structure is stabilized by an extensive O—H⋯N, C—H⋯O/Cl and C—H⋯π(ring) hydrogen-bonding network., The title compound, C24H21ClN2O, crystallizes with two unique mol­ecules in the asymmetric unit. In each mol­ecule, the central imidazole ring is substituted at the 2-, 4- and 5-positions by benzene rings. The 2-substituted ring carries a Cl atom at the 4-position. One of the imidazole N atoms in each mol­ecule has a propan-2-ol substituent. In the crystal, a series of O—H⋯N, C—H⋯O and C—H⋯Cl hydrogen bonds, augmented by several C—H⋯π(ring) inter­actions, generate a three-dimensional network of mol­ecules stacked along the a-axis direction.

In the title compound, C22H18N2O3S, the two independent molecules in the asymmetric unit form a dimerviaN—H...O hydrogen bonds. In the crystal, the molecular layers can be found in the (110) plane, connected by C—H...π interactions. Atoms of the furan ring of one independent molecule are disordered over two sets of sites with an occupancy ratio 0.735 (3):0.265 (3).

In the crystal of the title compound, C16H15N5S·C2H6OS, both the 1,2,4-triazole derivative molecules and the disordered [refined occupancy ratio = 0.604 (1):0.396 (1)] dimethyl sulfoxide solvent molecules form centrosymmetric dimers, by way of pairwise N—H...S and C—H...O hydrogen bonds, respectively. In the crystal, the two types of dimer are connected by N—H...O hydrogen bonds, forming infinite chains parallel to [101]. The packing is assisted by π–π stacking and C—H...π(ring) and N—H...π(ring) interactions.

In the title compound, C23H17N3O, there is a short intramolecular C—H...O contact present, and the conformation about the C=N bond is E. The phenyl and benzylidene rings make dihedral angles of 28.21 (15) and 37.65 (14)° with the mean plane of the quinoline moiety. In the crystal, molecules are linked by N—H...O and C—H...O hydrogen bonds, forming chains propagating along [001], with the O atom accepting three hydrogen bonds.

The conformation of the title molecule, C19H19N3O4S·C2H6OS, which crystallized as a DMSO solvate, is partially determined by an intramolecular N—H...O hydrogen bond, forming anS(6) loop. The thienopyridine bicyclic system is almost planar, with an r.m.s. deviation of 0.002 Å. The benzene ring makes a dihedral angle of 65.44 (8)° with the mean plane of the thienopyridine bicyclic system. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with anR22(8) ring motif. Within the dimers, which stack along thea-axis direction, there is a weak π–π interaction [centroid-to-centroid distance = 3.5428 (11) Å] involving inversion-related thiophene rings. In addition, N—H...O and C—H...O hydrogen bonds help to consolidate the packing,viathe solvent molecules.

In the title compound, C10H6ClNO2S, the dihedral angle between the planes of the 4-chlorophenyl and thiazolidine rings is 8.62 (9)°. In the crystal, molecules form undulating ribbons running approximately parallel to (101) through N—H...O hydrogen bonds.

The title compound, C15H12N4O2, contains two independent molecules in the asymmetric unit. These differ in terms of dihedral angles that the phenyl and 2-pyridyl rings subtend with the central five-membered ring; 15.2 (2) and 2.9 (2)°, respectively, in one molecule, 8.9 (2) and 5.1 (2)°for the second. In the crystal, the independent molecules each self-associate to form layers through N—H...O and C—H...O hydrogen bonding. The layers associate through π–π interactions between the phenyl rings and isolated carbon–carbon double bonds [shortest midpoint–centroid distance = 3.347 (4) Å]. The crystal studied was refined as a two-component twin.

In the title salt, C6H16N22+·2CNS−, the cyclohexane ring adopts a chair conformation. In the crystal, N—H...N hydrogen bonds encloseR42(8) rings involving two N atoms from the cyclohexane-1,4-diammonium cations as donors with the N atoms of two thiocyanate anions as acceptors. The crystal structure is further stabilized by intermolecular N—H...S hydrogen bonds that combine with these contacts to form a three-dimensional network.

The title compound, C24H20ClN5O2S·0.5H2O, has three independent molecules in the asymmetric unit and two water molecules of crystallization, one of which is equally disordered over two sites. The three unique organic molecules differ in the conformations of the substituents on the pyrazole ring. In the crystal, extensive O—H...O, O—H...N, N—H...O and C—H...O hydrogen bonding generates a three-dimensional network and C—H...π interactions are also observed.

In the title compound, C16H13ClN2O2S, the dihedral angle between the 4-chlorophenyl ring and the pyridine ring is 63.53 (6)°. There is an intramolecular C—H...O contact present. In the crystal, molecules are linked by pairs of N—H...S hydrogen bonds, forming inversion dimers. The dimers are linked by C—H...O and C—H...N hydrogen bonds, forming slabs parallel to theabplane.

The structure of the title compound, C21H20N2O3, was originally determined at ambient temperature [Wuet al.(2007).Inorg. Chim. Acta,360, 3069–3074]. In this determination, with data collected at 150 K, the asymmetric unit comprises two independent molecules (1 and 2) that differ considerably in their conformations. In particular, the methyl group at the mid-point of molecule 2 is disordered over two sites. This was modelled with restraints so that the geometries of the two components are comparable and the disorder components refined to an occupancy ratio of 0.750 (6):0.250 (6). Intramolecular O—H...N and intermolecular N—H...O hydrogen bonds stabilize the structure with significant additional input from C—H...π interactions.

In the title compound, C24H20N4O2S, the benzimidiazole moiety is essentially planar within 0.020 (1) Å (r.m.s. deviation = 0.012 Å). Its mean plane makes a dihedral angle of 85.80 (3)° with the plane of the central pyridine ring while the methoxyphenyl ring makes a dihedral angle of 57.28 (4)° with this plane. In the crystal, N—H...N hydrogen bonds form sheets parallel to (010).

In the title compound, C16H12N4OS, the bicyclic triazolothiadiazole core is approximately planar, with an r.m.s. deviation of 0.018 Å. The phenyl rings are inclined to its mean plane by 7.66 (7) and 71.79 (7)°. In the crystal, molecules are linkedviaa C—H...π interaction and a π–π interaction [intercentroid distance = 3.2942 (9) Å] involving inversion-related triazole rings. These interactions result in the formation of chains propagating along [10-1].

The packing in the crystal of the title molecule, C28H25N3O3S, is aided by intermolecular N—H...O and C—H...O hydrogen bonds. In the crystal, the ethyl group of the ester is disordered over two sets of sites with refined occupancies of 0.760 (8) and 0.240 (8).

In the crystal, complementary N—H⋯O hydrogen bonds form dimers which are then associated into chains parallel to the c axis through O—H⋯N hydrogen bonds involving the lattice water mol­ecule., In the title mol­ecule, C27H25N3O3S·H2O, the dihedral angle between the planes of the thienyl ring and the pendant p-tolyl group is 39.25 (6)°, while that between the pyridine ring and the pendant phenyl ring is 44.37 (6)°. In addition, there is a slight twist in the bicyclic core, with a dihedral angle of 2.39 (4)° between the thienyl and pyridine rings. The conformation of the carbamoyl moiety is partially determined by an intra­molecular N—H⋯O hydrogen bond. In the crystal, complementary N—H⋯O hydrogen bonds form dimers which are then associated into chains parallel to the c axis through O—H⋯N hydrogen bonds involving the water mol­ecule of crystallization. Electron density associated with an additional solvent mol­ecule of partial occupancy and disordered about a twofold axis was removed with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s).

In the title molecule, C22H22N2O4S, the bicyclic core is slightly folded [1.9 (1)°], while pairwise intermolecular N—H...O hydrogen bonding forms dimers across centers of symmetry. The dihedral angle between the phenyl ring an the six-membered ring of the bicyclic core is 75.50 (4)°. The molecular conformation is stabilized by an intramolecular N—H...O hydrogen bond with graph-set motifS(6) and by a weak C—H...O contact, forming anS(7) motif. In the crystal, π–π interactions [centroid-to-centroid distance = 3.7484 (10) Å] between phenyl rings and two weak C—H...π interactions are also observed.

In the title molecule, C21H14N4O4, the phenyl rings make dihedral angles of 39.61 (8) and 9.4 (1)°, respectively, with the central pyrazole ring. The dihedral angle between the pyrazole and dinitrophenyl rings is 46.95 (5)°. In the crystal, molecules pack in helical stacks parallel to theaaxis aided by weak C—H...O interactions.

In the title compound, C22H18ClN3O, the carbazole ring system is essentially planar (r.m.s deviation = 0.003 Å), and makes a dihedral angle of 9.01 (8)° with the plane of the chlorophenyl ring. In the crystal, neighbouring molecules are linked into centrosymmetricR22(8) dimers by pairs of N—H...O interactions and into a three-dimensional network by C—H...π interactions. The dimers are arranged into layers parallel to (010).

In the title compound, C14H17N3S, the dihedral angle between the planes of the benzene ring and the thiosemicarbazone group (r.m.s. deviation = 0.031 Å) is 8.45 (4)°. A short intramolcular N—H...N contact is seen. In the crystal, weak N—H...S hydrogen bonds connect the molecules intoC(4) chains propagating in the [010] direction, with adjacent molecules in the chain related by 21screw-axis symmetry.

The conformation of the title compound, C14H19N3S, is partially determined by an intramolecular N-H center dot center dot center dot N hydrogen-bond interaction, although the N-H center dot center dot center dot N angle of 108 degrees is quite small. The cyclohexylidene ring has a chair conformation and its mean plane is inclined to the benzene ring by 46.30 (8)degrees. In the crystal, molecules are linked by pairs of N-H center dot center dot center dot S hydrogen bonds, forming inversion dimers, with an R-2(2)(8) ring motif. The dimers are reinforced by pairs of C-H center dot center dot center dot S hydrogen bonds, and are linked by further weak C-H center dot center dot center dot S hydrogen bonds, forming chains propagating along [100].

In the title compound, C23H24BrNO5, the central 1,4-dihydropyridine ring of the 1,2,3,4,5,6,7,8,9,10-decahydroacridine ring system adopts a half-chair conformation. The two cyclohexene rings fused to the central ring both have a twisted-boat conformation. The mean planes of the bromohydroxyphenyl ring and the major and minor components of the disordered ethyl aminoacetate moiety make dihedral angles of 78.99 (12), 85.9 (2) and 88.3 (9)°, respectively, with the 1,4-dihydropyridine ring. The terminal ethyl group of the ethyl aminoacetate moiety is disordered over two sets of sites with refined occupancies of 0.768 (17) and 0.232 (17). The molecular conformation is stabilized by an intramolecular O—H...O hydrogen bond, forming anS(8) ring motif. In the crystal, C—H...O hydrogen bonds connect the molecules into layers parallel to (001), enclosingR12(7) ring motifs.

The asymmetric unit of the title compound, C22H21N3O2, consists of two independent molecules (AandB) having differing conformations. The differences mainly concern the dihedral angles which the hydroxyphenyl and dimethylphenyl rings subtend to the central phenylene ring, these being 30.16 (6) and 58.60 (6)° in moleculeAand 13.42 (7) and 60.31 (7)° inB. With the exception of the dimethyphenyl substituent, the conformations of the rest of each molecule are largely determined by intramolecular O—H...N and N—H...O hydrogen bonds. In the crystal, N—H...O hydrogen bonds link the molecules into chains extending parallel to theaaxis in which the types of molecules alternate in an …A…B…A…B… fashion.

The title compound, C21H21NO5, crystallizes with two molecules in the asymmetric unit. In each molecule, the central 1,4-dihydropyridine ring adopts a shallow sofa conformations (with the C atom bearing the phenol ring as the flap), whereas the pendant cyclohexene rings both have twisted-boat conformations. Each molecule features an intramolecular O-H center dot center dot center dot O hydrogen bond, which closes an S(8) ring. In the crystal, the molecules are linked by O-H center dot center dot center dot O, C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions, forming a three-dimensional network.

The asymmetric unit of the title compound, C18H17N3O2, comprises three independent molecules (1, 2 and 3). In molecule 1, the dihedral angles between the pyrazolone ring and the pendant phenyl and hydroxybenzene rings are 54.43 (6) and 28.72 (6)°, respectively. The corresponding data for molecule 2 are 86.84 (6) and 25.69 (5)°, respectively, and for molecule 3 are 47.41 (7) and 17.09 (7)°, respectively. The three molecules feature an intramolecular C—H...O interaction, which closes anS(6) ring in each case. In the crystal, molecules are linked by O—H...O hydrogen bonds, which generate [100] chains incorporating all three asymmetric molecules. Two weak C—H...O interactions connect three independent molecules to each other along the c-axis direction.

In the title compound, C9H15N3S, the cyclopentyl ring adopts an envelope conformation with one of the methylene C atoms as the flap. The thiosemicarbazide fragment is almost planar (r.m.s. deviation = 0.038 angstrom) and a short intramolecular N-H center dot center dot center dot N contact occurs. In the crystal, molecules are linked into helical (4(1) symmetry) chains propagating in [001] by N-H center dot center dot center dot N and N-H center dot center dot center dot S hydrogen bonds. A very weak C-H center dot center dot center dot S interaction is also observed.

In the title compound, C21H19N3O3S, the 5,6,7,8-tetrahydropyridine ring adopts a half-chair conformation. The fused-thieno[2,3-d]pyrimidine ring system is essentially planar (r.m.s. deviation = 0.001 Å) and forms a dihedral angle of 2.66 (6)° with the attached phenyl ring. The three-dimensional crystal packing is stabilized by C—H...O and C—H...N hydrogen bonds and C—H...π interactions.

In the title compound, C17H17N5, the dihedral angle between the 1H-pyrazolo[3,4-b]pyridine ring system (r.m.s. deviation = 0.001 Å) and the attached phenyl group is 2.56 (6)°. The propylamino side chain has a contorted conformation [Car—N—C—C = −77.97 (16)° and N—C—C—C = −57.37 (17)°]. An intramolecular C—H...N interaction closes anS(6) ring. In the crystal, inversion dimers linked by pairs of N—H...N hydrogen bonds generateR22(12) loops. Aromatic π–π stacking interactions [centroid–centroid distance = 3.5726 (8) Å] are also observed.

In the title compound, C17H17N3O3S, the cyclopentane ring is disordered over two sets of sites with an occupancy ratio of 0.775 (8):0.225 (8) for the affected atoms. The thiazolidinyl ring is planar (r.m.s. deviation = 0.024 Å) and forms a dihedral angle of 65.13 (8)° with the attached phenyl ring. The molecular packing is stabilized by C—H...O and C—H...π interactions, forming a three-dimensional structure.

The asymmetric unit of the title compound, C54H64O12S4, consists of one half of the mol-ecule, which is located on an inversion centre. The heterocyclic six-membered ring adopts a distorted envelope conformation with the spiro C atom as the flap. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds with an R (2) 2(14) motif, forming a chain along the b-axis direction.