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A series of novel 2-iminothiazolidin-4-one analogs have been synthesized from limonaketone, and structurally characterized by HR-MS

The title compound, C17H12O4, was synthesized from the dye alizarin. The dihedral angle between the mean plane of the anthraquinone ring system (r.m.s. deviation = 0.039 Å) and the dioxepine ring is 16.29 (8)°. In the crystal, the molecules are linked by C—H...O hydrogen bonds, forming sheets lying parallel to the ab plane. The sheets are connected through π–π and C=O...π interactions to generate a three-dimensional supramolecular network. Hirshfeld surface analysis was used to investigate intermolecular interactions in the solid-state: the most important contributions are from H...H (43.0%), H...O/O...H (27%), H...C/C...H (13.8%) and C...C (12.4%) contacts.

International audience; The synthesis and crystal structure of one-dimensional (1-D) coordination polymer from an angular dipyridyl ligand 2,5-bis(pyridine-4-yl)-1,3,4-oxadiazole (4-pox) and CuCl 2 2H 2 O, [Cu I (4-poxH)(SCN)(μ 1,3-SCN)] n (named complex 1), are reported. The investigated copper(I) complex crystallizes in the monoclinic crystal system with space group P 2 1 / n. UV-vis and FTIR suggest the co-presence of the 4-pox ligand and the pseudohalide, in the isolated complex. This was confirmed by a crystallographic study which shows that the copper is in a tetrahedral environment, linked to two thiocyanate groups and to two nitrogen atoms, one belonging to the pyridine ring and the others to thiocyanate group. The crystallographic study also reveals the protonation of the unbound organic ligand pyridine. The crystal cohesion is assured by different intermolecular hydrogen bonds, π-π stacking, and coordination bonds (N-Cu and S-Cu). Therefore, the one-dimensional coordination chains are further interconnected by hydrogen bonds and π-π stacking to from a three-dimensional supramolecular framework. This behaviour was confirmed by Hirshfeld surface analysis. The thermal analysis reveals that complex 1 is thermally stable up to 160 °C. The magnetic measurements indicated the diamagnetic nature of this Cu I coordination polymer.

A novel pyrazolo-enaminones, bipyrazoles and bipyrazolopyridines from 1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)butane-1,3-dione and 4-methyl-2-phenyl-2H-pyrazolo[3,4-b]pyridine-3,6(3aH,7H)-dione have been synthesized by assisted heating with microwave radiation without any catalyst. The pyridine and pyrazole ring formation has been developed from easily accessible enamino keto esters by formylation followed by intramolecular cyclization. The general applicability for the synthesis of the important pyrazolo-enaminones, bipyrazoles and pyrazolo-pyridines heterocycles was attributed to simplicity of operation, synthesis without catalyst, energy efficiency (shorter reaction time under microwave irradiation), good yields, more environmentally friendly and more cost-effective procedure. The antioxidant activity of new heterocyclic compounds was evaluated by free radical scavenging by DPPH assay. Several of these compounds showed good activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria.

International audience; In this study, 3,3'-di(pyridin-4-yl)-(2,2'-dimethoxy-[1,1'-biphenyl]) (L) was synthetized, structurally characterized by X-ray crystallography and combined with HgCl2, CoCl2, or ZnSiF6 for the formation of three coordination polymers ((HgCl2)2(L), (CoCl2)2(L)2.CHCl3, and Zn(SiF6)(L)2). The crystal structures of synthesis compound indicate the formation of different types of coordination modes, and each adopts a mono (1D) or tri-dimensional (3D) framework by C-H•••π interactions. In (CoCl2)2(L)2, the combination of Co(II) with L forms a metallomacrocycle, while in the other compounds two helical infinite networks were characterized. Compounds (HgCl2)2(L) made of two helical chains with opposite chirality (P and M), and Zn(SiF6)(L)2 exhibits helical tubular assemblies of the L attached to two Zn(SiF6) pillars. This work may pave the way to further study the chemical, structural and physicochemical properties of metal-organic coordination polymers.

The title compound, C

International audience; Polysubstituted naphthalenes and their analogues have been found in nature or synthesized, and have attracted increasing attention due to their numerous pharmacological and biological activities. The present study describes a synthesis of novel series of methoxynaphthalene derivatives using the Stobbe condensation reaction method. The chemical structures of these compounds were confirmed by spectroscopic techniques such as 1H and 13C NMR, IR, LC-HRMS spectral data and X-ray crystallography. The supramolecular assembly in the structures reported here is dominated by C—H···O hydrogen bonds for compounds 5, 6, 8, 11, 14 and 17 and O—H···O for compound 12. The molecules are also arranged by C–H···π interaction and/or π—π stacking, which are responsible for the formation and stability of the molecular assemblies. Hirshfeld surface analysis was also performed in order to obtain reliable structural information in concurrence with experimental results, and intermolecular interactions that exist inside the crystal have been investigated. Additionally, DFT calculations have been used to analyze the electronic and geometric frontier molecular orbital and Molecular Electrostatic Potential map analyses of the compounds were produced using the optimized structures.

International audience; In this work, the compound 2 named ethyl (1,1-dichloro-1a,5,5,7-tetramethyl-8-oxo-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-6-yl)glycinate (C20H29Cl2NO3) was synthesized from the α,β-unsaturated sesquiterpenicketone1 using the azido-Schmidt reaction catalyzed by titanium tetrachloride (TiCl4). The structure of the newly synthesized enaminone 2 was fully identified on the basis of its HRMS, FT-IR, UV-Visible, NMR (1 H & 13 C) spectral data, and X-ray crystallography. The compounds 1 and 2 were evaluated for their cytotoxic activity in four human cancer cell lines, fibrosarcoma (HT-1080), lung carcinoma (A-549), and breast (MCF-7 and MDA-MB-231). Data showed that compound 1 wasthe most activeagainst HT-1080 and A-549 cells with IC50 values between 13.28 and 16.41 µM.Thetheoretical Study Theory (DFT) was used to predict the molecular proprieties which lead to the highest potential of cytotoxic effect, in accordance to the experimental spectroscopic data.

The crystal structure of 4-allyl-2-meth­oxy-6-nitro­phenol, which crystallizes in the centrosymmetric space group P with three independent mol­ecules in the asymmetric unit, is reported along with the Hirshfeld surface analysis., The asymmetric unit of the title compound, C10H11NO4, which was synthesized via nitration reaction of eugenol (4-allyl-2-meth­oxy­phenol) with a mixture of nitric acid and sulfuric acid, consists of three independent mol­ecules of similar geometry. Each mol­ecule displays an intra­molecular hydrogen bond involving the hydroxide and the nitro group forming an S(6) motif. The crystal cohesion is ensured by inter­molecular C—H⋯O hydrogen bonds in addition to π–π stacking inter­actions between the aromatic rings [centroid–centroid distances = 3.6583 (17)–4.0624 (16) Å]. The Hirshfeld surface analysis and the two-dimensional fingerprint plots show that H⋯H (39.6%), O⋯H/H⋯O (37.7%), C⋯H/H⋯C (12.5%) and C⋯C (4%) are the most important contributors towards the crystal packing.

A new quinoline-based hydrazone compound, has been synthesized by a condensation reaction of 2-chloro-3-formyl­quinoline with phenyl­hydrazine. The quinoline ring system is essentially planar (r.m.s. deviation = 0.012 Å), and forms a dihedral angle of 8.46 (10)° with the phenyl ring substituent., A new quinoline-based hydrazone, C16H12ClN3, was synthesized by a condensation reaction of 2-chloro-3-formyl­quinoline with phenyl­hydrazine. The quinoline ring system is essentially planar (r.m.s. deviation = 0.012 Å), and forms a dihedral angle of 8.46 (10)° with the phenyl ring. The mol­ecule adopts an E configuration with respect to the central C=N bond. In the crystal, mol­ecules are linked by a C—H⋯π-phenyl inter­action, forming zigzag chains propagating along the [10] direction. The N—H hydrogen atom does not participate in hydrogen bonding but is directed towards the phenyl ring of an adjacent mol­ecule, so linking the chains via weak N—H⋯π inter­actions to form of a three-dimensional structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (35.5%), C⋯H/H⋯C (33.7%), Cl⋯H/H⋯Cl (12.3%), N⋯H/H⋯N (9.5%) contacts.

The NiII atom in the mononuclear title complex has an almost regular octa­hedral N4O2 coordination geometry. In the crystal, the complex mol­ecules are linked in a three-dimensional network through strong O—H⋯N hydrogen bonds., The reaction of 2,5-bis­(pyridin-4-yl)-1,3,4-oxa­diazole (4-pox) and thio­cyanate ions, used as co-ligand with nickel salt NiCl2·6H2O, produced the title complex, [Ni(NCS)2(C12H8N4O)2(H2O)2]. The NiII atom is located on an inversion centre and is octa­hedrally coordinated by four N atoms from two ligands and two pseudohalide ions, forming the equatorial plane. The axial positions are occupied by two O atoms of coordinated water mol­ecules. In the crystal, the mol­ecules are linked into a three-dimensional network through strong O—H⋯N hydrogen bonds. Hirshfeld surface analysis was used to investigate the inter­molecular inter­actions in the crystal packing.

International audience; A concise and versatile synthetic strategy for the total synthesis of arylnaphthalene lignans and aza-analogs was developed. The main objective was to develop synthetic tactics for the creation of the lactone and lactam unit that would give access to an array of synthetic, natural, and/or bioactive compounds through rather simple chemical manipulation. The flexibility and potentiality of these new processes were further illustrated by the total synthesis of retrojusticidin B (13b), justicidin C (14b), and methoxy-vitedoamine A (22a). In this study, a series of novel aryl-naphthalene lignans and aza-analogs were synthesized, and the cytotoxic activities of all compounds on cancer cell growth were evaluated. The target compounds were structurally characterized by 1H NMR (nuclear magnetic resonance), 13C NMR, infrared, high-resolution mass spectrometry, and X-ray crystallography. The IC50 values of these compounds on five tumor cell lines (A549, HS683, MCF-7, SK-MEL-28, and B16-F1) were obtained by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay. Five of the compounds exhibited excellent activity compared to 5-fluorouracil and etoposide against the five cell lines tested, with IC50 values ranging from 1 to 10 μM.

A novel homobimetallic cobalt(II) complex, [Co2(bpt)2(H2O)4](NO3)2·2H2O (bpt = 3,5-bis(2-pyridyl)-1,2,4-triazolate), has been synthesized and characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV–Visible and FTIR techniques. The crystal structure determination shows that the dinuclear complex crystallizes in the triclinic crystal system with the P 1 - space group. The (N′,N1,N2,N″)2 double bridging coordination mode is realised with a distorted octahedral N4O2-coordinated cobalt centre. The structure cohesion is ensured by different intermolecular hydrogen bonds, π–π stacking interactions and intermolecular lone-pair···π interactions. The structure consists of [Co2(bpt)2]2+ dimeric units with a cobalt-cobalt distance of 4.170(2) A. Magnetic measurements carried out on the homobimetallic complex indicate a relatively weak antiferromagnetic interaction between the two cobalt centres. This complex exhibited antimicrobial activity against several strains of the fungal phytopathogens Verticillium dahliae and Fusarium oxysporum fsp. melonis, as well as against the phytopathogenic bacteria Agrobacterium tumefaciens, suggesting its use in crop protection.

The dihedral angle between the mean plane of the anthra­quinone ring system and the dioxepine ring in the title compound is 16.29 (8)°. The packing is consolidated by C—H⋯O, π–π and C=O⋯π inter­actions., The title compound, C17H12O4, was synthesized from the dye alizarin. The dihedral angle between the mean plane of the anthra­quinone ring system (r.m.s. deviation = 0.039 Å) and the dioxepine ring is 16.29 (8)°. In the crystal, the mol­ecules are linked by C—H⋯O hydrogen bonds, forming sheets lying parallel to the ab plane. The sheets are connected through π–π and C=O⋯π inter­actions to generate a three-dimensional supra­molecular network. Hirshfeld surface analysis was used to investigate inter­molecular inter­actions in the solid-state: the most important contributions are from H⋯H (43.0%), H⋯O/O⋯H (27%), H⋯C/C⋯H (13.8%) and C⋯C (12.4%) contacts.

A new series of diverse triazoles linked to the hydroxyl group of totarol were synthesized using click chemistry approach. The structures of these compounds were elucidated by HRMS, IR and NMR spectroscopy. The structure of compound 3 g was also confirmed by x-ray single crystal diffraction. The cytotoxicity of these compounds was evaluated by the MTT method against four cancer cell lines, including fibrosarcoma HT-1080, lung carcinoma A-549 and breast adenocarcinoma (MDA-MB-231 and MCF-7), and the results indicated that all compounds showed weak to moderate activities against all cancer cell lines with IC50 values ranging from 14.44 to 46.25 μM. On the basis of our research the structure–activity relationships (SAR) of these compounds were discussed. This work provides some important hints for further structural modification of totarol towards developing novel and highly effective anticancer drugs respectively. It is interesting to note that compound 3 g indicated a very significant cytotoxicity against HT-1080 and A-549 cell lines. The molecular docking showed that compound 3 g activated the caspase-3 and inhibited tubulin by forming stable protein–ligand complexes.

The structure of this new derivative of Euphorbioside [systematic name: (1S,2R,3R,5R,8R)-8-((R,E)-3-hydroxybut-1-en-1-yl)-1,5-dimethyl-6-oxabicyclo[3.2.1]octane-2,3-diol hydrate] was determined by its single-crystal X-ray structure, and to studies with the use of NMR, LC/HRMS and IR spectra. The title compound is built up from two fused five- and six-membered rings, with an additional hydroxybut-1-en-1-yl group and water molecule. The five-membered ring, which has an envelope conformation, makes dihedral angles of 77.46(13)° with the benzene ring. The water molecule forms O—H…O hydrogen bond. In the crystal, intermolecular O—H…O and C—H…O hydrogen bonds lead to the formation of three-dimensional framework. The nature of intermolecular interactions in the supramolecular structure Hirshfeld surface analysis and 2D fingerprint was carried out. The most important contributions for the crystal packing are from H•••H (75.2%) and O•••H/H•••O (24.6%) interactions. Additionally, DFT calculations have been used to analyze the electronic and geometric frontier molecular orbital, Molecular Electrostatic Potential map analyses, Mulliken and Natural bond charges were produced by using the optimized structures.

New series of benzohydrazide/benzoic acid derivatives were synthesized (4a-b and 5a-b) and subjected to solid-state characterization by NMR spectroscopic measurements. The molecular and crystal structures of 4a and 5a have also been examined by single-crystal X-ray crystallography were reveal that naphthalene frameworks are close to planarity. Besides, the dihedral angle between the mean plane of the naphthalene ring system and the phenyl ring is 2.26(7) and 78.87(8)° for 4a and 5a, respectively. The molecules are linked through N—H⋯O and C—H⋯O hydrogen bonds, forming chains parallel to the ab plane in benzohydrazide and O—H⋯O contacts in benzoic acid. The sheets are further stacked through C—H⋯π interactions resulting in the formation of a 3D supramolecular network. Hirshfeld surface analysis has also been performed to investigate intermolecular interactions in the solid-state; the most important contributions for the crystal packing are from H⋯H, C⋯H/H⋯C, and O⋯H/H⋯O interactions. Additionally, DFT calculations with the B3LYP/6-311G (d, p) level of the theory have been used to analyze the Mulliken atomic charges, molecular electrostatic potential map, and non-linear optical properties of the compounds were produced using the optimized structures. Moreover, the natural bond orbital analysis is conducted to explore the interactions among different orbital and lone pairs taking place within the compounds. The energy framework calculations suggest that the contacts formed between molecules are largely dispersive.

The title compound, C22H28O3, was prepared by a direct acetylation reaction of naturally occurring totarolenone. The molecule contains three fused rings, which exhibit different conformations. The central ring has a half-chair conformation, while the non-aromatic oxo-substituted ring has a screw-boat conformation. In the crystal, molecules are linked by C—H...O hydrogen bonds and C—H...π interactions, forming sheets parallel to the bc plane. The carbonyl O atoms and the C atom at the 6-position of the cyclohexene ring are each disordered over two sets of sites with major occupancy components of 0.63 (7) and 0.793 (14), respectively.

This article describes firstly the synthesis of a new series of isoxazole 5a-e from p-methoxythymol, extracted from Tetraclinis Articulata, as starting material involving 1,3-dipolar cycloaddition reaction and secondly a detailed study of the molecular packing and intermolecular interactions in crystals of five related 5-((2-isopropyl-4-‑methoxy‑5-methylphenoxy)methyl)-3-phenylisoxazole derivatives. All compounds were synthesized and subjected to solid state characterization by single-crystal X-ray diffraction analysis, and to studies with the use of NMR and Hirshfeld surface analysis. All structures display intermolecular C—H···O hydrogen bonding and C—H···π interactions, forming layers in the crystal lattice. The crystal structures of compounds 5a; 5c and 5d are consolidated by π—π interactions. Hirshfeld surface analysis, the dnorm surfaces, electrostatic potential and two-dimensional fingerprint plots were examined to verify the contributions of the different intermolecular contacts within the supramolecular structure. The most important contributions for the crystal packing are from H···H, H···C/C···H and O···H/H···O interactions. Additionally, DFT calculations have been used to analyze the electronic and geometric frontier molecular orbital and Molecular Electrostatic Potential map analyses of the compounds were produced using the optimized structures.

Reaction of 2,4-pentanedione with thiosemicarbazide in 1:2 ratio produces cyclic pyrazoline thiosemicarbazone (H2L2 with L2 = C7H12N6S2). The obtained ligand has been characterized by elemental analysis, UV–Visible, FTIR, 1H and 13C NMR. The results suggest that the ligand is in pyrazolinic form, and finally the structure has been confirmed by single crystal X-ray diffraction. The [(L2•)Cu(SCN)] copper complex has been prepared by reaction of H2L2 and thiocyanate salt with copper acetates and has been fully characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV–Visible, FTIR, and Raman spectroscopies. TGA analysis and magnetic measurements were also performed. Single-crystal X-ray diffraction reveals that the complex is a neutral monomer with copper in distorted tetrahedral environment. The anionic ligand (L2•)− remained in cyclic form and is coordinated as terdentate ligand (SNS). The title complex results from a double deprotonation coupled with a monoelectronic oxidation of H2L2 and it may be seen as a CuII-ligand radical type complex. The copper ion is tetra coordinated (CuN2S2) by two sulfur and one nitrogen of (L2•)− and by thiocyanate nitrogen atoms. The new [(L2•)Cu(SCN)] complex crystallizes in the monoclinic system and C 2/c space group. Full-Potential Linearized Augmented Planewave Method (FLAPW) calculations based on the Density-Functional Theory (DFT) principle are performed to shed light on both electronic and magnetic structures as well. [(L2•)Cu(SCN)] showed a greater activity than its parental ligand H2L2 against two strains of the phytopathogenic fungus Verticillium dahliae while a moderate antibacterial activity was recorded with both against Agrobacterium tumefaciens strains and Pseudomonas syringae pv. syringae.

A new α-amino-1H Indazolyl-phosphonates derivative 3a–e were synthesized and subjected to solid state characterization by single-crystal X-ray diffraction analysis, and to study their NMR and Hirshfeld surface analysis. The P atom exhibits tetrahedral geometry involving two O-ethyl groups, a C atom and a double-bonded O atom. The P–C bond has an approximately staggered conformation, with the aniline and substituted groups in gauche positions with respect to the P O double bond. The molecules are arranged as centrosymmetric or pseudocentrosymmetric dimers connected by two N–H⋯O P hydrogen bonds and also by C–H … π interaction in the case of structures 3a–e, which are responsible for the formation and stability of the molecular assemblies. Hirshfeld surface analysis (dnorm surface and two-dimensional (2D) fingerprint plots) revealed the nature of intermolecular contacts. The most important contributions for the crystal packing are from H⋯H, H⋯C/C⋯H, O⋯H/H⋯O, and H⋯N/N⋯H interactions. In addition, frontier molecular orbitals and Molecular Electrostatic Potential map of the compounds was produced by using the optimized structures.

A new copper (II) mono-dimensional coordination polymer based on 2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole (L) as bridging ligand, noted [CuLCl2]n, has been synthesized by reaction of L with copper salt (CuCl2·2H2O) and characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV–Visible, and FTIR techniques. The copper cation lies on an inversion centre and displays elongated octahedral coordination geometry. The equatorial positions are occupied by the N atoms of two ligands, whereas the axial positions are occupied by the chlorine atoms. The 1,3,4-thiadiazole and the pyridyl rings linked to the metal are approximately coplanar, with a maximum deviation from the mean plane of 0.330 (2) A. The Cu2+ cations form the infinite chains parallel to c-axis and the organic molecules are linked to Cu atoms in zigzag chains building an infinity tape running along [0 0 1] direction. The cohesion of the polymeric complex structure is ensured by C–H⋯Cl weak hydrogen bonds and π–π interactions between pyridyl and thiadiazole rings forming a three-dimensional structure, as established by Hirshfeld surface analysis. This new 1-D copper coordination polymer exhibited elevated antimicrobial activity against several strains of the fungal phytopathogens Verticillium dahliae and Fusarium oxysporum fsp. melonis suggesting its use as a fungicide in crop protection.

The bis(2,5-di(pyridin-2-yl)-1,3,4-thiadiazole-κ2N,N′)-bis(thiocyanato-κ1N)cobalt(II) complex has been synthetized from the reaction of 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole (L) with metallic salt CoCl2.6H2O and thiocyanate ion (SCN−) as coligand in H2O/CH3CN at room temperature. The synthetized complex (CoL2(SCN)2) has been fully characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, as well as UV–Visible, FTIR, Raman, and NMR spectroscopy. TGA analysis and magnetic measurements were also performed. CoL2(SCN)2 crystallizes in monoclinic symmetry and P 21/c space group with two independent cobalt crystallographic sites, where each cobalt atom is localized in a distorted octahedral environment CoN6, with the thiadiazole molecules (L) as bidentate ligands in equatorial sites and terminal SCN− ions in axial positions. The crystal cohesion is assured by intermolecular hydrogen bonding, C–H⋯π and π–π stacking; in addition to the N–Cu coordination bonds. This has been confirmed by the three dimensional Hirshfeld surface analysis and the two dimensional fingerprint plots that highlight the dominance of intermolecular interactions C⋯H/H⋯C and S⋯H/H⋯S. The thermal analysis of CoL2(SCN)2 reveals that this complex is thermally stable up to 200 °C. Variable-temperature magnetic susceptibility measurements on CoL2(SCN)2 complex indicated an antiferromagnetic exchange between the two non-equivalent cobalt(II) ions with a ferrimagnetic behaviour.

Treatment of thiosemicarbazones prepared from sesquiterpenes with ethyl 2-bromoacetate in the presence of sodium acetate afforded the corresponding thiazolidin-4-ones. The structures of all the newly synthesized compounds were established by considering spectral and single-crystal X-ray diffraction data. The title compound, ethyl 2-((Z)-2-{(Z)-[(1aR,5aR,9aS)-1,1-dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-ylidene]hydrazono}-4-oxothiazolidin-3-yl)acetate, C23H31Cl2N3O3S, 5, crystallizes in the orthorhombic noncentrosymmetric space group P212121 with Z = 4. Within the molecule in the crystal structure, the cyclohexene ring has an envelope conformation and the cycloheptane ring, to which it is fused, has a boat conformation. In the crystal, molecules are linked by C—H...Cl hydrogen bonds forming chains propagating along the b-axis direction. The absolute configuration of the molecule in the crystal could be fully confirmed from anomalous dispersion effects [Flack parameter = −0.04 (2)]. Thiosemicarbazones 1 and 2 are efficient inhibitors for steel corrosion in 1 M H2SO4 solution, with a maximum efficiency of 92.28% at 10−3 M. Furthermore, thiosemicarbazone compounds were found to be more efficient than thiazolidin-4-one derivatives. In addition, cyclic voltammetry was used to characterize the tested molecules, as well to estimate the experimental value of the energy band gap.

Treatment of thiosemicarbazones prepared from sesquiterpenes with ethyl 2-bromoacetate in the presence of sodium acetate afforded the corresponding thiazolidin-4-ones. The structures of all the newly synthesized compounds were established by considering spectral and single-crystal X-ray diffraction data. The title compound, ethyl 2-((Z)-2-{(Z)-[(1aR,5aR,9aS)-1,1-dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-ylidene]hydrazono}-4-oxothiazolidin-3-yl)acetate, C

There are two independent molecules (AandB) in the asymmetric unit of the title compound, C11H19N3S. In moleculeB, two C atoms and the associated H atoms of the cyclohexene ring are disordered over two sets of sites with a site occupancy ratio of 0.649 (7):0.351 (7). The N—N—C—N fragments of the hydrazinecarbothioamide segments of both molecules are not planar, with a torsion angle of −5.8 (3)° forAand 11.6 (3)° forB. The stability of the conformations of both molecules is aided by the formation of intramolecular N—H...N hydrogen bonds. In the crystal, N—H...S hydrogen bonds link like molecules intoR22(8)A+Bdimers. These dimers are interconnected by additional N—H...S contacts, forming chains along thec-axis direction. The structure was refined as a two-component inversion twin.

In the title compound, C17H17N3O3·H2O, the dihedral angle between the 4,6-dimethyl-pyrazolo[3,4-b]pyridine-3-one unit [maximum deviation = 0.048 (2) Å] and the phenyl ring is 5.1 (1)°. The structure is characterized by disorder of the carboxylate O atoms, which are split into two parts with a major component of 0.898 (4). In the crystal, the organic molecules and lattice water molecules are linked via O—H...O, O—H...N and N—H...O hydrogen bonds. The molecules are also linked by C—H...π and weak offset π–π stacking interactions, forming sheets parallel to (001).

In the almost planar (r.m.s. deviation = 0.038 Å) title compound, C10H10N4O3, an intramolecular N—H...O interaction closes anS(6) ring. In the crystal, aromatic π–π stacking interactions occur [inter-centroid distance = 3.65 (2) Å].

In the title compound, C17H16N2O5, the dihedral angles between the central urea [N—C(=O)—N] fragment and its attached benzene rings are 20.20 (14) and 24.24 (13)°; the dihedral angle between the aromatic rings is 42.1 (1)°. The molecular conformation is consolidated by two intramolecular N—H...O hydrogen bonds, which both generateS(6) rings. In the crystal, inversion dimers linked by pairs of C—H...O interactions generateR22(14) loops. The dimers are linked by further C—H...O interactions into (011) sheets.