[4‐(Tri­fluoro­methyl)­phenyl]­aceto­nitrile

The crystal structure of the title compound, C₉H₆F₃N, at 123 K contains mol­ecules linked together via several C—H?F and C—H?N contacts, the strongest of which are 2.58 and 2.65 Å, respectively. Apparently, an F atom in the CF₃ group is able to compete with a cyano N atom for aromatic H atoms but is less prone to interact with the more acidic methyl­ene H atoms. The Ph–CH₂CN torsion angle is ?6.4 (2)° and the planar phenyl ring exhibits a typical deformation of the endo angles at the ipso‐C atoms, due to the difference in the electron‐withdrawing power of the CF₃ and CH₂CN substituents.     

Tetrakis­(tri­phenyl­phosphine)silver(I) tetra­phenyl­borate aceto­nitrile solvate

In the title compound, [Ag{P(C₆H₅)}₄][B{P(C₆H₅)}₄]·CH₃CN, the Ag ion resides on a crystallographic twofold rotation axis and is tetrahedrally coordinated. There is a disparity between the two independent Ag—P distances. This is due, in part, to the temperature differences (all previous determinations are at room temperature) but also to the packing effects of various anions.     

Pentaaceto­nitrile­bromo­aluminium(III) bis­[tetra­bromo­aluminium(III)] aceto­nitrile solvate

An­hydro­us aluminium(III) tribromide crystallizes from aceto­nitrile as a disolvate, AlBr₃·2MeCN, in the form [AlBr(C₂H₃N)₅][AlBr₄]₂·C₂H₃N, which is isomorphous with its orthorhombic chloride counterpart.     

1:2 Complexes of chloranilic acid with pyrazole and imidazole,and the aceto­nitrile solvate of a 1:1 complex with imidazole

2,5‐Di­chloro‐3,6‐di­hydroxy‐1,4‐benzo­quinone (chloranilic acid) forms X—H?Y (X, Y = N or O) and C—H?Cl hydrogen bonds with pyrazole and imidazole to afford bis­(pyrazolium) di­chloro­anilate and bis­(imidazolium) di­chloro­anilate, (I) and (II), both 2C₃H₅N₂⁺·C₆Cl₂O₄^2?, and imidazolium chloro­anilate aceto­nitrile solvate, C₃H₅N₂⁺·­C₆HCl₂O₄^?·C₂H₃N, (III). Their crystal structures demonstrate three novel supramolecular architectures based on supramolecular synthons to build a ladder, (I), a two‐dimensional network, (II), and a flat ribbon, (III).     

Two benzoyl­aminoacridinedione derivatives

The title compounds, 10‐benzoyl­amino‐1,2,3,4,5,6,7,8,9,10‐deca­hydroacridine‐1,8‐dione monohydrate, C₂₀H₂₀N₂O₃·H₂O, and 10‐p‐toluoylamino‐1,2,3,4,5,6,7,8,9,10‐deca­hydroacridine‐1,8‐dione monohydrate, C₂₁H₂₂N₂O₃·H₂O, consist of partially hydrogenated acridine moieties with one benzoyl­amino substituent on the central ring. The acridine moiety suffers considerable deviations from planarity. The central ring in the acridine moiety is a boat, while the outer rings adopt sofa conformations.     

Tetrakis(3,5‐di­methyl­pyridine)­dihydrido­silicon dibromide bis(aceto­nitrile) solvate and 3,5‐dimethylpyridinium bromide

In the course of an attempt to synthesize tetrakis(3,5‐di­methyl­pyridine)­dihydridosilicon dibromide, crystals of its aceto­nitrile disolvate, C₂₈H₃₈N₄Si²⁺·2Br^?·2C₂H₃N, (I), and of 3,5‐di­methyl­pyridinium bromide, C₇H₁₀N⁺·Br^?, (II), were obtained in the same reaction flask. They have both been structurally characterized.     

Two Uranyl Complexes with Pyromellitic Acid. A Heterometallic Complex with U=O–CuII Interaction

Two uranyl complexes based on pyromellitic acid were hydrothermally synthesized, and their X‐ray single‐crystal diffraction structures were determined. Complex [UO₂(Hbtec)]^–(Himd)⁺ · H₂O ( 1 ) (H₄btec = pyromellitic acid, imd = imidazole), is an ionic complex, which shows a typical (4, 4) topological structure in the space. A heterometallic complex, UO₂Cu(btec)(phen) ( 2 ) (phen = 1,10‐phenanthroline) results from the reaction of uranyl nitrate and copper(II) bromide with pyromellitic acid. The structure of complex 2 revealed that the chains of UO₇ and CuO₃N₂ units were connected to each other through the carboxyl groups and U=O–Cu interactions to create a two‐dimensional framework.     

Synthesis of 3‐imidazolylazole derivatives from a new nitrile oxide

The synthesis of a series of 3‐Imidazolylazole derivatives using cycloaddition reactions of a useful new nitrile oxide is described.     

Two optically active iso­quinoline derivatives

In the two title optically active tetra­hydro­iso­quinoline derivatives, namely 3‐hydroxy­methyl‐4‐phenyl‐1,2,3,4‐tetra­hydro­isoquinolin‐2‐ium bromide methanol hemisolvate, C₁₆H₁₈NO⁺·Br^?·0.5CH₃OH, (IIb), and 2‐formyl‐3‐hydroxy­methyl‐4‐phenyl‐1,2,3,4‐tetra­hydro­iso­quinoline, C₁₇H₁₇NO₂, (III), the absolute configurations have been confirmed as 3R,4R by structure refinement using Bijvoet‐pair reflections. The hydroxy­methyl and phenyl groups in (IIb) are oriented in equatorial and pseudo‐equatorial positions, respectively, whereas in (III), the corresponding groups are in axial and pseudo‐axial positions, respectively; the hydroxy­methyl and phenyl groups are trans with respect to one another in both structures. The heterocyclic rings in (IIb) and (III) adopt envelope conformations inverted with respect to each other. In both structures, the mol­ecules are linked through hydrogen bonds.     

Two new dimeric naphthoquinones with neuraminidase inhibitory activity from Lithospermum erythrorhizon

The crude methanol extract of roots of Lithospermum erythrorhizon was subjected to successive chromatographic fractionation which afforded two new dimeric naphthoquinone derivatives shikometabolin E (2) and shikometabolin F (3) as well as one known compound shikometabolin A (1). The structures of compounds 1–3 were elucidated by using UV, MS, 1D and 2D NMR spectroscopic analysis. The two new dimeric naphthoquinone derivatives showed significant neuraminidase inhibitory activities.     

(Aceto­nitrile)­[2,6‐bis­(pyrazol‐1‐yl)­pyridine](isonicotin­amide)copper(II)–tetra­fluoro­borate–aceto­nitrile (1/2/2)

Molecules of the title compound, [Cu(C₂H₃N)(C₁₁H₉N₅)(C₆H₆N₂O)](BF₄)₂·2C₂H₃N, comprise (aceto­nitrile)[2,6‐bis(pyrazol‐1‐yl)­pyridine](isonicotin­amide)copper(II) cations, tetra­fluoro­borate anions and lattice aceto­nitrile mol­ecules. The cations have distorted square‐pyramidal geometries in which the N₃‐donor, viz. 2,6‐bis­(pyrazol‐1‐yl)­pyridine, and the N‐donor, viz. the isonicotin­amide ligand, occupy the four basal positions, with the coordinated aceto­nitrile N‐donor atom occupying the apical position. Pairs of cations are linked by N—H?F hydrogen bonds through tetra­fluoro­borate anions, forming centrosymmetric dimers, which are further linked by C—H?O hydrogen bonds into two‐dimensional undulating sheets, three of which interpenetrate to generate a two‐dimensional network.     

2-isoxazoline derivatives—VIII : The reaction of nitrile oxides with tropone

The reaction of nitrile oxides with tropone yields a mixture of at least 8 products, the structures of which are based on spectral and chemical evidence. Both addition of the 1,3-dipole to the carbonyl group and cycloadditions to the CC double bonds system have been observed. Peri-, regio- and stereo-selectivity of the 1,3-dipole cycloaddition are discussed and rationalized on the basis of simple perturbation theory approach.     

Two dibenzodiazepinone molecules with dissimilar dimeric associations and apparent different tautomeric forms

In two dibenzodiazepinones, viz. the tricyclic core structure, 5H‐dibenzo[b,e]diazepin‐11(10H)‐one, C₁₃H₁₀N₂O, and an acylated derivative, 1‐(11‐hydroxy‐5H‐dibenzo[b,e]diazepin‐5‐yl)‐2‐{4‐[3‐(1H‐imidazol‐1‐yl)propyl]piperidin‐1‐yl}ethanone ethanol monosolvate, C₂₆H₂₉N₅O₂·C₂H₅OH, dimeric association via hydrogen‐bond bridging between the cyclic amide entities is evident, but there are considerable differences between the parent compound and the amidated derivative. Highly consistent with reported structures of related tricyclic lactams, two molecules of the nonsubstituted compound are bridged through two N—H...O hydrogen bonds across a crystallographic centre of symmetry and the bond lengths of the cyclic amide entity correspond to the amino–oxo (lactam) tautomeric form. In contrast, the structure of the derivative shows two similar, but crystallographically unique, molecules hydrogen bonded into a dimeric unit exhibiting an approximate (noncrystallographic) C2 axis. The bond lengths of the two derivative cyclic amide groups support their potential presence in the hydroxyimine (lactim) tautomeric forms, with the resulting possibility of intermolecular tautomerism. Likely driving forces for the two extreme configurations are discussed.     

Bis­[μ‐3{5}‐(2‐pyridyl)­pyrazolido]­bis­[(aceto­nitrile)copper(II)] diperchlorate

The title compound, [Cu₂(C₈H₆N₃)₂(C₂H₃N)₂](ClO₄)₂, con­tains a centrosymmetric dinuclear dication, with square‐pyrami­dal Cu^II centres linked by two 1,2‐pyrazolide bridging groups. There is a weak apical interaction between each Cu ion and a perchlorate O atom.     

Intramolecular nitrile oxide-alkene cycloaddition of sugar derivatives with unmasked hydroxyl group(s)

[reaction: see text] Intramolecular nitrile oxide-alkene cycloaddition (INOC) of sugar derivatives with one to four free hydroxyl group(s) is reported. The INOC reaction, using chloramine-T, in the presence of silica gel, to generate nitrile oxides from oximes, proceeded smoothly to afford five- or six-membered carbocycles in good to excellent yields. This new methodology alleviates protection/deprotection steps and makes the synthetic route shorter and more efficient.     

Bis(μ‐di‐2‐pyridyl­aminato 1‐oxide)­bis­[(tri­fluoro­acetato)copper(II)] aceto­nitrile disolvate

The crystal structure of the title compound, [Cu₂(C₂F₃O₂)₂(C₁₀H₈N₃O)₂]·2CH₃CN, contains discrete [Cu₂(CF₃COO)₂(O‐dpa)₂] mol­ecules (O‐dpaH is di‐2‐pyridyl­amine 1‐oxide) which have imposed crystallographic twofold symmetry and an aceto­nitrile mol­ecule of solvation. The O‐dpa⁻ ligand is both bidentate and bridging, linking two Cu atoms with a separation of 3.4270 (11) Å. Each Cu atom is surrounded by four coordinated atoms that are almost coplanar, with dimensions Cu—N = 1.940 (2) and 1.984 (3) Å, and Cu—O = 1.912 (2) and 1.945 (2) Å.     

Two 1,4‐dihydropyridine derivatives with potential calcium‐channel antagonist activity

The title compounds, benzyl 4‐(3‐chloro‐2‐fluorophenyl)‐2‐methyl‐5‐oxo‐4,5,6,7‐tetrahydro‐1H‐cyclopenta[b]pyridine‐3‐carboxylate, C₂₃H₁₉ClFNO₃, (I), and 3‐pyridylmethyl 4‐[2‐fluoro‐3‐(trifluoromethyl)phenyl]‐2,6,6‐trimethyl‐5‐oxo‐1,4,5,6,7,8‐hexahydroquinoline‐3‐carboxylate, C₂₆H₂₄F₄N₂O₃, (II), belong to a class of 1,4‐dihydropyridines whose members sometimes display calcium modulatory properties. The 1,4‐dihydropyridine ring in each structure has a shallower than usual shallow‐boat conformation and is nearly planar in (I). In each structure, the halogen‐substituted benzene ring is oriented such that the halogen substituents are in a synperiplanar orientation with respect to the 1,4‐dihydropyridine ring plane. The oxocyclopentene ring in (I) is planar, while the oxocyclohexene ring in (II) has a half‐chair conformation, which is less commonly observed than the envelope conformation usually found in related compounds. In (I), the frequently observed intermolecular N—H...O hydrogen bond between the amine group and the carbonyl O atom of the oxocyclopentene ring of a neighbouring molecule links the molecules into extended chains; there are no other significant intermolecular interactions. By contrast, the amine group in (II) forms an N—H...N hydrogen bond with the pyridine ring N atom of a neighbouring molecule. Additional C—H...O interactions complete a two‐dimensional hydrogen‐bonded network. The halogen‐substituted benzene ring has a weak intramolecular π–π interaction with the pyridine ring. A stronger π–π interaction occurs between the 1,4‐dihydropyridine rings of centrosymmetrically related molecules.