Chiral NMR discrimination of the diastereoisomeric salts of the H3‐antagonist 2‐[3‐(1H‐imidazol‐4‐ylmethyl)piperidin‐1‐yl]‐1H‐benzimidazole

Diastereomeric salts with optically pure (S)‐α‐methoxy‐α‐(trifluoromethyl)phenylacetic acid (MTPA) were used to discriminate the enantiomers of the chiral H₃‐antagonist 2‐[3‐(1H‐imidazol‐4‐ylmethyl)piperidin‐1‐yl]‐1H‐benzimidazole. Chemical‐shift differences (Δδ) in NMR spectra strongly depend on solvent and stoichiometric ratio. The better observable differentiation occurred for the proton at the 2‐position of the imidazole ring. Copyright © 2009 John Wiley & Sons, Ltd.     

(Z)‐5‐[4‐(Dimethylamino)benzylidene]‐2‐(piperidin‐1‐yl)‐1,3‐thiazolidin‐4(5H)‐one

The molecules of the title compound, C₁₇H₂₁N₃OS, are characterized by a wide C—C—C angle at the methine C atom linking the aryl and thiazolidine rings, associated with a short repulsive intramolecular S...H contact between atoms in these two rings. A single piperidine–arene C—H...π hydrogen bond links pairs of molecules into centrosymmetric dimers.     

3‐[4‐(4‐Fluoro­phenyl)­piperazin‐1‐yl­methyl]‐5‐methyl‐1,3‐benzoxazol‐2(3H)‐one and 3‐[4‐(2‐fluoro­phenyl)­piperazin‐1‐yl­methyl]‐5‐methyl‐1,3‐benzoxazol‐2(3H)‐one

The title compounds, both C₁₉H₂₀FN₃O₂, contain essentially planar benzoxazolinone ring systems, within which the C—N bond distances and angles do not differ significantly between the two compounds. In both cases, the piperazine ring adopts an almost perfect chair conformation and the benzoxazo­l­inone ring system lies nearly perpendicular to it. The structures contain intermolecular C—H⋯O contacts, and the interactions between the benzoxazolinone and fluoro­phenyl­piperazine portions of the mol­ecules are segregated.     

A supramolecular ladder motif in 2‐(2,2,6,6‐tetra­methyl­piperidin‐1‐yl­oxy)­propane‐1,3‐diol

An O—H⋯O hydrogen‐bonded step‐ladder motif was observed in the crystal structure of the title compound, C₁₂H₂₅NO₃. The ladder arrangement is typical of 1,2‐ and 1,3‐diols with a synclinal orientation of the diol functionality.     

4‐[2‐(4‐Cyano­phenyl)ethenyl]‐N‐methyl­pyridinium tetra­phenyl­borate

In the title compound, C₁₅H₁₃N₂⁺·C₂₄H₂₀B⁻, the pyridyl ring of the cation makes a dihedral angle of 1.6° with the benzene ring. Each is rotated in the same direction with respect to the central –C—CH=CH—C– linkage, by 3.8 and 5.3°, respectively. The anions have a slightly distorted tetra­hedral geometry. Mol­ecular packing analysis was carried out using the packing energy portioning scheme in the program OPEC. Around each anion in the crystal structure there are eight anions, which inter­act with the central anion through C—H⋯π inter­actions. The cations are hydrogen bonded in a head‐to‐tail fashion, forming chains along [10].     

Crystallographic report: Chloro[1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol]zinc(II) chloride hydrate, [(C23H36N4O3)ZnCl]Cl·H2O

The zinc(II) center in the molecule of [(C₂₃H₃₆N₄O₃)ZnCl]Cl·H₂O is coordinated by four nitrogen atoms of HL (1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol) and one chloro anion. The coordination moieties are connected by hydrogen bonds to form a one‐dimensional structure. Copyright © 2005 John Wiley & Sons, Ltd.     

1‐Acetyl‐3‐[1‐(4‐methoxyphenyl)‐2‐oxopropylidene]‐1H‐indol‐2(3H)‐one: a twinned crystal

The crystal of the title compound, C₂₀H₁₇NO₄, which was used for collecting intensity data was twinned. Each of the two crystallographically independent mol­ecules in the asymmetric unit has a planar indole moiety perpendicular to a planar oxo­propyl moiety. The distribution of the bonds at the central C atom joining the oxo­propyl, phenyl and indole substituents is also planar. The packing is stabilized by intermolecular C—H?O interactions, as well as by dipole–dipole and van der Waals interactions.     

Bis­(aceto­nitrile‐κN)[(1RS,4RS,8SR,11SR)‐1,4,8,11‐tetra­aza­tetra­decane‐κ4N]copper(II) bis{tetrakis­[3,5‐bis­(tri­fluoro­methyl)­phenyl]­borate} 0.31‐hydrate

The title compound, [Cu(C₂H₃N)₂(C₁₀H₂₄N₄)](C₃₂H₁₂BF₂₄)₂·0.31H₂O, crystallizes as an ionic species with no interactions between the ions. The [Cu^II(cyclam)(MeCN)₂]²⁺ dication (cyclam is 1,4,8,11‐tetra­aza­tetra­decane), located on a 2/m symmetry site, forms as a distorted octahedral species with four Cu—N_cyclam bonds of 2.013 (2) Å and two C—N_MeCN bonds of 2.499 (4) Å. The [B{C₆H₃(CF₃)‐3,5}₄]⁻ anion, located on a twofold axis, is a distorted octahedral species. A small amount of water is present, occupying sites between columns of ions.     

A series of 1‐[2‐aryl‐1‐diazenyl]‐3‐({3‐[2‐aryl‐1‐diazenyl]perhydrobenzo[d]imidazol‐1‐yl}methyl)perhydrobenzo[d]imidazoles. Synthesis and characterization

Reaction of diazonium salts with solutions of 1,2‐diaminocyclohexane mixed with formaldehyde affords the 1‐[2‐aryl‐1‐diazenyl]‐3‐({3‐[2‐aryl‐1‐diazenyl]perhydrobenzo[d]imidazol‐1‐yl}methyl)perhydrobenzo‐[d]imidazoles ( 6 ), a new series of bis‐triazenes with different connectivity than any previous type of bis‐triazene reported. The products have been characterized principally by NMR and IR spectroscopy, elemental analysis and unequivocally by X‐ray crystallography. The methylene protons of the perhydroimidazole rings are diastereotopic giving rise to a doublet of doublets pattern in the ¹H NMR spectra. However, detailed analysis of the NMR spectra shows that there is more than one set of doublet‐of‐doublet signals, suggesting the presence of different rotameric forms of the products. The ¹³C NMR spectral assignments were assisted by COSY and DEPT experiments with selected compounds.     

One‐dimensional structure of catena‐poly[tetra­ethyl­ammonium [tetra­cyano­iron(III)‐μ‐cyano‐[bis­(ethyl­ene­diamine)­cadmium(II)]‐μ‐cyano] tetra­hydrate]

The title compound, {(C₈H₂₀N)[CdFe(CN)₆(C₂H₈N₂)₂]·4H₂O}_n, was isolated from the aqueous system Cd²⁺/ethyl­ene­diamine (en)/[Fe(CN)₆]³⁻ in the presence of [Et₄N]Br. The crystal structure is dominated by a one‐dimensional motif, viz. a negatively charged 2,2‐CT (cis–trans) [–Cd(en)₂—NC—Fe(CN)₄—CN–]_nⁿ⁻ chain. The Cd and Fe atoms of the anion and the N atom of the cation all lie on twofold axes. The ethyl groups of the cation are equally disordered over two orientations. The cationic building block of the chain consists of a Cd^II atom coordinated by two chelating en ligands, and the distorted octa­hedral coordination is completed by two bridging cyano ligands in cis positions. The anionic building block is an [Fe(CN)₆]³⁻ anion in which the Fe^III atom is octa­hedrally coordinated by six cyano ligands; two of the cyano ligands, in trans positions, are bridging. The uncoordinated water mol­ecules link neighbouring chains through O—H⋯N and N—H⋯O hydrogen bonds.     

4‐[2‐(3‐Methoxyphenyl)ethenyl]‐N‐methylpyridinium tetraphenylborate

In the title compound, C₁₅H₁₆NO⁺·C₂₄H₂₀B⁻, the pyridinium ring of the cation makes a dihedral angle of 4.3 (2)° with the benzene ring. Each is rotated in the same direction with respect to the central C—CH=CH—C linkage, by 10.0 (2) and 7.8 (2)°, respectively. The anions have a slightly distorted tetrahedral geometry. The most interesting feature of the structure is that the anions form a honeycomb‐like hexagonal structure down the b axis through C—H...π interactions. The hexagon is constructed from six BPh₄⁻ anions. The cations interact in a head‐to‐tail fashion along [010], forming chains, and pack antiparallel inside the above honeycomb‐like structure through C—H...π interactions.     

(1S)‐1‐Phenylethanaminium 4‐{[(1S,2S)‐1‐hydroxy‐2,3‐dihydro‐1H,1′H‐[2,2′‐biinden]‐2‐yl]methyl}benzoate

The title molecular salt, C₈H₁₂N⁺·C₂₆H₂₁O₃⁻, contains a dimeric indane pharmacophore that demonstrates potent anti‐inflammatory activity. The indane group of the anion exhibits some disorder about the α‐C atom, which appears common to many structures containing this group. A model to account for the slight disorder was attempted, but this was deemed unsuccessful because applying bond‐length constraints to all the bonds about the α‐C atom led to instability in the refinement. The absolute configuration was determined crystallographically as S,S,S by anomalous dispersion methods with reference to both the Flack parameter and Bayesian statistics on Bijvoet differences. The configuration was also determined by an a priori knowledge of the absolute configuration of the (1S)‐1‐phenylethanaminium counter‐ion. The molecules pack in the crystal structure to form an infinite two‐dimensional hydrogen‐bond network in the (100) plane of the unit cell.     

3‐[5‐(4‐Chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid and the corresponding methyl ester

The synthesis of 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid, C₁₉H₁₇ClN₂O₃, (I), and its corresponding methyl ester, methyl 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionate, C₂₀H₁₉ClN₂O₃, (II), is regiospecific. However, correct identification of the regioisomer formed by spectroscopic techniques is not trivial and single‐crystal X‐ray analysis provided the only means of unambiguous structure determination. Compound (I) crystallizes with Z′ = 2. The propionic acid groups of the two crystallographically unique molecules form a hydrogen‐bonded dimer, as is typical of carboxylic acid groups in the solid state. Conformational differences between the methoxybenzene and pyrazole rings give rise to two unique molecules. The structure of (II) features just one molecule in the asymmetric unit and the crystal packing makes greater use than (I) of weak C—H...A interactions, despite the lack of any functional groups for classical hydrogen bonding.     

4,6‐Dimethyl‐2‐[(4‐phenylpiperidin‐1‐yl)methyl]isothiazolo[5,4‐b]pyridin‐3(2H)‐one and 4,6‐dimethyl‐2‐[(4‐phenyl‐1,2,3,6‐tetrahydropyridin‐1‐yl)methyl]isothiazolo[5,4‐b]pyridin‐3(2H)‐one

In the crystal structures of the title compounds, C₂₀H₂₃N₃OS, (II), and C₂₀H₂₁N₃OS, (III), significant differences occur in the conformation of, respectively, the phenylpiperidine and phenyltetrahydropyridine substituents at the 2‐position of the isothiazolopyridine system. The piperidine ring adopts a chair conformation, while the tetrahydropyridine ring assumes a half‐chair form. The phenylpiperidine and phenyltetrahydropyridine fragments exhibit different conformations resulting from the steric and conjugation effects in the phenyl ring, respectively. Theoretical calculations show that both conformations are energetically stable and correspond to a minimum of energy for the analyzed systems. The molecular packing in (II) is influenced by π–π interactions of the isothiazolopyridine systems, with a shortest centroid‐to‐centroid separation of 3.5843 (11) Å between pyridine rings. In the crystal structure of (III), the molecules are linked by C—H...O hydrogen bonds and C—H...π interactions.     

16‐[3‐Methoxy‐4‐(2‐piperidin‐1‐yl­ethoxy)­benzyl­idene]‐17‐oxoandrost‐5‐en‐3β‐yl acetate monohydrate

The title compound, C₃₆H₄₉NO₅·H₂O, has the outer two six‐membered rings of the steroid nucleus in chair conformations. The central ring B of the steroid nucleus is in an 8β,9α‐half‐chair conformation, while ring D of the steroid adopts a slightly distorted 13β,14α‐half‐chair conformation. The piperidine ring is in a chair conformation. The methoxy­benzyl­idene moiety has an E configuration with respect to the carbonyl group at position 17. Intermolecular O—H?O and O—H?N hydrogen bonds link the steroid and water mol­ecules into chains which run parallel to the b axis.     

Di­thio­cyanatobis­[4,4,5,5‐tetra­methyl‐2‐(4‐pyridyl‐κN)‐1H‐imidazoline‐1‐oxyl]­zinc(II)

In the title compound, [Zn(NCS)₂(C₁₂H₁₆N₃O)₂], the Zn^II ion has a distorted tetrahedral coordination. It is bonded to two thio­cyanate and two pyridyl N atoms. The metal ion and the two thio­cyanate ligands lie on a mirror plane with the Zn—N_py and average Zn—N_NCS bond distances being 2.036 (2) and 1.931 (4) Å, respectively     

Syntheses of N‐[3‐(1‐methyl‐1H‐2‐imidazolyl)propyl]benzamides and N‐[3‐(1‐methyl‐1H‐2‐imidazolyl)propyl]benzenesulfonamides

A series of substituted N‐(4‐substituted‐benzoyl)‐N‐[3‐(1‐methyl‐1H‐imidazol‐2‐yl)propyl]amines ( 13 ) and N‐arylsulfonyl‐N‐[3‐(1‐methyl‐1H‐imidazol‐2‐yl)propyl]amines ( 14 ) were prepared from the reaction of 3‐(1‐methyl‐1H‐imidazol‐2‐yl)propan‐1‐amine ( 7 ) with substituted benzoyl chloride or substituted‐benzene sulfonyl chloride respectively. Compound 7 was prepared by two independent methods.     

Crystallographic report: 1‐[4‐(2‐Thienyl)phenyl]germatrane

In the title compound, germanium is penta‐coordinated and adopts a trigonal bipyramidal geometry. The (2‐thienyl)phenyl group and the nitrogen atom each occupy an apical position with a transannular N→Ge bond distances of 2.247(4) and 2.219(4) Å for the two independent molecules. Copyright © 2005 John Wiley & Sons, Ltd.     

A series of three bis­[2‐(methyl/tri­fluoro­methyl)‐4H‐3,1‐benzoxazin‐4‐one] compounds

Each of the three title compounds, namely 6,6′‐methyl­ene­bis­(2‐methyl‐4H‐3,1‐benz­oxazin‐4‐one), C₁₉H₁₄N₂O₄, 6,6′‐methyl­ene­bis­(2‐tri­fluoro­methyl‐4H‐3,1‐benz­oxazin‐4‐one), C₁₉H₈F₃N₂O₄, and 6,6′‐bi­(2‐tri­fluoro­methyl‐4H‐3,1‐benz­oxazin‐4‐one), C₁₈H₆F₆N₂O₄, contains two planar benz­ox­azin­one fragments. In the first two compounds, these planes are virtually perpendicular to each other, while the third compound is planar overall. The electronic effects of the substituent groups on the oxazine moiety result in distortion of the bond angles at the C atoms of the C=O and C=N bonds, and in redistribution of electronic density in the oxazine rings. The latter leads to different bond lengths within this ring in the three mol­ecules. All the mol­ecules form stacks in their crystals with distances of 3.2–3.6 Å between adjacent mol­ecules in a stack.