Different hydrogen‐bonded structures in three 2‐thienyl‐substituted tetrahydro‐1,4‐epoxy‐1‐benzazepines

The molecules of (2RS,4SR)‐2‐exo‐(5‐bromo‐2‐thienyl)‐7‐chloro‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C₁₄H₁₁BrClNOS, (I), are linked into cyclic centrosymmetric dimers by C—H...π(thienyl) hydrogen bonds. Each such dimer makes rather short Br...Br contacts with two other dimers. In (2RS,4SR)‐2‐exo‐(5‐methyl‐2‐thienyl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C₁₅H₁₅NOS, (II), a combination of C—H...O and C—H...π(thienyl) hydrogen bonds links the molecules into chains of rings. A more complex chain of rings is formed in (2RS,4SR)‐7‐chloro‐2‐exo‐(5‐methyl‐2‐thienyl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C₁₅H₁₄ClNOS, (III), built from a combination of two independent C—H...O hydrogen bonds, one C—H...π(arene) hydrogen bond and one C—H...π(thienyl) hydrogen bond.     

2‐Ethyl‐1‐[5‐(4‐methylphenyl)pyrazol‐3‐yl]‐3‐(thiophene‐2‐carbonyl)isothiourea: molecular ribbons containing three types of hydrogen‐bonded ring

The title compound, C₁₈H₁₈N₄OS₂, was prepared by reaction of S,S‐diethyl 2‐thenoylimidodithiocarbonate with 5‐amino‐3‐(4‐methylphenyl)‐1H‐pyrazole using microwave irradiation under solvent‐free conditions. In the molecule, the thiophene unit is disordered over two sets of atomic sites, with occupancies of 0.814 (4) and 0.186 (4), and the bonded distances provide evidence for polarization in the acylthiourea fragment and for aromatic type delocalization in the pyrazole ring. An intramolecular N—H...O hydrogen bond is present, forming an S(6) motif, and molecules are linked by N—H...O and N—H...N hydrogen bonds to form a ribbon in which centrosymmetric R₂²(4) rings, built from N—H...O hydrogen bonds and flanked by inversion‐related pairs of S(6) rings, alternate with centrosymmetric R₂²(6) rings built from N—H...N hydrogen bonds.     

Two isomorphous azastilbene derivatives: 1‐(2‐chlorobenzyl)‐4‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]pyridinium chloride and 1‐(2‐bromobenzyl)‐4‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]pyridinium bromide

The crystal structures of the two title (E)‐stilbazolium halogenates, C₂₀H₁₇ClNO⁺·Cl⁻ and C₂₀H₁₇BrNO⁺·Br⁻, are isomorphous, with an isostructurality index of 0.985. The azastyryl fragments are almost planar, with dihedral angles between the benzene and pyridine rings of ca 4.5°. The rings of the benzyl groups are, in turn, almost perpendicular to the azastyryl planes, with dihedral angles larger than 80°. The cations and anions are connected by O—H...X⁻ (X = halogen) hydrogen bonds. The halide anions are `sandwiched' between the charged pyridinium rings of neighbouring molecules, and weak C—H...O hydrogen bonds and C—H...X and C—H...π interactions also contribute to the crystal structures.     

2‐Ethyl‐6‐methylpyridin‐3‐ol and its salt bis(2‐ethyl‐3‐hydroxy‐6‐methylpyridinium) succinate

The title compounds, C₈H₁₁NO, (I), and 2C₈H₁₂NO⁺·C₄H₄O₄²⁻, (II), both crystallize in the monoclinic space group P2₁/c. In the crystal structure of (I), intermolecular O—H...N hydrogen bonds combine the molecules into polymeric chains extending along the c axis. The chains are linked by C—H...π interactions between the methylene H atoms and the pyridine rings into polymeric layers parallel to the ac plane. In the crystal structure of (II), the succinate anion lies on an inversion centre. Its carboxylate groups interact with the 2‐ethyl‐3‐hydroxy‐6‐methylpyridinium cations via intermolecular N—H...O hydrogen bonds with the pyridine ring H atoms and O—H...O hydrogen bonds with the hydroxy H atoms to form polymeric chains, which extend along the [01] direction and comprise R₄⁴(18) hydrogen‐bonded ring motifs. These chains are linked to form a three‐dimensional network through nonclassical C—H...O hydrogen bonds between the pyridine ring H atoms and the hydroxy‐group O atoms of neighbouring cations. π–π interactions between the pyridine rings and C—H...π interactions between the methylene H atoms of the succinate anion and the pyridine rings are also present in this network.     

(E)‐N′‐(4‐Chlorobenzylidene)‐, (E)‐N′‐(4‐bromobenzylidene)‐ and (E)‐N′‐[4‐(diethylamino)benzylidene]‐ derivatives of 4‐hydroxybenzohydrazide

The 4‐chloro‐ [C₁₄H₁₁ClN₂O₂, (I)], 4‐bromo‐ [C₁₄H₁₀BrN₂O₂, (II)] and 4‐diethylamino‐ [C₁₈H₂₁N₃O₂, (III)] derivatives of benzylidene‐4‐hydroxybenzohydrazide, all crystallize in the same space group (P2₁/c), (I) and (II) also being isomorphous. In all three compounds, the conformation about the C=N bond is E. The molecules of (I) and (II) are relatively planar, with dihedral angles between the two benzene rings of 5.75 (12) and 9.81 (17)°, respectively. In (III), however, the same angle is 77.27 (9)°. In the crystal structures of (I) and (II), two‐dimensional slab‐like networks extending in the a and c directions are formed via N—H...O and O—H...O hydrogen bonds. The molecules stack head‐to‐tail viaπ–π interactions involving the aromatic rings [centroid–centroid distance = 3.7622 (14) Å in (I) and 3.8021 (19) Å in (II)]. In (III), undulating two‐dimensional networks extending in the b and c directions are formed via N—H...O and O—H...O hydrogen bonds. The molecules stack head‐to‐head viaπ–π interactions involving inversion‐related benzene rings [centroid–centroid distances = 3.6977 (12) and 3.8368 (11) Å].     

Polymorphism in 2‐(4‐hydroxy‐2,6‐dimethylanilino)‐5,6‐dihydro‐4H‐1,3‐thiazin‐3‐ium chloride

Details of the structures of two conformational polymorphs of the title compound, C₁₂H₁₇N₂OS⁺·Cl⁻, are reported. In form (I) (space group P), the two N—H groups of the cation are in a trans conformation, while in form (II) (space group P2₁/c), they are in a cis arrangement. This results in different packing and hydrogen‐bond arrangements in the two forms, both of which have extended chains lying along the a direction. In form (I), these chains are composed of centrosymmetric R₄²(18) (N—H...Cl and O—H...Cl) hydrogen‐bonded rings and R₂²(18) (N—H...O) hydrogen‐bonded rings. In form (II), the chains are formed by centrosymmetric R₄²(18) (N—H...Cl and O—H...Cl) hydrogen‐bonded rings and by R₄²(12) (N—H...Cl) hydrogen‐bonded rings.     

Hydrogen‐bonding patterns in 3‐alkyl‐3‐hydroxyindolin‐2‐ones

The molecules of racemic 3‐benzoylmethyl‐3‐hydroxyindolin‐2‐one, C₁₆H₁₃NO₃, (I), are linked by a combination of N—H...O and O—H...O hydrogen bonds into a chain of centrosymmetric edge‐fused R₂²(10) and R₄⁴(12) rings. Five monosubstituted analogues of (I), namely racemic 3‐hydroxy‐3‐[(4‐methylbenzoyl)methyl]indolin‐2‐one, C₁₇H₁₅NO₃, (II), racemic 3‐[(4‐fluorobenzoyl)methyl]‐3‐hydroxyindolin‐2‐one, C₁₆H₁₂FNO₃, (III), racemic 3‐[(4‐chlorobenzoyl)methyl]‐3‐hydroxyindolin‐2‐one, C₁₆H₁₂ClNO₃, (IV), racemic 3‐[(4‐bromobenzoyl)methyl]‐3‐hydroxyindolin‐2‐one, C₁₆H₁₂BrNO₃, (V), and racemic 3‐hydroxy‐3‐[(4‐nitrobenzoyl)methyl]indolin‐2‐one, C₁₆H₁₂N₂O₅, (VI), are isomorphous in space group P. In each of compounds (II)–(VI), a combination of N—H...O and O—H...O hydrogen bonds generates a chain of centrosymmetric edge‐fused R₂²(8) and R₂²(10) rings, and these chains are linked into sheets by an aromatic π–π stacking interaction. No two of the structures of (II)–(VI) exhibit the same combination of weak hydrogen bonds of C—H...O and C—H...π(arene) types. The molecules of racemic 3‐hydroxy‐3‐(2‐thienylcarbonylmethyl)indolin‐2‐one, C₁₄H₁₁NO₃S, (VII), form hydrogen‐bonded chains very similar to those in (II)–(VI), but here the sheet formation depends upon a weak π–π stacking interaction between thienyl rings. Comparisons are drawn between the crystal structures of compounds (I)–(VII) and those of some recently reported analogues having no aromatic group in the side chain.     

Similarities and differences in the structures of 5‐bromo‐6‐hydroxy‐7,8‐dimethylchroman‐2‐one and 6‐hydroxy‐7,8‐dimethyl‐5‐nitrochroman‐2‐one

The title compounds, C₁₁H₁₁BrO₃, (I), and C₁₁H₁₁NO₅, (II), respectively, are derivatives of 6‐hydroxy‐5,7,8‐trimethylchroman‐2‐one substituted at the 5‐position by a Br atom in (I) and by a nitro group in (II). The pyranone rings in both molecules adopt half‐chair conformations, and intramolecular O—H...Br [in (I)] and O—H...O_nitro [in (II)] hydrogen bonds affect the dispositions of the hydroxy groups. Classical intermolecular O—H...O hydrogen bonds are found in both molecules but play quite dissimilar roles in the crystal structures. In (I), O—H...O hydrogen bonds form zigzag C(9) chains of molecules along the a axis. Because of the tetragonal symmetry, similar chains also form along b. In (II), however, similar contacts involving an O atom of the nitro group form inversion dimers and generate R₂²(12) rings. These also result in a close intermolecular O...O contact of 2.686 (4) Å. For (I), four additional C—H...O hydrogen bonds combine with π–π stacking interactions between the benzene rings to build an extensive three‐dimensional network with molecules stacked along the c axis. The packing in (II) is much simpler and centres on the inversion dimers formed through O—H...O contacts. These dimers are stacked through additional C—H...O hydrogen bonds, and further weak C—H...O interactions generate a three‐dimensional network of dimer stacks.     

(6‐Oxido‐2‐oxo‐1,2‐dihydropyrimidine‐5‐carboxylato‐κ2O5,O6)bis[2‐(2‐pyridyl)‐1H‐benzimidazole‐κ2N2,N3]manganese(II) monohydrate

In the title compound, [Mn(C₅H₂N₂O₄)(C₁₂H₉N₃)₂]·H₂O, the Mn^II centre is surrounded by three bidentate chelating ligands, namely, one 6‐oxido‐2‐oxo‐1,2‐dihydropyrimidine‐5‐carboxylate (or uracil‐5‐carboxylate, Huca²⁻) ligand [Mn—O = 2.136 (2) and 2.156 (3) Å] and two 2‐(2‐pyridyl)‐1H‐benzimidazole (Hpybim) ligands [Mn—N = 2.213 (3)–2.331 (3) Å], and it displays a severely distorted octahedral geometry, with cis angles ranging from 73.05 (10) to 105.77 (10)°. Intermolecular N—H...O hydrogen bonds both between the Hpybim and the Huca²⁻ ligands and between the Huca²⁻ ligands link the molecules into infinite chains. The lattice water molecule acts as a hydrogen‐bond donor to form double O...H—O—H...O hydrogen bonds with the Huca²⁻ O atoms, crosslinking the chains to afford an infinite two‐dimensional sheet; a third hydrogen bond (N—H...O) formed by the water molecule as a hydrogen‐bond acceptor and a Hpybim N atom further links these sheets to yield a three‐dimensional supramolecular framework. Possible partial π–π stacking interactions involving the Hpybim rings are also observed in the crystal structure.     

Methanol[1‐(methoxymethanimidoyl)‐2‐(pyridin‐2‐ylmethyl)guanidine]bis(perchlorato)copper(II)

The title complex, [Cu(ClO₄)₂(C₉H₁₃N₅O)(CH₃OH)], was synthesized from a methanolysis reaction of N‐(methylpyridin‐2‐yl)cyanoguanidine (L³) and copper(II) perchlorate hexahydrate in a 1:1 molar ratio. The Cu^II ion is six‐coordinated by an N₃O₃ donor set which confers a highly distorted and asymmetric octahedral geometry. Three N‐donor atoms from the chelating 1‐(methoxymethanimidoyl)‐2‐(pyridin‐2‐ylmethyl)guanidine (L^3m) ligand and one O atom from the methanol molecule define the equatorial plane, with two perchlorate O atoms in the apical sites, one of which has a long Cu—O bond of 2.9074 (19) Å. The dihedral angle between the five‐ and six‐membered chelate rings is 8.21 (8)°. Two molecules are associated into a dimeric unit by intermolecular N—H...O(perchlorate) hydrogen bonds. Additionally, the weakly coordinated perchlorate anions also link adjacent [Cu(ClO₄)₂(L^3m)(CH₃OH)] dimers by hydrogen‐bonding interactions, resulting in a two‐dimensional layer in the (100) plane. Further C—H...O hydrogen bonds link the two‐dimensional layers along [100] to generate a three‐dimensional network.     

Hydrogen‐bonded ribbons in ethyl (E)‐3‐[2‐amino‐4,6‐bis(dimethylamino)pyrimidin‐5‐yl]‐2‐cyanoacrylate and 2‐[(2‐amino‐4,6‐di‐1‐piperidylpyrimidin‐5‐yl)methylene]malononitrile

The pyrimidine rings in ethyl (E)‐3‐[2‐amino‐4,6‐bis(dimethylamino)pyrimidin‐5‐yl]‐2‐cyanoacrylate, C₁₄H₂₀N₆O₂, (I), and 2‐[(2‐amino‐4,6‐di‐1‐piperidylpyrimidin‐5‐yl)methylene]malononitrile, C₁₈H₂₃N₇, (II), which crystallizes with Z′ = 2 in the space group, are both nonplanar with boat conformations. The molecules of (I) are linked by a combination of N—H...N and N—H...O hydrogen bonds into chains of edge‐fused R₂²(8) and R₄⁴(20) rings, while the two independent molecules in (II) are linked by four N—H...N hydrogen bonds into chains of edge‐fused R₂²(8) and R₂²(20) rings. This study illustrates both the readiness with which highly‐substituted pyrimidine rings can be distorted from planarity and the significant differences between the supramolecular aggregation in two rather similar compounds.     

Exo conformers of N‐(pyridin‐2‐yl)‐ and N‐(pyridin‐3‐yl)norbornene‐5,6‐dicarboximide crystals

Two isomeric pyridine‐substituted norbornenedicarboximide derivatives, namely N‐(pyridin‐2‐yl)‐exo‐norbornene‐5,6‐dicarboximide, (I), and N‐(pyridin‐3‐yl)‐exo‐norbornene‐5,6‐dicarboximide, (II), both C₁₄H₁₂N₂O₄, have been crystallized and their structures unequivocally determined by single‐crystal X‐ray diffraction. The molecules consist of norbornene moieties fused to a dicarboximide ring substituted at the N atom by either pyridin‐2‐yl or pyridin‐3‐yl in an anti configuration with respect to the double bond, thus affording exo isomers. In both compounds, the asymmetric unit consists of two independent molecules (Z′ = 2). In compound (I), the pyridine rings of the two independent molecules adopt different conformations, i.e. syn and anti, with respect to the methylene bridge. The intermolecular contacts of (I) are dominated by C—H...O interactions. In contrast, in compound (II), the pyridine rings of both molecules have an anti conformation and the two independent molecules are linked by carbonyl–carbonyl interactions, as well as by C—H...O and C—H...N contacts.     

N‐tert‐Butyl‐N′‐[5‐cyano‐2‐(4‐methylphenoxy)phenylsulfonyl]urea,a new TXA2 receptor antagonist

The title compound, C₁₉H₂₁N₃O₄S, crystallizes in the space group P2/c with two molecules in the asymmetric unit. The conformation of both molecules is very similar and is mainly determined by an intramolecular N—H...O hydrogen bond between a urea N atom and a sulfonyl O atom. The O and second N atom of the urea groups are involved in dimer formation via N—H...O hydrogen bonds. The intramolecular hydrogen‐bonding motif and conformation of the C—SO₂—NH(C=O)—NH—C fragment are explored and compared using the Cambridge Structural Database and theoretical calculations. The crystal packing is characterized by π–π stacking between the 5‐cyanobenzene rings.     

Tolterodinium (+)‐(2R,3R)‐hydrogen tartrate

In the crystal structure of (R)‐N,N‐diisopropyl‐3‐(2‐hydroxy‐5‐methyl­phenyl)‐3‐phenyl­propyl­aminium (2R,3R)‐hydrogen tartrate, C₂₂H₃₂NO⁺·C₄H₅O₆⁻, the hydrogen tartrate anions are linked by O—H⋯O hydrogen bonds to form helical chains built from (9) rings. These chains are linked by the tolterodine molecules via N—H⋯O and O—H⋯O hydrogen bonds to form separate sheets parallel to the (101) plane.     

A hydrogen‐bonded chain of rings in 5‐amino‐1‐(4‐methoxybenzoyl)‐3‐methylpyrazole and a three‐dimensional hydrogen‐bonded framework in 5‐amino‐3‐methyl‐1‐(2‐nitrobenzoyl)pyrazole

The molecules of 5‐amino‐1‐(4‐methoxybenzoyl)‐3‐methylpyrazole, C₁₂H₁₃N₃O₂, (I), and 5‐amino‐3‐methyl‐1‐(2‐nitrobenzoyl)pyrazole, C₁₁H₁₀N₄O₃, (II), both contain intramolecular N—H...O hydrogen bonds. The molecules of (I) are linked into a chain of rings by a combination of N—H...N and N—H...π(arene) hydrogen bonds, while those of (II) are linked into a three‐dimensional framework structure by N—H...N and C—H...O hydrogen bonds.     

2‐[2‐(Pyrrolidin‐2‐yl)propan‐2‐yl]‐1H‐pyrrole and its amide derivative 1‐{2‐[2‐(1H‐pyrrol‐2‐yl)propan‐2‐yl]pyrrolidin‐1‐yl}ethanone

In the title compounds, C₁₁H₁₈N₂, (II), and C₁₃H₂₀N₂O, (III), the pyrrolidine rings have twist conformations. Compound (II) crystallizes with two independent molecules (A and B) in the asymmetric unit. The mean planes of the pyrrole and pyrrolidine rings are inclined to one another by 89.99 (11) and 89.35 (10)° in molecules A and B, respectively. In (III), the amide derivative of (II), the same dihedral angle is much smaller, at only 13.42 (10)°. In the crystal structure of (II), the individual molecules are linked via N—H...N hydrogen bonds to form inversion dimers, each with an R²₂(12) graph‐set motif. In the crystal structure of (III), the molecules are linked via N—H...O hydrogen bonds to form inversion dimers with an R²₂(16) graph‐set motif.     

5‐Formylsalicylic acid and 5‐(benzimidazolium‐2‐yl)salicylate

Both title compounds are derivatives of salicylic acid. 5‐Formylsalicylic acid (systematic name: 5‐formyl‐2‐hydroxybenzoic acid), C₈H₆O₄, possesses three good hydrogen‐bond donors and/or acceptors coplanar with their attached benzene ring and abides very well by Etter's hydrogen‐bond rules. Intermolecular O—H...O and some weak C—H...O hydrogen bonds link the molecules into a planar sheet. Reaction of this acid and o‐phenylenediamine in refluxing ethanol produced in high yield the new zwitterionic compound 5‐(benzimidazolium‐2‐yl)salicylate [systematic name: 5‐(1H‐benzimidazol‐3‐ium‐2‐yl)‐2‐hydroxybenzoate], C₁₄H₁₀N₂O₃. Each imidazolium N—H group and its adjacent salicyl C—H group chelate one carboxylate O atom via hydrogen bonds, forming seven‐membered rings. As a result of steric hindrance, the planes of the molecules within these pairs of hydrogen‐bonded molecules are inclined to one another by ∼74°. There are also π–π stacking interactions between the parallel planes of the imidazole ring and the benzene ring of the salicyl component of the adjacent molecule on one side and the benzimidazolium component of the molecule on the other side.     

Four related esters: two 4‐(aroylhydrazinyl)‐3‐nitrobenzoates and two 3‐aryl‐1,2,4‐benzotriazine‐6‐carboxylates

The molecules of both methyl 4‐[2‐(4‐chlorobenzoyl)hydrazinyl]‐3‐nitrobenzoate, C₁₅H₁₂ClN₃O₅, (I), and methyl 4‐[2‐(2‐fluorobenzoyl)hydrazinyl]‐3‐nitrobenzoate, C₁₅H₁₂FN₃O₅, (II), contain an intramolecular N—H...O hydrogen bond, and both show electronic polarization in the nitrated aryl ring. In both compounds, molecules are linked by a combination of N—H...O and C—H...O hydrogen bonds to form sheets, which are built from R₄³(18) rings in (I) and from R₄⁴(28) rings in (II). In each of methyl 3‐phenyl‐1,2,4‐benzotriazine‐6‐carboxylate, C₁₅H₁₁N₃O₂, (III), and methyl 3‐(4‐methylphenyl)‐1,2,4‐benzotriazine‐6‐carboxylate, C₁₆H₁₃N₃O₂, (IV), the benzotriazine unit shows naphthalene‐type delocalization. There are no hydrogen bonds in the structures of compounds (III) and (IV), but in both compounds, the molecules are linked into chains by π–π stacking interactions involving the benzotriazine units. The mechanism of chain formation is the same in both (III) and (IV), and the different orientations of the two chains can be related to the approximate relationship between the unit‐cell metrics for (III) and (IV).     

Hydrogen‐bonded sheet structures in methyl 4‐(4‐chloroanilino)‐3‐nitrobenzoate and methyl 1‐benzyl‐2‐(4‐chlorophenyl)‐1H‐benzimidazole‐5‐carboxylate

In methyl 4‐(4‐chloroanilino)‐3‐nitrobenzoate, C₁₄H₁₁ClN₂O₄, (I), there is an intramolecular N—H...O hydrogen bond and the intramolecular distances provide evidence for electronic polarization of the o‐quinonoid type. The molecules are linked into sheets built from N—H...O, C—H...O and C—H...π(arene) hydrogen bonds, together with an aromatic π–π stacking interaction. The molecules of methyl 1‐benzyl‐2‐(4‐chlorophenyl)‐1H‐benzimidazole‐5‐carboxylate, C₂₂H₁₇ClN₂O₂, (II), are also linked into sheets, this time by a combination of C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions.     

Two polymorphs of N‐(2‐methoxyphenyl)‐4‐oxo‐4H‐chromone‐3‐carboxamide

The title compound, C₁₇H₁₃NO₄, crystallizes in two polymorphic forms, each with two molecules in the asymmetric unit and in the monoclinic space group P2₁/c. All of the molecules have intramolecular hydrogen bonds involving the amide group. The amide N atoms act as donors to the carbonyl group of the pyrone and also to the methoxy group of the benzene ring. The carbonyl O atom of the amide group acts as an acceptor of the β and β′ C atoms belonging to the aromatic rings. These intramolecular hydrogen bonds have a profound effect on the molecular conformation. In one polymorph, the molecules in the asymmetric unit are linked to form dimers by weak C—H...O interactions. In the other, the molecules in the asymmetric unit are linked by a single weak C—H...O hydrogen bond. Two of these units are linked to form centrosymmetric tetramers by a second weak C—H...O interaction. Further interactions of this type link the molecules into chains, so forming a three‐dimensional network. These interactions in both polymorphs are supplemented by π–π interactions between the chromone rings and between the chromone and methoxyphenyl rings.