Ropinirole hydro­chloride,a dopamine agonist

Ropinirole hydro­chloride, or diethyl[2‐(2‐oxo‐2,3‐dihydro‐1H‐indol‐4‐yl)ethyl]ammonium chloride, C₁₆H₂₅N₂O⁺·Cl⁻, belongs to a class of new non‐ergoline dopamine agonists which bind specifically to D2‐like receptors with a selectivity similar to that of dopamine (D3 > D2 > D4). The N atom in the ethyl­amine side chain is protonated and there is a hydrogen bond between it and the Cl⁻ ion. In the crystal structure, two cations and two anions form inversion‐related cyclic dimers via N—H⋯Cl hydrogen bonds.     

Protopine hydro­chloride

Protopine hydro­chloride (5,6,14,14a‐tetra­hydro‐14a‐hydroxy‐7‐methyl‐8H­‐bis­[1,3]benzodioxolo­[5,6‐a:4,5‐g]­quinolizinium chloride, C₂₀H₂₀NO₅⁺·Cl^?) is the salt of the iso­quinoline alkaloid protopine. It is formed by the action of dilute hydro­chloric acid on the protopine free base. The N‐methyl and hydroxyl groups are in a trans configuration in the quinolizine ring and the central quinolizine N—C bond is unusually long [1.579 (2) Å]. The crystal is a racemate.     

Clarithromycin hydro­chloride 3.5‐hydrate

The absolute configuration was determined for the title compound, C₃₈H₇₀NO₁₃⁺·Cl^?·3.5H₂O. The cation contains a 14‐membered macrocyclic lactone and two sugars, namely cladinose and desos­amine. The six‐membered rings of the sugars adopt chair conformations. The structure is stabilized by strong hydrogen bonds, with O?O distances in the range 2.486 (9)–2.830 (5) Å; other distances are N?O = 2.860 (5), N?Cl = 3.134 (4) and O?Cl = 3.303 (4) Å.     

Dorzolamide hydro­chloride: an anti­glaucoma agent

Dorzolamide hydro­chloride [systematic name: (4S)‐trans‐4‐ethyl­ammonio‐6‐methyl‐5,6‐dihydro‐4H‐thieno[2,3‐b]thio­pyran‐2‐sulfonamide 7,7‐dioxide chloride], C₁₀H₁₇N₂O₄S₂⁺·Cl⁻, belongs to a class of drugs called carbonic anhydrase inhibitors. The ethyl­ammonio side chain is in an extended conformation and is protonated at the N atom, which is hydrogen bonded to the Cl⁻ anion. The dihedral angle between the planes of the thio­phene ring and the sulfonamide group is 80.7 (1)°. A comparison is made with the dorzolamide bound in human carbonic anhydrase in the solid state. Hydrogen bonding is mediated by Cl⁻ anions, resulting in indirect connectivity between the mol­ecules.     

6‐Amino­nicotinic acid hydro­chloride

The title compound, 2‐amino‐5‐carboxy­pyridinium chloride, C₆H₇N₂O₂⁺·Cl^?, was isolated from a 1 M HCl aqueous solution containing 2‐amino‐5‐cyano­pyridine. The structure is held together by extensive hydrogen bonding between the chloride ions and the carboxylic acid, amino and pyridinium H atoms. The mol­ecules pack as sheets, with the sheets at a distance of 3.21 (3) Å from one another.     

Multicentre hydrogen bonds in a 2:1 aryl­sulfonyl­imidazol­one ­hydro­chloride salt

The title compound, (S)‐(+)‐4‐[5‐(2‐oxo‐4,5‐di­hydro­imidazol‐1‐yl­sulfonyl)­indolin‐1‐yl­carbonyl]­anilinium chloride (S)‐(+)‐1‐[1‐(4‐amino­benzoyl)­indoline‐5‐sulfonyl]‐4‐phenyl‐4,5‐di­hydro­imidazol‐2‐one, C₂₄H₂₃N₄O₄S⁺·Cl^?·C₂₄H₂₂N₄O₄S, crystallizes in space group C2 from a CH₃OH/CH₂Cl₂ solution. In the crystal structure, there are two different conformers with their terminal C₆ aromatic rings mutually oriented at angles of 67.69 (14) and 61.16 (15)°. The distances of the terminal N atoms (of the two conformers) from the chloride ion are 3.110 (4) and 3.502 (4) Å. There are eight distinct hydrogen bonds, i.e. four N—H?Cl, three N—H?O and one N—H?N, with one N—H group involved in a bifurcated hydrogen bond with two acceptors sharing the H atom. C—H?O contacts assist in the overall hydrogen‐bonding process.     

Two phenanthroline hydro­chlorides

The crystal and molecular structures of two phenanthroline hydro­chlorides have been determined at 173 K. 1,10‐Phenanthrolin‐1‐ium chloride, C₁₂H₉N₂⁺·Cl^?, crystallizes in two stacks of exactly planar mol­ecules. Both stacks are approximately parallel to the (02) plane and the planes composing the different stacks enclose an angle of 13.29 (3)°. Tris(1,10‐phenanthrolin‐1‐ium) dichloride (hydrogen chloride) chloride chloro­form solvate, 3C₁₂H₉N₂⁺·2Cl^?·HCl·Cl^?·CHCl₃, displays an interesting network of Cl^? mediated hydrogen bonds between the two different phenanthrolinium moieties and between a phenanthrolinium and the chloro­form solvate. In addition, a hydrogen bond between the HCl and the third Cl^? ion is formed. The C—N—C angle at the protonated N atoms is, in all phenanthrolinium units of both structures, significantly larger than the C—N—C angle at the non‐protonated N atom.     

p‐Phenyl­azoaniline hydro­chloride from powder data: protonation site and UV–visible spectra

The crystal structure of the title compound, (4‐amino­phenyl)phenyl­diazenium chloride, C₁₂H₁₂N₃⁺·Cl^?, was determined from X‐ray laboratory powder data, and the protonation on the azo group was confirmed by the neutron powder data. The cations form stacks along [100], while the chloride anions form hydrogen bonds to all three H atoms attached to N atoms. The absorption maximum of the crystalline salt is shifted bathochromically by 850 cm^?1, compared with that in ethanol solution.     

A new photochromic tetra­hydro­indolizine

The title compound, di­methyl 10b′‐(4‐fluoro­styryl)‐8′,9′‐di­methoxy‐4‐nitro‐5′,6′‐di­hydrospiro­[9H‐fluorene‐9,1′(10b′H)‐pyrrolo­[2,1‐a]­iso­quinoline]‐2′,3′‐di­carboxyl­ate, C₃₈H₃₁FN₂O₈, is a new photochromic tetra­hydro­indolizine. One of the C—C bonds at the spiro C atom is very long [1.630 (2) Å], thus explaining the photochromic behaviour.     

Dispersion of magnetic nanoparticles in a polymorphic liquid crystal

In order to enhance the phase stability of dispersions of magnetic nanoparticles (NPs) in a polymorphic liquid crystal, new ligands have been designed consisting of a terphenyl-based liquid crystalline core. The most stable dispersions were obtained with 7 nm super-paramagnetic Fe₃O₄ NPs decorated with the new ligands in place of 10 nm ferromagnetic CoFe₂O₄ spherical NPs.     

6‐Acetonyldi­hydro­avicine

The title compound, 1‐(5‐methyl‐5,6‐di­hydro­[1,3]­dioxolo­[4′,5′:4,5]­benzo­[c][1,5]­dioxolo­[4,5‐j]­phenanthridin‐6‐yl)­acetone, C₂₃H₁₉NO₅, isolated from the stem bark of Zanthoxy­lum rhoifolium, crystallizes as a racemate in space group P. The structure shows two aromatic ring systems, each terminated by a five‐membered dioxole ring, coupled by an N‐containing ring. The core of the mol­ecule is almost planar; the planes of the two ring systems form an angle of 18.42 (6)°. The packing shows the mol­ecules parallel to each other and about 3.5 Å apart with graphite‐type interactions. The N‐methyl and acetone groups, which are anti with respect to one another, lie out of the plane and pack in spaces between neighbouring mol­ecules.     

Two carbamoyl‐substituted di­hydro­pyrimidines: potential mimics of di­hydro­pyridine calcium channel blockers

The structures of two conformationally similar 1,4‐di­hydro­pyrimidines with a novel carbamoyl substitution, viz. 6‐methyl‐5‐(N‐methyl­carbamoyl)‐4‐phenyl‐1,2,3,4‐tetrahydro­py­rimidine‐2‐thione monohydrate, C₁₃H₁₅N₃OS·H₂O, (I), and 4‐(4‐chloro­phenyl)‐6‐methyl‐5‐(N‐methyl­carbamoyl)‐1,2,3,4‐tetra­hydro­pyrimidine‐2‐thione monohydrate, C₁₃H₁₄ClN₃OS·H₂O, (II), exhibit the structural features of 1,4‐di­hydro­pyridine calcium channel blockers. In both structures, the pyrimidine ring adopts a flattened boat conformation and the carbamoyl side chain is in an extended conformation with an anticlinal orientation. The phenyl ring occupies a pseudo‐axial position with respect to the pyrimidine ring in these structures. Both compounds crystallize with one mol­ecule of water, which participates in a two‐dimensional hydrogen‐bonding network. The mol­ecules are linked into dimers by N—H·S hydrogen bonds in both structures.     

A di­deoxy­dide­hydro­nucleoside derivative

We have synthesized a di­deoxy­dide­hydro­nucleoside derivative, 2(S)‐acetoxymethyl‐4‐[4‐amino‐2‐oxopyrimidin‐1(2H)‐yl]‐2,5‐di­hydro­furan, C₁₁H₁₃N₃O₄, which is an analogue of the potently anti‐HIV active compound, di­deoxy‐dide­hydro­cytidine (d4C). The target compound crystallizes with two mol­ecules in the asymmetric unit that differ primarily in the orientation of the C6′‐acetyl group. One mol­ecule has an extended conformation and the orientation of the acetyl group in the second mol­ecule gives an unusual hooked‐shaped conformation. The two conformers form A–B dimers via N—H?N hydrogen bonds. The dimers link via N—H?O hydrogen bonds to form chains parallel to the b cell axis.     

1,5‐Dianilinopentane‐1,3,5‐trione: a crystal structure containing two polymorphic domains

Single crystals of the title compound, C₁₇H₁₆N₂O₃, were obtained by gas diffusion. The observed diffraction pattern is compatible with a superposition of reflections from two monoclinic unit cells with the space group C2/c. The two cells share the a and b axes but not the c axis. Both structures contain layers parallel to (001), with molecules connected by intermolecular N—H...O=C hydrogen bonds. The bonding between adjacent layers is weak. Layer displacements result in a crystal structure containing two closely related polymorphic domains. The structure of one polymorph can be derived from the structure of the other if subsequent layers are displaced by (a/4, b/4, 0) for odd‐numbered layers and by (a/4, −b/4, 0) for even‐numbered layers. Three different crystals were analysed and their observed diffraction patterns were similar, showing all three crystals to contain the polymorphic domain structure.     

A new polymorphic form and crystal solvates of N-(3-methylthio-1,2,4-thiadiazol-5-yl-aminocarbonylmethyl)cytisine

By the single-crystal X-ray diffraction the structures of a new polymorphic form and crystal solvates of N-(3-methylthio-1,2,4-thiadiazol-5-yl-aminocarbonylmethyl)cytisine (C₁₆H₁₉N₅O₂S₂) with dioxane and pyridine have been determined. The crystal structures of solvates are isostructural to previously investigated benzene solvated crystal. Crystal solvates are formed at 2:1 ratio of “host” and solvents. Conformations of the host molecules found in the asymmetric unit of crystal solvates are different like it was observed in benzene solvated crystal. A new polymorphic form is obtained from ethyl acetate.     

Inclusion compounds of 2,5‐di­phenyl­hydro­quinone

The crystal structures of three 1:2 inclusion compounds that consist of host mol­ecule 2,5‐di­phenyl­hydro­quinone (C₁₈H₁₄O₂) and the guest mol­ecules 2‐pyridone (C₅H₅NO), 1,3‐di­phenyl‐2‐propen‐1‐one (chalcone, C₁₅H₁₂O) and 1‐(4‐meth­oxy­phenyl)‐3‐phenyl‐2‐propen‐1‐one (4′‐methoxy­chal­cone, C₁₆H₁₄O₂) were determined in order to study the ability of guest mol­ecules in inclusion compounds to undergo photoreaction. All of the crystals were found to be photoresistant. The three inclusion compounds crystallize in triclinic space group . In each case, the host/guest ratio is 1:2, with the host mol­ecules occupying crystallographic centers of symmetry and the guest mol­ecules occupying general positions. The guest mol­ecules in each of the inclusion compounds are linked to the host mol­ecules by hydrogen bonds. In the inclusion compound where the guest mol­ecule is pyridone, the host mol­ecule is disordered so that the hydroxy groups are distributed between two different sites, with occupancies of 0.738 (3) and 0.262 (3). The pyridone mol­ecules form dimers via N—H⋯O hydrogen bonds.     

A novel crystal form of metacetamol: the first example of a hydrated form

We report the crystal structure and crystallization conditions of a first hydrated form of metacetamol (a hemihydrate), C₈H₉NO₂·0.5H₂O. It crystallizes from metacetamol‐saturated 1:1 (v/v) water–ethanol solutions in a monoclinic structure (space group P2₁/n) and contains eight metacetamol and four water molecules per unit cell. The conformations of the molecules are the same as in polymorph II of metacetamol, which ensures the formation of hydrogen‐bonded dimers and R₂²(16) ring motifs in its crystal structure similar to those in polymorph II. Unlike in form II, however, these dimers in the hemihydrate are connected through water molecules into infinite hydrogen‐bonded molecular chains. Different chains are linked to each other by metacetamol–water and metacetamol–metacetamol hydrogen bonds, the latter type being also present in polymorph I. The overall noncovalent network of the hemihydrate is well developed and several types of hydrogen bonds are responsible for its formation.     

(Tetra­hydro­furan)­potassium mer‐trans‐tris­(carbazolyl)­di­chloro(tetra­hydro­furan)­zirconate

In the title compound, [K(C₄H₈O)][ZrCl₂(C₁₂H₈N)₃(C₄H₈O)], the Zr atom is pseudo‐octahedral, with two Cl ligands in trans positions. There is extensive interaction between the potassium cation and two of the aromatic carbazolyl ligands in η⁶ [C⃛K = 3.167 (3)–3.331 (3) Å] and η² [C⃛K = 3.147 (3)–3.268 (2) Å] fashions.