Apparent basicities of the surfaces characterizing the dominant crystal habits of distinct polymorphic forms of 4-aminosulfonamide (original) (raw)
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Journal of Pharmaceutical Sciences, 1972
An evaluation of entropies and enthalpies of transition and fusion and a comparison of X-ray diffraction patterns and IR spectra of polymorphic forms of structurally related compounds were undertaken to obtain information which might prove useful in correlating the frequency of occurrence of polymorphism with certain aspects of chemical structure. Sixteen sulfonamides were selected for study. The screening procedures used in this research identified polymorphism in eight compounds and solvates in two compounds. The p-amino group, the acidic N1-hydrogen atom, and the oxygens of the sulfonamide group have been implicated in the various hydrogen-bonding arrangements which distinguish one polymorphic form from another. It is postulated that electron-withdrawing and electron-donating groups at the N1-position influence the strength of the hydrogen bonds which form and, hence, the tendency of these compounds to exhibit more than one crystalline form. In some cases, however, minor alterations in structure result in disproportionate changes in the compactness of the crystal lattice, and this fact makes it difficult to develop broad generalizations applicable to large groups of compounds.
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 1981
CTHIoN402S, M r = 214.25, monoclinic, P2~/c, a = 9.912(1), b = 7.530(1), c = 24.496(2)A, fl = 95.32 (1) °, V = 1820.4 (6)A 3, D c = 1.563 Mg m -3, Z = 8 (two molecules in the asymmetric unit), F(000) = 896. The final R = 0.045 for 3331 intensities.
Journal of Molecular Structure, 2010
a b s t r a c t 4-Sulfamoyl-N-(3-morpholinopropyl) benzamide (P10), N-(3-morpholinopropyl)benzene-1,4-disulfonamide (P20) and their hydrochloride salts (P11 and P22) were prepared. The X-ray molecular structure of these compounds was determined. The gas-phase structure of these drugs was computed using Beck-e3LYP/6-31G(d) and Becke3LYP/6-311 + G(d,p) model chemistries. The conformational behavior of these systems in water was examined using the solvation CPCM model. In the solid state, gas phase and in solution the conformations of the basic compounds P10 and P20 possess a characteristic L-shaped structure stabilized via an intramolecular hydrogen bonding system of the NAHÁ Á ÁN type. This hydrogen bond is not present in P11 and P22. A network of intermolecular hydrogen bonds mediated by the Cl atoms and crystal-packing forces in P11 and P22 stabilize a more extended structure in the solid state.
Molecular packings and specific-bond patterns in sulfonamides
New Journal of Chemistry, 2014
A novel approach to topological analysis of molecular packings and intermolecular bonding patterns is described and tested on the crystal structures of 1463 sulfonamide derivatives taken from the Cambridge Structural Database, as well as three newly synthesized ones. We have revealed strong correlations between the local and overall topological motifs of hydrogen and halogen specific intermolecular bonds; as a rule, a particular local connection type of the molecules provides only one most preferred pattern of intermolecular bonds and vice versa. Molecular packings are found to be almost independent of the existence or absence of specific bonds and in more than 1/3 of cases they obey Kitaigorodskii's model of close packing. The peculiar shapes of the sulfonamide molecules in some cases give rise to a special 'butterfly' packing that is topologically less dense than close packings. The correlations found can be used to predict the main peculiarities of molecular crystals with a prospective expert system. † Electronic supplementary information (ESI) available: Crystallographic data for compounds I-III. Tables S1-S10 contain distributions of connection types and the overall topological motifs in molecular packings and specific-bonding patterns in 1463 sulfonamide derivatives. CCDC 989765-989767. For ESI and crystallographic data in CIF or other electronic format see
Canadian Journal of Chemistry, 1996
The redistribution of charge and electronic kinetic energy was studied during rotation about the S-N bonds of sulfonamide and fluorosulfonamide. The rotational potentials and electronic topological features of both compounds were evaluated at the HFl6-31G* level of theory and their electron densities partitioned into atomic contributions using FASTINT, an updated version of the PROAIM program. The results indicate that the stability of each rotamer is strongly dependent upon the hybridization of the sulfonamide nitrogen. The hybridization of the nitrogen was determined by examination of the positions and magnitudes of the electrostatic and Laplacian minima in the nonbonded region of the sulfonarnide nitrogen atom. Independent assessments of hybridization were made using nitrogen pyramidalization altitudes. The rotational barriers in these compounds were found to arise mainly from energetic penalties resulting from adding electrons to already electron-rich sulfonyl oxygens while removing electron density from other more electronegative atoms. The fluorine-substituted analogue provided an example in which the sulfur and oxygen atoms were much less electron rich, causing an enhancement of the nitrogen rehybridization effects. The extent of covalent bonding between pertinent pairs of atoms in sulfonamide and fluorosulfonamide was assessed throughout the rotational pathway using the BONDER program. In contrast with much existing dogma, all of these findings were consistent with the same general model of charge and energy flow that has been shown to determine the internal rotational barriers in amides.
Ab initio prediction of polymorphic structures of pyrazinamide: A validation study
Journal of the Serbian Chemical Society, 2016
A validation study to predict the possible stable polymorphs of Pyrazinamide within a low energy conformational region of the flexible torsion angle was made through a potential energy surface (PES) scan by gas phase optimisation using the MP2/6-31G(d,p) method. Hypothetical crystal structures with favourable packing density for each of the stable conformers generated from the PES scan were generated using a global search with a repulsion only potential field. The densest crystal structures with stable energy were analyzed with more accurate lattice energy minimisation via distributed multipole analysis using a repulsion-dispersion potential. The stability of the predicted crystal structures with similar close packing to the known experimental polymorphs of Pyrazinamide molecule was analyzed by inspecting their intermolecular short contacts. Studies to analyze the second derivative mechanical properties from the hessian matrix were carried out to emphasise the thermodynamic stabilit...
Ab initio prediction of the polymorphic structures of pyrazinamide – A validation study
A validation study to predict the possible stable polymorphs of pyrazinamide within the low energy conformational region of the flexible torsion angle was performed through a potential energy surface (PES) scan by gas phase optimisation using the MP2/6-31G(d,p) method. Hypothetical crystal structures with favourable packing density for each of the stable conformers generated from the PES scan were generated using a global search with a repulsion only potential field. The densest crystal structures with stable energy were analyzed with more accurate lattice energy minimisation via distributed multipole analysis using the repulsion–dispersion potential. The stability of the predicted crystal structures with similar close packing to the known experimental polymorphs of the pyrazinamide molecule were analyzed by inspecting their intermolecular short contacts. Studies to analyze the second derivative mechanical properties from the Hessian matrix were realised to emphasise the thermodynamic stability of predicted polymorphs of pyrazinamide.
Quantum chemical studies on crystal structures of sulphacetamide and sulphasalazine
Indian Journal of Pure & Applied Physics, 2011
Quantum chemical calculations of sulphacetamide, N-acetyl-4-amino benzene sulphonamide and sulphasalazine, 2-hydroxy-5-[4-(1H-pyridin2-ylidenesulphamoyl)-phenylazo]-benzoic acid have been carried out by Gaussian-03 software. The molecular structures of sulphacetamide and sulphasalazine crystallize in the tetragonal and monoclinic system with space groups P4 1 and P2 1 /c, respectively. The stability of the molecular structure in sulphacetamide is due to a network of strong N−H…O and C−H…O hydrogen bond interactions and in sulphasalazine is due to strong hydrogen bonds like O-H…O and N−H…N type of interactions along with non-conventional - and C−H…O interactions. Comparison with RHF and DFT computational calculations supports the observations.