The Crystal Structure of 3-Methoxy-estra-1,3,5(10)triene-16αBr,17αOH

The steroid 3-Methoxy-estra-1,3,5(10)triene-16αBr,17αOH crystallizes in the orthorhombic space group P 2₁2₁2₁ with lattice constants a = 30.653(5) Å, b = 9.039(2) Å, c = 6.098(1) Å. The single molecule has an intramolecular O H…︁ Br interaction. Intermolecular interactions are only of van der Waals type. Ring A is nearly planar, ring B has a nearly half chair conformation, ring C has a chair conformation and ring D an envelope conformation.     

Crystal and Molecular Structure of 3-Methoxy-estra-1,3,5(10)-trien-17β-ol

The crystal structure determination of the title compound was undertaken to determine the conformational flexibility of the steroid skeleton. 3-Methoxy-estra-1,3,5(10)-trien-17β-ol (C₁₉H₂₆O₂) crystallizes in the space group P2₁2₁2₁ with Z = 12, a = 12.589(2), b = 16.274(5), and c = 23.535(6) Å. The structure was solved by direct methods and refined to R = 0.056. Three symmetry independent molecules having different molecular conformations were observed in the crystal. The most flexible region of the molecules is the B ring which adopts following conformations: 7α,8β-half-chair, 8β-sofa, and an intermediate form between half-chair and sofa.     

The crystal and molecular structure of 5α,8α-epidioxyergosta-6,22-dien-3β-acetate

From the mushroom species Tricholoma populinum LANGE which shows interesting pharmaceutical effects the steroid 5α,8α-epidioxyergosta-6,22-dien-3β-ol has been isolated. The acetate of this compound crystallizes in the monoclinic space group P 2₁ with two molecules in the unit cell of dimensions a = 19.788, b = 7.241, c = 9.914 Å, β = 103,97°. The final R-value is 0.079 for 1082 reflections.     

Crystallographic Investigations of 3β‐acetoxy‐5α‐cholestan‐6‐one‐semicarbazone ‐ A Steroid

The crystal structure of 3b‐acetoxy‐5a‐cholestan‐6‐one‐semicarbazone (C₃₀H₅₁O₃N₃) has been determined by X‐ray diffraction methods. It crystallizes in the orthorhombic space group P2₁2₁2₁ with cell parameters a = 11.641(1), b = 16.552(1) c = 31.181(4) Å and Z = 8. The structure has been refined to an R‐value of 0.050 for 4407 observed reflections. Two molecules in the asymmetric unit have been observed. In both the crystallographically independent molecules, all the three six‐membered rings (A, B and C ) of steroid nucleus exist in chair conformation, while the five‐ membered ring D exists in 13β distorted‐envelope in molecule‐I and 13β, 14α half‐chair conformation in molecule‐II. Three intermolecular N‐H … O hydrogen bonds have been observed.     

The Molecular and Crystal Structure of 3β-O-(2′,3′ -O-isoropylidene-α-L-rhamnopyranosyl) — digitoxigenin

3β-O-(2′,3′ -O-isoropylidene-α-L-rhamnopyranosyl) — digitoxigenin crystallizes in the monoclinic space group P 2₁ with two molecules C₃₂H₄₈O₈ per unit cell and the lattice constants a = 7.865, b = 6.470, c = 29.803 Å, β = 93.95°. The structure was solved by direct methods of phases determination and subsequently refined by least squares technique to the final R-value 0.06. The position of the lactone ring is disordered in the crystal.     

Crystal and molecular structure of 1,21-diacetoxy-11β,17-dihydroxy-4-methyl-19-norpregna-1,3,5(10),8(14)-tetraen-20-one,C25H30O7

The structure of the title compound has been determined by X-ray diffraction techniques. It crystallizes in the monoclinic space group P 2₁ with 2 formula units C₂₅H₃₀O₇ in the unit cell. The lattice constants are a = 10.194, b = 11.790, c = 9.515 Å, and β = 100.69°. The structure was solved by direct methods using MULTAN-78 and refined by least-squares calculations to R = 0.061. The molecular configuration and conformation are discussed. The influence of the acetoxy groups and the 11-hydroxyl group on the steroid backbone is of special interest. There are two symmetry independent intermolecular but no intramolecular hydrogen bridges.     

Crystal and Molecular Structure of 6α-Methyl-3,20-Dioxo-5β-Pregnan-17α-yl Acetate

The title compound 6α-methyl-3.20-dioxo-5β-pregnan-17α-yl acetate crystallizes in the monoclinic space group P 2₁ with two molecules in the unit cell and the lattice parameters a = 10.889, b = 11.056, c = 9.8029 Å, β = 101.51° The crystal structure is isostructural with medroxyprogesterone acetate and refined by full matrix least squares calculations up to the discrepancy factor R = 0.051.     

Crystallographic Analysis of Acetyl β ‐boswellic acid

The crystal structure of the title compound (3 α ‐acetoxy‐urs‐12‐en‐24‐oic acid, C₃₂H₅₀O₄) has been determined by X‐ray crystallographic techniques. The compound crystallizes into orthorhombic space group P2₁2₁2₁ with unit cell parameters : a = 12.773(2), b=16.381(4), c=27.929(7)Å. The structure has been solved by direct methods and refined to R = 0.054 for 4930 observed reflections. The structure contains two crystallographically independent molecules in the asymmetric unit which are almost identical in geometry. Rings A, B, D and E have chair conformations while ring C assumes a sofa conformation in both the molecules. The molecules in the structure are linked together by intra‐ and intermolecular O‐H…= and C‐H…O hydrogen bonds.     

3 β ‐Acetoxy‐5 α ‐cholestan‐6‐one: A Steroid

The crystal and molecular structure of 3 β ‐Acetoxy‐5 α ‐cholestan‐6‐one has been determined by X‐ray crystallographic techniques. The compound crystallizes in the space group P2₁ with cell parameters : a = 13.060(3), b=6.299(2), c=17.152(6)Å; β =96.47(3)o, V = 1402.02ų, Z = 2, R = 0.072 for 1921 observed reflections. The six‐membered rings (A, B and C) exist in the chair conformations while the five‐membered ring‐d assumes half‐chair. All rings of the steroid skeleton are trans connected.     

Crystal and molecular structure of (20R)-19-nor-5β,14β-pregnane-3β,14,20-triol 3,20-diacetate

The title compound (20R)-19-nor-5β,14β-pregnane-3β,14,20-triol 3,20-diacetate crystallizes in the monoclinic space group P2₁ with 4 formula units C₂₄H₃₈O₅ in the unit cell. The lattice parameters are a = 14.324, b = 12.569, c = 12.685 Å, β = 90.21°. The crystal structure was determined by direct methods and refined by the least-squares procedure to the discrepancy factor R = 0.042. Bond length, bond angles, ring conformations, as well as the absolute configuration at C20 were determined. In the crystal the molecules are linked to infinite chains by two hydrogen bonds.     

The Crystal and Molecular Structure of 1α,2α-Methylene Gibberellin A3 Methyl Ester

The three-dimensional structure of the 1α,2α-methylene gibberellin A₃ methyl ester has been determined by single-crystal X-ray diffraction techniques. The crystals are monoclinic, space group P 2₁ with two molecules in the unit cell of dimensions a = 9.236, b = 7.109, c = 14.155 Å and β = 104.61º. The structure was refined to an R-value of 0.0983 for 1359 observed reflections.     

Crystal and molecular structure of 3β-hydroxy-5β-estr-8(14)-en-17-one

The title compound crystallizes in the orthorhombic space group P2₁2₁2₁ with 4 formula units C₁₈H₂₆O₂ in the unit cell. The lattice constants are a = 10.356(2) Å, b = 19.743(3) Å, and c = 7.487(1) Å. The structure was solved by direct methods of phases determination and refined by least-squares calculations to the conventional R = 0.054. The configuration and conformation of the molecule were determined and compared with those of Δ-8,14-anhydrodigitoxigenin.     

Crystal and Molecular Structure of bis[diaaqua(1H‐cyclopenta(2,1‐b:3,4‐b')(dipyridine ‐2,5‐dione))N ickel(II)]dihydrate

The title compound [Ni(CPDD)(H₂O)₂]₂(H ₂O )₂, {]Ni₂(C₄₄H₂₈N₈O₁₂)] (H₂O)₂ }, where CPDD = 1H‐cyclopenta(2,1‐b:3,4‐b')(dipyridine‐2,5‐dione) has been prepared and its crystal structure determined by single crystal X‐ray diffraction at room temperature. The complex crystallizes in the triclinic space group P1 w ith two molecules in the asymmetric unit. The cell dimensions are a=10.452(1),b=14.098(1) & c=16.023 Å; D=110.13(1), E=100.63(1) & J=100.85(1)°. The two independent molecules in the asymmertic unit are related by pseudo two fold symmetry. In both the molecules the coordination environment around the Ni(II) may be best described as a distorted octahedral. Due to some delocalization of charge towards one of the oxygens(O1a) from the O2a atom some degree of bond localization has been observed. The individual diones of both the molecules are almost right angles at the metal atom. A long the y‐axis inversion related molecules are forming pseudo‐dimers through hydrogen bonding.     

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.     

The crystal structure of α‐SrGaBO4

A new compound α‐SrGaBO₄ has been synthesized by solid state reaction at high temperatures, and its structure has been solved by direct methods from powder X‐ray diffraction. α‐SrGaBO₄ has an orthorhombic system, Pccn space group, with lattice parameters a = 15.3154(7) Å, b = 8.9186(4) Å, c = 5.8130(3) Å, and Z = 8. The structure consists of infinite chains run parallel to the c axis and built up of GaO₄ tetrahedral and BO₃ triangles. The basic unit of these chains is a six ‐ membered Ga₂BO₈ ring formed by two GaO₄ tetrahedra and one BO₃ triangles. The Sr atom is bonded to eight oxygen atoms. The strontium atoms serve to hold the chains together through co‐ordination with oxygen atoms. DTA curve of noncrystalline glassy SrGaBO₄ was discussed. The XRD results show no phase transition occurs between ‐173 °C and 127 °C. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Structure of 1,2,3‐Tribromoindane,C9H7Br3

The title compound (C₉H₇Br₃) crystallizes in the triclinic space group with Z = 2; R = 0.043 for 1518 observed reflections [I = 2σ (I)]. The average Br‐C distance is 1.974 Å, Br‐C‐C angle is 110.0°. The five‐membered ring adopts a somewhat flattened structure. The atoms C1 and C3 have opposite configurations. The whole molecule has approximate (non‐crystallographic) C_s‐symmetry.     

Structure of 3β, 20-diacetoxy-16α-methyl-allopregn-17(20)-ene

C₂₆H₄₀O₄, a steroid (3β, 20-diacetoxy-16α-methyl-allopregn-17(20)-ene) crystallizes in the orthorhombic space group P2₁2₁2₁. The unit cell parameters are a = 10.745(2), b = 11.190(3), c = 20.208(1) Å. The structure has been elucidated by direct methods. The final residual index (R) converges to 0.042, weighted residual index (wR) being 0.044. Rings A and B adopt normal chair conformation whereas ring C is found to be very close to chair and ring D exists in 14α-envelope conformation. The ring junctions A/B, B/C, C/D are trans-fused about the bonds C5–C10, C8–C9 and C123–C14, respectively.     

The crystal and molecular structure of 1β-azido-gibberellin A1 monoetherate

The three-dimensional structure of 1β-azido-gibberellin A₁ monoetherate has been established by X-ray analysis. The compound crystallizes from acetone-diethylether in the monoclinic space group P2₁ with two gibberellin and two diethylether molecules in the unit cell of dimensions a = 7.799, b = 20.745, c = 8.036 Å, β = 110.23°. The final R-value is 0.059 for 2855 reflections.     

The Morphology of Some Hydrothermally Synthesized Li-Minerals: A-Zeolite, α-Eucryptite, β-Spodumene and β-Eucryptite

The hydrothermal treatment of glass with the composition 2 LiF, Al₂O₃, 3 SiO₂ at 1 kbar in the range of 150 °C to 850 °C gave rise to the formation of A-zeolite with orthorhombic unit cell with å = 10.31 Å/b̊ = 8.18 Å/c̊ = 5.0 Å (space group Pna2₁), α-eucryptite, trigonal, å = 13.4 Å/bº = 13.4/Å/cº = 9.0 Å (space group R 3 ), β-spodumene, pseudocubic/tetragonal, å = 7.53 Å/b̊ = 7.53 Å/c̊ = 9.15 Å (space group P4₃2₁2), β-eucryptite, monoclinic, å = 7.75 Å/b̊ = 5.2 Å/c̊ = 11.16 Å (space group P6₂22). The morphology and development of the mineral phases depend on the temperature of formation.     

Die Molekül- und Kristallstruktur von 1.1′-Bis-[phenyl-glyoxyloyl]-ferrocen

The 1.1′-Bis-[phenylglyoxyloyl]-ferrocen (PGF) crystallizes within the monoclinic space group P₁/c with the lattice constants a = 7,338 Å, b = 16,872 Å, c = 8,046 Å, β = 87,0°. The PGF belongs to metal-π-complexes. With the iron atom in the center of symmetry, both the heavy atom ligands are centrosymmetric-to each other. The two cyclopentadinyl rings linked to the iron atom are arranged in the sandwichtype with staggered conformation. The mean planes are separated by 3,32 Å. In a single phenyl-glyoxyloyl molecule exists an expanded Csp²–Csp² bondlength (1,528 Å). The two plane parts of the molecule are twisted around this bond. These two plane parts consist on the one hand of the carbon-5-ring and a C  O group and on the other hand of the carbon-6-ring and a C  O group. The dihedral angle is 62,5°. The expanded bond length mentioned is explained by Coulomb repelling forces of partially charged atoms. The packing of the molecules in the crystal lattice is discussed in detail.