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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.

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.

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 R 4 4(18) and R 2 2(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.

Three organic salts of sparfloxacin, a difluorinated third-generation fluoroquinolone antibiotic, have been synthesized and their crystal structures determined. The salts, sparfloxacinium 4-nitrobenzoate dihydrate, C19H23F2N4O3 +·C7H4NO4 −·2H2O (I), sparfloxacinium 2-phenylacetate, C19H23F2N4O3 +·C8H7O2 − (II), and sparfloxacinium 4-methylbenzoate trihydrate, C19H23F2N4O3 +·C8H7O2 −·3H2O (III), exhibit similar inter-species packing interactions. The overall crystal structures each, however, have their own distinct characteristics, which are described here along with a Hirshfeld surface analysis of the various atom–atom contacts involving the sparfloxacinium cations. In the crystal structure of III, an extended supramolecular tape of edge-fused hydrogen-bonded water pentagons was found. These pentagonal water and tape motifs are compared to related constructs in a broad selection of structure types, ranging from macromolecules to small molecules, clathrates, and exotic `ice' formations on clean metal surfaces.

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.

As part of our ongoing investigation on the chemical and biological properties of piperazinium salts, we synthesized three novel compounds: 1-ethyl­piperazinium 3,5-di­nitro­benzoate (I), 1-methyl­piperazinium 3,5-di­nitro­benzoate (II) and 1-methyl­piperazinium 4-iodo­benzoate (III). The crystal structures of these compounds are built up of organic layers formed by the strong connection between the mol­ecules by hydrogen bonds of type N—H...O. These layers are linked through N—H...O hydrogen bonds and C—H...O inter­actions or C—I...N halogen bonding, leading to the formation of a three-dimensional network., Funding for this research was provided by: Spanish Ministerio de Ciencia e Innovacion (grant No. PID2020-113558RB-C41 to Santiago Garcia-Granda); Gobierno del Principado de Asturias (grant No. GRUPIN-ID2018-170 to Santiago GarciaGranda); University of Mysore (grant to Sriramapura D. Archana); Darmstadt University of Technology (studentship to Hemmige S. Yathirajan).

In the title compound, C

In the title compound, C

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.

Three 2-substituted benzimidazole esters each exhibit different types of mol­ecular disorder and different patterns of supra­molecular assembly., The crystal structures of three benzimidazole esters containing aryl or heterocyclic substituents at position 2 are reported, and all three exhibit disorder of mol­ecular entities. In ethyl 1-methyl-2-[4-(prop-2-yn­oxy)phen­yl]-1H-benzimidazole-5-carboxyl­ate, C20H18N2O3, (I), the prop-2-yn-1-oxyphenyl unit is disordered over two sets of atomic sites having effectively equal occupancies, 0.506 (5) and 0.494 (5). The propyl substituent in ethyl 1-propyl-2-(pyren-1-yl)-1H-benzimidazole-5-carboxyl­ate, C29H24N2O2, (II), is disordered over two sets of atomic sites having occupancies 0.601 (8) and 0.399 (8), and the ester unit in ethyl 1-methyl-2-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1H-benzimidazole-5-carboxyl­ate, C21H19ClN4O2 (III), is disordered over two sets of atomic sites having occupancies 0.645 (7) and 0.355 (7). In each of the C—H⋯π(arene) hydrogen bonds in (I), the donor and acceptor form parts of different disorder components, so that no continuous aggregation is possible. The mol­ecules of (II) are linked by a single C—H⋯O hydrogen bond into C(10) chains, which are linked into sheets by a π–π stacking inter­action, whereas those of (III) are just linked into C(13) chains, again by a single C—H⋯O hydrogen bond. Comparisons are made with the structures of some related compounds.

Among six closely related 1-halobenzoyl-4-(2-meth­oxy­phen­yl)piperazines, those with Z′ = 1 form one-dimensional hydrogen-bonded assemblies, those with Z′ = 2 form two-dimensional hydrogen-bonded assemblies, and that with Z′ = 4 forms a three-dimensional hydrogen-bonded assembly. Pseudosymmetry and inversion twinning are apparent when Z′ > 1., Six 1-halobenzoyl-4-(2-meth­oxy­phen­yl)piperazines have been prepared using carbodi­imide-mediated coupling reactions between halo­benzoic acids and N-(2-meth­oxy­phen­yl)piperazine. The mol­ecules of 1-(4-fluoro­benzo­yl)-4-(2-meth­oxy­phen­yl)piperazine, C18H19FN2O2 (I), are linked into a chain of rings by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds. 1-(4-Chloro­benzo­yl)-4-(2-meth­oxy­phen­yl)piperazine, C18H19ClN2O2 (II), crystallizes in the space group Pca21 with Z′ = 4 and it exhibits both pseudosymmetry and inversion twinning: a combination of six C—H⋯O and two C—H⋯π(arene) hydrogen bonds generate a three-dimensional assembly. In 1-(4-bromo­benzo­yl)-4-(2-meth­oxy­phen­yl)piperazine, C18H19BrN2O2 (III), which also crystallizes in space group Pca21 but with Z′ = 2, the bromo­benzoyl unit in one of the mol­ecules is disordered. Pseudosymmetry and inversion twinning are again present, and a combination of three C—H⋯O and one C—H⋯π(arene) hydrogen bonds generate a two-dimensional assembly. A single C—H⋯O hydrogen bond links the mol­ecules of 1-(4-iodo­benzo­yl)-4-(2-meth­oxy­phen­yl)piperazine, C18H19IN2O2 (IV), into simple chains but in the isomeric 3-iodo­benzoyl analogue (V), which crystallizes in space group P212121 with Z′ = 2, a two-dimensional assembly is generated by a combination of four C—H⋯O and two C—H⋯π(arene) hydrogen bonds; pseudosymmetry and inversion twinning are again present. A single C—H⋯O hydrogen bond links the mol­ecules of 1-(2-fluoro­benzo­yl)-4-(2-meth­oxy­phen­yl)piperazine, C18H19FN2O2 (VI), into simple chains. Comparisons are made with the structures of some related compounds.

Co-crystallization from methanol of 3-amino-1H-pyrazole with 3,5-dinitrobenzoic acid produces 3-amino-1H-pyrazol-2-ium 3,5-dinitrobenzoate monohydrate, C3H6N3 +·C7H3N2O6 −·H2O, (I), while similar co-crystallization of this pyrazole with an equimolar quantity of fumaric acid produces bis(3-amino-1H-pyrazol-2-ium) fumarate–fumaric acid (1/1), 2C3H6N3 +·C4H2O4 2−·C4H4O4, (II). The reaction of 3-amino-1H-pyrazole with a dilute solution of nitric acid in methanol yields a second, orthorhombic polymorph of 3-amino-1H-pyrazol-2-ium nitrate, C3H6N3 +·NO3 −, (III). In each of (I)–(III), the bond distances in the cation provide evidence for extensive delocalization of the positive charge. In each of (I) and (II), an extensive series of O—H...O and N—H...O hydrogen bonds links the components into complex sheets, while in the structure of (III), the ions are linked by multiple N—H...O hydrogen bonds into a three-dimensional arrangement. Comparisons are made with the structures of some related compounds.

In this study, four new piperazinium salts, namely, 4-phenyl-piperazin-1-ium 4-eth-oxy-benzoate monohydrate, C

Fifteen 4-(2-meth­oxy­phen­yl)piperazin-1-ium salts with organic anions exhibit a range of hydrogen-bonded supra­molecular assemblies in the form of finite aggregates, a chain of rings, ribbons, sheets and three-dimensional networks., Fifteen 4-(2-meth­oxy­phen­yl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. In the isostructural 4-chloro­benzoate and 4-bromo­benzoate salts, C11H17N2O+·C7H4ClO2 − (I) and C11H17N2O+·C7H4BrO2 − (II), and the 4-iodo­benzoate salt C11H17N2O+·C7H4IO2 − (III), the ions are linked by N—H⋯O hydrogen bonds, forming centrosymmetric R 4 4(12) four-ion aggregates; a similar aggregate is formed in the 2-chloro­benzoate salt (V), isomeric with (I). In the 2-fluoro­benzoate salt C11H17N2O+·C7H4FO2 − (IV), and the isomorphous pair of salts, the 2-bromo­benzoate (VI), isomeric with (II) and 2-iodo­benzoate (VII), isomeric with (III), N—H⋯O and C—H⋯π(arene) interactions link the components into three-dimensional arrays. Four-ion R 4 4(12) aggregates are also found in the 2-methyl­benzoate, 4-amino­benzoate and 4-nitro­benzoate salts, C11H17N2O+·C8H7O2 − (VIII), C11H17N2O+·C7H6NO2 − (IX) and C11H17N2O+·C7H4NO4 − (X), but those in (IX) are linked into complex sheets by an additional N—H⋯O hydrogen bond. In the 3,5-dinitrobenzoate salt, C11H17N2O+·C7H3N2O6 −·2H2O (XI), N—H⋯O and O—H⋯O hydrogen bonds link the components into a complex ribbon structure. In the picrate salt, C11H17N2O+·C6H2N3O7 − (XII), the four-ion aggregates are linked into chains of rings by C—H⋯O hydrogen bonds. In the hydrogen maleate salt, C11H17N2O+·C4H3O4 − (XIII), two- and three-centre hydrogen bonds link the ions into a ribbon structure while both anions contain very short but asymmetric O—H⋯O hydrogen bonds, having O⋯O distances of 2.4447 (16) and 2.4707 (17) Å. O—H⋯O Hydrogen bonds link the anions in the hydrogen fumarate salt (XIV), isomeric with (XIII), into chains that are linked into sheets via N—H⋯O hydrogen bonds. In the hydrogen (2R,3R)-tartrate salt, C11H17N2O+·C4H5O6 −·1.698H2O (XV), the anions are linked into sheets by O—H⋯O hydrogen bonds. Comparisons are made with the structures of some related compounds.

Two new substituted propanedioate esters have been synthesized using a three-component solvent-free thermal reaction between diethyl propanedioate (diethyl malonate), 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde and an aryl azide, forming two new C—C bonds in a single step. The products diethyl (RS)-2-[(4-bromophenyl)(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methyl]propanedioate, C24H25BrN2O5 (I), and diethyl (RS)-2-[(4-chlorophenyl)(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methyl]propanedioate, C24H25ClN2O5 (II), are isomorphous, with Z′ = 2 in space group P21/n. The two independent molecules in compound (I) are both fully ordered, while each of the independent molecules in compound (II) is disordered, but in different ways. In one molecule of (II), the N-phenyl ring is disordered over two sets of atomic sites having occupancies 0.635 (10) and 0.365 (10), and in the other molecule the ester function is disordered over two sets of atomic sites having occupancies 0.690 (5) and 0.310 (5). In both structures, the two independent molecules adopt different conformations and, in each structure, the molecules are linked into complex sheets by a combination of N—H...O, C—H...O and C—H...π(arene) hydrogen bonds. Comparisons are made with some related structures.

In each of the title newly synthesized and closely related N-{[4-(3-aryl-4-sydnonyl­idene­amino)-5-sulfanyl­idene-1H-1,2,4-triazol-3-yl]meth­yl}benzamides, which crystallized as ethanol monosolvates, the independent components are linked by hydrogen bonds to form centrosymmetric four-mol­ecule aggregates., Two new N-{[4-(3-aryl-4-sydnonyl­idene­amino)-5-sulfanyl­idene-1H-1,2,4-triazol-3-yl]meth­yl}benzamides have been prepared by acid-promoted condensation reactions between 3-aryl-4-formyl­sydnones and N-[(4-amino-5-sulfanyl­idene-1H-1,2,4-triazol-3-yl)meth­yl]benzamide, and both have been crystallized as ethanol monosolvates. N-{[4-(3-Phenyl-4-sydnonyl­idene­amino)-5-sulfanyl­idene-1H-1,2,4-triazol-3-yl]meth­yl}benzamide ethanol monosolvate, C19H15N7O3S·C2H6O (I), and N-({4-[3-(4-methyl­phen­yl)-4-sydnonyl­idene­amino]-5-sulfanyl­idene-1H-1,2,4-triazol-3-yl}meth­yl)benzamide ethanol monosolvate, C20H17N7O3S·C2H6O (II), differ only in the presence of a methyl group for (II) instead of a hydrogen atom for (I), and in both of them the ethanol component is disordered over two sets of atomic sites having occupancies of 0.836 (6) and 0.164 (6) in (I), and 0.906 (6) and 0.094 (6) in (II). Combinations of O—H⋯O and N—H⋯O hydrogen bonds link the mol­ecules into cyclic, centrosymmetric four-mol­ecule aggregates. Comparisons are made with the structures of some related compounds.

Two series of functionalized chalcones have been synthesized from a common family of precursors, and the structures of three examples from each series have been determined. The supra­molecular assembly, based upon C—H⋯O and C—H⋯π(arene) hydrogen bonds, is different in all of the examples examined., Five examples each of 3-(5-ar­yloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-[4-(prop-2-yn-1-yl­oxy)phen­yl]prop-2-en-1-ones and the corresponding 1-(4-azido­phen­yl)-3-(5-ar­yloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones have been synthesized in a highly efficient manner, starting from a common source precursor, and structures have been determined for three examples of each type. In each of 3-[5-(2-chloro­phen­oxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yl­oxy)phen­yl]prop-2-en-1-one, C28H21ClN2O3, (Ib), the isomeric 3-[5-(2-chloro­phen­oxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yl­oxy)phen­yl]prop-2-en-1-one, (Ic), and 3-[3-methyl-5-(naphthalen-2-yl­oxy)-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn­yloxy)phen­yl]prop-2-en-1-one, C32H24N2O3, (Ie), the mol­ecules are linked into chains of rings, formed by two independent C—H⋯O hydrogen bonds in (Ib) and by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds in each of (Ic) and (Ie). There are no direction-specific inter­molecular inter­actions in the structure of 1-(4-azido­phen­yl)-3-[3-methyl-5-(2-methyl­phen­oxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C26H21N5O2, (IIa). In 1-(4-azido­phen­yl)-3-[5-(2,4-di­chloro­phen­oxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C25H17Cl2N5O2, (IId), the di­chloro­phenyl group is disordered over two sets of atomic sites having occupancies 0.55 (4) and 0.45 (4), and the mol­ecules are linked by a single C—H⋯O hydrogen bond to form cyclic, centrosymmetric R 2 2(20) dimers. Similar dimers are formed in 1-(4-azido­phen­yl)-3-[3-methyl-5-(naphthalen-2-yl­oxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C29H21N5O2, (IIe), but here the dimers are linked into a chain of rings by two independent C—H..π(arene) hydrogen bonds. Comparisons are made between the mol­ecular conformations within both series of compounds.

1,3-Disubstituted chalcones have been converted into 3,5-disubstituted 4,5-di­hydro­pyrazole-1-carbo­thio­amides by reaction with thio­semicarbazide. Two isomorphous chalcone precursors form hydrogen-bonded sheets, while in two isomorphous reduced pyrazole products, hydrogen-bonded chains of rings are formed: in a third product, the mol­ecules are linked into complex sheets., Chalcones of type 4-XC6H4C(O)CH=CHC6H4(OCH2CCH)-4, where X = Cl, Br or MeO, have been converted to the corresponding 4,5-di­hydro­pyrazole-1-carbo­thio­amides using a cyclo­condensation reaction with thio­semicarbazide. The chalcones 1-(4-chloro­phen­yl)-3-[4-(prop-2-yn­yloxy)phen­yl]prop-2-en-1-one, C18H13ClO2, (I), and 1-(4-bromo­phen­yl)-3-[4-(prop-2-yn­yloxy)phen­yl]prop-2-en-1-one, C18H13BrO2, (II), are isomorphous, and their mol­ecules are linked into sheets by two independent C—H⋯π(arene) inter­actions, both involving the same aryl ring with one C—H donor approaching each face. In each of the products (RS)-3-(4-chloro­phen­yl)-5-[4-(prop-2-yn­yloxy)phen­yl]-4,5-di­hydro­pyrazole-1-carbo­thio­amide, C19H16ClN3OS, (IV), (RS)-3-(4-bromo­phen­yl)-5-[4-(prop-2-yn­yloxy)phen­yl]-4,5-di­hydro­pyrazole-1-carbo­thio­amide, C19H16BrN3OS, (V), and (RS)-3-(4-meth­oxy­phen­yl)-5-[4-(prop-2-yn­yloxy)phen­yl]-4,5-di­hydro­pyrazole-1-carbo­thio­amide, C20H19N3O2S, (VI), the reduced pyrazole ring adopts an envelope conformation with the C atom bearing the 4-prop-2-yn­yloxy)phenyl substituent, which occupies the axial site, displaced from the plane of the four ring atoms. Compounds (IV) and (V) are isomorphous and their mol­ecules are linked into chains of edge-fused rings by a combination of N—H⋯S and C—H⋯S hydrogen bonds. The mol­ecules of (VI) are linked into sheets by a combination of N—H⋯S, N—H⋯N and C—H⋯π(arene) hydrogen bonds. Comparisons are made with the structures of some related compounds.

In each of two isostructural 3-(5-ar­yloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-(thio­phen-2-yl)prop-2-en-1-ones, the thio­phene unit is disordered over two sets of atomic sites and a combination of C—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules into sheets., Two new chalcones containing both pyrazole and thio­phene substituents have been prepared and structurally characterized. 3-(3-Methyl-5-phen­oxy-1-phenyl-1H-pyrazol-4-yl)-1-(thio­phen-2-yl)prop-2-en-1-one, C23H18N2O2S (I), and 3-[3-methyl-5-(2-methyl­phen­oxy)-1-phenyl-1H-pyrazol-4-yl]-1-(thio­phen-2-yl)prop-2-en-1-one, C24H20N2O2S (II), are isomorphous as well as isostructural, and in each the thio­phene substituent is disordered over two sets of atomic sites having occupancies 0.844 (3) and 0.156 (3) in (I), and 0.883 (2) and 0.117 (2) in (II). In each structure, the mol­ecules are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds. Comparisons are made with some related compounds.

In the crystals of three new 6-aryl-2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazo­les (where aryl is phenyl, 4-fluoro­phenyl or 4-bromo­phen­yl), the mol­ecules are linked by a combination of N—H⋯N and C—H⋯π inter­actions to form chains when the 6-aryl substituent is phenyl or 4-fluoro­phenyl and a three-dimensional framework when the 6-aryl group is 4-bromo­phenyl., Three title compounds, namely, 2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]-6-phenyl­imidazo[2,1-b][1,3,4]thia­diazole, C26H19ClN4S, (I), 2-(4-chloro­benz­yl)-6-(4-fluoro­phen­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazole, C26H18ClFN4S, (II), and 6-(4-bromo­phen­yl)-2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazole, C26H18BrClN4S, (III), have been prepared using a reductive condensation of indole with the corresponding 6-aryl-2-(4-chloro­benz­yl)imidazo[2,1-b][1,3,4]thia­diazole-5-carbaldehydes (aryl = phenyl, 4-fluoro­phenyl or 4-bromo­phen­yl), and their crystal structures have been determined. The asymmetric unit of compound (I) consists of two independent mol­ecules and one of the mol­ecules exhibits disorder of the 4-chloro­benzyl substituent with occupancies 0.6289 (17) and 0.3711 (17). Each type of mol­ecule forms a C(8) chain motif built from N—H⋯N hydrogen bonds, which for the fully ordered mol­ecule is reinforced by C—H⋯π inter­actions. In compound (II), the chloro­benzyl unit is again disordered, with occupancies 0.822 (6) and 0.178 (6), and the mol­ecules form C(8) chains similar to those in (I), reinforced by C—H⋯π inter­actions involving only the major disorder component. The chloro­benzyl unit in compound (III) is also disordered with occupancies of 0.839 (5) and 0.161 (5). The mol­ecules are linked by a combination of one N—H⋯N hydrogen bond and four C—H⋯π inter­actions, forming a three-dimensional framework.

The reaction of 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde with phenols under basic conditions yields the corresponding 5-aryloxy derivatives; the subsequent reaction of these carbaldehydes with substituted acetophenones yields the corresponding chalcones, which in turn undergo cyclocondensation reactions with hydrazine in the presence of acetic acid to form N-acetylated reduced bipyrazoles. Structures are reported for three 5-aryloxycarbaldehydes and the 5-piperidino analogue, and for two reduced bipyrazole products. 5-(2-Chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde, C17H13ClN2O2, (II), which crystallizes with Z′ = 2 in the space group P\overline{1}, exhibits orientational disorder of the carbaldehyde group in each of the two independent molecules. Each of 3-methyl-5-(4-nitrophenoxy)-1-phenyl-1H-pyrazole-4-carbaldehyde, C17H13N3O4, (IV), 3-methyl-5-(naphthalen-2-yloxy)-1-phenyl-1H-pyrazole-4-carbaldehyde, C21H16N2O2, (V), and 3-methyl-1-phenyl-5-(piperidin-1-yl)-1H-pyrazole-4-carbaldehyde, C16H19N3O, (VI), (3RS)-2-acetyl-5-(4-azidophenyl)-5′-(2-chlorophenoxy)-3′-methyl-1′-phenyl-3,4-dihydro-1′H,2H-[3,4′-bipyrazole] C27H22ClN7O2, (IX) and (3RS)-2-acetyl-5-(4-azidophenyl)-3′-methyl-5′-(naphthalen-2-yloxy)-1′-phenyl-3,4-dihydro-1′H,2H-[3,4′-bipyrazole] C31H25N7O2, (X), has Z′ = 1, and each is fully ordered. The new compounds have all been fully characterized by analysis, namely IR spectroscopy, 1H and 13C NMR spectroscopy, and mass spectrometry. In each of (II), (V) and (IX), the molecules are linked into ribbons, generated respectively by combinations of C—H...N, C—H...π and C—Cl...π interactions in (II), C—H...O and C—H...π hydrogen bonds in (V), and C—H...N and C—H...O hydrogen bonds in (IX). The molecules of compounds (IV) and (IX) are both linked into sheets, by multiple C—H...O and C—H...π hydrogen bonds in (IV), and by two C—H...π hydrogen bonds in (IX). A single C—H...N hydrogen bond links the molecules of (X) into centrosymmetric dimers. Comparisons are made with the structures of some related compounds.

Three 1-[(1,3-benzodioxol-5-yl)methyl]-4-(halobenzo­yl)piperazines adopt very similar mol­ecular conformations but, while the mol­ecules of the 3-fluoro­benzoyl are linked by hydrogen bonds into a three-dimensional structure, there are no hydrogen bonds in either of the 2,6-di­fluoro­benzoyl and 2,4-di­chloro­benzoyl analogues., In each of the compounds 1-[(1,3-benzodioxol-5-yl)methyl]-4-(3-fluoro­benzo­yl)piperazine, C19H19FN2O3 (I), 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,6-di­fluoro­benzo­yl)piperazine, C19H18F2N2O3 (II), and 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,4-di­chloro­benzo­yl)piperazine, C19H19Cl2N2O3 (III), the piperazine rings adopt a chair conformation with the (1,3-benzodioxol-5-yl)methyl substituent occupying an equatorial site: the five-membered rings are all slightly folded across the O⋯O line leading to envelope conformations. The dihedral angle between the planar amidic fragment and the haloaryl ring is 62.97 (5)° in (I) but 77.72 (12)° and 75.50 (5)° in (II) and (III), respectively. Despite their similarity in constitution and conformation, the supra­molecular inter­actions in (I)–(III) differ: in (I), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into a three-dimensional framework structure, but there are no hydrogen bonds of any sort in either (II) or (III), although the structure of (III) contains a short Cl⋯Cl contact between inversion-related pairs of mol­ecules.

The syntheses and structures of five molecular salts of protonated 4,4,7,7-tetramethyl-3a,5,6,7a-tetrahydrobenzothiazol-2-ylamine (C11H19N2S+) with different deprotonated carboxylic acids (4-methylbenzoic acid, 4-bromobenzoic acid, 3,5-dinitrobenzoic acid, fumaric acid and succinic acid) are reported, namely 2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium 4-methylbenzoate, C11H19N2S+·C8H7O2 −, (I), 2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium 4-bromobenzoate, C11H19N2S+·C7H4BrO2 −, (II), 2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium 3,5-dinitrobenzoate, C11H19N2S+·C7H3N2O6 −, (III), bis(2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium) fumarate, 2C11H19N2S+·C4H2O4 2−,(IV), and the 1:1 co-crystal of bis(2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium) succinate and 2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium hydrogen succinate 4,4,7,7-tetramethyl-3a,5,6,7a-tetrahydrobenzothiazol-2-ylamine, 1.5C11H19N2S+·0.5C4H4O4 2−·0.5C4H5O4 −. 0.5C11H18N2S, (V). In every case, the cation protonation occurs at the N atom of the thiazole ring and the six-membered ring adopts a half-chair conformation (in some cases, the deviating methylene groups are disordered over two sets of sites). The C—N bond lengths of the nominal –NH+=C—NH2 fragment of the cation are indistinguishable, indicating a significant contribution of the –NH—C=N+H2 resonance form to the structure. The packing for (I)–(V) features a robust local R 2 2(8) loop motif in which the cation forms two near-linear N—H...O hydrogen bonds from the N+—H group and syn H atom of the amine group to the carboxylate group of an adjacent anion [(V) shows disorder of one of these bonds over N—H...O and N...H—O contributors but the same R 2 2(8) loop results for both disorder components]. The anti H atom of the –NH2 group also forms an N—H...O hydrogen bond, which results in [001] chains in (I) and (II), isolated centrosymmetric tetramers in (III) and [100] chains in (IV) and (V). Hirshfeld fingerprint plots and contact percentages for the different types of contacts of the cations are discussed.

In three amides, each containing a N-(benzo[d]thia­zol­yl) substituent, different combinations of N—H⋯O, N—H⋯N, C—H⋯O and C—H⋯N hydrogen bonds and Br⋯Br inter­actions lead to supra­molecular assemblies in one, two and three dimensions., Crystal structures are reported for three amides containing N-benzo[d]thia­zole substituents. In N-(benzo[d]thia­zol-6-yl)-3-bromo­benzamide, C14H9BrN2OS, where the two ring systems are nearly parallel to one another [dihedral angle = 5.8 (2)°], the mol­ecules are linked by N—H⋯O and C—H⋯N hydrogen bonds to form ribbons of R 3 3(19) rings, which are linked into sheets by short Br⋯Br inter­actions [3.5812 (6) Å]. N-(6-Meth­oxy­benzo[d]thia­zol-2-yl)-2-nitro­benzamide, C15H11N3O4S, crystallizes with Z′ = 2 in space group Pna21: the dihedral angles between the ring systems [46.43 (15) and 66.35 (13)°] are significantly different in the independent mol­ecules and a combination of two N—H⋯N and five C—H⋯O hydrogen bonds links the mol­ecules into a three-dimensional network. The mol­ecules of 5-cyclo­propyl-N-(6-meth­oxy­ben­zo[d]thia­zol-2-yl)­isoxazole-3-carboxamide, C15H13N3O3S, exhibit two forms of disorder, in the meth­oxy group and in the cyclo­propyl­isoxazole unit; symmetry-related pairs of mol­ecules are linked into dimers by pairwise N—H⋯N hydrogen bonds. Comparisons are made with the structures of some related compounds.

In the title compound, C

The hydrogen-bonded assembly of 3-amino-1H-pyrazol-2-ium 3,5-di­nitro­benzoate monohydrate and bis­(3-amino-1H-pyrazol-2-ium) fumarate fumaric acid is two-dimensional, but that in the ortho­rhom­bic form of the simple salt 3-amino-1H-pyrazol-2-ium nitrate is three-dimensional., Co-crystallization from methanol of 3-amino-1H-pyrazole with 3,5-di­nitro­benzoic acid produces 3-amino-1H-pyrazol-2-ium 3,5-di­nitro­benzoate monohydrate, C3H6N3 +·C7H3N2O6 −·H2O, (I), while similar co-crystallization of this pyrazole with an equimolar qu­antity of fumaric acid produces bis­(3-amino-1H-pyrazol-2-ium) fumarate–fumaric acid (1/1), 2C3H6N3 +·C4H2O4 2−·C4H4O4, (II). The reaction of 3-amino-1H-pyrazole with a dilute solution of nitric acid in methanol yields a second, ortho­rhom­bic polymorph of 3-amino-1H-pyrazol-2-ium nitrate, C3H6N3 +·NO3 −, (III). In each of (I)–(III), the bond distances in the cation provide evidence for extensive delocalization of the positive charge. In each of (I) and (II), an extensive series of O—H⋯O and N—H⋯O hydrogen bonds links the components into complex sheets, while in the structure of (III), the ions are linked by multiple N—H⋯O hydrogen bonds into a three-dimensional arrangement. Comparisons are made with the structures of some related compounds.

In the title compound, C18H18N4O6, the piperazine ring adopts a chair conformation, the amidic N atom is planar (sum of angles = 360°) and the non-amidic N atom is pyramidal (343°). There are no hydrogen bonds of any kind in the crystal, but the molecules are linked by two independent π(nitrobenzene)...π(methoxybenzene) stacking interactions to form π-stacked sheets with inter-centroid separations of 3.8444 (12) and 3.9197 (12) Å.

Two new substituted propane­dioate esters have been synthesized using a three-component solvent-free thermal reaction. The products, which are isomorphous, differ only in the presence of a bromo­phenyl group in one, where the mol­ecules are fully ordered, as compared with a chloro­phenyl group in the other, where the mol­ecules exhibit two types of disorder., Two new substituted propane­dioate esters have been synthesized using a three-component solvent-free thermal reaction between diethyl propane­dioate (diethyl malonate), 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde and an aryl azide, forming two new C—C bonds in a single step. The products diethyl (RS)-2-[(4-bromo­phen­yl)(5-methyl-3-oxo-2-phenyl-2,3-di­hydro-1H-pyrazol-4-yl)meth­yl]propane­dioate, C24H25BrN2O5 (I), and diethyl (RS)-2-[(4-chloro­phen­yl)(5-methyl-3-oxo-2-phenyl-2,3-di­hydro-1H-pyrazol-4-yl)meth­yl]propane­dioate, C24H25ClN2O5 (II), are isomorphous, with Z′ = 2 in space group P21/n. The two independent mol­ecules in compound (I) are both fully ordered, while each of the independent mol­ecules in compound (II) is disordered, but in different ways. In one mol­ecule of (II), the N-phenyl ring is disordered over two sets of atomic sites having occupancies 0.635 (10) and 0.365 (10), and in the other mol­ecule the ester function is disordered over two sets of atomic sites having occupancies 0.690 (5) and 0.310 (5). In both structures, the two independent mol­ecules adopt different conformations and, in each structure, the mol­ecules are linked into complex sheets by a combination of N—H⋯O, C—H⋯O and C—H⋯π(arene) hydrogen bonds. Comparisons are made with some related structures.

The structures are reported for five salts formed by reactions between N-(4-fluorophenyl)piperazine and aromatic acids. In 4-(4-fluorophenyl)piperazin-1-ium 2-fluorobenzoate monohydrate, C10H14FN2 +·C7H4FO2 −·H2O, (I), the components are linked by a combination of N—H...O and O—H...O hydrogen bonds to form a chain of alternating R 4 6(12) and R 6 6(16) rings. The ionic components of 4-(4-fluorophenyl)piperazin-1-ium 2-bromobenzoate 0.353-hydrate, C10H14FN2 +·C7H4BrO2 −·0.353H2O, (II), are linked by N—H...O hydrogen bonds to form a centrosymmetric four-ion aggregate containing an R 4 4(12) motif, and these aggregates are linked into a molecular ladder by a single C—H...π(arene) hydrogen bond. 4-(4-Fluorophenyl)piperazin-1-ium 2-iodobenzoate, C10H14FN2 +·C7H4IO2 −, (III), crystallizes with Z′ = 2 in space group P\overline{1}: the four independent ions are linked by N—H...O hydrogen bonds to form a non-centrosymmetric aggregate again containing an R 4 4(12) motif, and aggregates of this type are linked into a ribbon by a combination of C—H...O and C—H...π(arene) hydrogen bonds. The anion in 4-(4-fluorophenyl)piperazin-1-ium 2,4,6-trinitrophenolate, C10H14FN2 +·C6H2N3O7 −, (IV), shows clear evidence of extensive electronic delocalization from the phenolate O atom into the adjacent ring. The ions are linked by a combination of two-centre N—H...O and three-centre N—H...(O)2 hydrogen bonds to form centrosymmetric four-ion aggregates containing three types of ring. The ions in 4-(4-fluorophenyl)piperazin-1-ium 3,5-dinitrobenzoate, C10H14FN2 +·C7H3N2O6 −, (V), are again linked by N—H...O hydrogen bonds to form centrosymmetric R 4 4(12) aggregates, which are themselves linked by a C—H...π(arene) hydrogen bond to form sheets, the stacking of which leads to the formation of narrow channels, containing disordered and/or mobile solvent entities. Comparisons are made with some related structures.

Crystal structures are reported for N-(4-methoxyphenyl)piperazine (MeOPP), (I), and for its 3,5-dinitrobenzoate, 2,4,6-trinitrophenolate (picrate) and 4-aminobenzoate salts, (II)–(IV), the last of which crystallizes as a monohydrate. In MeOPP, C11H16N2O, (I), the 4-methoxyphenyl group is nearly planar and it occupies an equatorial site on the piperazine ring: the molecules are linked into simple C(10) chains by N—H...O hydrogen bonds. In each of the salts, i.e., C11H17N2O+·C7H3N2O6 −, (II), C11H17N2O+·C6H2N3O7 −, (III), and C11H17N2O+·C7H6NO2 −·H2O, (IV), the effectively planar 4-methoxyphenyl substituent again occupies an equatorial site on the piperazine ring. In (II), two of the nitro groups are disordered over two sets of atomic sites and the bond distances in the anion indicate considerable delocalization of the negative charge over the C atoms of the ring. The ions in (II) are linked by two N—H...O hydrogen bonds to form a cyclic, centrosymmetric four-ion aggregate; those in (III) are linked by a combination of N—H...O and C—H...π(arene) hydrogen bonds to form sheets; and the components of (IV) are linked by N—H...O, O—H...O and C—H...π(arene) hydrogen bonds to form a three-dimensional framework structure. Comparisons are made with the structures of some related compounds.

Four 1-aryl-1H-pyrazole-3,4-dicarboxylate derivatives, one acid, two esters and a dicarbohydrazide have been synthesized starting from 3-aryl sydnones, and structurally characterized. There is an intramolecular O—H...O hydrogen bond in 1-phenyl-1H-pyrazole-3,4-dicarboxylic acid, C11H8N2O4, (I), and the molecules are linked into a three-dimensional framework structure by a combination of O—H...O, O—H...N, C—H...O and C—H...π(arene) hydrogen bonds. In each of the two esters dimethyl 1-phenyl-1H-pyrazole-3,4-dicarboxylate, C13H12N2O4, (II), and dimethyl 1-(4-methylphenyl)-1H-pyrazole-3,4-dicarboxylate, C14H14N2O4, (III), C—H...O hydrogen bonds lead to the formation of cyclic centrosymmetric dimers: in (III), one of the methoxycarbonyl groups is disordered over two sets of atomic sites having occupancies 0.71 (2) and 0.29 (2). An intramolecular N—H...O hydrogen bond is present in the structure of 1-(4-methoxyphenyl)-1H-pyrazole-3,4-dicarbohydrazide, C12H14N6O3, (IV), and the molecules are linked into a three-dimensional framework structure by a combination of N—H...O, N—H...N, N—H...π(arene) and C—H...O hydrogen bonds. Comparisons are made with the structures of a number of related compounds.

The 2-ethyl­phenyl group in the title compound is disordered over two sets of atomic sites and the mol­ecules are linked into a three-dimensional array by a combination of C—H⋯O hydrogen bonds and nitro⋯π(arene) inter­actions., In the mol­ecule of the title compound, C15H14N2O2, the 2-ethyl­phenyl group is disordered over two sets of atomic sites having occupancies of 0.515 (19) and 0.485 (19), and the dihedral angle between the two partial-occupancy aryl rings is 6(2)°. A combination of C—H⋯O hydrogen bonds and nitro⋯π(arene) inter­actions links the mol­ecules into a continuous three-dimensional framework structure. Comparisons are made with the structures of some related compounds.

Four closely related N-(3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)benzamides, bearing different substituents on the benzamide ring, have been synthesized and structurally characterized. In each of N-(3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-3-fluorobenzamide, C22H18FNO2S, (I), N-(3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-4-chlorobenzamide, C22H18ClNO2S, (II), N-(3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-2,6-difluorobenzamide, C22H17F2NO2S, (III), and N-(3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-2-methoxybenzamide, C23H21NO3S, (IV), the last of which crystallizes with Z′ = 2 in the space group P\overline{1}, the fused six-membered ring adopts a half-chair conformation. In each of (I)–(III), this ring is disordered over two sets of atomic sites having occupancies of 0.811 (6) and 0.189 (6) in (I), 0.645 (7) and 0.355 (7) in (II), and 0.784 (6) and 0.216 (6) in (III), such that the two disorder components of the ring are almost enantiomeric. Molecules of (I) are linked into chains by π–π stacking interactions, and those of (II) are linked into chains by a C—H...π hydrogen bond. A combination of two C—H...O hydrogen bonds and two C—H...π hydrogen bonds links the molecules of (III) into complex sheets, but the molecules of (IV) are linked by a combination of two hydrogen bonds, one each of the C—H...O and C—H...π types, to form centrosymmetric tetramers. The structures of (I)–(IV) are compared with that of the unsubstituted analogue N-(3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)benzamide and a new refinement of the parent amine 2-amino-3-benzoyl-4,5,6,7-tetrahydrobenzo[b]thiophene, using the original data set, has found that here too the fused six-membered ring exhibits conformational disorder, with occupancies of 0.887 (9) and 0.113 (9). Comparisons are made with some related compounds.

In the cation of the title mol­ecular salt, one of the non-H substituents on the piperidine ring occupies an equatorial site and the other an axial site. The ions are linked into sheets by a combination of one N—H⋯O and two C—H⋯O hydrogen bonds., Ebastine, 4-(benzhydr­yloxy)-1-[4-(4-tert-butyl­phen­yl)-4-oxobut­yl]piperidine, reacts with 3,5-di­nitro­benzoic acid in methanol solution to give the title 1:1 salt, ebastinium 3,5-di­nitro­benzoate, C32H40NO2 +·C7H3N2O6 −. In the cation, the disubstituted aryl ring exhibits orientational disorder over two sets of atomic sites having occupancies 0.706 (4) and 0.294 (6), with a dihedral angle of 41.2 (5)° between the two orientations: the bulky Ph2CH—O– substituent occupies an axial site on the piperidine ring. The two ions in the selected asymmetric unit are linked by a nearly linear N—H⋯O hydrogen bond and this, in combination with two C—H⋯O hydrogen bonds, links the ions into complex sheets.

In each of 1-(4-fluorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C21H19F4N3O2S, (I), 1-(4-chlorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C21H19ClF3N3O2S, (II), and 1-(3-methylphenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C22H22F3N3O2S, (III), the reduced pyridine ring adopts a half-chair conformation with the methylsulfonyl substituent occupying an equatorial site. Although compounds (I) and (II) are not isostructural, having the space groups Pbca and P212121, respectively, their molecular conformations are very similar, but the conformation of compound (III) differs from those of (I) and (II) in the relative orientation of the N-benzyl and methylsulfonyl substituents. In compounds (II) and (III), but not in (I), the trifluoromethyl groups are disordered over two sets of atomic sites. Molecules of (I) are linked into centrosymmetric dimers by C—H...π(arene) hydrogen bonds, molecules of (II) are linked by two C—H...O hydrogen bonds to form ribbons of R 3 3(18) rings, which are themselves further linked by a C—Cl...π(arene) interaction, and a combination of C—H...O and C—H...π(arene) hydrogen bonds links the molecules of (III) into sheets. Comparisons are made with the structures of some related compounds.

The molecular structure, vibrational wave numbers, NLO, NBO, MEP and HOMO, LUMO analysis of 4-[2(5-Ethylpyridin-2-yl)ethoxy]benzaldehyde oxime were reported. The theoretically predicted geometrical parameters are in agreement with the XRD data. Using NBO analysis the change in the electron density in the anti-bonding orbital and stabilization energies have been calculated to give clear evidence of stabilization in the hyper-conjugation of hydrogen bonded interactions. The calculated first hyperpolarizability is 46.761 times that of the standard NLO material urea. From molecular electrostatic potential plot, phenyl ring, pyridine ring and oxygen atoms are the most electronegative regions and the hydrogen atom in the OH group is the most electropositive region. ALIE surfaces and Fukui functions have been calculated in order to obtain information related to the local reactivity properties of the title molecule. Intra-molecular non-covalent interactions have also been searched for. In order to investigate autoxidation and degradation properties we have calculated bond dissociation energies for all single acyclic bonds. To determine which atoms have the most pronounced interactions with water molecules we have conducted molecular dynamics simulations and calculated radial distribution functions. Molecular docking studies suggest that the title compound can be a lead compound for developing new anti-cancerous drug. (C) 2016 Elsevier B.V. All rights reserved.

In the title compound, C61H15ClN2O3, the heterocyclic ring adopts an envelope conformation, folded across the N...N line, with the 2,5-dimethoxyphenyl unit occupying a quasi-axial site. There are two N—H...O hydrogen bonds in the structure: one hydrogen bond links molecules related by a 41 screw axis to form a C(6) chain, and the other links inversion-related pairs of molecules to form an R 2 2(8) ring. The ring motif links all of the chains into a continuous three-dimensional framework structure. Comparisons are made with the structures of some related compounds.

The title compound, C19H12N2O3, obtained as an intermediate in the synthesis of a pyrrole derivative, is composed of a five-membered heterocycle with substituted groups via double or triple bonds as well as single bonds, without an asymmetric carbon atom. An intramolecular O—H...O link occurs. In the crystal, O—H...N hydrogen bonds link the molecules.

4-Antipyrine [4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one] and its derivatives exhibit a range of biological activities, including analgesic, antibacterial and anti-inflammatory, and new examples are always of potential interest and value. 2-(4-Chlorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide, C19H18ClN3O2, (I), crystallizes withZ′ = 2 in the space groupP\overline{1}, whereas its positional isomer 2-(2-chlorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide, (II), crystallizes withZ′ = 1 in the space groupC2/c; the molecules of (II) are disordered over two sets of atomic sites having occupancies of 0.6020 (18) and 0.3980 (18). The two independent molecules of (I) adopt different molecular conformations, as do the two disorder components in (II), where the 2-chlorophenyl substituents adopt different orientations. The molecules of (I) are linked by a combination of N—H...O and C—H...O hydrogen bonds to form centrosymmetric four-molecule aggregates, while those of (II) are linked by the same types of hydrogen bonds forming sheets. The related compoundN-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-(3-methoxyphenyl)acetamide, C20H21N3O3, (III), is isomorphous with (I) but not strictly isostructural; again the two independent molecules adopt different molecular conformations, and the molecules are linked by N—H...O and C—H...O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen-bondedR22(10) ring is the common structural motif.

Pyrazole and isoxazole rings differ only in the notional replacement of a potential hydrogen-bond-donor NH unit in pyrazole by a potential hydrogen-bond-acceptor O atom in isoxazole. It is thus of interest to compare the hydrogen-bonding characteristics of these rings. (4-Fluorophenyl)pyrazole undergoes protonation in the presence of 2,4,6-trinitrophenol to yield the salt 3-(4-fluorophenyl)-1H-pyrazolium 2,4,6-trinitrophenolate, C9H8FN2+·C6H2N3O7−, (I), whereas there is no proton transfer between 4-amino-N-(3,4-dimethyl-1,2-oxazol-5-yl)benzenesulfonamide and 3,5-dinitrobenzoic acid, whose reaction gives the 1:1 cocrystal, C11H13N3O3S·C7H4N2O6, (II). The bond lengths in salt (I) provide evidence for aromatic-type delocalization in the pyrazolium ring and for extensive delocalization of the negative charge into the ring of the trinitrophenolate anion. The O atoms of one of the nitro groups in the trinitrophenolate anion are disordered over two sets of atomic sites having occupancies of 0.571 (6) and 0.429 (6), but all of the other substituents on the carbocyclic rings are fully ordered. The ions in salt (I) are linked by an extensive series of N—H...O hydrogen bonds to form a three-dimensional framework structure, and in cocrystal (II), the molecular components are linked by a combination of O—H...N and N—H...O hydrogen bonds to form complex bilayers. Comparisons are made with some related compounds.

The cyclo­hexenone ring in the title compound adopts an envelope conformation and in the crystal, mol­ecules are linked by N—H⋯O and C—H⋯N hydrogen bonds, forming ribbons of edge-fused rings propagating along [010]., The title compound, C19H17Cl3N2O3, has been prepared in a cyclo­condensation reaction between 2,3,5-tri­chloro­benzaldehye and 4-acetyl-2-methyl-1H-imidazole. The cyclo­hexenone ring adopts an envelope conformation with the C atom substituted by the tri­chloro­phenyl ring as the flap. The mutually trans ester and aryl substituents both occupy equatorial sites. In the crystal, a combination of N—H⋯O and C—H⋯N hydrogen bonds links the mol­ecules into ribbons of edge-fused centrosymmetric rings, which enclose R 2 2(14) and R 4 4(16) alternate ring motifs, propagating along the b-axis direction.

A combination of O—H⋯N hydrogen bonds and C—Cl⋯π(pyrid­yl) inter­actions links the mol­ecules of the title compounds into (100) sheets., In the title racemic compound, C12H10ClNO, the dihedral angle between the benzene and pyridine rings is 74.34 (6)°. In the crystal, the mol­ecules are linked by O—H⋯N hydrogen bonds, forming zigzag C(5) [001] chains in which alternating R- and S-configuration mol­ecules are related by c-glide symmetry. In addition, inversion-related pairs of mol­ecules are linked into dimers by pairs of weak C—Cl⋯π(pyrid­yl) inter­actions, which link the hydrogen-bonded chains into (100) sheets. Structural comparisons are drawn with a number of related compounds.