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 structure of 17α‐acetoxyprogesterone,C23H32O4

The crystal structure of the title compound (C₂₃H₃₂O₄) has been determined by X‐ray diffraction methods. It crystallizes in the orthorhombic space group P2₁2₁2₁ with cell parameters: a = 10.86(1), b = 11.95(2), c = 15.65(5) Å and Z = 4. The structure has been refined to an R‐value of 0.045 for 1610 observed reflections. Ring A exists in sofa conformation, Ring B adopts a distorted chair conformation while as Ring C assumes a chair conformation. The five membered ring D adopts a half‐chair conformation. The crystal structure is stabilized by intra‐ and intermolecular C‐H…O interactions. (© 2004 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.     

Crystal and molecular structure of trans‐(±)‐3‐acetoxy‐2‐(4‐methoxyphenyl)‐4‐oxo‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine‐1‐oxide

The title compound is a structurally related isomer of diltiazem, a well known drug. This compound (C₁₈H₁₇NO₅S) crystallizes in the space group P2₁/n with a = 13.803(4), b = 7.704(3), c = 16.093(3) Å, β = 105.37(2)º, Z = 4, V = 1650.1(9) ų. The least‐squares refinement gave residual index R = 0.067 for 2831 observed reflections. The distorted seven‐membered ring in the molecule shows twist‐boat conformation. Hydrogen bonds in which the amide group at one molecule and a carbonyl group in the adjacent molecule are involved to form centrosymmetric dimers in the crystal. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Presence of pseudo‐peptide bond in the crystal structure of n‐(t‐butoxycarbonyl)‐ε‐n′‐benzyloxycarbony‐l‐lysyl‐l‐isoleucine (boc‐lys(obzl)‐ile)

The dipeptide Boc‐Lys(OBzl)‐Ile crystallizes in monoclinic space group P2₁ with cell parameters a = 5.003(1), b = 19.199(3), c = 15.270(2)Å, β =93.42(1)°, V = 1464.1(3)ų, Z = 2, D_cal = 1.117 Mg/m³ at T = 293 K. The structure was solved by direct methods and refined by full‐matrix least‐squares procedure to a final R = 0.096 and wR = 0.101 using 1379 reflections. The peptide unit is in trans conformation and the molecule takes up an extended conformation. In the lysine side chain, delocalization of electrons and pseudo peptide bond formation is observed at the interaction site of benzyloxycarbonyl group. Both N‐H…O and main chain C‐H…O hydrogen bonds stabilize the molecules in the unit cell in a parallel β‐sheet fashion. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of a ternary mononuclear copper (II) complex: 4‐chloro‐3‐methyl‐6[(N‐2‐picolyl)‐1′‐iminomethyl]phenolato copper(II)perchlorate

The complex crystallizes in monoclinic space group P2₁/n with unit cell parameters a = 7.295(4), b = 19.627(5), c = 12.770(4) Å, β = 101.25(4)º, V = 1793.2(12) ų, Z = 4, ρ = 1.684 Mg/m³ at T = 293(2)K. The structure was solved by Patterson method and refined by full‐matrix least‐squares procedures to final R = 0.0387 using 2906 observed reflections. The asymmetric unit of the complex contains a mononuclear tridentate ligand, a perchlorate group and a methanol molecule. The compound crystallizes as parallel layers of polymeric complex bridged through perchloarate groups. The molecular CuN₂OO′O′′₂ chromophore involves an elongated rhombic octahedral structure and the Cu‐ligand bond shows greater disparity. The five‐membered chelate ring and the pyridine ring lie in the same plane while the six membered chelate ring assumes sofa conformation. A strong O‐H…O inter molecular interaction plays a key role in the formation of dimer along b‐axis. (© 2006 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.     

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)     

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 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 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)     

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,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 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)     

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 4‐(1‐methyl‐1‐mesitylcyclobutane‐3‐yl)‐2‐aminothiazole

The crystal structure of 4‐(1‐methyl‐1‐mesitylcyclobutane‐3‐yl)‐2‐aminothiazole (C₁₇H₂₂N₂S₁) has been determined by X‐ray crystallographic techniques. The compound crystallizes in the triclinic space group P‐1 with Z = 6. The crystal structure was solved by direct methods and refined by full‐matrix least squares to a final R‐value of 0.052 for 2298 observed reflections [I > 2σ ( I ) ]. There are three crystallographically independent molecules, I, II and III. These molecules are held together by intermolecular N‐H...N hydrogen bonds. © 2006 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 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)     

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.     

Structure and conformation of n‐ (t‐butoxycarbonyl)‐l‐valine‐l‐phenylalanine‐methyl ester (Boc‐Val‐Phe‐OMe)

The crystal structure of N‐ (t‐butoxycarbonyl) ‐ L‐valine‐L‐phenylalanine‐methyl ester (Boc‐Val‐Phe‐OMe), C₂₀H₃₀N₂O₅ was determined by X‐ray diffraction methods. The dipeptide crystallizes in orthorhombic space group P2₁2₁2₁, with cell parameters a = 5.0680(1) Å, b = 13.8650(1) Å and c = 28.2630(1) Å, V = 2143.8(5) ų, F.W. = 378.46, Z = 4, D_calc = 1.173 Mg/m³, μ = 0.687 mm^‐1, F₀₀₀ = 816, CuKα = 1.5418 Å. The structure was solved by direct methods and final R1 and wR2 are 0.0659 and 0.1654, respectively. The peptide unit is in trans conformation [ω = 177.4(9)°]. The conformation angles ϕ₁, ψ₁, ϕ₂ and ψ₂ for the peptide backbone are: ‐96.5(13)°, 101.2(13)°, ‐123.9(12)° and 34.0(15)°. The N‐H…O and C‐H…O hydrogen bondings influence the packing of the molecules in the dipeptide crystal. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)