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The synthesis, crystal structure, and a Hirshfeld surface analysis of tris{N,N-diethyl-N′-[(4-nitrophenyl)(oxo)methyl]carbamimidothioato}cobalt(III) conducted at 180 K are presented. The complex consists of three N,N-diethyl-N′-[(4-nitrobenzene)(oxo)methyl]carbamimidothioato ligands, threefold symmetrically bonded about the CoIII ion, in approximately octahedral coordination, which generates a triple of individually near planar metallacyclic (Co—S—C—N—C—O) rings. The overall geometry of the complex is determined by the mutual orientation of each metallacycle about the crystallographically imposed threefold axis [dihedral angles = 81.70 (2)°] and by the dihedral angles between the various planar groups within each asymmetric unit [metallacycle to benzene ring = 13.83 (7)°; benzene ring to nitro group = 17.494 (8)°]. The complexes stack in anti-parallel columns about the \overline{3} axis of the space group (P\overline{3}), generating solvent-accessible channels along [001]. These channels contain ill-defined, multiply disordered, partial-occupancy solvent. Atom–atom contacts in the crystal packing predominantly (∼96%) involve hydrogen, the most abundant types being H...H (36.6%), H...O (31.0%), H...C (19.2%), H...N (4.8%), and H...S (4.4%).

The crystal structure and a Hirshfeld surface analysis of the substituted anilinium salt 4-(dimethylazaniumyl)-2-hydroxyanilinium dichloride monohydrate, C8H14N2O+·2Cl−·H2O, at low temperature (90 K) are presented. The organic cation is essentially planar: the r.m.s. deviation of its non-hydrogen atoms (aside from the two methyl groups) is 0.0045 Å. The methyl carbons are 1.3125 (12) Å and 1.1278 (12) Å either side of the mean plane. The crystal packing involves extensive hydrogen bonding of types O—H...Cl, N—H...Cl, N—H...OW, and OW—HW...Cl (where W = water), which arrange into chains of R24(12) motifs that combine to form corrugated layers parallel to (10\overline{1}). Atom–atom contacts for the cation primarily involve hydrogen, leading to the most abundant coverage percentages being 51.3% (H...H), 23.0% (H...Cl), 12.9% (H...O), and 9.7% (C...H).

The syntheses and crystal structure studies of four organic salts of trihexyphenidyl, viz., trihexyphenidylium [1-(3-cyclohexyl-3-hydroxy-3-phenylpropyl)piperidin-1-ium] 4-nitrobenzoate, C20H32NO+·C7H4NO4− (I), trihexyphenidylium 4-hydroxybenzoate, C20H32NO+·C7H5O− (II), trihexyphenidylium 4-bromobenzoate, C20H32NO+·C7H4BrO2− (III), and trihexyphenidylium thiophene-2-carboxylate hemihydrate, 2C20H32NO+·2C5H3O2S−·H2O (IV), conducted at 90 K are described. Structures I, II, and III are solvent free with one cation–anion pair per asymmetric unit, while IV crystallizes as a hemihydrate, having two cation–anion pairs and one water of crystallization in its asymmetric unit. Structures I and III exhibit configurational disorder of the cation. Structure IV also exhibits disorder, but only of the thiophene-2-carboxylate anions. Structure II is a non-merohedric twin by a twofold rotation about [403]. The main supramolecular motifs in I, II, and III are similar R22(10) rings between cation–anion pairs, although their packing within the crystals is distinct. As a consequence of having two cation–anion pairs and a water molecule in its asymmetric unit, the packing in IV is by far the most complex of the four structures, its hydrogen-bonding patterns being quite different from I, II, or III. In all the crystals studied, N—H...O, O—H...O, and C—H...O interactions are observed, plus C—H...Br close contacts for III.

The synthesis and crystal structure of a monoclinic polymorph of 2-amino-5-chlorobenzophenone oxime, C13H11ClN2O, are presented. The molecular conformation results from twisting of the phenyl and 2-amino-5-chloro benzene rings attached to the oxime group, which subtend a dihedral angle of 80.53 (4)°. In the crystal, centrosymmetric dimers are formed as a result of pairs of strong O—H...N hydrogen bonds. A comparison is made to a previously known triclinic polymorph, including differences in atom–atom contacts obtained via a Hirshfeld-surface analysis.

The synthesis, crystal structure and spectroscopic analysis of (E)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(4-chlorophenyl)prop-2-en-1-one (C17H13ClO3), a substituted chalcone, are described. The overall geometry of the molecule is largely planar (r.m.s. deviation = 0.1742 Å), but slightly kinked, leading to a dihedral angle between the planes of the benzene rings at either side of the molecule of 8.31 (9)°. In the crystal, only weak interactions determine the packing motifs. These include C—H...O and C—H...Cl hydrogen bonds and π–π overlap of aromatic rings.

The synthesis and crystal structure of C3HF3N2OS, systematic name 5-(trifluoromethyl)-1,3,4-thiadiazol-2(3H)-one (5-TMD-2-one), a compound containing the pharmacologically important heterocycle 1,3,4-thiadiazole, is presented. The asymmetric unit comprises six independent molecules (Z′ = 6), all of which are planar. The r.m.s. deviations from each mean plane range from 0.0063 to 0.0381 Å, not including the CF3 fluorine atoms. Within the crystal, two of the molecules form hydrogen-bonded dimers that in turn combine with inversion-related copies to form tetrameric constructs. Similar tetramers, but lacking inversion symmetry, are formed by the remaining four molecules. The tetramers are linked into tape-like motifs by S...O and O...O close contacts. The environments of each symmetry-independent molecule were compared via a Hirshfeld surface analysis. The most abundant atom–atom contacts are between fluorine atoms, while the strongest result from N—H...O hydrogen bonds.

The syntheses and crystal structures of four salts of amitriptynol (C20H25NO) with different carboxylic acids are described. The salts formed directly from solutions of amitriptyline (which first hydrolysed to amitriptynol) and the corresponding acid in acetonitrile to form amitriptynolium [systematic name: (3-{2-hydroxytricyclo[9.4.0.03,8]pentadeca-1(11),3,5,7,12,14-hexaen-2-yl}propyl)dimethylazanium] 4-methoxybenzoate monohydrate, C20H26NO+·C8H7O3−·H2O, (I), amitriptynolium 3,4-dimethoxybenzoate trihydrate, C20H26NO+·C9H9O4−·3H2O, (II), amitriptynolium 2-chlorobenzoate, C20H26NO+·C7H4ClO2−, (III), and amitriptynolium thiophene-2-carboxylate monohydrate, C20H26NO+·C5H3O2S−·H2O, (IV). Compound (III) crystallizes with two cations, two anions and six water molecules in the asymmetric unit. The different conformations of the amitriptynolium cations are determined by the torsion angles in the dimethylamino-propyl chains and the –CH2–CH2- bridge between the benzene rings in the tricyclic ring system, and are complicated by disorder of the bridging unit in II and III. The packing in all four salts is dominated by N—H...O and O—H...O hydrogen bonds. Hirshfeld surface analyses show that the amitriptynolium cations make similar inter-species contacts, despite the distinctly different packing in each salt.

The synthesis and crystal structure of the title compound, C12H16FNO3S, which is related to the herbicide flufenacet, are presented. The dihedral angle between the amide group and the fluorinated benzene ring is 87.30 (5)° and the N—C—C—S torsion angle defining the orientation of the methylsulfonyl substituent relative to the amide group is 106.91 (11)°. In the crystal, inversion-related molecules form dimers as a result of pairwise C—H...O hydrogen bonds, which appear to be reinforced by short O...π contacts [O...Cg = 3.0643 (11) Å]. A Hirshfeld surface analysis was used to quantify the various types of intermolecular contacts, which are dominated by H atoms.

Syntheses and X-ray crystal structures of four 4-(4-methoxyphenyl)piperazin-1-ium (MeOPP) salts, with 2,2,2-trifluoroacetate, C11H17N2O+·C2F3O2− (I), 2,3,4,5,6-pentafluorobenzoate, C11H17N2O+·C7F5O2−·H2O (II), 4-iodobenzoate C11H17N2O+·C7H4IO2−·H2O (III), and 4-methylbenzoate, C11H17N2O+·C8H7O2−·H2O (IV) anions are presented. The salts form directly from equimolar quantities of N-(4-methoxyphenyl)piperazine and the corresponding organic acid in methanol and crystallize from 1:1 methanol/ethyl acetate. Salt I is anhydrous whereas II, III, and IV are all monohydrates. In all cases, the MeOPP cation conformation is determined by the torsion about the N—C bond between the piperazinium and 4-methoxybenzene rings. Crystal packing in each structure is largely dictated by N—H...O and (in II, III, and IV) O—H...O hydrogen bonds, although each also features weak C—H...O-type hydrogen bonds. Salt II also has π–π-stacking interactions between cation and anion arene rings, and III exhibits I...I close contacts.

This paper compares variations on a structure model derived from an X-ray diffraction data set from a solid solution of chalcogenide derivatives of cis-1,2-bis(diphenylphosphanyl)ethylene, namely, 1,2-(ethene-1,2-diyl)bis(diphenylphoshpine sulfide/selenide), C26H22P2S1.13Se0.87. A sequence of processes are presented to ascertain the composition of the crystal, along with strategies for which aspects of the model to inspect to ensure a chemically and crystallographically realistic structure. Criteria include mis-matches between Fobs2 and Fcalc2, plots of |Fobs| vs |Fcalc|, residual electron density, checkCIF alerts, pitfalls of the OMIT command used to suppress ill-fitting data, comparative size of displacement ellipsoids, and critical inspection of interatomic distances. Since the structure is quite small, solves easily, and presents a number of readily expressible refinement concepts, we feel that it would make a straightforward and concise instructional piece for students learning how to determine if their model provides the best fit for the data and show students how to critically assess their structures.

Abstract Background Bioprospecting of actinobacteria isolated from Kubuqi desert, China for antibacterial, antifungal and cytotoxic metabolites production and their structure elucidation. Results A total of 100 actinobacteria strains were selectively isolated from Kubuqi desert, Inner Mongolia, China. The taxonomic characterization revealed Streptomyces as the predominant genus comprising 37 different species, along with the rare actinobacterial genus Lentzea. The methanolic extracts of 60.8% of strains exhibited potent antimicrobial activities against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Escherichia coli, Salmonella enterica, Saccharomyces cerevisiae and high to mild in vitro cytotoxicity against PC3 (prostate cancer) and A549 (lung carcinoma) cell lines. The metabolomics analysis by TLC, HPLC-UV/vis, HPLC-MS and NMR showed the presence of compounds with molecular weights ranging from 100 to 1000 Da. The scale-up fermentation of the prioritized anti-Gram-negative strain PU-KB10–4 (Streptomyces griseoviridis), yielded three pure compounds including; griseoviridin (1; 42.0 mgL− 1) with 20 fold increased production as compared to previous reports and its crystal structure as monohydrate form is herein reported for the first time, mitomycin C (2; 0.3 mgL− 1) and a new bacterial metabolite 4-hydroxycinnamide (3; 0.59 mgL− 1). Conclusions This is the first report of the bioprospecting and exploration of actinobacteria from Kubuqi desert and the metabolite 4-hydroxycinnamide (3) is first time isolated from a bacterial source. This study demonstrated that actinobacteria from Kubuqi desert are a potential source of novel bioactive natural products. Underexplored harsh environments like the Kubuqi desert may harbor a wider diversity of actinobacteria, particularly Streptomyces, which produce unique metabolites and are an intriguing source to develop medicinally valuable natural products.

The syntheses and crystal structures are presented for four organic salts of the 4-(4-nitrophenyl)piperazinium cation, namely, 4-(4-nitrophenyl)piperazinium hydrogen succinate, C10H14N3O2+·C4H5O4− (I), 4-(4-nitrophenyl)piperazinium 4-aminobenzoate monohydrate, C10H14N3O2+·C7H6NO2−·H2O (II), 4-(4-nitrophenyl)piperazinium 2-(4-chlorophenyl)acetate, C10H14N3O2+·C8H6ClO2− (III) and 4-(4-nitrophenyl)piperazinium 2,3,4,5,6-pentafluorobenzoate, C10H14N3O2+·C7F5O2− (IV). The salts form from mixtures of N-(4-nitrophenyl)piperazine and the corresponding acid [succinic acid (I), 4-aminobenzoic acid (II), 2-(4-chlorophenyl)acetic acid (III) and 2,3,4,5,6-pentafluorobenzoic acid (IV)] in mixed solvents of methanol and ethyl acetate. Salts I, III, and IV are anhydrous, whereas II is a monohydrate. In each structure, the overall conformation of the cation is determined by the disposition of the exocyclic N—C bond of the piperazine ring (either axial or equatorial) and twists about the N—C bond between the piperazine ring and its attached 4-nitrophenyl ring. The packing motifs in each structure are quite different, though all are dominated by strong N—H...O hydrogen bonds, which are augmented in I and II by O—H...O hydrogen bonds, and in III by a π–π stacking interaction between inversion-related 4-nitrophenyl groups.

The crystal structure of ethiprole {systematic name: 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-ethanesulfinyl-1H-imidazole-3-carbonitrile}, C13H9Cl2F3N4OS, a phenylpyrazole-based insecticide, is presented. The pyrazole ring carries four substituents: an N-bound 2,6-dichloro-4-trifluoromethylphenyl ring and C-bound amine, ethanesulfinyl, and cyano groups. The sulfur atom of the ethanesulfinyl group is trigonal–pyramidal and stereogenic. The structure exhibits whole-molecule configurational disorder due to superposition of enantiomers. The crystal packing is dominated by strong N—H...O and N—H...N hydrogen bonds, which form R44(18) and R22(12) ring motifs. Since the ethiprole molecule is quite small, and structure solution and refinement were straightforward, the structure presents a convenient instructional example for modelling whole-body disorder of a non-rigid molecule. To this end, a step-by-step overview of the model-building and refinement process is also given. The structure could form the basis of a useful classroom, practical, or workshop-style example.

The structure of 2-chloro-1-(3-hydroxyphenyl)ethanone, C8H7ClO2, an α-haloketone is described. The molecule is planar (r.m.s. deviation = 0.0164 Å) and in the crystal, inversion-symmetric dimers are formed as a result of pairs of strong O—H...O and weak C—H...O hydrogen bonds. A brief comparison is made with structurally related compounds deposited in the CSD. In addition, the synthesis and some spectroscopic details are presented.

The structure of the title compound, C15H8N4Cl2F6OS, a phenylpyrazole-based insecticide related to ethiprole, fipronil, and derivatives thereof is presented. The pyrazole ring has four chemically diverse substituents, namely a nitrogen-bound 2,6-dichloro-4-trifluoromethylphenyl and carbon-bound cyano, ethylsulfanyl, and 2,2,2-trifluoroacetamide groups. The pyrazole and phenyl rings are perpendicular, subtending a dihedral angle of 89.80 (5)°. In the crystal, strong N—H...O hydrogen bonds link the molecules into chains that extend parallel to the a-axis.

Benzyl N′-[(E)-2-hydroxybenzylidene]hydrazinecarboxylate, C15H14N2O3 (I) and benzyl N′-[(E)-5-bromo-2-hydroxybenzylidene]hydrazinecarboxylate (II), C15H13BrN2O3, have been synthesized by the reaction of either 2-hydroxybenzaldehyde or 5-bromo-2-hydroxybenzaldehyde with benzyl carbazate, respectively. Both the compounds crystallize in the monoclinic crystal system with space groups Pn (Z′ = 1, I) and P21/c (Z′ = 2, II). Molecular conformations in each structure are similar, and both structures feature strong intramolecular O—H...N hydrogen bonds, which form S(6) ring motifs. There are also strong N—H...O and weak C—H...O hydrogen bonds in both structures, but their modes of packing within their respective crystals are markedly different. Some comparisons are made with the structures of a few related compounds.

The low (90 K) and room (298 K) temperature crystal structures of topiramate azidosulfate [systematic name 2,3:4,5-bis-O-(1-methylethylidene)-β-d-fructopyranose azidosulfate], C12H19N3O8S, an intermediate in the synthesis of the anti-convulsant drug topiramate, are described. Topiramate azidosulfate (I) finds use as a reference impurity standard for topiramate. A modified synthesis and some spectroscopic details are also presented.

Synthesis and crystal structures of 1-benzoyl-4-(4-nitrophenyl)piperazine, C17H17N3O3, (I) and 1-(4-bromobenzoyl)-4-phenylpiperazine, C17H17BrN2O, (II) are described. Compounds I and II crystallize in the orthorhombic and monoclinic crystal systems with space groups Pna21 (Z′ = 2, I) and P21 (Z′ = 1, II), respectively. The crystal of II was a two-component aggregate, treated as a `twin' for data-acquisition purposes. There are no conventional hydrogen bonds in either I or II, but there are weaker C—H...O contacts. Each molecule consists of a central piperazine ring in a chair conformation, with either benzoyl and nitrophenyl (I) or 4-bromobenzoyl and phenyl (II) groups attached to different nitrogen atoms of the piperazine. The various atom–atom contact coverages as quantified by Hirshfeld surface analysis fingerprint plots are given.

The structure of ebastinium hydrogen fumarate {systematic name: 1-[4-(4-tert-butylphenyl)-4-oxobutyl]-4-(diphenylmethoxy)piperidin-1-ium (E)-3-carboxy-1-hydroxyprop-2-en-1-olate}, C32H40NO2+·C4H3O4−, a 1:1 salt formed in the reaction between ebastine and fumaric acid is presented. All examined crystals were found to be twinned by pseudo-merohedry. The structure is extensively disordered, with over half (20 out of 35) its non-hydrogen atoms modelled as lying over two sets of sites. In the crystal, cation–anion pairs are linked by a strong N—H...O hydrogen bond [N...O = 2.697 (11) Å]. These units interact via weaker C—H...O and C—H...π contacts to form layers lying parallel to the bc plane. The hydrogen fumarate anions are linked by a very short O—H...O hydrogen bond [O...O = 2.5402 (17) Å], augmented by weak C—H...O contacts into pairs of R22(6) ring motifs to form chains that extend parallel to the b-axis direction. Comparisons to similar crystal structures are presented.

A compilation of articles with a strong teaching element published since 2018 is presented alongside an overview of the articles in the special issue on this topic.

A simplified two-step synthesis of 3,6-dihydroxypicolinic acid (3-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxylic acid), C6H5NO4 (II), an intermediate in the metabolism of picolinic acid, is described. The crystal structure of II, along with that of a labile intermediate, dipotassium 3-hydroxy-6-(sulfonatooxy)pyridine-2-carboxylate monohydrate, 2K+·C6H3NO7S2−·H2O (I), is also described. Compound I comprises a pyridine ring with carboxylate, hydroxyl (connected by an intramolecular O—H...O hydrogen bond), and sulfate groups at the 2-, 3-, and 6-positions, respectively, along with two potassium cations for charge balance and one water molecule of crystallization. These components are connected into a three-dimensional network by O—H...O hydrogen bonds arising from the water molecule, C—H...O interactions and π–π stacking of pyridine rings. In II, the ring nitrogen atom is protonated, with charge balance provided by the carboxylate group (i.e., a zwitterion). The intramolecular O—H...O hydrogen bond observed in I is preserved in II. Crystals of II have unusual space-group symmetry of type Abm2 in which extended planar networks of O—H...O and N—H...O hydrogen-bonded molecules form sheets lying parallel to the ac plane, constrained to b = 0.25 (and 0.75). The structure was refined as a 50:50 inversion twin. A minor disorder component was modeled by reflection of the major component across a mirror plane perpendicular to c.

The title compound, C16H20N22+·2Br−·H2O (1) is a member of the class of compounds called viologens. Viologens are quaternary salts of dipyridyls and are especially useful as redox indicators as a result of their large negative one-electron reduction potentials. Compound 1 consists of a dication composed of a pair of 4-methylpyridine rings mutually joined at the 2-position, with a dihedral angle between the pyridine rings of 62.35 (4)°. In addition, the rings are tethered via the pyridine nitrogen atoms by a tetramethylene bridge. Charge balance is provided by a pair of bromide anions, which are hydrogen bonded to a single water molecule [DO...Br = 3.3670 (15) and 3.3856 (15) Å]. The crystal structure of 1, details of an improved synthesis, and a full analysis of its NMR spectra are presented.

ABSTRACT As the COVID-19 pandemic progresses, there is an increasing need for rapid, accessible assays for SARS-CoV-2 detection. We present a clinical evaluation and real-world implementation of the INDICAID COVID-19 rapid antigen test (INDICAID rapid test). A multisite clinical evaluation of the INDICAID rapid test using prospectively collected nasal (bilateral anterior) swab samples from symptomatic subjects was performed. The INDICAID rapid test demonstrated a positive percent agreement (PPA) and negative percent agreement (NPA) of 85.3% (95% confidence interval [95% CI], 75.6% to 91.6%) and 94.9% (95% CI, 91.6% to 96.9%), respectively, compared to laboratory-based reverse transcriptase PCR (RT-PCR) using nasal specimens. The INDICAID rapid test was then implemented at COVID-19 outbreak screening centers in Hong Kong as part of a testing algorithm (termed “dual-track”) to screen asymptomatic individuals for prioritization for confirmatory RT-PCR testing. In one approach, preliminary positive INDICAID rapid test results triggered expedited processing for laboratory-based RT-PCR, reducing the average time to confirmatory result from 10.85 h to 7.0 h. In a second approach, preliminary positive results triggered subsequent testing with an onsite rapid RT-PCR, reducing the average time to confirmatory result to 0.84 h. In 22,994 asymptomatic patients, the INDICAID rapid test demonstrated a PPA of 84.2% (95% CI, 69.6% to 92.6%) and an NPA of 99.9% (95% CI, 99.9% to 100%) compared to laboratory-based RT-PCR using combined nasal/oropharyngeal specimens. The INDICAID rapid test has excellent performance compared to laboratory-based RT-PCR testing and, when used in tandem with RT-PCR, reduces the time to confirmatory positive result. IMPORTANCE Laboratory-based RT-PCR, the current gold standard for COVID-19 testing, can require a turnaround time of 24 to 48 h from sample collection to result. The delayed time to result limits the effectiveness of centralized RT-PCR testing to reduce transmission and stem potential outbreaks. To address this, we conducted a thorough evaluation of the INDICAID COVID-19 rapid antigen test, a 20-minute rapid antigen test, in both symptomatic and asymptomatic populations. The INDICAID rapid test demonstrated high sensitivity and specificity with RT-PCR as the comparator method. A dual-track testing algorithm was also evaluated utilizing the INDICAID rapid test to screen for preliminary positive patients, whose samples were then prioritized for RT-PCR testing. The dual-track method demonstrated significant improvements in expediting the reporting of positive RT-PCR test results compared to standard RT-PCR testing without prioritization, offering an improved strategy for community testing and controlling SARS-CoV-2 outbreaks.

Abstract The reaction of gold reagents [HAuCl4•3H2O], [AuCl(tht)], or cyclometalated gold(III) precursor, [C^NAuCl2] with chiral ((R,R)-(-)-2,3-bis(t-butylmethylphosphino) quinoxaline) and non-chiral phosphine (1,2-Bis(diphenylphosphino)ethane, dppe) ligands lead to distorted Au(I), (1, 2, 4, 5) and novel cyclometalated Au(III) complexes (3, 6). These gold compounds were characterized by multinuclear NMR, microanalysis, mass spectrometry, and X-ray crystallography. The inherent electrochemical properties of the gold complexes were also studied by cyclic voltammetry and theoretical insight of the complexes was gained by density functional theory and TD-DFT calculations. The complexes effectively kill cancer cells with IC50 in the range of ~0.10–2.53 μΜ across K562, H460, and OVCAR8 cell lines. In addition, the retinal pigment epithelial cell line, RPE-Neo was used as a healthy cell line for comparison. Differential cellular uptake in cancer cells was observed for the compounds by measuring the intracellular accumulation of gold using ICP-OES. Furthermore, the compounds trigger early – late stage apoptosis through potential disruption of redox homeostasis. Complexes 1 and 3 induce predominant G1 cell cycle arrest. Results presented in this report suggest that stable gold-phosphine complexes with variable oxidation states hold promise in anticancer drug discovery and need further development.

The title compound, C21H25NO3 [systematic name: (1aR,4E,7aS,8E,10aS,10bR)-8-(2-aminobenzylidene)-1a,5-dimethyl-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one], was synthesized by the reaction of parthenolide [systematic name (1aR,7aS,10aS,10bS,E)-1a,5-dimethyl-8-methylene-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one] with 2-iodoaniline via Heck reaction conditions. The molecule is composed of fused ten-, five- (lactone), and three-membered (epoxide) rings. The lactone ring shows a flattened envelope-type conformation (r.m.s. deviation from planarity = 0.0477 Å), and bears a 2-aminobenzylidene substituent that is disordered over two conformations [occupancy factors 0.901 (4) and 0.099 (4)]. The ten-membered ring has an approximate chair–chair conformation. The dihedral angle between the 2-aminobenzylidine moiety (major component) and the lactone ring (mean plane) is 59.93 (7)°. There are no conventional hydrogen bonds, but there are a number of weaker C—H...O-type interactions.

The title structure, C12H8Cl2O2, is a putative metabolite of 3,5-dichlorobiphenyl (PCB 14). The dihedral angle between the two benzene rings of the title compounds is 58.86 (4)°. In the crystal, it displays intra- and intermolecular O—H...O hydrogen bonding and intermolecular O—H...Cl hydrogen...chlorine interactions. The intermolecular interactions form a two-dimensional network parallel to (010).

The title compound [systematic name: 4-(2,3-Dichlorophenyl)benzene-1,2-diol], C12H8Cl2O2, is a putative dihydroxylated metabolite of 2,3-dichlorobiphenyl (PCB 5). The title structure displays intramolecular O—H...O hydrogen bonding, and the π–π stacking distance between inversion-related chlorinated benzene rings of the title compound is 3.371 (3) Å. The dihedral angle between two benzene rings is 59.39 (8)°.

The title compound, C14H12Cl2O2, is a dimethoxylated derivative of 3,4-dichlorobiphenyl (PCB 14). The dihedral angle between the benzene rings is 42.49 (6)°. The methoxy groups on the non-chlorinated ring lie essentially in the plane of the benzene ring, with C—C—O—C torsion angles of 4.0 (2) and −2.07 (19)°. In the crystal, the compound displays π–π stacking interactions between inversion-related chlorinated benzene rings, with an interplanar stacking distance of 3.3695 (17) Å.

(Z)-5-[2-(Benzo[b]thiophen-2-yl)-1-(3,5-dimethoxyphenyl)ethenyl]-1H-tetrazole methanol monosolvate, C19H16N4O2S·CH3OH, (I), was prepared by the reaction of (Z)-3-(benzo[b]thiophen-2-yl)-2-(3,5-dimethoxyphenyl)acrylonitrile with tributyltin azide via a [3 + 2]cycloaddition azide condensation reaction. The structurally related compound (Z)-5-[2-(benzo[b]thiophen-3-yl)-1-(3,4,5-trimethoxyphenyl)ethenyl]-1H-tetrazole, C20H18N4O3S, (II), was prepared by the reaction of (Z)-3-(benzo[b]thiophen-3-yl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile with tributyltin azide. Crystals of (I) have two molecules in the asymmetric unit (Z′ = 2), whereas crystals of (II) have Z′ = 1. The benzothiophene rings in (I) and (II) are almost planar, with r.m.s deviations from the mean plane of 0.0084 and 0.0037 Å in (I) and 0.0084 Å in (II). The tetrazole rings of (I) and (II) make dihedral angles with the mean planes of the benzothiophene rings of 88.81 (13) and 88.92 (13)° in (I), and 60.94 (6)° in (II). The dimethoxyphenyl and trimethoxyphenyl rings make dihedral angles with the benzothiophene rings of 23.91 (8) and 24.99 (8)° in (I) and 84.47 (3)° in (II). In both structures, molecules are linked into hydrogen-bonded chains. In (I), these chains involve both tetrazole and methanol, and are parallel to the b axis. In (II), molecules are linked into chains parallel to the a axis by N—H...N hydrogen bonds between adjacent tetrazole rings.

The title compound, C28H32N2, (I), is one of a second generation of compounds designed and synthesized based on a very potent and selective α9α10 nicotinic acetylcholine receptor antagonist ZZ161C {1,1′-[[1,1′-biphenyl]-4,4′-diylbis(prop-2-yne-3,1-diyl)]bis(3,4-dimethylpyridin-1-ium) bromide}, which has shown analgesic effects in a chemotherapy-induced neuropathy animal model. Compound (I) was synthesized by the reaction of 4,4′-bis(3-bromoprop-1-yn-1-yl)-1,1′-biphenyl with piperidine at room temperature in acetonitrile. The single-crystal used for X-ray analysis was obtained by dissolving (I) in a mixture of dichloromethane and methanol, followed by slow evaporation of the solvent. In the crystal of (I), the biphenyl moiety has a twisted conformation, with a dihedral angle of 25.93 (4)° between the benzene rings. Both piperidine head groups in (I) are in the chair conformation and are oriented so that the N-atom lone pairs of each piperidine group point away from the central biphenyl moiety.

The title compounds, C26H28N2, (I), and C28H32N2, (II), were designed based on the structure of the potent α9α10 nicotinic acetylcholine receptor antagonist ZZ161C {1,1′-[[1,1′-biphenyl]-4,4′-diylbis(prop-2-yne-3,1-diyl)]bis(3,4-dimethylpyridin-1-ium) bromide}. In order to improve the druglikeness properties of ZZ161C for potential oral administration, the title compounds (I) and (II) were prepared by coupling 4,4′-bis(3-bromoprop-1-yn-1-yl)-1,1′-biphenyl with pyrrolidine, (I), and (S)-2-methylpyrrolidine, (II), respectively, in acetonitrile at room temperature. The asymmetric unit of (I) contains two half molecules that each sit on sites of crystallographic inversion. As a result, the biphenyl ring systems in compound (I) are coplanar. The biphenyl ring system in compound (II), however, has a dihedral angle of 28.76 (11)°. In (I), the two independent molecules differ in the orientation of the pyrrolidine ring (the nitrogen lone pair points towards the biphenyl rings in one molecule, but away from the rings in the other). The torsion angles about the ethynyl groups between the planes of the phenyl rings and the pyrrolidine ring N atoms are 84.15 (10) and −152.89 (10)°. In compound (II), the corresponding torsion angles are 122.0 (3) and 167.0 (3)°, with the nitrogen lone pairs at both ends of the molecule directed away from the central biphenyl rings.

As part of a comprehensive program to discover α9α10 nicotinic acetylcholine receptor antagonists, the title compounds C30H36N2, (I), and C36H48N2, (II), were synthesized by coupling 4,4′-bis(3-bromoprop-1-yn-1-yl)-1,1′-biphenyl with 4-methylpiperidine and 2,2,6,6-tetramethylpiperidine, respectively, in acetonitrile at room temperature. In compound (I), the biphenyl system has a twisted conformation with a dihedral angle of 26.57 (6)° between the two phenyl rings of the biphenyl moiety, while in compound (II), the biphenyl moiety sits on a crystallographic inversion centre so the two phenyl rings are exactly coplanar. The terminal piperidine rings in both compound (I) and compound (II) are in the chair conformation. In compound (I), the dihedral angles about the ethynyl groups between the planes of the phenyl rings and the piperidine ring N atoms are 37.16 (16) and 14.20 (17)°. In compound (II), the corresponding dihedral angles are both 61.48 (17)°. There are no noteworthy intermolecular interactions in (I), but in (II) there is a small π-overlap between inversion-related molecules (1 − x, 1 − y, 1 − z), with an interplanar spacing of 3.553 (3) Å and centroid-to-centroid separation of 3.859 (4) Å.

In the title compound, [CuCl(C17H19Cl4N3)]ClO4, the CuII ion adopts a distorted square-planar geometry defined by one chloride ligand and the three nitrogen atoms from the bis[(pyridin-2-yl)methyl](3,5,5,5-tetrachloropentyl)amine ligand. The perchlorate counter-ion is disordered over three sets of sites with refined occupancies 0.0634 (17), 0.221 (16) and 0.145 (7). In addition, the hetero-scorpionate arm of the bis[(pyridin-2-yl)methyl](3,5,5,5-tetrachloropentyl)amine ligand is disordered over two sets of sites with refined occupancies 0.839 (2) and 0.161 (2). In the crystal, weak Cu...Cl interactions between symmetry-related molecules create a dimerization with a chloride occupying the apical position of the square-pyramidal geometry typical of many copper(II) chloride hetero-scorpionate complexes.

The title compound, C19H17N3O3S (I), was prepared by a [3 + 2]cycloaddition azide condensation reaction using sodium azide and l-proline as a Lewis base catalyst. N-Methylation of compound (I) using CH3I gave compound (II), C20H19N3O3S. The benzothiophene ring systems in (I) and (II) are almost planar, with r.m.s deviations from the mean plane = 0.0205 (14) in (I) and 0.016 (2) Å in (II). In (I) and (II), the triazole rings make dihedral angles of 32.68 (5) and 10.43 (8)°, respectively, with the mean planes of the benzothiophene ring systems. The trimethoxy phenyl rings make dihedral angles with the benzothiophene rings of 38.48 (4) in (I) and 60.43 (5)° in (II). In the crystal of (I), the molecules are linked into chains by N—H...O hydrogen bonds with R21(5) ring motifs. After the N-methylation of structure (I), no hydrogen-bonding interactions were observed for structure (II). The crystal structure of (II) has a minor component of disorder that corresponds to a 180° flip of the benzothiophene ring system [occupancy ratio 0.9363 (14):0.0637 (14)].

The title compound, C19H22N2O3, {systematic name (1aR,4E,7aS,8E,10aS,10bR)-1a,5-dimethyl-8-[(pyrimidin-5-yl)methylidene]-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one} was obtained from the reaction of parthenolide [systematic name (1aR,7aS,10aS,10bR,E)-1a,5-dimethyl-8-methylene-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one] with 5-bromopyrimidine under Heck reaction conditions, and was identified as an E isomer. The molecule possesses ten-, five- (lactone) and three-membered (epoxide) rings with a pyrimidine group as a substituent. The ten-membered ring displays an approximate chair–chair conformation, while the lactone ring shows a flattened envelope-type conformation. The dihedral angle between the pyrimidine moiety and the lactone ring system is 29.43 (7)°.

The title compound, C20H23N3O6·CH3OH, was synthesized by [3 + 2] cycloaddition of (Z)-2,3-bis(3,4,5-trimethoxyphenyl)acrylonitrile with sodium azide and ammonium chloride in DMF/water. The central nitrogen of the triazole ring is protonated. The dihedral angles between the triazole ring and the 3,4,5-trimethoxyphenyl ring planes are 34.31 (4) and 45.03 (5)°, while that between the 3,4,5-trimethoxyphenyl rings is 51.87 (5)°. In the crystal, the molecules, along with two methanol solvent molecules are linked into an R44(10) centrosymmetric dimer by N—H...O and O—H...N hydrogen bonds.

The title compound, C33H35NO6 [systematic name: (Z)-3-(4-{(E)-[(E)-1a,5-dimethyl-9-oxo-2,3,7,7a-tetrahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-8(1aH,6H,9H,10aH,10bH)-ylidene]methyl}phenyl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile methanol hemisolvate], C33H35NO6·0.5CH3OH, was prepared by the reaction of (Z)-3-(4-iodophenyl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile with parthenolide [systematic name: (E)-1a,5-dimethyl-8-methylene-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one] under Heck reaction conditions. The molecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings with a {4-[(Z)-2-cyano-2-(3,4,5-trimethoxyphenyl)ethenyl]phenyl}methylidene group as a substituent. The 4-[(Z)-2-cyano-2-(3,4,5-trimethoxyphenyl)ethenyl]phenyl group on the parthenolide exocyclic double bond is oriented in a trans position to the lactone ring to form the E isomer. The dihedral angle between the benzene ring of the phenyl moiety and the lactone ring mean plane is 21.93 (4)°.

The title compound, C12H14N6O, consists of three pyrazole rings bound via nitrogen to the distal ethane carbon of methoxy ethane. The dihedral angles between the three pyrazole rings are 67.62 (14), 73.74 (14), and 78.92 (12)°. In the crystal, molecules are linked by bifurcated C—H,H...N hydrogen bonds, forming double-stranded chains along [001]. The chains are linked via C—H...O hydrogen bonds, forming a three-dimensional framework structure. The crystal was refined as a perfect (0.5:0.5) inversion twin.

In the crystal structure of the title compound, C6H2Cl2INO2, there are weak C—H...Cl interactions and I...O [3.387 (4) Å] close contacts. These interactions form sheets in the ac plane, with the closest contact between adjacent planes occurring between inversion-related nitro O atoms [3.025 (8) Å]. The molecule possesses mirror symmetry, with the halogen, N and C atoms all lying in the mirror plane. Hence, the dihedral angle between the benzene ring and the nitro group is 90°.

The title monosuccinate derivative of melampomagnolide B [systematic name: 4-(((1aR,7aS,10aS,10bS,E)-1a-methyl-8-methylene-9-oxo-1a,2,3,6,7,7a,8,9,10a,10b-decahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-5-yl)methoxy)-4-oxobutanoic acid], C19H24O7, was obtained from the reaction of melampomagnolide B with succinic anhydride under nucleophilic addition reaction conditions. The molecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings. The internal double bond in the ten-membered ring has the cis geometry (i.e. it is the E isomer). The lactone ring has an envelope-type conformation, with the (chiral) C atom opposite the lactone O atoms as the flap atom. In the crystal, O—H...O hydrogen bonds link the molecules into chains parallel to the b-axis direction.

The title compound, C21H23BrO3 [systematic name: (3E,3aS,6Z,9R,9aS,9bS)-3-(2-bromobenzylidene)-9-hydroxy-6,9-dimethyl-3,3a,4,5,7,8,9,9a-octahydroazuleno[4,5-b]furan-2(9bH)-one] was prepared by the reaction of 1-bromo-2-iodobenzene with micheliolide [systematic name: (3aS,R,9aS,9bS,Z)-9-hydroxy-6,9-dimethyl-3-methylene-3,3a,4,5,7,8,9,9a-octahydroazuleno[4,5-b]furan-2(9bH)-one] under Heck reaction conditions. The title compound exhibits intramolecular O—H...O hydrogen bonding between the hydroxy group and the lactone ring O atom, forming a ring of graph-set motif S(6). The 2-bromophenyl group is trans to the lactone ring, indicating that this is the E isomer (geometry of the exocyclic C=C bond). The dihedral angle between the benzene ring of the 2-bromophenyl moiety and the mean plane of the lactone ring is 51.68 (7)°.

The title compound, C18H24N2O4·H2O {systematic name: (1aR,7aS,8R,10aS,10bS,E)-5-hydroxymethyl-8-[(1H-imidazol-1-yl)methyl]-1a-methyl-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one monohydrate}, an imidazole derivative of melampomagnolide B was synthesized under Michael addition conditions. The molecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings. The internal double bond of the ten-membered ring identifies it as the cis or E isomer. The lactone ring has an envelope-type conformation, with the (chiral) C atom opposite the lactone O atoms as the flap atom. In the crystal, O—H...O, O—H...N and weak C—H...O hydrogen bonds link the molecules (along with water) into sheets parallel to the bc plane.

The title compound, C17H27NO3·0.08H2O {sytematic name: (3R,3aS,9R,9aS,9bS)-3-[(dimethylamino)methyl]-9-hydroxy-6,9-dimethyl-3,3a,4,5,7,8,9,9a-octahydroazuleno[4,5-b]furan-2(9bH)-one 0.08-hydrate}, exhibits intramolecular O—H...O hydrogen bonding to form a ring of graph-set motif S(6). As well as this intramolecular hydrogen bond with the lactone-ring O atom, the hydroxy H atom forms an O—H...O hydrogen bond to the low-occupancy partial water molecule [occupancy = 0.078 (2)]. The water molecule is correlated with disorder of the N(CH3)2 group [major–minor occupancy factors are 0.922 (2):0.078 (2)]. The dihedral angle between the mean planes of the trans-fused seven-membered ring and the lactone ring is 4.42 (9)°.

The title compound, C21H25NO3 [systematic name: (3aS,9aR,10aR,10bS,E)-3-[(E)-4-(4-aminobenzylidene)-6,9a-dimethyl-3a,4,5,8,9,9a,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-2(3H)-one] was obtained from the reaction of parthenolide [synonym: 4,5-epoxygermacra-1(10),11(13)-dieno-12,6-lactone] with 4-iodoaniline under Heck reaction conditions. It was identified as the E-isomer (conformation about the exocyclic methylidene C=C bond; the conformation about the C=C bond in the ten-membered ring is also E). The molecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings with a 4-aminophenyl group as a substituent. The ten-membered ring displays an approximate chair–chair conformation, while the lactone ring has an envelope conformation with the C atom bonded to the ring O atom as the flap. The dihedral angle between the benzene ring of the 4-aminophenyl moiety and the lactone ring mean plane is 23.50 (8)°. In the crystal, molecules are linked via N—H...O hydrogen bonds, between the amine group and the lactone and epoxide ring O atoms, forming chains propagating along the b-axis direction. Adjacent chains are linked via C—H...O interactions, forming an undulating two-dimensional network lying parallel to the plane (001). The absolute structure of the molecule in the crystal was confirmed by resonance scattering [Flack parameter = 0.03 (3)].

In the title salt, [Ni(C12H14N6O)2](CF3SO3)2·2H2O, the NiII cation is located on an inversion centre and is coordinated by six N atoms from two tridentate 1-methoxy-2,2,2-tris(pyrazol-1-yl)ethane ligands in a distorted octahedral geometry. The Ni—N distances range from 2.0594 (12) to 2.0664 (12) Å, intra-ligand N—Ni—N angles range from 84.59 (5) to 86.06 (5)°, and adjacent inter-ligand N—Ni—N angles range between 93.94 (5) and 95.41 (5)°. In the crystal, inversion-related pyrazole rings are π–π stacked, with an interplanar spacing of 3.4494 (18) Å, forming chains that propagate parallel to the a-axis direction. Intermolecular O—H...O hydrogen bonds are present between water molecules and trifluoromethanesulfonate anions.

In the title salt, [Ni(C12H14N6O)2](CF3SO3)2·2CH3OH, the NiII ion is coordinated by six N atoms from two tridentate 1-methoxy-2,2,2-tris(pyrazol-1-yl)ethane ligands in a distorted octahedral geometry. The NiII ion is situated on an inversion centre. The Ni—N distances range from 2.0589 (19) to 2.0757 (19) Å, intra-ligand N—Ni—N angles range from 84.50 (8) to 85.15 (8)°, and adjacent inter-ligand N—Ni—N angles range between 94.85 (8) and 95.50 (8)°. In the crystal, O—H...O hydrogen bonds between methanol solvent molecules and trifluoromethanesulfonate anions are observed.

In the title molecule, C16H14Cl4O, the dihedral angle between the least-square planes of the benzene rings is 84.40 (7)°. No unusual intermolecular interactions are present.