A pseudopolymorph of valdecoxib

Yathirajan, H. S.; Narasegowda, Rajenahally S.; Nagaraja, Padmarajaiah; Bolte, Michael

doi:10.1107/s1600536804033598

Cited by 6 publications

(5 citation statements)

References 3 publications

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“…The stacking of molecules along the c -axis of 1 - 107 and along the a -axis of 1 - 112 (SC B ) is repeated in methyl 4-aminobenzoate 45 ( 2-II ), dimethyl terephthalate 46 ( 3 ), methyl 4-bromobenzoate 47 ( 4 ) and its iodo 47 ( 5 ) and ethynyl 48 ( 6 ) analogues, methyl 4-(bromomethyl)benzoate 49 ( 7 ) and methyl 4-methylbenzoate 50 ( 8 ). Form 1 - 112 is even 2D similar (SC C) with polymorph 2-II of 4-aminobenzoate, 45 with which it shares a centrosymmetric double layer consisting of two layers of H-bonded chains.…”

Section: Resultsmentioning

confidence: 99%

“…The stacking of molecules along the c-axis of 1-107 and along the a-axis of 1-112 (SC B) is repeated in methyl 4-aminobenzoate 45 (2-II), dimethyl terephthalate 46 (3), methyl 4-bromobenzoate 47 (4) and its iodo 47 (5) and ethynyl 48 4; (e) alternative representation of the same sequence, highlighting molecule types 1 (green), 2 (gray), and 3 (pink). H), but here the separation between adjacent molecular centroids is substantially increased by 0.5 Å. SC H is also present in three polymorphs of ethyl 4-aminobenzoate 52 (10).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Four Polymorphs of Methyl Paraben: Structural Relationships and Relative Energy Differences

Gelbrich

Braun

Ellern

et al. 2013

Crystal Growth & Design

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Four polymorphic forms of methyl paraben (methyl 4-hydroxybenzoate, 1), denoted 1-I (melting point 126 °C), 1-III (109 °C), 1-107 (107 °C), and 1-112 (112 °C), have been investigated by thermomicroscopy, infrared spectroscopy, and X-ray crystallography. The crystal structures of the metastable forms 1-III, 1-107, and 1-112 have been determined. All polymorphs contain the same O–H···O=C connected catemer motif, but the geometry of the resulting H-bonded chain is different in each form. The Z′ = 3 structure of 1-I (stable form; space group Cc) contains local symmetry elements. The crystal packing of each of the four known crystal structures of 1 was compared with the crystal structures of 12 chemical analogues. Close two-dimensional relationships exist between 1-112 and a form of methyl 4-aminobenzoate and between 1-107 and dimethyl terephthalate. The lattice energies of the four methyl paraben structures have been calculated with a range of methods based on ab initio electronic calculations on either the crystal or single molecule. This shows that the differences in the induction energy of the different hydrogen-bonded chain geometries have a significant effect on relative lattice energies, but that conformational energy, repulsion, dispersion, and electrostatic also contribute.

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Section: Resultsmentioning

confidence: 99%

“…The stacking of molecules along the c-axis of 1-107 and along the a-axis of 1-112 (SC B) is repeated in methyl 4-aminobenzoate 45 (2-II), dimethyl terephthalate 46 (3), methyl 4-bromobenzoate 47 (4) and its iodo 47 (5) and ethynyl 48 4; (e) alternative representation of the same sequence, highlighting molecule types 1 (green), 2 (gray), and 3 (pink). H), but here the separation between adjacent molecular centroids is substantially increased by 0.5 Å. SC H is also present in three polymorphs of ethyl 4-aminobenzoate 52 (10).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Four Polymorphs of Methyl Paraben: Structural Relationships and Relative Energy Differences

Gelbrich

Braun

Ellern

et al. 2013

Crystal Growth & Design

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“…Like any other COX-2 selective inhibitor, etoricoxib selectively inhibits isoform 2 of the enzyme cyclo-oxigenase (COX-2). The crystal structure of valdecoxib, a non-steroidal antiinflammatory drug (Malathy Sony et al, 2005), a pseudopolymorph of valdecoxib (Yathirajan et al, 2005) and celecoxib, a COX-II inhibitor (Vasu Dev et al, 1999) have been reported. In the view of the importance of etoricoxib, this paper presents the crystal structure of the title compound, etoricoxib picrate.…”

Section: Methodsmentioning

confidence: 99%

“…For background to coxibs, traditional non-steroidal anti-inflammatory drugs, see: Rimon et al (2010); Shriner et al (1980); Patrignani et al (2003). For related structures, see: Malathy Sony et al (2005);Vasu Dev et al (1999); Yathirajan et al (2005). For standard bond lengths, see: Allen et al (1987).…”

Section: Related Literaturementioning

confidence: 99%

Etoricoxibium picrate

et al. 2010

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In the cation of the title salt (systematic name: 5-{5-chloro-3-[4-(methylsulfonyl)phenyl]-2-pyridyl}-2-methylpyridinium 2,4,6-trinitrophenolate), C18H16ClN2O2S+·C6H2N3O7 −, the mean planes of the two pyridine rings in the bipyridine unit are twisted by 33.9 (2)° with respect to each other. The dihedral angles between the mean planes of the sulfonylbenzene ring and the chloropyridine and methylpyridine rings are 51.2 (0) and 49.3 (9)°, respectively. The picrate anion interacts with the protonated N atom through a bifurcated N—H⋯(O,O) hydrogen bond, forming an R 1 2(6) ring motif with the N atom from the methylpyridine group of an adjacent cation. N—H⋯O hydrogen bonds, weak C—H⋯O and π–π stacking interactions [centroid–centroid distances = 3.8192 (9)and 3.6749 (9)] occur in the crystal packing, creating a two-dimensional network structure along [110].

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“…A solvatomorph of valdecoxib has been reported, where the unit cell contains half a molecule of ethyl methyl ketone in the asymmetric unit 123. The crystal packing is stabilized by NH···O hydrogen bonds, and the conformation of the compound is similar to that of the nonsolvated orthorhombic crystal form.…”

Section: Structural Characterization and Properties Of Polymorphs Andmentioning

confidence: 99%

Polymorphism and Solvatomorphism 2005

Brittain¹

2007

Journal of Pharmaceutical Sciences

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A pseudopolymorph of valdecoxib

Abstract: Key indicatorsSingle-crystal X-ray study T = 173 K Mean '(C±C) = 0.003 A Ê Disorder in solvent or counterion R factor = 0.044 wR factor = 0.131 Data-to-parameter ratio = 14.6For details of how these key indicators were automatically derived from the article, see

Cited by 6 publications

References 3 publications

Four Polymorphs of Methyl Paraben: Structural Relationships and Relative Energy Differences

Four Polymorphs of Methyl Paraben: Structural Relationships and Relative Energy Differences

Etoricoxibium picrate

Polymorphism and Solvatomorphism 2005

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