Crystal and molecular structure of (21R)-3β-acetoxy-14,21-epoxy-5β,14β-card-20(22)-enolide

The title compound (21R)-3β-acetoxy-14,21-epoxy-5β,14β-card-20(22)-enolide crystallizes in the monoclinic space group P2₁ with 2 formular units C₂₅H₃₄O₅ in the unit cell. The lattice parameters are a = 13.471, b = 7.959, c = 10.514 Å and β = 102.73°. The crystal structure was determined by direct methods and refined by least-squares procedures to the discrepancy factor R = 0.045. Bond length, bond angles, ring conformations and the configuration at C(21) were determined. Intermolecular interactions are only of van der Waals type.     

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.     

The Crystal Structure of 3-Methoxy-estra-1,3,5(10)-triene-16α Br,17β OH

The steroid 3-Methoxy-estra-1,3,5(10)-triene-16αBr,17βOH crystallizes in the tetragonal space group P 4₁ with the lattice constants a = b = 10,358(2) Å, c = 32,591(5) Å. The crystal structure contains two symmetry independent molecules. Significant differences for the two molecules occur in all the four rings of the steroid sceleton. The molecules are linked by hydrogen bridges and Br…︁ Br contacts. The differences between the two symmetry independent molecules are interpreted as due to different intermolecular interaction.     

Crystal and Molecular Structures of Modified Progestagens (IV). 17α-Azidomethyl-17β-hydroxy-estra-4,9-dien-3-one,C19H25N3O2

The crystal and molecular structure of 17α-azidomethyl-17β-hydroxy-estra-4,9-dien-3-one has been determined by X-ray structure analysis. It crystallizes in the orthorhombie space group P 2₁2₁2₁ with cell parameters a = 9.118(1), b = 9.252(1), and c = 20.444(2) Å. The structure was solved by MULTAN-82 and refined to R = 0.042 for 1408 observed reflections. Steroid ring and 17β-side chain conformations are discussed in the paper. Intermolecular hydrogen bridges between hydroxyl groups and carbonyl oxygen atoms link molecules forming chains in c-direction.     

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 3-methoxy-estra-1,3,5(10)-triene-14β,17β-diol,C19H26O3

The crystal and molecular structure of 3-methoxy-estra-1,3,5(10)-triene-14β,17β-diol has been determined by single crystal X-ray analysis. It crystallizes in the orthorhombic space group P2₁2₁2₁ with cell parameters a = 8.965(2), b = 30.520(7), and c = 6.031(2) A. The structure was solved by the POSIT system and refined by least-squares calculations to the conventional R factor of 0.075. The steroid rings A, B, and C have planar, 7α, 8β-half chair, and chair conformations, respectively. The ring D is intermediate between 13α, 14β-half chair and 13α-envelope. Rings B and C are trans-fused, and rings C and D are cis-fused. There are intra- as well as intermolecular hydrogen bonds between both hydroxyl groups of the steroid molecule.     

Crystal structure,thermal and compositional deformations of β‐CsB5O8

The crystal structure of β‐CsB₅O₈ has been determined from X‐ray powder diffraction data using synchrotron radiation: Pbca, a = 7.8131(3) Å, b = 12.0652(4) Å, c = 14.9582(4) Å, Z = 8, ρ_calc = 2.967 g/cm³, R‐p = 0.076, R‐wp = 0.094. β‐CsB₅O₈ was found to be isostructural with β‐KB₅O₈ and β‐RbB₅O₈. The crystal structure consists of a double interlocking framework built up from B‐O pentaborate groups. The crystal structure exhibits a highly anisotropic thermal expansion: α_a = 53, α_b = 16, α_c = 14 · 10^‐6/K; the anisotropy may be caused by partial straightening of the screw chains of the pentaborate groups. The similarity of the thermal and compositional (Cs‐Rb‐K substitution) deformations of CsB₅O₈ is revealed: increasing the radius of the metal by 0.01 Å leads to the same deformations of the crystal structure as increasing the temperature by 35°C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

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.     

Crystal structure of 4-(2-hydroxyethyl)-4-aza-5α-androstan-17β-ol “HS-478”

The crystal structure of HS-478 (aqueous solvate) has been determined by direct method and refined by block diagonal least squares to R₀ = 0.043. The intensity was measured in a four-circle diffractometer in the ω/2θ scanning mode, CuKα radiation. The crystals are triclinic P1, a = 6.721(3), b = 66.532(3), c = 12.188(5) Å, α = 96.86(2)°, β = 82.82(2)°, and γ = 114.68(2)°. Rings A, B, C are chair whereas ring D is envelope. Rings A/B and B/C are trans fused, whereas rings C/D are quasi trans. The hydroxyethyl side chain connected to N(4) has conformation of (−t, t).     

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.     

Crystal and molecular structure of 1‐allyl‐5‐(4‐methylbenzoyl)‐4‐(4‐methylphenyl)pyrimidine‐2(1H)‐thione

The crystal structure of 1‐allyl‐5‐(4‐methylbenzoyl)‐4‐(4‐methylphenyl)pyrimidine‐2(1H)‐thione (C₂₂H₂₀N₂OS) has been determined from three dimensional single crystal X‐ray diffraction data. The title compound crystallizes in the monoclinic space group P 2₁/c, with a = 10.6674(13), b = 10.1077(7), c = 17.9467(19) Å, β = 98.460(9)°, V = 1914.0(3) ų, D_calc = 1.251 g cm^–3, Z = 4. In the title compound, the allyl group shows positional disorder. Molecules are linked by C‐H···O, C‐H···N and C‐H···S intermolecular interactions forming two‐dimensional network. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

Crystal structure of 2‐(2'‐hydroxyphenyl)‐6‐tributylstannyl‐4‐(3H )‐quinazolinone and 2‐(2'‐hydroxyphenyl)‐6‐iodo‐4‐(3H)‐quinazolinone

The structures of the title compounds C₂₆H₃₇N₂O₂Sn ( I ) and C₁₄H₉IN₂O₂ ( II ) were determined by single‐crystal X‐ray diffraction technique. Compound I crystallizes in the triclinic space group P1 with a = 9.560(3) Å, b = 16.899(6) Å, c = 17.872(5) Å, α = 65.957(7)°, β = 83.603(5)°, γ ( = 75.242(5)°, V = 2549.8(13) ų, Z = 4, and D =1.374 g/cm³. The compound consists of a quinazolinone ring with phenol and tributylstannyl moieties. Compound II crystallizes in the monoclinic space group P2₁/c with a = 7.6454(12) Å, b = 5.9270(9) Å, c = 27.975(4) Å; α = 90°, β = 95.081(3)°, γ = 90°, V = 1262.7(3) ų, Z = 4, and D = 1.915 g/cm³. The compound consists of a quinazolinone ring with phenol and iodine substituents. For both I and II , the short intramolecular O–H…N and two long intermolecular N–H…O hydrogen bonds are highly effective in holding the molecular system in a stable state. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Gel growth and characterization of β ‐DL‐methionine

DL‐Methionine [C₅H₁₁NO₂S] is one of the essential amino acids in humans. It has two crystalline forms, viz., α‐ and β‐ methionine. In the present study, β ‐ form is crystallized in silica gel; under suitable pH conditions by single diffusion method. The grown crystals were characterized by density measurement and single crystal X‐ray diffraction. Fourier transform infrared (FTIR) spectroscopic studies, thermal analysis and scanning electron microscopic (SEM) studies were also made as part of the structural studies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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 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.     

Effect of Terminal Groups on Formation of Crystal Structure in α,γ-Disubstituted n-Alkanes

The crystal and molecular structure of 1,16-dibromohexadecane have been determined by X-ray diffraction. Crystal data; empirical formula, C₁₆H₃₂Br₂, formula weight M_r = 384.24, monoclinic, P2₁/a, a = 31.00(2), b = 5.38(1), c = 5.48(1) Å, β = 90.8(2)°, V = 914(3) ų, Z = 2, D_x = 1.396 g/cm³, δ(CuKα) = 1.5418 Å, μ(CuKα) = 55.41 cm⁻¹, F(000) = 396.00, T = 293 ± 1 K, wR = 0.082, R = 0.054 for 940 unique reflections [I > 3.00σ(I)]. The molecular skeleton has an all trans zigzag hydrocarbon chain. The crystal has a layer structure, but the directions of molecular axes in neighbouring layers alternate. This molecular packing resembles to that of 1,16-hexadecanediol, whereas n-alkanes or α-monosubstituted n-alkanes do not appreciably have these molecular arrangement. The effect of terminal groups at both ends of α,ω-disubstituted n-alkanes on the crystal structure is discussed.     

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 structure of N‐[(1Z)‐1‐(3‐methyl‐3‐phenylcyclobutyl)‐2‐thiomorpholin‐4‐ylethylidene] thiourea

The crystal structure of N‐[(1Z)‐1‐(3‐methyl‐3‐phenylcyclobutyl)‐2‐thiomorpholin‐4‐ylethylidene] thiourea (C₁₈H₂₆N₄S₂) has been determined by X‐ray crystallographic techniques. The compound crystallizes in the orthorhombic space group Pbca, with unit cell parameters: a = 15.692(3), b = 20.803(8), c = 11.979(6)Å, Z = 8, V = 3911(7)ų. The crystal structure was solved by direct methods and refined by full‐matrix least squares to a final R‐value of 0.084 for 1447 observed reflections [I > 2σ ( I ) ]. In the thiosemicarbazide moiety, the S = C bond length is 1.656(6), N‐C‐N angle is 115.6(5)°. The crystal structure is stabilized by the intermolecular N‐H...S hydrogen bonds. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)