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.     

Structural studies of crystalline oligosaccharides VI: Crystal structure and conformation of benzyl‐4,6‐O‐benzylidene‐3‐O‐benzoyl‐β‐D‐galactoside

Monsaccharides are the building blocks of polysaccharides and hence are the simplest sugar molecules to study the conformation and molecular structures of sugars. Benzyl‐4,6‐O‐benzylidene‐3‐O‐benzoyl‐β‐D‐galactoside is a key intermediate in the synthesis of polysaccharides. Crystal structural investigation of the title compound was undertaken to establish their chemical structure as well as to study their solid state conformation. Crystals of the title compound, obtained from water/methanol, are orthorhombic, space group P2₁2₁2₁, with cell dimensions a=11.290 (4), b=9.941 (1), c= 21.442(2)Å, V= 2406ų, Z=4, D_obs= 1.42 gm/cm³, D_calc=1.423 g/cm³, 2886 reflections were collected on a CAD‐4 diffractometer. The structure was solved by direct methods and refined to a final reliability index of 4.7%. The galactoside sugar has the chair conformation with C2' and C5' deviating from the mean plane of the other atoms of the sugar. The 4,6‐O‐benzylidene ring also has a chair conformation with the benzoyl group proximal to O6'. The crystal structure is stabilized by O‐H…O hydrogen bonds involving O2' as donor and three C‐H…O hydrogen bond interactions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

Structure and conformation of a nickel complex: {2‐Hydroxo‐3‐piperidine‐1‐yl‐methyl‐N,N′(bis‐5‐bromobenzylpropylenediimine)nickel(II)perchlorate}

The title compound, a nickel complex [C₂₃H₂₆N₃O₂Br₂Ni.(ClO₄)] (CCDC 199520) crystallizes in triclinic space group P with the cell parameters a = 10.2560(4), b = 10.8231(4), c = 12.0888(5)Å, α = 99.404(1), β = 99.780(1), γ = 92.252(1)° and V = 1301.49(9)ų. The structure was solved by Patterson method and refined by full‐matrix least‐squares procedures to a final R = 0.0497 using 6287 observed reflections. In the complex, the piperidine ring takes chair conformation and the geometry around the Ni ion is slightly distorted square planar. The dihedral angle between the planes [N‐Ni‐N and O‐Ni‐O] is 9.4(1)°. The chelate ring containing both the nitrogen atoms adopts twisted boat conformation. The molecules in the crystal are stabilized by N‐H…O and C‐H…O types of hydrogen bonds in addition to a C‐H…π interaction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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 Spiro[2‐benzoyl‐cyclohexyl‐4,5‐diphenylpyrrolidine‐3,3'‐chroman‐4‐one]

3‐Phenyl‐chroman‐4‐one is the basic unit of isoflavonoids which are found in the plants of the sub‐family papilionoidae of Leguminosae. They are known to possess antifungal and antibacterial properties. Crystal data of the title compound : Monoclinic, space group P2₁/c, a = 14.021(3), b = 18.682(4), c = 11.362(2) Å, β = 95.75(3)°, R = 0.066. The two phenyl rings directly attached to the pyrrolidine ring are nearly perpendicular to it. The dihydropyrone moiety adopts a half‐chair conformation while the cyclohexane ring attached to the pyrrolidine ring adopts a chair conformation. The best plane passing through the chroman‐4‐one moiety makes a dihedral angle of 82.2(3)° with the pyrrolidine ring. The molecule is stabilized by one intra‐ and two intermolecular C‐H...O hydrogen bonds.     

The Crystal and Molecular Structure of 11,12‐dibromo‐ 7,8—benzo‐1,5‐di(p—tolylsulphonyl)‐1,5‐diazacyclononan

The crystal structure of the title compound, C₂₅H₂₆Br₂N₂O₄S₂ was determined by single crystal X‐ray diffraction technique. The crystals are monoclinic, space group C 2/c, with a=20.7142(2) Å b=11.7910(2) Å, c= 10.6735(3) Å, β=98.549(2)°, V=2577.94(9) ų, Z=4. The structure was solved by direct methods and refined by least‐squares methods to a final R=0.046 for 1866 observed reflections with I>2sigma(I). The title compound, displays disordered geometry around the C1 atom located almost on twofold axis. The nine‐membered heterocylic ring is close to the half‐chair conformation. The dihedral angle between phenyl rings is 34.2(1)°.     

Crystal and Molecular Structure of Desmodin

The crystal structure of the title compound has been determined from X‐ray diffraction. The compound crystallizes from benzene in the orthorhombic system, space group P2₁2₁2₁, with unit cell parameters: a = 8.485(2), b = 9.816(2), c = 22.597(4) Å, Z = 4, V = 1881.9(7) ų. The structure was determined by direct methods and refined to a final R‐factor of 0.04. Six membered rings B and E are planar. Ring A and ring C are in slightly distorted sofa conformation. Ring D is in envelope conformation. The structure is stabilised by weak intermolecular 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.     

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 2,6‐bis(4‐chlorophenyl)‐3‐phenylpiperidin‐4‐one

The crystal structure of the title compound is described. The chemical formula of the compound is C₂₃H₁₉Cl₂NO. The compound is found to crystallize in monoclinic system with space group P2₁/c, Z = 4. The unit cell dimensions are a = 15.137(3) Å, b = 8.9171(18) Å, c = 14.779(3) Å, β = 91.461(4)° and V = 1994.2(7) ų, D_calc = 1.320 gcm^‐3. The final R factor is 4.4%. The central piperidone ring of the molecule adopts a slightly distorted chair conformation, the mean torsion angle being 52.3°; the phenyl rings are planar. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Crystal and Molecular Structure of tert‐Butoxycarbonyl ‐ α‐aminoisobutyryl ‐ isoleucyl ‐methylester

The crystal structure of the synthetic peptide Boc — Aib — Ile ‐ OMe (C₁₆ H₃ 0 N₂ O₅ ) has been determined from three‐dimensional X — ray diffraction data. The peptide crystallizes in triclinic space group P1 with a = 9.570(9), b = 10.261(7), c = 10.610(2) Å , α = 101.9(0), β = 91.7(0), γ = 98.6(0)° V = 1006.1(12) ų, Z = 2, D_calc = 1.09 Mg m^‐3. The structure was solved by direct methods and refined by full‐matrix least‐squares method to an R value of 0.072 (λ = 1.5418Å). The conformation of Aib residue in molecule A is αL and in molecule B is αR. The Ile residue in molecule A adopts folded conformation, while in molecule B it is in the extended region. The peptide units are trans and show significant deviations from planarity.     

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 Structure of N,N'‐Bis(3‐(o‐dimethylaminoimino‐ethyl) ‐2‐hydroxy‐5‐methyl)‐benzylpiperazine

The structure of the synthesized title compound, C₃₀H₄₆N₆O₂ , was solved by using X‐ray diffraction techniques. The compound crystallized in monoclinic space group P2₁/n with cell dimensions a = 14.0629(7), b = 6.5696(3), c = 17.7948(8)Å, β = 111.35(2)°, V = 1531.2(1)ų, Z = 2, D_cal = 1.134 Mgm^‐3 and T = 293(2)K. The molecule possesses a center of symmetry, and hence, there is half a molecule in the asymmetric unit. The piperazine ring adopts chair conformation with the substituents at the equatorial position, subtending a dihedral angle of 88.87(1)° with the phenyl ring. The phenyloxy hydrogen is involved in an intramolecular O‐H...N type of hydrogen bond.     

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).     

Crystal structure of a daturalactone – A withanolide

The crystal structure of a daturalactone derivative has been determined by X-ray structural analysis. The compound crystallizes in orthorhomic space group P2₁2₁2₁ with cell parameters a - 15.141(1) Å, b - 18.425(1) Å, c - 19.251(2) Å. The structure was solved by direct methods and refined to R - 0.082. The asymmetric unit contains two non-equivalent molecules. Extensive hydrogen bonding is present. The conformations of the rings are A: a distorted half-chair, B: a perfect half-chair, C: a chair, D: an envelope-half chair and E: a twist boat. Ring junctions A/B, B/C, C/D are all trans fused. Methyl carbons C(18), C(19), C(27) and the lactone moiety is β-oriented whereas the methyl carbons C(21) and C(28) are α-oriented.     

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.     

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.     

Crystal and Molecular Structure of (9R)‐10,11‐dihydro‐6′‐methoxy‐cinchonan‐9‐ol‐4‐chlorobenzoate hydrochloride

The crystal structure of the title compound has been determined by single crystal X‐ray diffraction methods. C₂₇H₂₉N₂O₃Cl.HCl is one of the cinchona alkaloids. It crystallizes in the space group P2₁2₁2₁ with a = 11.745(3), b = 12.353(6), c = 17.253(6) Å and Z = 4. The structure was refined to a final R value of 0.062 for 2155 observed reflections. The C—N distances are unequal in the quinoline ring system. In quinulidine ring, the bonds around N are more tetrahedral. The spatial arrangement and torsion angles show the open conformation of the molecule. The molecular packing is stabilized by hydrogen bonding.     

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)