Three new olanzapine structures: the acetic acid monosolvate,and the propan‐2‐ol and propan‐2‐one hemisolvate monohydrates

The crystal structures of three new solvates of olanzapine [systematic name: 2‐methyl‐4‐(4‐methylpiperazin‐1‐yl)‐10H‐thieno[2,3‐b][1,5]benzodiazepine], namely olanzapine acetic acid monosolvate, C₁₇H₂₀N₄S·C₂H₄O₂, (I), olanzapine propan‐2‐ol hemisolvate monohydrate, C₁₇H₂₀N₄S·0.5C₃H₈O·H₂O, (II), and olanzapine propan‐2‐one hemisolvate monohydrate, C₁₇H₂₀N₄S·0.5C₃H₆O·H₂O, (III), are presented and compared with other known olanzapine forms. There is a fairly close resemblance of the molecular conformation for all studied analogues. The crystal structures are built up through olanzapine dimers, which are characterized via C—H...π interactions between the aliphatic fragment (1‐methylpiperazin‐4‐yl) and the aromatic fragment (benzene system). All solvent (guest) molecules participate in hydrogen‐bonding networks. The crystal packing is sustained via intermolecular N_host—H...O_guest, O_guest—H...N_host, O_guest—H...O_guest and C_host—H...O_guest hydrogen bonds. It should be noted that the solvent propan‐2‐ol in (II) and propan‐2‐one in (III) show orientational disorder. The propan‐2‐ol molecule lies close to a twofold axis, while the propan‐2‐one molecule resides strictly on a twofold axis through the carbonyl C atom. In both cases, the water molecules present positional disorder of the H atoms.     

Magnesium iodide–4,4′‐bipyridine–water (1/3/4) and strontium iodide–4,4′‐bipyridine–propan‐1‐ol (1/2.5/2)

Both of the title compounds, catena‐poly­[[[tetra­aqua­magnesium(I)]‐μ‐4,4′‐bi­pyridine‐κ²N:N′] diiodide bis(4,4′‐bi­pyridine) solvate], {[Mg(C₁₀H₈N₂)(H₂O)₄]I₂·2C₁₀H₈N₂}_n, (I), and catena‐poly­[[[μ‐4,4′‐bi­pyridine‐bis­[di­iodo­bis­(propan‐1‐ol)­strontium(I)]]‐di‐μ‐4,4′‐bi­pyridine‐κ⁴N:N′] bis(4,4′‐bi­pyri­dine) solvate], {[Sr₂I₄(C₁₀H₈N₂)₃(C₃H₈O)₄]·2C₁₀H₈N₂}_n, (II), are one‐dimensional polymers which are single‐ and double‐stranded, respectively, the metal atoms being linked by the 4,4′‐bi­pyridine moieties. The Mg complex, (I), is [cis‐{(H₂O)₄Mg(N‐4,4′‐bi­pyridine‐N′)_(2/2)}]_(∞|∞)I₂·4,4′‐bi­pyridine and Mg has a six‐coordinate quasi‐octahedral coordination environment. The Sr complex, (II), is isomorphous with its previously defined Ba counterpart [Kepert, Waters & White (1996). Aust. J. Chem. 49 , 117–135], being [(propan‐1‐ol)₂I₂Sr(N‐4,4′‐bi­pyridine‐N′)_(3/2)]_(∞|∞)·4,4′‐bi­pyridine, with the I atoms trans‐axial in a seven‐coordinate pentagonal–bipyramidal Sr environment.     

Solvates of zafirlukast

The crystal structures of three solvates of zafirlukast [systematic name: cyclopentyl N‐{1‐methyl‐3‐[2‐methyl‐4‐(o‐tolylsulfonylaminocarbonyl)benzyl]‐1H‐indol‐5‐yl}carbamate], viz. the monohydrate, C₃₁H₃₃N₃O₆S·H₂O, (I), the methanol solvate, C₃₁H₃₃N₃O₆S·CH₃OH, (II), and the ethanol solvate, C₃₁H₃₃N₃O₆S·C₂H₅OH, (III), have been determined by single‐crystal X‐ray diffraction analysis. All three compounds crystallize in the monoclinic crystal system. Zafirlukast adopts a similar Z‐shaped conformation in all three solvates. The methanol and ethanol solvates are isostructural. The packing of the zafirlukast mol­ecules in all three crystal structures is similar and is expressed by hydrogen‐bonded mol­ecules that are related by translation, along (101) in (I) and along the b axis in (II) and (III). The methanol and ethanol solvent mol­ecules are hydrogen bonded to two mol­ecules of zafirlukast. The water mol­ecule, on the other hand, acts as a connector via hydrogen bonds between three mol­ecules of zafirlukast. The solvent mol­ecules are not released at temperatures below the melting points of the solvates.     

Niclosamide methanol solvate and niclosamide hydrate: structure,solvent inclusion mode and implications for properties

Structural studies have been carried out of two solid forms of niclosamide [5‐chloro‐N‐(2‐chloro‐4‐nitrophenyl)‐2‐hydroxybenzamide, NCL], a widely used anthelmintic drug, namely niclosamide methanol monosolvate, C₁₃H₈Cl₂N₂O₄·CH₃OH or NCL·MeOH, and niclosamide monohydrate, denoted H_A. The structure of the methanol solvate obtained from single‐crystal X‐ray diffraction is reported for the first time, elucidating the key host–guest hydrogen‐bonding interactions which lead to solvate formation. The essentially planar NCL host molecules interact viaπ‐stacking and pack in a herringbone‐type arrangement, giving rise to channels along the crystallographic a axis in which the methanol guest molecules are located. The methanol and NCL molecules interact via short O—H...O hydrogen bonds. Laboratory powder X‐ray diffraction (PXRD) measurements reveal that the initially phase‐pure NCL·MeOH solvate readily transforms into NCL monohydrate within hours under ambient conditions. PXRD further suggests that the NCL monohydrate, H_A, is isostructural with the NCL·MeOH solvate. This is consistent with the facile transformation of the methanol solvate into the hydrate when stored in air. The crystal packing and the topology of guest‐molecule inclusion are compared with those of other NCL solvates for which the crystal structures are known, giving a consistent picture which correlates well with known experimentally observed desolvation properties.     

Supramolecular hydrogen bonding of [5,10,15,20‐tetrakis(4‐carboxyphenyl)porphyrinato]palladium(II) in the presence of competing solvents

The title porphyrin compound forms hydrogen‐bonded adducts with methanol (1:1), [Pd(C₄₈H₂₈N₄O₈)]·CH₄O, (I), and with water and N,N‐dimethylformamide (1:4:4), [Pd(C₄₈H₂₈N₄O₈)]·4C₃H₇NO·4H₂O, (II). In (I), the metalloporphyrin unit lies across a mirror plane in Cmca, while in (II), this unit lies across an inversion center in P. Extended supramolecular hydrogen‐bonded arrays are formed in (I) by intermolecular interactions between the carboxylic acid functions, either directly or through the methanol species. These layers have a wavy topology and large interporphyrin pores, which are filled in the crystal structure by double interpenetration as well as enclathration of additional non‐interacting nitrobenzene solvent molecules. The supramolecular aggregation in (II) can be characterized by cascaded porphyrin layers, wherein adjacent porphyrin molecules are hydrogen bonded to one another through molecules of water that are incorporated into the hydrogen‐bonding scheme. Molecules of dimethylformamide partly solvate the carboxylic acid groups and fill the interporphyrin space in the crystal structure.     

Hydrogen‐bonded assemblies of 5,10,15,20‐tetrakis(4‐hydroxyphenyl)porphyrin with dimethylformamide,dimethylacetamide and water

The title free base porphyrin compound forms hydrogen‐bonded adducts with N,N‐dimethylformamide, C₄₄H₃₀N₄O₄·4C₃H₇NO, (I), a mixture of N,N‐dimethylformamide and water, C₄₄H₃₀N₄O₄·4C₃H₇NO·H₂O, (II), and a mixture of N,N‐dimethylacetamide and water, C₄₄H₃₀N₄O₄·6C₃H₇NO·2H₂O, (III). Total solvation of the four hydroxy functions of the porphyrin molecules characterizes all three compounds, thus preventing its supramolecular association into extended network architectures. In (I), the asymmetric unit consist of two five‐component adduct species, while in (III), the nine‐component entities reside on centres of inversion. This report provides the first structural characterizations of the free base tetra(hydroxyphenyl)porphyrin. It also demonstrates that the presence of strong Lewis bases, such as dimethylformamide or dimethylacetamide, in the crystallization mixture prevents direct supramolecular networking of the porphyrin ligands via O—H...O—H hydrogen bonds, due to their competing O—H...N(base) interaction with the hydroxy functions. The crystal packing of compounds (I)–(III) resembles that of other hydrogen‐bonding‐assisted tetraarylporphyrin clathrates.     

Expanding the structural landscape of niclosamide: a high Z′ polymorph,two new solvates and monohydrate HA

Three new crystalline phases are reported for the drug niclosamide [5‐chloro‐N‐(2‐chloro‐4‐nitrophenyl)‐2‐hydroxybenzamide], C₁₃H₈Cl₂N₂O₄. A new high‐Z′ polymorph (denoted Form II) is described, with four molecules in the asymmetric unit in the space group P2/n. The structure exhibits pseudosymmetry, including local translations and screw‐type operations. The niclosamide molecules are linked by O—H...O hydrogen bonds into chains, and the chains are packed so that the molecules form face‐to‐face (stacking) and end‐to‐end interactions within layers perpendicular to the chains. There are two different layer arrangements, giving a structure that is relatively complex. In the acetone and acetonitrile solvates, the incorporated solvent molecules accept hydrogen bonds from the OH groups of niclosamide, and the niclosamide molecules are stacked in a face‐to‐face manner. In the acetone solvate, C₁₃H₈Cl₂N₂O₄·C₃H₆O, V‐shaped arrangements are formed in which the nitrobenzene ends of the niclosamide molecules are brought into face‐to‐face contact. In the acetonitrile solvate, C₁₃H₈Cl₂N₂O₄·CH₃CN, stacking occurs by translation along a short axis (ca 3.8 Å) and the crystals are frequently observed to be twinned by twofold rotation around that axis. The acetonitrile molecules occupy channels in the structure. A complete structure is provided for niclosamide monohydrate, C₁₃H₈Cl₂N₂O₄·H₂O, polymorph H_A, obtained by Rietveld refinement against laboratory powder X‐ray diffraction data. It has been suggested that this compound is related to the methanol solvate of niclosamide [Harriss, Wilson & Radosevljevic Evans (2014). Acta Cryst. C 70 , 758–763], but it is found that the two are not fully isostructural: they contain isostructural two‐dimensional layers, but the layers are arranged differently in the two structures. This suggests that H_A may have the potential for polytypism, and features in the Rietveld difference curve indicate that a polytype fully isostructural with the methanol solvate might be present.     

Synthesis and characterization of a novel long‐alkyl‐chain ester‐substituted benzimidazole gelator and its octan‐1‐ol solvate

The synthesis of a novel benzimidazole derivative with a long‐chain‐ester substituent, namely methyl 8‐[4‐(1H‐benzimidazol‐2‐yl)phenoxy]octanoate, (3), is reported. Ester (3) shows evidence of aggregation in solution and weak gelation ability with toluene. The octan‐1‐ol solvate, methyl 8‐[4‐(1H‐benzimidazol‐2‐yl)phenoxy]octanoate octan‐1‐ol monosolvate, C₂₂H₂₆N₂O₃·C₈H₁₈O, (4), exhibits a four‐molecule hydrogen‐bonded motif in the solid state, with N—H…O hydrogen bonds between benzimidazole molecules and O—H…N hydrogen bonds between the octan‐1‐ol solvent molecules and the benzimidazole unit. The alkyl chains of the ester and the octan‐1‐ol molecules are in unfolded conformations. The phenylene ring is canted by 10.27 (6)° from the plane of the benzimidazole ring system. H…C contacts make up 20.7% of the Hirshfeld surface coverage. Weak C—H…π interactions involving the benzimidazole alkyl chain and three aromatic rings are observed.     

Red,orange and yellow crystals of 4,5‐­bis(4‐methoxy­phenyl)‐2‐(3‐nitro­phenyl)‐1H‐imidazole

Red non‐solvate crystals of the title compound from ethanol, C₂₃H₁₉N₃O₄, orange solvate crystals from tert‐butanol, C₂₃H₁₉N₃O₄·C₄H₁₀O, yellow solvate crystals from dioxane–water, C₂₃H₁₉N₃O₄·0.5C₄H₈O₂, and intense yellow solvate crystals from benzene–N,N′‐dimethylformamide, C₂₃H₁₉N₃O₄·C₆H₆, differ from each other in their molecular conformation and hydrogen‐bonding scheme. The bathochromic shifts of the crystal color are explained by the molecular planarity and charge‐transfer effect among the imidazole mol­ecules.     

Channel‐forming solvate crystals and isostructural solvent‐free powder of 5‐hydroxy‐6‐methyl‐2‐pyridone

Crystals of 5‐hydroxy‐6‐methyl‐2‐pyridone, (I), grown from a variety of solvents, are invariably trigonal (space group R); these are 5‐hydroxy‐6‐methyl‐2‐pyridone acetone 0.1667‐solvate, C₆H₇NO₂·0.1667C₃H₆O, (Ia), and 6‐methyl‐5‐hydroxy‐2‐pyridone propan‐2‐ol 0.1667‐solvate, C₆H₇NO₂·0.1667C₃H₈O, (Ib), and the forms from methanol, (Ic), water, (Id), benzonitrile, (Ie), and benzyl alcohol, (If). They incorporate channels running the length of the c axis that contain extensively disordered solvent molecules. A solvent‐free sublimed powder of 5‐hydroxy‐6‐methyl‐2‐pyridone microcrystals is essentially isostructural. Inversion‐related host molecules interact via pairs of N—H...O hydrogen bonds to form R₂²(8) dimers. Six of these dimers form large R₁₂⁶(42) puckered rings, in which the O atom of each N—H...O hydrogen bond is also the acceptor in an O—H...O hydrogen bond that involves the 5‐hydroxy group. The large R₁₂⁶(42) rings straddle the axes and form stacked columns viaπ–π interactions between inversion‐related molecules of (I) [mean interplanar spacing = 3.254 Å and ring centroid–centroid distance = 3.688 (2) Å]. The channels are lined by methyl groups, which all point inwards to the centre of the channels.     

Hirshfeld surface analysis of sulfameter (polymorph III), sulfameter dioxane monosolvate and sulfameter tetrahydrofuran monosolvate,all at 296 K

The ability of the antibacterial agent sulfameter (SMT) to form solvates is investigated. The X‐ray crystal structures of sulfameter solvates have been determined to be conformational polymorphs. Both 1,4‐dioxane and tetrahydrofuran form solvates with sulfameter in a 1:1 molar ratio. 4‐Amino‐N‐(5‐methoxypyrimidin‐2‐yl)benzenesulfonamide (polymorph III), C₁₁H₁₂N₄O₃S, (1), has two molecules of sulfameter in the asymmetric unit cell. 4‐Amino‐N‐(5‐methoxypyrimidin‐2‐yl)benzenesulfonamide 1,4‐dioxane monosolvate, C₁₁H₁₂N₄O₃S·C₄H₈O₂, (2), and 4‐amino‐N‐(5‐methoxypyrimidin‐2‐yl)benzenesulfonamide tetrahydrofuran monosolvate, C₁₁H₁₂N₄O₃S·C₄H₈O, (3), crystallize in the imide form. Hirshfeld surface analyses and fingerprint analyses were performed to study the nature of the interactions and their quantitative contributions towards the crystal packing. Finally, Hirshfeld surfaces, fingerprint plots and structural overlays were employed for a comparison of the two independent molecules in the asymmetric unit of (1), and also for a comparison of (2) and (3) in the monoclinic crystal system. A three‐dimensional hydrogen‐bonding network exists in all three structures, involving one of the sulfone O atoms and the aniline N atom. All three structures are stabilized by strong intermolecular N—H...N interactions. The tetrahydrofuran solvent molecule also takes part in forming significant intermolecular C—H...O interactions in the crystal structure of (3), contributing to the stability of the crystal packing.     

Pyridine and 3‐methylpyridine solvates of the triple sulfa drug constitutent sulfamethazine

Sulfonamides display a wide variety of pharmacological activities. Sulfamethazine [abbreviated as SMZ; systematic name 4‐amino‐N‐(4,6‐dimethylpyrimidin‐2‐yl)benzenesulfonamide], one of the constitutents of the triple sulfa drugs, has wide clinical use. Pharmaceutical solvates are crystalline solids of active pharmaceutical ingredients (APIs) incorporating one or more solvent molecules in the crystal lattice, and these have received special attention, as the solvent molecule can impart characteristic physicochemical properties to APIs and solvates, therefore playing a significant role in drug development. The ability of SMZ to form solvates has been investigated. Both pyridine and 3‐methylpyridine form solvates with SMZ in 1:1 molar ratios. The pyridine monosolvate, C₁₂H₁₄N₄O₂S·C₅H₅N, crystallizes in the orthorhombic space group Pna 2₁, with Z = 8 and two molecules per assymetric unit, whereas the 3‐methylpyridine monosolvate, C₁₂H₁₄N₄O₂S·C₆H₇N, crystallizes in the orthorhombic space group P 2₁2₁2₁, with Z = 4. Crystal structure analysis reveals intramolecular N—H…N hydrogen bonds between the molecules of SMZ and the pyridine solvent molecules. The solvent molecules in both structures play an active part in strong intermolecular interactions, thereby contributing significantly to the stability of both structures. Three‐dimensional hydrogen‐bonding networks exist in both structures involving at least one sulfonyl O atom and the amine N atom. In the pyridine solvate, there is a short π–π interaction [centroid–centroid distance = 3.926 (3) Å] involving the centroids of the pyridine rings of two solvent molecules and a weak intermolecular C—H…π interaction also contributes to the stability of the crystal packing.     

Brucine and two solvates

The crystal structures of brucine (2,3‐di­methoxy­strychnidin‐10‐one), C₂₃H₂₆N₂O₄, brucine acetone solvate, C₂₃H₂₆N₂O₄·C₃H₆O, and brucine 2‐propanol solvate dihydrate, C₂₃H₂₆N₂O₄·C₃H₇O·2H₂O, have been determined. Crystals of brucine and its 2‐propanol solvate dihydrate exhibit similar monolayer sheet packing, whereas crystals of the acetone solvate adopt a different mode of packing, as brucine pillars. The solvent appears to control the brucine self‐assembly on the basis of common donor–acceptor properties of the surfaces.     

Sulfapyridine (polymorph III), sulfapyridine dioxane solvate,sulfapyridine tetrahydrofuran solvate and sulfapyridine piperidine solvate,all at 173 K

The X‐ray crystal structures of solvates of sulfapyridine have been determined to be conformational polymorphs. 4‐Amino‐N‐(1,2‐dihydropyridin‐2‐ylidene)benzenesulfonamide (polymorph III), C₁₁H₁₁N₃O₂S, (1), 4‐amino‐N‐(1,2‐dihydropyridin‐2‐ylidene)benzenesulfonamide 1,3‐dioxane monosolvate, C₁₁H₁₁N₃O₂S·C₄H₈O₂, (2), and 4‐amino‐N‐(1,2‐dihydropyridin‐2‐ylidene)benzenesulfonamide tetrahydrofuran monosolvate, C₁₁H₁₁N₃O₂S·C₄H₈O, (3), crystallized as the imide form, while piperidin‐1‐ium 4‐amino‐N‐(pyridin‐2‐yl)benzenesulfonamidate, C₅H₁₂N⁺·C₁₁H₁₀N₃O₂S⁻, (4), crystallized as the piperidinium salt. The tetrahydrofuran and dioxane solvent molecules in their respective structures were disordered and were refined using a disorder model. Three‐dimensional hydrogen‐bonding networks exist in all structures between at least one sulfone O atom and the aniline N atom.     

Cinnamic acid hydrogen bonds to isoniazid and N′‐(propan‐2‐ylidene)isonicotinohydrazide,an in situ reaction product of isoniazid and acetone

A new polymorph of the cinnamic acid–isoniazid cocrystal has been prepared by slow evaporation, namely cinnamic acid–pyridine‐4‐carbohydrazide (1/1), C₉H₈O₂·C₆H₇N₃O. The crystal structure is characterized by a hydrogen‐bonded tetrameric arrangement of two molecules of isoniazid and two of cinnamic acid. Possible modification of the hydrogen bonding was investigated by changing the hydrazide group of isoniazid via an in situ reaction with acetone and cocrystallization with cinnamic acid. In the structure of cinnamic acid–N′‐(propan‐2‐ylidene)isonicotinohydrazide (1/1), C₉H₈O₂·C₉H₁₁N₃O, carboxylic acid–pyridine O—H...N and hydrazide–hydrazide N—H...O hydrogen bonds are formed.     

catena‐Poly[[[tetrakis(μ‐acetato‐κ2O:O′)dirhodium(II)]‐μ‐[1,3‐bis(dimethylamino)propan‐2‐ol‐κ2N:N′]] tetrahydrofuran hemisolvate]

In the structure of the title compound, {[Rh₂(C₂H₃O₂)₄(C₇H₁₈N₂O)]·0.5C₄H₈O}_n or {[Rh₂(O₂CMe)₄(Hbdmap)]·0.5C₄H₈O}_n, where Hbdmap is 1,3‐bis­(dimethyl­amino)propan‐2‐ol, each Hbdmap ligand is coordinated to two [Rh₂(O₂CMe)₄] units by two N atoms, resulting in a polymeric chain structure. The observed coordination mode of the Hbdmap mol­ecule is unprecedented.     

A concise synthesis of a highly substituted 6‐(1H‐benzimidazol‐1‐yl)‐5‐nitrosopyrimidin‐2‐amine: synthetic sequence and the molecular and supramolecular structures of one product and two intermediates

A concise and efficient synthesis of 6‐benzimidazolyl‐5‐nitrosopyrimidines has been developed using Schiff base‐type intermediates derived from N⁴‐(2‐aminophenyl)‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine. 6‐Methoxy‐N⁴‐{2‐[(4‐methylbenzylidene)amino]phenyl}‐5‐nitrosopyrimidine‐2,4‐diamine, (I), and N⁴‐{2‐[(ethoxymethylidene)amino]phenyl}‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine, (III), both crystallize from dimethyl sulfoxide solution as the 1:1 solvates C₁₉H₁₈N₆O₂·C₂H₆OS, (Ia), and C₁₄H₁₆N₆O₃·C₂H₆OS, (IIIa), respectively. The interatomic distances in these intermediates indicate significant electronic polarization within the substituted pyrimidine system. In each of (Ia) and (IIIa), intermolecular N—H…O hydrogen bonds generate centrosymmetric four‐molecule aggregates. Oxidative ring closure of intermediate (I), effected using ammonium hexanitratocerate(IV), produced 4‐methoxy‐6‐[2‐(4‐methylphenyl‐1H‐benzimidazol‐1‐yl]‐5‐nitrosopyrimidin‐2‐amine, C₁₉H₁₆N₆O₂, (II) [Cobo et al. (2018). Private communication (CCDC 1830889). CCDC, Cambridge, England], where the extent of electronic polarization is much less than in (Ia) and (IIIa). A combination of N—H…N and C—H…O hydrogen bonds links the molecules of (II) into complex sheets.     

Supramolecular hydrogen‐bonded networks in cytosinium succinate and cytosinium 4‐nitrobenzoate cytosine monohydrate

In cytosinium succinate (systematic name: 4‐amino‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium 3‐carboxypropanoate), C₄H₆N₃O⁺·C₄H₅O₄⁻, (I), the cytosinium cation forms one‐dimensional self‐assembling patterns by intermolecular N—H...O hydrogen bonding, while in cytosinium 4‐nitrobenzoate cytosine monohydrate [systematic name: 4‐amino‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium 4‐nitrobenzoate 4‐aminopyrimidin‐2(1H)‐one solvate monohydrate], C₄H₆N₃O⁺·C₇H₄NO₄⁻·C₄H₅N₃O·H₂O, (II), the cytosinium–cytosine base pair, held together by triple hydrogen bonds, leads to one‐dimensional polymeric ribbons via double N—H...O hydrogen bonds. This study illustrates clearly the different alignment of cytosine molecules in the crystal packing and their ability to form supramolecular hydrogen‐bonded networks with the anions.     

Planarity of benzoylthiocarbazate tuberculostatics. III. Diesters of 3‐(2‐hydroxybenzoyl)dithiocarbazic acid

Searches for new tuberculostatic agents are important considering the occurrence of drug‐resistant strains of Mycobacterium tuberculosis . The structures of three new potentially tuberculostatic compounds, namely isopropyl methyl (2‐hydroxybenzoyl)carbonohydrazonodithioate, C₁₂H₁₆N₂O₂S₂, (Z )‐benzyl methyl (2‐hydroxybenzoyl)carbonohydrazonodithioate, C₁₆H₁₆N₂O₂S₂, and dibenzyl (2‐hydroxybenzoyl)carbonohydrazonodithioate propan‐2‐ol monosolvate, C₂₂H₂₀N₂O₂S₂·C₃H₈O, were determined by X‐ray diffraction. The mutual orientation of the three main fragments of the compounds, namely an aromatic ring, a dithioester group and a hydrazide group, can influence the biological activity of the compounds. In all three of the structures studied, the C(=O)NH group is in the anti conformation. In addition, the presence of the hydroxy group in the ortho position of the aromatic ring in all three structures leads to the formation of an intramolecular hydrogen bond stabilizing the planarity of the molecules.     

2,4‐Di­nitro­phenyl­hydrazones of 2,4‐di­hydroxy­benz­aldehyde, 2,4‐di­hydroxy­aceto­phenone and 2,4‐di­hydroxy­benzo­phenone

In 2,4‐di­hydroxy­benz­aldehyde 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­amide solvate {or 4‐[(2,4‐di­nitro­phenyl)­hydrazono­methyl]­benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate}, C₁₃H₁₀N₄O₆·C₃H₇NO, (X), 2,4‐di­hydroxy­aceto­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­am­ide solvate (or 4‐{1‐[(2,4‐di­nitro­phenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate), C₁₄H₁₂N₄O₆·C₃H₇NO, (XI), and 2,4‐di­hydroxy­benzo­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­acet­amide solvate (or 4‐­{[(2,4‐di­nitro­phenyl)hydrazono]phenyl­methyl}benzene‐1,3‐diol N,N‐di­methyl­acet­amide solvate), C₁₉H₁₄N₄O₆·C₄H₉NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent mol­ecule.