Crystal and molecular structure of (E)-21-Methoxycarbonyl-19-nor-pregna-4,8(14),20-trien-3-one

The crystal and molecular structure of the title compound has been determined by X-ray diffraction techniques. It crystallizes in the orthorhombic space group P 2₁2₁2₁ with cell parameters a = 12.662 Å, b = 17.995 Å, c = 8.433 Å. The structure was solved by direct methods using MULTAN-78 and refined by least-squares calculations to the conventional R = 0.061. The ring conformations of the steroid skeleton and the 17β-side chain conformation are discussed in detail.     

Crystal Structure of 14-Deoxy-11,12-Didehydroandrographolide — A Diterpenoid

The crystal structure of 14-deoxy-11,12-didehydroandrographolide has been determined by X-ray structure analysis. The compound crystallizes in the trigonal space group P3₁ with cell parameters a = b 15.860(3), c = 6.437(2) Å. The structure has been solved by direct methods and refined to R = 0.048. The six-membered rings are trans-fused and both are in the chair conformation. The furan ring is planar with maximum deviation −0.011 (4) Å for C(14). Molecular are held together by hydrogen bonds.     

Crystal and molecular structure of 2-(1-[alkyl,aryl)-2-acylhydrazino]-4,6-diaryloxy-1,3,5-triazine,C20H19Br2N5O3

The crystal and molecular structure of the title compound has been determined by X-ray diffraction techniques. It crystallizes in the monoclinic space group P 2₁/c with cell parameters a = 8.760 Å, b = 26.863 Å, c = 9.678 Å, and β = 106.03°. The structure was solved by the heavy atom method and refined by least-squares calculations to the conventional R value of 0.075.     

Crystal structure of N‐(2‐methoxyphenyl)‐3,6‐diphenyl‐1,4‐dihydro‐1,2,4,5‐tetrazine‐1‐carbonamide

The title compound, C₂₂H₁₉N₅O₂, was prepared and its structure was determined by X‐ray diffraction [CCDC 216074]. The compound crystallizes from ethanol in the orthorhombic system, space group P2₁2₁2₁, with unit cell parameters: a =10.048(1) Å, b = 13.935 (2) Å, c =14.607(2) Å, Z =4, and V=2045.3(5) ų. The crystal structure was solved by direct methods and refined by full‐matrix least‐squares to a final R‐value of 0.0516 with 3621 unique reflections. The central six‐membered ring of the compound has a boat conformation and is not homoaromatic, in which adjacent atoms N1 and N4 deviate from the plane of the ring by 0.4546(33) Å and 0.3786(33) Å, respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of cholest-4-ene-3,6-dione: A steroid

The crystal structure of cholest-4-ene-3,6-dione (C₂₇H₄₄O₂) has been determined by X-ray diffraction methods. The compound crystallizes in the monoclinic crystal system (space group P2₁) with the unit cell parameters a = 10.503(4) Å, b = 8.059(1) Å, c = 14.649(1) Å, β = 105.4(2)°, and Z = 2. The structure has been refined to an R value of 0.035 for 2252 observed reflections. Ring A of the steroid nucleus exists in a sofa conformation, while rings B and C adopt a chair conformation. The five-membered ring D exhibits a half-chair conformation. The molecules in the unit cell are linked together by the C-H?O hydrogen bonds.     

X-ray structure analysis of 3β-hydroxy-4-(1,4-oxazin-4-yl)-androstane (C31H54NO2)

The crystal structure of 3β-hydroxy-4-(1,4-oxazin-4-yl)-androstane (C₃₁H₅₄NO₂) has been determined by X-ray crystallographic techniques. The compound crystallizes in the orthorhombic space group P2₁2₁2 with the following unit-cell parameters: a = 7.124(1) Å, b = 10.127(1) Å, c = 40.660(1) Å, V = 2933.4(1) ų, and Z = 4. The structure has been solved by direct methods and refined to an R factor of 0.067. Three six-membered rings, A, C, and E, exist in the chair conformation, while the ring B adopts a distorted half-chair conformation. The five-membered ring, D, has a distorted envelope conformation. The crystal structure is stabilized by strong intermolecular O-H...O hydrogen bonds.     

X-ray crystal structure analysis of parthenin–A sesquiterpene lactone

The crystal structure of parthenin has been determined by X-ray structure analysis. The compound crystallizes in the tetragonal space group P4₁ with cell parameters a = b = 6.8677(2), c = 28.6851(4) Å. The structure has been solved by direct methods and refined to R = 0.039. The seven-membered ring assumes a chair conformation while the two five-membered rings have envelope shapes. The A/B and B/C junctions are trans. Molecules are held together by hydrogen bonds.     

X-ray structure analysis of 4-pregnen-11α-ol-3,20-dione—A steroid

The crystal structure of 4-Pregnen-11α-ol-3,20-dione has been determined by X-ray structure analysis. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with cell parameters a = 8.4415(4), b = 10.6884(3), c = 20.1273(5) Å. The structure has been solved by direct methods and refined to R = 0.050. Ring A exists in half-chair conformation. Rings B and C adopt a chair conformation, and ring D is a 13α-envelope. The A/B ring junction is quasi-trans, whilst ring systems B/C and C/D are trans fused about the bonds C(8)–C(9) and C(13)–C(14). Molecules are held together by hydrogen bonds.     

α-substituted Phosphoryl Compounds (II). The Crystal and Molecular Structure of Diphenyl-[5,6-dichloro-1, 3-benzodioxol-(2)]-phosphine-oxide,C19H13O3PCl2

The compound crystallizes in the monoclinic space group P 2₁/c with four molecules per unit cell, and with the lattice parameters a = 11.807 Å, b = 13.070 Å, c = 11.312 Å, β = 96.74°. With X-ray diffraction data collected on a four circle diffractometer, the crystal structure has been determined by direct methods and refined to an R-value of 0.061 for 2735 measured and symmetrically independent reflections. The substance is a derivative of acetales of formyl diphenyl phosphine oxides. Correlations between the geometry of the structure and NMR-data are of interest.     

α-substituted phosphoryl compounds (III). The crystal and molecular structure of diphenyl[1,3-benzodithiolyl-(2)]-phosphinoxide,C19H15OPS2

Diphenyl[1,3-benzodithiolyl-(2)]-phosphinoxide crystallizes in the monoclinic space group P 2₁/c with four molecules per unit cell. The lattice parameters are a = 9.600 Å, b = 11.270 Å, c = 16.484 Å; β = 99.72°. With X-ray diffraction data collected at an automatic four circle diffractometer, the crystal structure has been solved by direct methods and refined to an R-value of 0.08 for 2690 measured and symmetrically independent reflections. The substance is a derivative of acetales of formyl diphenyl phosphine oxides. Correlations between the geometry of the structure and NMR-data are of interest.     

The Crystal and Molecular Structure of 1-Allyl-5-benzoyl-4-phenylpyrimidine-2-one hemihydrate

The crystal structure of C₂₀H₁₆N₂O₂. 0.5 H₂O has been determined from three dimensional X-ray diffraction data. The crystals are monoclinic, space group C 2/c, with a = 24.491(3) Å, b =10.241(2) Å, c = 16.643(2) Å, β =126.63(1)°, V = 3350.0(9) ų, D_calc = 1.290 g. cm⁻³, Z = 8. The structure was solved by direct methods and refined by least-squares methods to a final R = 0.0625 for 1358 observed unique reflections (F² ⩾ 2σ(F²)].     

Crystal Structure of Fibrillar Sodium Trimolybdate Hydrate by Powder Diffraction Method

The crystal structure of polycrystalline fibrillar sodium trimolybdate Na₂Mo₃O₁₀. 3 H₂O, has been solved ab initio by Powder Diffraction – Direct Methods package POWSIM. The structure was refined by the Rietveld method with final discrepancy factors R_F = 6.9 and R_wp = 17.1%. The structure consists of polymeric chains of Mo-O polyhedra parallel to the b axis. The space group is C2/m (12), a = 17.179(1), b = 3.7757(3), c = 10.8571(8) Å, β = 115.417(6)°, V = 636.06(6) ų, Z = 2.     

Crystal and Molecular Structure of 4-methoxy-carbonyl methyl-2,9-bis(phenylsulfonyl)-1,2,3,4-tetrahydro β-carboline : benzene solvate

The crystal structure of the title compound has been determined from X-ray diffraction data. The compound crystallizes from benzene in the monoclinic system, space group P2₁/a, with unit cell parameters: a = 12.676(2), b = 20.333(3), c = 12.947(2) Å, β = 113.12(1)°, Z = 4, V = 3069.0(8) ų. The trial structure was determined by direct methods and refined to a final R-index of 0.044. The six-membered heterocyclic ring adopts half-chair conformation. Of the two phenylsulfonyl groups, the one substituted at the indole nitrogen (N1) is equatorial, while the other (at N2) is axial. The methyl acetate group is approximately perpendicular to the β-carboline moiety.     

2′-Methyl-3′-nitroflavone

The crystal and molecular structure of the title compound has been determined by direct methods and refined to a final R of 0.044. The compound crystallizes in space group P2₁/n with cell dimensions a = 16.681(2), b = 3.838(1), c = 20.550(4) Å, and β = 104.21(2)°. The phenyl and benzene rings of the title molecule are quite planar. The γ-pyrone ring exhibits maximum deviation 0.032(4) Å from planarity and makes a dihedral angle of 139.8(2)° with the 2-phenyl substituent.     

Crystal and molecular structure of 5,6-diphenyl-2-(α-formyl-benzyliden)-2H-thiopyranes

The crystal and molecular structure of the title compound has been determined by X-ray diffraction techniques. It crystallizes in the monoclinic space group P2₁/n with cell parameters a = 6.101(3) Å, b = 14.365(6) Å, c = 21.888(7) Å, β = 90.20(4)°, Z = 4. The structure was solved by direct methods and refined by least-squares calculations to an R value of 0.074. The molecule exists in solid state in the Z configuration. The very short intramolecular O S distance of 2.654(8) Å can be explained with polar interactions between the O and S atoms.     

Crystal structure of R(–)–1–Tosyl–2–methylpyrrolidine

The crystal structure of R(–)-1-tosyl-2-methylpyrrolidine has been determined by X-ray structure analysis. The compound crystallizes in the monoclinic space group P2₁ with cell parameters a = 7.858(1), b = 14.929(6), c = 11.128(1) Å, β = 105.42(1)°. The structure has been solved by direct methods and refined to R = 0.046. There are two crystallographically independent molecules A and B in the asymmetric unit. The pyrrolidine ring of molecule A is disordered with atom C4 occupying two possible sites. The S atom has a distorted tetrahedral coordination in both the molecules. Two bifurcated hydrogen bonds are observed. Molecules are held together by hydrogen bonds.     

X‐ray diffraction refinement of the crystal structure of anosovite prepared from leucoxene

The crystal structure of anosovite, (Ti_1.69Al_0.26Fe_0.05)³⁺(Ti_0.97Zr_0.03)⁴⁺O₅, prepared by carbothermal reduction of leucoxene under vacuum at 1450°C has been refined by Rietveld method using powder X‐ray diffraction data. It was found that it represents slightly monoclinically deformed pseudobrookite type structure with lattice parameters a = 9.8111 Å, b = 3.7509 Å, c = 9.9468 Å, β = 90.628°. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Crystal and Molecular Structure of 4-Hydroxy-4′-nitro- biphenyl and its Potassium Salt

The crystal and molecular structures of the title compounds have been solved by single crystal X-ray analysis. 4-Hydroxy-4′-nitro-biphenyl (NBO) crystallizes in the centrosymmetric, monoclinic space group P2₁/n with a = 6.036(4) Å, b = 12.392(3) Å, c = 13.346(8) Å, β = 96.46(3)° and 4 molecules in the unit cell. Its potassium salt (NBOK) similarly belongs to P2₁/a with a = 11.277(2) Å, b = 7.3606(6) Å, c = 14.383(3) Å, β = 107.804(7)° and also 4 molecules in the unit cell. The structure of NBO was refined by full matrix least-squares calculation to R = 0.043 for 1105 observed reflections, the structure of NBOK to R = 0.041 for 2288 observed reflections, respectively. NBO and NBOK crystallize in layer-like structures. The biphenyl molecules of NBO are arranged as corrugated ribbons in layers. The ionic and polar moiety of NBOK (potassium, oxygen, and crystal water) are separated by biphenyl units to form layers. The almost planar biphenyl units of NBOK are arranged in pairs and exhibit a short molecular distance of 3.08 Å within one pair.     

The Crystal and Molecular Structure of Mesogenic Malonates (II)

The crystal and molecular structures of three diethyl-2-{n-[4-(4-nitrophenylazo)-phenoxy]alkyl}malonate with n = 5 (5 PhNO₂), 7 (7PhNO₂), 9 (9 PhNO₂) and an analogous diethyl-2-[4(4-cyanophenylazo)phenoxy]pentylmalonate (5 PhCN) have been determined with CuK_a or MoK_a: 5 PhNO₂: a = 8.007(6) Å, b = 11.960(8) Å, c = 13.516(9) Å, α = 77.10(6)°, β = 81.80(5)°, γ = 83.15(5)°; R = 0.053; 7PhNO₂: a = 8.074(4) Å, b = 11.592(5) Å, c = 14.422(7) Å, α = 87.43(3)°, β = 82.46(3)°, γ = 85.43(3)°; R = 0.072; 9 PhNO₂: a = 5.520(5) Å, b = 13.628(9) Å, c = 20.220(11) Å, α = 100.02(4)°, β = 95.49(4)°, γ = 101.02(4)°; R = 0.042; 5 PhCN: a = 8.018(6) Å, b = 11.960(8) Å, c = 13.566(7) Å, α = 77.82(5)°, β = 81.89(5)°, γ = 82.69(5)°; R = 0.067 (isotropically refined). All these structures belong to the triclinic space groups P1 . The arrangements of the molecules in the crystal of the homologous series of nPhNO₂ suggest two different types of packing independent of n even, odd or large, small. 5 PhCN represents an isomorphous structure to 5 PhNO₂. Isomophism between 7 PhNO₂ and 7 PhCN was confirmed by cocrystallization of these two compounds whose crystal structure was also determined.     

Crystal structure of a dehydroabietate derivative

The crystal structure of methyl-16, nor-5-hydroxy-6,7,15-trioxo dehydroabietate has been determined from three-dimensional X-ray diffraction data. The compound crystallizes in the orthorhombic space group P2₁2₁2 with unit cell parameters a = 19.226(3) Å, b = 11.075(3) Å, c = 8.375(2) Å, Z = 4, V = 1783.3(7) ų, d₀ = 1.36 gcm⁻³. The gross structure was determined by direct methods which on refinement yielded a final value of R index as 0.038. Ring A is a chair, ring B an envelope whereas the ring C adopts a strictly planar conformation. The rings A and B are trans fused. The ester group at C4 is cis fused to methyl carbon C15 whereas another methyl carbon C18 and oxo O(15) of the isopropyl group at C13 are rotated to positions 0.107(3) Å and 0.179(2) Å out of the plane of ring C.