Polymorphic form II of 4,4′-methyl­enebis(benzene­sulfonamide)

In the title compound, C13H14N2O4S2 (alternative names: diphenyl­methane-4,4′-disulfonamide, nirexon, CRN: 535–66-0), the two benzene rings form a dihedral angle of 70.8 (1)°. There are two sets of shorter (H⋯O < 2.1 Å) and longer (H⋯O > 2.4 Å) N—H⋯O hydrogen bonds per sulfonamide NH2 group, which together result in hydrogen-bonded sheets parallel (102). Adjacent sheets are connected to one another by an additional N—H⋯N inter­action so that a three-dimensional network of hydrogen-bonded mol­ecules is formed. The investigated polymorph is identical with the form II previously described by Kuhnert-Brandstätter & Moser [(1981). Mikrochim. Acta, 75, 421–440]

Structural Properties, Order-Disorder Phenomena and Phase Stability of Orotic Acid Crystal Forms

Orotic acid (OTA) is reported to exist in the anhydrous (AH), monohydrate (Hy1) and dimethylsulfoxide monosolvate (SDMSO) forms. In this study we investigate the (de)hydration/desolvation behavior, aiming at an understanding of the elusive structural features of anhydrous OTA by a combination of experimental and computational techniques, namely, thermal analytical methods, gravimetric moisture (de)sorption studies, water activity measurements, X-ray powder diffraction, spectroscopy (vibrational, solid-state NMR), crystal energy landscape and chemical shift calculations. The Hy1 is a highly stable hydrate, which dissociates above 135°C and loses only a small part of the water when stored over desiccants (25°C) for more than one year. In Hy1, orotic acid and water molecules are linked by strong hydrogen bonds in nearly perfectly planar arranged stacked layers. The layers are spaced by 3.1 Å and not linked via hydrogen-bonds. Upon dehydration the X-ray powder diffraction and solid-state NMR peaks become broader indicating some disorder in the anhydrous form. The Hy1 stacking reflection (122) is maintained, suggesting that the OTA molecules are still arranged in stacked layers in the dehydration product. Desolvation of SDMSO, a non-layer structure, results in the same AH phase as observed upon dehydrating Hy1. Depending on the desolvation conditions different levels of order-disorder of layers present in anhydrous OTA are observed, which is also suggested by the computed low energy crystal structures. These structures provide models for stacking faults as intergrowth of different layers is possible. The variability in anhydrate crystals is of practical concern as it affects the moisture dependent stability of AH with respect to hydration

Butallyl­onal 1,4-dioxane hemisolvate

The asymmetric unit of the title compound [systematic name: 5-(1-bromo­prop-2-en-1-yl)-5-sec-butyl­pyrimidine-2,4,6-trione 1,4-dioxane hemisolvate], C11H15BrN2O3·0.5C4H8O2, contains one half-mol­ecule of 1,4-dioxane and one mol­ecule of butallyl­onal, with an almost planar barbiturate ring [largest deviation from the mean plane = 0.049 (5) Å]. The centrosymmetric dioxane mol­ecule adopts a nearly ideal chair conformation. The barbiturate mol­ecules are linked together by an N—H⋯O hydrogen bond, giving a single-stranded chain. Additionally, each dioxane mol­ecule acts as a bridge between two anti­parallel strands of hydrogen-bonded barbiturate mol­ecules via two hydrogen bonds, N—H⋯O(dioxane)O⋯H—N. Thus, a ladder structure is obtained, with the connected barbiturate mol­ecules forming the ‘stiles’ and the bridging dioxane mol­ecules the ‘rungs’

Gliquidone

The title compound {systematic name: N-cyclo­hexyl­carba­moyl-4-[2-(7-meth­oxy-4,4-dimethyl-1,3-dioxo-1,2,3,4-tetra­hydro­isoquinolin-2-yl)eth­yl]benzene­sulfonamide}, C27H33N3O6S, displays an intra­molecular N—H⋯O=S inter­action, as well as inter­molecular N—H⋯O=C hydrogen bonds. The latter inter­actions lead to the formation of hydrogen-bonded chains parallel to the c axis. The conformation of the sulfonyl­urea fragment is in agreement with a recent theoretical study [Kasetti et al. (2010 ▶). J. Phys. Chem. B, 114, 11603–11610]

Solid-State Forms of β-Resorcylic Acid: How Exhaustive Should a Polymorph Screen Be?

An extensive experimental screen, coupled with a computational study, revealed seven new solid-state forms of β-resorcylic acid. The known, stable polymorph II° shows a reversible phase transformation to the new, kinetically stable, probably disordered high temperature form I. The study provides a consistent picture of the solid-state of β-resorcylic acid

Extensive sequential polymorphic interconversion in the solid-state: Two hydrates and ten anhydrous phases of hexamidine diisethionate

Crystal polymorphism and solvent inclusion is a dominant research area in the pharmaceutical industry and continues to unveil complex systems. Here, we present the solid-state system of hexamidine diisethionate (HDI), an antiseptic drug compound forming a dimorphic dihydrate as well as ten anhydrous polymorphs. The X-ray and neutron crystal structures of the hydrated crystal forms and related interaction energies show no direct interaction between the cation and water but very strong interactions between cation and anion, and anion and water. This is observed macroscopically as high stability of the hydrate against dehydration by temperature and humidity. The anhydrous polymorphs reveal a rare case of sequential and reversible polymorphic transformations, which are characterized by thermal analysis and variable-temperature powder X-ray diffraction (PXRD). While most transitions are accompanied by significant structural changes, the low-energy transitions can only be detected as slight changes in the reflection positions with temperature. HDI thus represents a model compound to investigate polymorphic transitions with small structural changes

Benzyl­sulfamide

The crystal of the title compound [systematic name: 4-(benzyl­amino)­benzene­sulfonamide], C13H14N2O2S, displays a hydrogen-bonded framework structure. Mol­ecules are doubly N—H⋯O hydrogen bonded to one another via their NH2 groups and sulfonyl O atoms. These inter­actions generate a hydrogen-bonded ladder structure parallel to the a axis, which contains fused R 2 2(8) rings. The NH group serves as the hydrogen-bond donor for a second set of inter­molecular N—H⋯O=S inter­actions

Polythia­zide

The crystal structure of the title compound, C11H13ClF3N3O4S3 (systematic name: 6-chloro-2-methyl-3-{[(2,2,2-trifluoro­eth­yl)sulfan­yl]meth­yl}-3,4-dihydro-2H-1,2,4-benzothia­diazine-7-sul­f­on­amide 1,1-diox­ide; CRN: 346–18–9), exhibits a two-dimensional network of hydrogen-bonded mol­ecules parallel to (01). The NH and NH2 groups act as donor sites and the sulfonyl O atoms as acceptor sites in N—H⋯O hydrogen bonds, and a C—H⋯O interaction also occurs. The thiadiazine ring adopts an envelope conformation with the N atom bonded to sulfur at the tip of the flap, and the methyl substituent is in an axial position