Crystal structures of synthetic analgetics. IV. Dextropropoxyphene.

The molecular and cystal structure of dextropropoxyphene has been determined by X-ray methods. The crystals are monoclinic, space group P21, with unit cell dimensions a=9.257(2) A; b=9.048(3) A; c=12.074(7) A; beta=93.01(4)degrees. The phase problem was solved by direct methods and the model refined to an R-value of 0.038 for 1799 observed reflections. E.s.d's are, in average, 0.004 A and O.3 degrees in interatomic distances and angles, respectively. The propylamine chain in nearly fully extended, the dihedral angel C4-C5-C7-N being -174.2 degrees. The conformation of this side chain is similar to that in the hydrochloride of the title compound. Thus the proposed bioactive conformation is not preferred by propoxyphene in the crystalline state, as was the case for the free base of methadone.     

Über Pterinchemie. Mitteilung. Die Kristallstruktur von 5,6,7-Trimethyl-5,6,7,8-tetrahydropterindihydrochlorid-monohydrat

The crystal structure of 5,6,7-trimethyl-5,6,7,8-tetrahydropterine-dihydrochloride-monohydrate The crystal structure of the title compound has been determined by X-ray analysis (direct methods) and refined with 947 structure amplitudes to R = 0.026. The crystal system is orthorhombic, space group Pna2₁, with unit cell dimensions a = 14.081, b = 14.623, c = 6.773 Å. The molecule is protonated at the N(1)- and N(5)-position. The tetrahydropyrazine ring exists in a conformation in which C(6) deviates markedly from the mean plane of the other five atoms. The CH₃-groups at N(5) and C(6) possess a trans configuration with a pseudoaxial and an axial conformation respectively. The CH₃-groups at C(6) and C(7) in return possess the cis configuration, whereby the CH₃-group at C(7) occupies an equatorial conformation.     

Density functional theory study on the structure and vibrational frequencies of glycylglycine

Eleven possible conformers of glycylglycine have been studied by using the BLYP, B3LYP methods of density functional theory and the HF method at the basis set of 6-311++G**. BLYP (using Becke's and Lee-Yang-Parr's correlation functionals), ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations have been carried out to study the structure and vibrational spectra of glycylglycine. Glycylglycine crystal structure has been determined by X-ray diffraction analysis. The title compound has been crystallizes in the orthorhombic space group C1, with Z=4. And the unit cell parameters are: a=8.1184(12)A, b=9.5542(14)A, c=7.8192(11)A and V=577.95(15)A(3). Molecular conformation calculations have got 11 possible conformers. In these possible conformers, the most stable one has been selected. The BLYP/6-311++G** and scaled HF/6-311++G** frequencies correspond well with available experimental assignments of the normal vibrational modes. Comparison of the observed fundamental vibrational frequencies of glycylglycine and calculated results by density functional B3LYP and Hartree-Fock (HF) methods indicates that B3LYP is superior to the scaled Hartree-Fock (HF) for molecular vibrational issues.     

3-(3,4-亚甲二氧基)苯基-6-孟氧基-6,6a-二氢-呋喃并[3,4-d]异噁唑啉-4(3aH)-酮的合成和晶体结构

标题化合物是由5-(R)-(l-孟氧基)-2(5H)-呋喃酮与3,4-亚甲二氧基苯甲醛肟在次氯酸钙作为氧化剂的条件下,进行的区域选择性原位1,3-偶极环加成反应得到。结构通过单晶X-射线衍射法确定, C22H27NO6其晶体属正交晶系, 空间群为P212121, Mr = 401.45, a = 6.2600(3), b = 10.7300(11), c = 31.2160(25) , V = 2096.8(3) 3, Z = 4, Dc = 1.272 g/cm3, μ = 0.09 mm-1, F(000) = 856。最终的可靠因子为R f = 0.073, wR = 0.186。在分子结构中,平面1(异噁唑啉环)与平面2(呋喃酮环)之间的二面角为67.4°, 孟氧基中的环己烷环为椅式构象,呋喃酮并异噁唑啉环上的3个手性中心的构型为SC3a, RC6, RC6a。     

MOLECULAR STRUCTURE OF 2-[BIS(2-CHLOROETHYL)-AMINO]-6-BUTYLOXYMETHYL-TETRAHYDRO-2H-1, 3,2-OXA-ZAPHOSPHORINE-2-OXIDE

<正> The molecular structure of 2-[bis(2-chloroethyl)-amino]-6-t-butyloxymethyl-tetrahydro-2H-1,3,2-oxazaphosphorine-2-oxide has been determined by X-ray diffraction method.The crystal(C12H25Cl2NaO3P)is monoclinic with space group P21/a,a=11.965(2),b=10.335(3),c=14.543(5)A,β=102.24(2)°,V=1758(2)A3,Mr=347.22,Z=4,Dx=1.31 g/cm3,μ=4.66 cm-1,F(000)=736,R=0.051,Rw=0.054.The six-membered ring in this compound is in a distorted chair conformation with the t-butyloxymethyl group and the phosphoryl oxygen atom in equatorial positions which lead to cis-configuration.     

Na6 TlSb4: synthesis,structure, and bonding. An electron-rich salt with a chain conformation and a Tl-Tl bond length determined by the cation

The title compound forms on fusion and annealing of a stoichiometric mixture of the elements. The structure was determined by single-crystal X-ray diffraction methods in the monoclinic space group C2/c, with a = 15.154(3) A, b = 10.401(2) A, c = 17.413(4) A, and beta = 113.57(3) degrees, Z = 8. Four-membered Tl-Sb1-Sb4-Sb3 rings interlinked by pairs of Sb2 bridges generate swinglike repeat units [Tl(2)Sb(8)] that are further interlinked through external Tl-Tl bonds to form infinite one-dimensional chains. Cations play a major role in the structure. In contrast to the Zintl-phase K(6)Tl(2)Sb(3) with similar swinglike [Tl(4)Sb(6)] repeating units and Tl-Tl interlinkages, Na(6)TlSb(4) has a more compact conformation of the chains and a notably smaller cell volume than expected. The new phase is metallic with two excess cations according to empirical electron counting, EHTB band calculations for the anion, and the compound's measured resistivities and magnetic susceptibilities. The notably shorter Tl-Tl bond in the present salt (2.954 A) can be directly attributed to the smaller cation and reduced intercation repulsions across that bond.     

Structural studies of metabolic products of dopamine. IV. Crystal and molecular structure of (-)-noradrenaline.

The crystal structure of (-)-noradrenaline has been determined by X-ray methods, using 1000 observed reflections collected by counter diffractometer techniques. The crystals are orthorhombic, space group P212121, with a=8.611(2), B=6.138(2), And c=14.912(4) A. Least-squares refinements yielded a conventional R-factor of 0.036. Standard deviations in bond lengths are 0.003 A and in bond angles 0.2 degrees. The crystal structure of (-)-noradrenaline corresponds closely to that of (-)-adrenaline in molecular geometry, conformation, and arrangement in the crystals. The results of the structure investigations are discussed in relation to the biological activity of these biogenic amines.     

Resolution and Crystal Structure of 9α-(3-Azabicyclo[3,3,1]nonanyl)- 2''-cyclopentyl-2''-hydroxyl-2''-thienylacetate

The crystal structure of 9α-(3-azabicyclo[3,3,1]nonanyl)-2'-cyclopentyl-2'-hydro-xyl-2'-thienylacetate (C16H27NO3S, Mr = 349.48) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombic, space group P212121 with a = 14.937(3), b = 8.1673(16), c = 15.423(3) (A), V = 1881.5(6) (A)3, Z = 4, Dc =1.234 g/cm3, μ = 0.188 mm-1, F(000) = 752, the final R = 0.0468 and wR = 0.1251. The bicyclo[3,3,1]nonane ring system adopts the most favored twin-chair conformation. The crystal structure shows the existence of intramolecular O-H…O hydrogen bonds by which a one-dimensional chain struc- ture is formed.     

Synthesis and Crystal Structure of Tetramethyl 4aH-Pyrido [1, 2-a] Quinoline-1,2,3,4-Tetracarboxylate

1 INTRODUCTION Alkaloids and their derivatives are ubiquitous in natural products, and most of those compounds are of biological activities. Therefore, the structure modifi- cation of alkaloids is always the point that organic chemists and medicinal chemists focus on[1~10]. Qui- nolizine ring system is an important kind of alkaloid, which has a nitrogen atom shared by two six-mem- bered rings. Many medicines have quinolizine ring system, such as reserpine[11, 12] and berberine[13]. How- …     

Über Pterinchemie. 61. Mitteilung. Die Kristallstruktur von 5-Formyl-6,7-dimethyl-5,6,7,8-tetrahydropterin

The crystal structure of 5-formyl-6,7-dimethyl-5,6,7,8-tetrahydropterine The crystal structure of the title compound, a tetrahydropterine, has been determined by X-ray analysis (direct method) and refined with 1579 structure amplitudes to R = 0.054. The crystal system is triclinic, space group P1 , with unit cell dimensions a = 7.171, b = 7.255, c = 12.369 Å, α = 100.64, β = 93.32, γ = 98.27°. The tetrahydropyrazine ring exists in a distinctly flattened conformation. The C(13)- and C(14)-CH₃-groups possess a cis-configuration with axial position for C(13)-CH₃ and equatorial for C(14)-CH₃. The carbonyl-group of the N-formyl function has an (E)-configuration.     

Structural and spectral studies on N-(4-chloro)benzoyl-N′-(4-tolyl)thiourea

The crystal and molecular structure of the N-(4-chloro)benzoyl-N′-(4-tolyl)thiourea (C₁₅H₁₃N₂OSCl, M_r=304.79) is determined by X-ray diffraction. The crystal structure is monoclinic, space group: P2₁/n, a=16.097(6), b=4.5989(2), c=19.388(7) Å and β=89.299(6)° V=1434.7(9)ų, Z=4. FTIR and NMR spectra have been characterized. The interactions of intramolecular and intermolecular hydrogen bonds have been discussed. Density functional theory (DFT) (B3LYP) methods have been used to determine the structure and energies of stable conformers. Minimum energy conformations are calculated as a function of the torsion angle θ (C13–N1–C14–N2) varied every 30°. The optimized geometry corresponding to crystal structure is the most stable conformation. This has partly been attributed to intramolecular hydrogen bonds. With the basis sets of the 6-311G* quality, the DFT calculated bond parameters and harmonic vibrations are predicted in a very good agreement with experimental data.     

New insights into an old reaction. High-resolution x-ray powder diffraction of Wiberg's aminoalane intermediate

In accordance with the procedure described by E. Wiberg, Me(3)Al-NH(3) was heated as a bulk material in inert atmosphere to give a colorless liquid which slowly loses methane. Close to the end of this elimination reaction, the melt crystallized to give a microcrystalline powder of (Me(2)AlNH(2))(x)(). The structure of this intermediate has been solved by the method of high-resolution X-ray powder diffraction. The compound crystallizes in the monoclinic space group C2/c with the cell parameters of a = 15.0047(6) A, b = 8.7500(2) A, c = 24.4702(8) A, and beta = 107.290(2) degrees, with eight trimers (Me(2)AlNH(2))(3) per unit cell. These trimers crystallize in a boat conformation in contrast to the known trimers of the same composition where a twist-boat conformation had been found by single crystal determination. Different conformers of (Me(2)AlNH(2))(3) have been investigated by theoretical methods (HF/6-31G(d), B3LYP/6-31G(d), B3LYP/6-311G(d,p), MP2(fc)/6-31G(d), and MP2(fc)/6-311G(d,p)). The twist-boat and the chair conformer correspond to minima at the potential energy surface, whereas the boat conformer corresponds to a first-order transition state (relative energies of 0.45-2.56 kJ/mol (boat) and 6.66-11.91 kJ/mol (chair)). Relaxed scans of the potential energy surface at the HF/6-31G(d) and B3LYP/6-31G(d) levels have shown that the boat conformer (C(s)() symmetry) connects two enantiomers of the twist-boat form (C(2) symmetry).     

Synthesis and Crystal Structure of 1-[4-(Pyrimidin-2-yl)piperazin-1-ylmethyl]-1H-benzotriazole

1 INTRODUCTION Based on the reported 1.65 ? high resolution crystal structure of spinach KARI (ketol-acid reduc- toisomerase) complex[1], we obtained 279 molecules with low binding energy toward KARI from MDL/ ACD 3D database searching, using program DOCK 4.0[2]. These potential structures provide further information for the design of new KARI inhibitors, one of novel derivatives of which as the title com- pound has been synthesized. Its crystal structure will provide us more inf…     

Synthesis and Crystal Structure of 1-（4-Chlorophenyl）-2-cyano-3-amino-3a-hydroxy-3a,3b ,6, 7-te trah y drobenzo[ 4,5]indene

1 INTRODUCTION dimerization of α,β-unsaturated ketones[10]. Herein we discuss the crystal structure of the title compound In the early seventies three groups of investiga- synthesized by the reaction of 2-cyano-3-(4-chloro- tors[1~3] have established that low-valent titanium phenyl)-3-(1-tetralon-2-yl) induced by TiCl4/Zn system. can abstract oxygen from ketones or aldehydes, lead- When 2-cyano-3-(4-chlorophenyl)-3-(1-tetra- lon-2-yl) ing to the formation of olefins. A variety of other…     

Synthesis and Crystal Structure of 3-（2,4-Dichlorophenyl）- 4-dydroxy-5-cyclohexanyl-△3-dihydrofuran-2-one

The title compound 3-（2,4-dichlorophenyl）-4-dydroxy-3-（2,4-dichlorophenyl）-4- dydroxy-5-cyclohexanyl-A3-dihydrofuran-2-one 5 has been synthesized by the cyclization of methyl O-（2,4-dichlorophenyl-acetyl）-1-hydroxycyclo-hexane-carboxylate 4, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group Pi with a = 6.8192（3）, b = 10.5053（5）, c = 10.5811（5）A,α = 71.681（10）, β = 78.905（12）, γ = 81.036（12）°, C15H14C1203, Mr = 313.18, V= 702.44（6）A3, Z = 2, De= 1.481 g/cm^3, F（000） = 324,μ = 0.465 mm^-1, S = 1.006, the final R = 0.0331 and wR = 0.1363 for 2505 observed reflections with I 〉 2σ（I） and 183 variable parameters. The crystal analysis shows that the cyclohexene unit of the title compound has a quasi-chair conformation, and a one-dimensional chain structure is formed via the intermolecular hydrogen bond O（1）-H（101）…O（2）.     

Synthesis and Crystal Structure of 3-Benzyl-5-cyclohexylamino-6-phenyl-3,6-dihydro-l,2,3-triazolo[4,5-d]pyrimidin-7-one

The title compound 3-benzyl-5-cyclohexylamino-6-phenyI-3,6-dihydro-1,2,3-triazolo[4,5-d]pyrimidin-7-one (C23H24N6O, Mr = 400.48) has been synthesized by means of tandem aza-Wittig reaction, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 6.5550(6), b - 10.3711(10), c = 31.265(3)(A), β = 93.827(2)° ,V = 2120.8(4) (A)3, Z = 4, Dc = 1.254 g/cm3, S = 1.025, μ(MoKa) = 0.081 mm-1, F(000) = 848, R = 0.0576 and wR = 0.1368. X-ray analysis reveals that all ring atoms in the triazolopyrimidinone moiety are almost coplanar and the cyclohexyl ring adopts a chair conformation.     

Gas electron diffraction analysis on S-methyl thioacetate, CH3C(O)SCH3

The molecular structure of S-methyl thioacetate, CH3C(O)SCH3, was determined by gas electron diffraction (GED) with the assistance of quantum chemical calculations (B3LYP/6-31G and MP2/6-31G). Experimental and theoretical methods result in a structure with syn conformation (C=O double bond syn with respect to the S-C(H3) single bond). The following skeletal geometric parameters were derived from the GED analysis (ra values with 3sigma uncertainties): C=O = 1.214(3), C-C = 1.499(5), S-C(sp2) = 1.781(6), S-C(sp3) = 1.805(6) angstroms, O=C-C = 123.4(8) degrees, O=C-S = 122.8(5) degrees and C-S-C = 99.2(9) degrees.     

X-ray crystallographic, spectroscopic and quantum chemical studies on ethyl 2-cyano-3-N ,N-dimethyl amino acrylate

Structural and spectral characteristics of ethyl 2-cyano-3-N,N-dimethyl amino acrylate have been studied by methods of X-ray crystallography, infrared spectroscopy and quantum chemistry. The compound crystallizes in monoclinic space group P2(1)/n with unit cell parameters a=4.26(1)A, b=11.16(1)A, c=19.63(3)A and beta=95.5(1) degrees . The X-ray based three-dimensional structure analysis has been carried out by direct methods and fully refined. Density functional theory calculations for potential energy curves, optimized geometries and vibrational spectra have been carried out using 6-31 G and 6-31 G basis sets and B3LYP functionals. These suggest the possibility of existence of two structural isomers for the molecule-a more stable s-cis and a less stable s-trans isomer, having enthalpy difference of 2.85 kcal/mol. The optimized molecular geometry is in agreement with experimental geometry from X-ray analysis and suggests a preferential s-cis conformation for the molecule in the solid state. Based on experimental and theoretical studies, it may be concluded that the molecule has an almost planar conformation with the cyanide group also lying in the molecular plane; the deviation from planarity does not exceed 3 degrees . The structure is stabilized by the presence of intra-molecular and inter-molecular interactions.     

Structural studies of metabolic products of dopamine. III. Crystal and molecular structure of (--)-adrenaline.

The crystal structure of (--)-adrenaline has been determined by X-ray methods, using 831 observed reflections collected by counter methods. The crystals are monoclinic, space group P2-1 with a=7.873(2), b=6.790(2), c=8.638(2) A and beta=98.01(2) degrees. Least-squares refinements yielded a conventional R-factor of 0.053. Standard deviations in bond lengths are 0.005-0.006 A and in bond lengths aree 0.005-0.006 A and in bond angles 0.4 degrees. The adrenaline molecules were found to exist as zwitterions in the crystals. The conformation of the adrenaline molecule corresponds closely to that usually encountered among the salts of the sympathomimetic amines. The crystals consist of molecular double layers parallel to (100). The molecules within a layer are linked through hydrogen bonds of the types N--H...O and O--H...O, whereas the layers are connected by van der Waals interactions.     

Synthesis and Characterization of N-(2,3,4,6-Tetra-O-acetyl-β-D-glucopyranosyl)-thiocarbamic-4-hydroxy-benzoyl Hydrazine Dihydrate

A new complex of N-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-thiocarbamic 4-hydroxy-benzoyl hydrazine dihydrate, C22H27N3O10S·2H2O, was synthesized and its structure was determined by X-ray crystallography and TG/DTG methods. The compound belongs to the orthorhombic system, which crystallizes in space group P212121, with a=1.0275(3), b=1.3419(4), c=2.0234(6), V=2.7899(16) nm3, and Z=4. The hexopyranosyl ring adopts a 4C1 conformation. All the substituents are at equatorial positions. The molecules are linked into a three-dimensional framework via intermolecular interactions. Atoms O5 and O9 show positional disorders.